feat: Initial commit

At this point we have some allocation routines but no work on the actual
language has been done.

20 files changed, 1947 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..6a08077
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,5 @@
+# Output artifacts
+/bin
+
+# Local notes, etc.
+/local
diff --git a/scripts/build_debug.sh b/scripts/build_debug.sh
new file mode 100755
index 0000000..fcdf16a
--- /dev/null
+++ b/scripts/build_debug.sh
@@ -0,0 +1,5 @@
+#!/bin/sh
+set -e -u -o pipefail
+mkdir -p bin/debug
+clang -std=c23 -ggdb -O0 -Wall -Wextra -fsanitize=undefined,address -o bin/debug/sand src/{cli,core}/*.c
+clang -std=c23 -ggdb -O0 -Wall -Wextra -fsanitize=undefined,address -o bin/debug/unit src/{unit,core}/*.c
diff --git a/scripts/build_release.sh b/scripts/build_release.sh
new file mode 100755
index 0000000..6f42aed
--- /dev/null
+++ b/scripts/build_release.sh
@@ -0,0 +1,5 @@
+#!/bin/sh
+set -e -u -o pipefail
+mkdir -p bin/release
+clang -std=c23 -O3 -Wall -Wextra -o bin/release/sand src/{cli,core}/*.c
+clang -std=c23 -O3 -Wall -Wextra -o bin/release/unit src/{unit,core}/*.c
diff --git a/scripts/git-pre-commit-hook.sh b/scripts/git-pre-commit-hook.sh
new file mode 100755
index 0000000..d6297e7
--- /dev/null
+++ b/scripts/git-pre-commit-hook.sh
@@ -0,0 +1,12 @@
+#!/bin/sh
+set -e -u -o pipefail
+
+# All of this is output for humans, not programs.
+exec >&2
+
+unit="$(scripts/unit_test.sh)"
+if [ $? -ne 0 ]; then
+	echo "$unit"
+	echo "You have failing unit tests. Aborting git commit."
+	exit 1
+fi
diff --git a/scripts/unit_test.sh b/scripts/unit_test.sh
new file mode 100755
index 0000000..6369974
--- /dev/null
+++ b/scripts/unit_test.sh
@@ -0,0 +1,5 @@
+#!/bin/sh
+set -e -u -o pipefail
+mode="${1:-debug}"
+scripts/build_$mode.sh
+bin/$mode/unit || gdb bin/$mode/unit
diff --git a/src/cli/main.c b/src/cli/main.c
new file mode 100644
index 0000000..4d96aa2
--- /dev/null
+++ b/src/cli/main.c
@@ -0,0 +1,13 @@
+#include "../core/state.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(int argc, char *argv[]) {
+	(void)argc;
+	(void)argv;
+
+	printf("TODO\n");
+
+	return EXIT_SUCCESS;
+}
diff --git a/src/core/allocator.c b/src/core/allocator.c
new file mode 100644
index 0000000..5444b39
--- /dev/null
+++ b/src/core/allocator.c
@@ -0,0 +1,87 @@
+#include "allocator.h"
+
+#include <assert.h>
+#include <stdint.h>
+#include <string.h>
+#include <stddef.h>
+
+#define DEFAULT_ALIGNMENT ((size_t)_Alignof(max_align_t))
+
+void *sand_allocate_aligned(SandAllocator *a, size_t size, size_t alignment) {
+	assert(a != NULL);
+	assert(size > 0);
+	assert(alignment > 0);
+	void *ptr = a->allocate(size, alignment, a->user_data);
+	assert(ptr == NULL || sand_pointer_is_aligned(ptr, alignment));
+	return ptr;
+}
+
+void *sand_allocate(SandAllocator *a, size_t size) {
+	return sand_allocate_aligned(a, size, DEFAULT_ALIGNMENT);
+}
+
+void *sand_reallocate_aligned(SandAllocator *a, void *old_ptr, size_t old_size, size_t new_size, size_t alignment) {
+	assert(a != NULL);
+	assert(old_ptr != NULL);
+	assert(old_size > 0);
+	assert(new_size > 0);
+	assert(alignment > 0);
+
+	if (a->reallocate != NULL) {
+		void *new_ptr = a->reallocate(old_ptr, old_size, new_size, alignment, a->user_data);
+		assert(sand_pointer_is_aligned(new_ptr, alignment));
+		return new_ptr;
+	} else {
+		void *new_ptr = a->allocate(new_size, alignment, a->user_data);
+		if (new_ptr == NULL) {
+			return NULL; // Note that we HAVEN'T freed `old_ptr`!
+		}
+		assert(sand_pointer_is_aligned(new_ptr, alignment));
+		memmove(new_ptr, old_ptr, old_size); // Can't know if they overlap.
+		a->deallocate(old_ptr, old_size, a->user_data);
+		return new_ptr;
+	}
+}
+
+void *sand_reallocate(SandAllocator *a, void *old_ptr, size_t old_size, size_t new_size) {
+	return sand_reallocate_aligned(a, old_ptr, old_size, new_size, DEFAULT_ALIGNMENT);
+}
+
+void sand_deallocate(SandAllocator *a, void *old_ptr, size_t old_size) {
+	assert(a != NULL);
+	assert(old_ptr != NULL);
+	assert(old_size > 0);
+
+	if (old_ptr == NULL) {
+		return;
+	}
+	a->deallocate(old_ptr, old_size, a->user_data);
+}
+
+bool sand_is_valid_alignment(size_t alignment) {
+	// Only powers of two are allowed as alignments for simplicity.
+	return alignment % 2 == 0;
+}
+
+void *sand_align_pointer_forward(void *ptr, size_t alignment) {
+	intptr_t p = (intptr_t)ptr;
+	intptr_t a = alignment;
+	intptr_t ap = ((p + a - 1) & ~(a - 1));
+	void *result = (void *)ap;
+	assert(sand_pointer_is_aligned(result, alignment));
+	return result;
+}
+
+size_t sand_align_size_forward(size_t n, size_t alignment) {
+	size_t result = ((n + alignment - 1) & ~(alignment - 1));
+	assert(sand_size_is_aligned(result, alignment));
+	return result;
+}
+
+bool sand_pointer_is_aligned(void *pointer, size_t alignment) {
+	return ((uintptr_t)pointer & (alignment - 1)) == 0;
+}
+
+bool sand_size_is_aligned(size_t n, size_t alignment) {
+	return (n & (alignment - 1)) == 0;
+}
diff --git a/src/core/allocator.h b/src/core/allocator.h
new file mode 100644
index 0000000..e67a08b
--- /dev/null
+++ b/src/core/allocator.h
@@ -0,0 +1,69 @@
+#ifndef SAND_ALLOCATOR_H
+#define SAND_ALLOCATOR_H
+
+// This module defines a generic allocator interface. All allocations in this
+// family of programs happen through this allocation interface.
+//
+// As references to `SandAllocator`s are passed all around the program, the
+// convention adopted here is to allow single-variable (mainly `a`) names for
+// these.
+
+#include <stddef.h>
+#include <stdbool.h>
+
+typedef struct {
+	// Shall return a new piece of writable and readable memory of size `size` and with alignment `alignment`.
+	// This function may return `NULL` to indicate out-of-memory.
+	// Caller promises to call `deallocate` or `reallocate` on the returned pointer.
+	void *(* allocate)(size_t size, size_t alignment, void *user_data);
+
+	// Shall the allocation made at `old_ptr`.
+	// Unlike with `realloc(3)`, `old_ptr` is not nullable.
+	// This operation is assumed to be infallible, as there is no reasonable way to recover.
+	// FIXME: This should take alignment as well.
+	void (* deallocate)(void *old_ptr, size_t old_size, void *user_data);
+
+	// Resize the allocation at `old_ptr` from `old_size` to `new_size`.
+	// `alignment` is guaranteed to be the same as passed to the original call to `allocate`.
+	// `old_ptr` and `old_size` are guaranteed to be from the last successful invocation of `allocate` or `reallocate`.
+	// This function may return `NULL` to indicate out-of-memory, however `old_ptr` should still remain valid in that case.
+	// The struct member itself may be `NULL`, in which case a default implementation is used.
+	void *(* reallocate)(void *old_ptr, size_t old_size, size_t new_size, size_t alignment, void *user_data);
+
+        // Custom data which is passed to every function in the interface. The
+        // allocator can use this for extra metadata it needs to keep.
+        void *user_data;
+} SandAllocator;
+
+
+// Allocates a chunk of memory with the given size and alignment.
+// Returns `NULL` on failure.
+// Caller assumes ownership of returned pointer, must free with `sand_deallocate`.
+void *sand_allocate_aligned(SandAllocator *, size_t size, size_t alignment);
+
+// Same as `sand_allocate_aligned` but with default alignment.
+void *sand_allocate(SandAllocator *, size_t size);
+
+// Resize the allocation at `old_ptr` from `old_size` to `new_size`.
+// `alignment` is guaranteed to be the same as passed to the original call to `allocate`.
+// Returns a new pointer or `NULL` if reallocation fails.
+// If `NULL` is returned, `old_ptr` remains valid.
+// Caller assumes ownership of returned pointer (or retains ownership of old pointer).
+void *sand_reallocate_aligned(SandAllocator *, void *old_ptr, size_t old_size, size_t new_size, size_t alignment);
+
+// Same as `sand_reallocate_aligned` but with default alignment.
+void *sand_reallocate(SandAllocator *, void *old_ptr, size_t old_size, size_t new_size);
+
+// Frees `old_ptr`.
+// `old_ptr` is nullable, in which case `old_size` is ignored.
+// `old_size` must match the size passed to last call to `sand_allocate` or `sand_reallocate`.
+void sand_deallocate(SandAllocator *, void *old_ptr, size_t old_size);
+
+// The following are only intended to be used by allocator implementations.
+bool sand_is_valid_alignment(size_t alignment);
+bool sand_pointer_is_aligned(void *pointer, size_t alignment);
+void *sand_align_pointer_forward(void *ptr, size_t alignment);
+bool sand_size_is_aligned(size_t n, size_t alignment);
+size_t sand_align_size_forward(size_t n, size_t alignment);
+
+#endif
diff --git a/src/core/arena_allocator.c b/src/core/arena_allocator.c
new file mode 100644
index 0000000..cbde038
--- /dev/null
+++ b/src/core/arena_allocator.c
@@ -0,0 +1,98 @@
+#include "arena_allocator.h"
+
+#include <assert.h>
+#include <stddef.h>
+#include <stdbool.h>
+
+SandArena sand_create_arena(SandAllocator *a) {
+	return (SandArena) {
+		.parent = a,
+		.current_region = NULL,
+	};
+}
+
+#define MAX(a, b) ({ \
+		__auto_type _a = (a);\
+		__auto_type _b = (b);\
+		_a > _b ? _a : _b;\
+		})
+
+#define REGION_DEFUALT_SIZE ((size_t)2048)
+
+static SandRegion *allocate_new_region(SandAllocator *a, size_t size, size_t alignment) {
+	size_t padded_size = size + (alignment - 1);
+	size_t capacity = MAX(padded_size, REGION_DEFUALT_SIZE) ;
+	size_t region_size = offsetof(SandRegion, data) + capacity;
+	SandRegion *result = sand_allocate_aligned(a, region_size, _Alignof(SandRegion));
+	if (result == NULL) {
+		return NULL;
+	}
+	result->capacity = capacity;
+	result->used = 0;
+	return result;
+}
+
+static void *allocate(size_t size, size_t alignment, void *user_data) {
+	SandArena *arena = user_data;
+
+	// This is the first allocation made within the arena. Let's allocate the initial region.
+	if (arena->current_region == NULL) {
+		SandRegion *first_region = allocate_new_region(arena->parent, size, alignment);
+		if (first_region == NULL) {
+			return NULL;
+		}
+		first_region->prev = NULL;
+		arena->current_region = first_region;
+	}
+
+	SandRegion *iter = arena->current_region;
+	while (true) { // Loop looking for a region.
+		void *aligned_ptr = sand_align_pointer_forward(iter->data + iter->used, alignment);
+		void *end_ptr = iter->data + iter->capacity;
+		if (aligned_ptr + size > end_ptr) { // This pointer region doesn't have room; allocate a new one and try again.
+			SandRegion *new_region = allocate_new_region(arena->parent, size, alignment);
+			if (new_region == NULL) {
+				return NULL;
+			}
+
+			new_region->prev = arena->current_region;
+			arena->current_region = iter;
+
+			iter = new_region; // Next time is guaranteed to succeed.
+			continue;
+		} else { // Yay, we found a spot!
+			iter->used += aligned_ptr - (void *)iter->data;
+			return aligned_ptr;
+		}
+	}
+
+	assert(false); // unreachable
+}
+
+static void deallocate(void *old_ptr, size_t old_size, void *user_data) {
+	(void)old_ptr;
+	(void)old_size;
+	(void)user_data;
+	return; // No-op, as all allocations are freed when the arena is freed.
+}
+
+// Returns a `SandAllocator` which is valid as long as the arena is.
+// The arena must not be moved afterwards, as the allocator retains a pointer to the arena.
+SandAllocator sand_get_allocator_for_arena(SandArena *arena) {
+	return (SandAllocator) {
+		.allocate = allocate,
+		.reallocate = NULL, // TODO: Special case for if it is the last allocation of the current region.
+		.deallocate = deallocate,
+		.user_data = arena,
+	};
+}
+
+void sand_destroy_arena(SandArena *arena) {
+	SandRegion *iter = arena->current_region;
+	while (iter != NULL) {
+		SandRegion *next = iter->prev;
+		size_t region_size = offsetof(SandRegion, data) + iter->capacity;
+		sand_deallocate(arena->parent, iter, region_size);
+		iter = next;
+	}
+}
diff --git a/src/core/arena_allocator.h b/src/core/arena_allocator.h
new file mode 100644
index 0000000..5fba78a
--- /dev/null
+++ b/src/core/arena_allocator.h
@@ -0,0 +1,33 @@
+#ifndef SAND_ARENA_ALLOCATOR_H
+#define SAND_ARENA_ALLOCATOR_H
+
+// This module defines an arena allocator which implements `SandAllocator`. It
+// is useful if one needs to allocate a lot of objects with the same lifetime
+// very quickly. When the arena is destroyed, all objects allocated within are
+// freed.
+
+#include "allocator.h"
+
+// This should only be used internally by an arena allocator.
+// It is only public because of C's stone-age """modules""".
+typedef struct _SandRegion {
+	struct _SandRegion *prev;
+	size_t capacity;
+	size_t used;
+	unsigned char data[];
+} SandRegion;
+
+typedef struct {
+	SandAllocator *parent;
+	SandRegion *current_region;
+} SandArena;
+
+SandArena sand_create_arena(SandAllocator *parent);
+
+// Returns a `SandAllocator` which is valid as long as the arena is.
+// The arena must not be moved afterwards, as the allocator retains a pointer to the arena.
+SandAllocator sand_get_allocator_for_arena(SandArena *);
+
+void sand_destroy_arena(SandArena *);
+
+#endif
diff --git a/src/core/page_allocator.c b/src/core/page_allocator.c
new file mode 100644
index 0000000..a20aa76
--- /dev/null
+++ b/src/core/page_allocator.c
@@ -0,0 +1,91 @@
+#include "page_allocator.h"
+
+#include <assert.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <sys/mman.h>
+
+#define MIN(a, b) \
+	({ \
+		__auto_type _a = (a); \
+		__auto_type _b = (b); \
+		_a > _b ? _a : _b; \
+	})
+
+static void *allocate(size_t size, size_t alignment, void *user_data) {
+	(void)user_data;
+
+	long _page_size = sysconf(_SC_PAGESIZE);
+	if (_page_size < 0) {
+		return NULL;
+	}
+	assert(_page_size > 512); // Sanity check
+	size_t page_size = _page_size;
+
+	// First of all, the actual allocation size needs to be a multiple of the page size.
+	if (size >= SIZE_MAX - page_size) {
+		return NULL; // Nice overflow, idiot.
+	}
+	size_t aligned_size = sand_align_size_forward(size, page_size);
+
+        // Furthermore, page alignment may not be enough, i.e. the required
+        // alignment is larger than the page size. So we compute how much extra
+        // memory (overallocation) is required. That gives us the size of the final allocation.
+        size_t max_drop_size = alignment - MIN(alignment, page_size);
+	size_t raw_size = (max_drop_size <= aligned_size - page_size)
+		? aligned_size
+		: sand_align_size_forward(aligned_size + max_drop_size, page_size);
+
+	void *raw_ptr = mmap(/* hint = */ NULL,
+	                 /* length = */ raw_size,
+	                 /* protection = */ PROT_READ | PROT_WRITE,
+	                 /* flags  = */ MAP_PRIVATE | MAP_ANONYMOUS,
+			 /* fd = */ -1,
+			 /* offset = */ 0);
+	if (raw_ptr == MAP_FAILED) {
+		return NULL;
+	}
+
+        // At this point we have our properly aligned pointer, which is
+        // guaranteed to point to a region of at least `size`. Now we just have
+        // to clean up after ourselves... The superflous bytes could be at the
+        // beginning or the end or both.
+        void *aligned_ptr = sand_align_pointer_forward(raw_ptr, alignment);
+
+	assert(aligned_ptr >= raw_ptr);
+	size_t drop_size = aligned_ptr - raw_ptr;
+	if (drop_size > 0) {
+		munmap(raw_ptr, drop_size);
+	}
+
+	size_t remaining_size = raw_size - drop_size;
+	if (remaining_size > aligned_size) {
+		munmap(aligned_ptr + aligned_size, remaining_size - aligned_size);
+	}
+
+	return aligned_ptr;
+}
+
+static void deallocate(void *old_ptr, size_t old_size, void *user_data) {
+	(void)user_data;
+
+        // The actual allocation will be roughly a multiple of the page size
+        // (disregarding the cleanup at the end of `allocate`). This calculation
+        // matches that of the start of `allocate`.
+        long page_size = sysconf(_SC_PAGESIZE);
+        assert(old_size < SIZE_MAX - page_size);
+        size_t aligned_size = sand_align_size_forward(old_size, page_size);
+
+        // This _should_ unmap the correct pages.
+        munmap(old_ptr, aligned_size);
+}
+static SandAllocator vtable = {
+	.allocate = allocate,
+	.deallocate = deallocate,
+	.reallocate = NULL, // TODO
+	.user_data = NULL,
+};
+
+SandAllocator *sand_get_page_allocator() {
+	return &vtable;
+}
diff --git a/src/core/page_allocator.h b/src/core/page_allocator.h
new file mode 100644
index 0000000..506cd8f
--- /dev/null
+++ b/src/core/page_allocator.h
@@ -0,0 +1,11 @@
+#ifndef SAND_PAGE_ALLOCATOR_H
+#define SAND_PAGE_ALLOCATOR_H
+
+// This module defines an allocator (i.e. an implementation of `SandAllocator`)
+// which allocates virtual memory pages.
+
+#include "allocator.h"
+
+SandAllocator *sand_get_page_allocator();
+
+#endif
diff --git a/src/core/std_allocator.c b/src/core/std_allocator.c
new file mode 100644
index 0000000..ecfa806
--- /dev/null
+++ b/src/core/std_allocator.c
@@ -0,0 +1,37 @@
+#include "std_allocator.h"
+
+#include <stdlib.h>
+
+static void *allocate(size_t size, size_t alignment, void *user_data) {
+	(void)user_data;
+
+	// `aligned_alloc(3)` requires that the requested size be a multiple of the requested alignment.
+	// this is safe to do, because we ignore `old_size` everywhere else.
+	size_t actual_size = (size + alignment - 1) & ~(alignment - 1);
+
+	return aligned_alloc(alignment, actual_size);
+}
+
+static void deallocate(void *old_ptr, size_t old_size, void *user_data) {
+	(void)old_size;
+	(void)user_data;
+	free(old_ptr);
+}
+
+static void *reallocate(void *old_ptr, size_t old_size, size_t new_size, size_t alignment, void *user_data) {
+	(void)old_size;
+	(void)alignment;
+	(void)user_data;
+
+	// fixme: does `realloc(3)` preserve alignment?
+	return realloc(old_ptr, new_size);
+}
+
+SandAllocator sand_new_std_allocator() {
+	return (SandAllocator) {
+		.allocate = allocate,
+		.deallocate = deallocate,
+		.reallocate = reallocate,
+		.user_data = NULL,
+	};
+}
diff --git a/src/core/std_allocator.h b/src/core/std_allocator.h
new file mode 100644
index 0000000..6170272
--- /dev/null
+++ b/src/core/std_allocator.h
@@ -0,0 +1,11 @@
+#ifndef SAND_STD_ALLOCATOR_H
+#define SAND_STD_ALLOCATOR_H
+
+// This module defines an allocator (i.e. an implementation of `SandAllocator`)
+// which simply passes allocations to libc's sallocator.
+
+#include "allocator.h"
+
+SandAllocator sand_new_std_allocator();
+
+#endif
diff --git a/src/unit/allocator_utils.h b/src/unit/allocator_utils.h
new file mode 100644
index 0000000..f0af88c
--- /dev/null
+++ b/src/unit/allocator_utils.h
@@ -0,0 +1,86 @@
+#ifndef SAND_UNIT_ALLOCATOR_UTILS_H
+#define SAND_UNIT_ALLOCATOR_UTILS_H
+
+// This module defines some tests for running against allocators.
+
+#include "../core/allocator.h"
+
+#include "greatest.h"
+
+inline TEST test_allocator_basic_usage(SandAllocator *a) {
+	size_t count = 100;
+	int *ptr = sand_allocate(a, sizeof(int) * count);
+	ASSERT_NEQm("Small allocation should not fail", ptr, NULL);
+	// Unit tests are run under address sanitizer, so this should catch when
+	// returned memory isn't actually writable.
+	for (size_t i = 0; i < count; ++i) {
+		ptr[i] = 123;
+	}
+	// FIXME: I don't really know how to test this.
+	sand_deallocate(a, ptr, sizeof(int) * count);
+	PASS();
+}
+
+inline TEST test_allocator_reallocation(SandAllocator *a) {
+	size_t count = 50;
+	int *ptr = sand_allocate(a, sizeof(int) * count);
+	ASSERT_NEQm("Small allocation should not fail", ptr, NULL);
+
+	for (size_t i = 0; i < count; ++i) {
+		ptr[i] = 123;
+	}
+
+	size_t new_count = 100;
+	int *new_ptr = sand_reallocate(a, ptr, sizeof(int) * count, sizeof(int) * new_count);
+	ASSERT_NEQm("Small reallocation should not fail", new_ptr, NULL);
+
+	for (size_t i = 0; i < count; ++i) {
+		ASSERT_EQm("Reallocated memory is copied over", new_ptr[i], 123);
+	}
+
+	// Just like `test_std_allocator_basic_usage` this should
+	// ensure newly allocated memory is reallocated.
+	for (size_t i = count; i < new_count; ++i) {
+		new_ptr[i] = 456;
+	}
+
+	sand_deallocate(a, new_ptr, sizeof(int) * new_count);
+	PASS();
+}
+
+inline TEST test_allocator_weird_alignments(SandAllocator *a) {
+	size_t alignments[] = {2,4,8,16,32,64,128,256,1024};
+
+	for (unsigned i = 0; i < sizeof(alignments)/sizeof((alignments)[0]); ++i) {
+		int *allocation = sand_allocate_aligned(a, sizeof(*allocation), alignments[i]);
+		*allocation = 123; // ASAN will crash us if invalid memory is returned.
+		sand_deallocate(a, allocation, sizeof(*allocation));
+	}
+
+	PASS();
+}
+
+inline TEST test_allocator_unreasonably_large_allocation_fails_gracefully(SandAllocator *a) {
+#if defined(__has_feature)
+#  if __has_feature(address_sanitizer)
+	SKIPm("Test does not work under address_sanitizer");
+#  endif
+#endif
+
+	// Compute a request size which is very unlikely to be available.
+	//                    kibi   mebi   gibi   tebi -byte
+	size_t size = (size_t)1024 * 1024 * 1024 * 1024;
+
+	void *result = sand_allocate(a, size);
+	ASSERT_EQm("Allocation should fail", result, NULL);
+
+	PASS();
+}
+
+#define RUN_ALLOCATOR_TESTS(DO)             \
+	DO(test_allocator_basic_usage)      \
+	DO(test_allocator_reallocation)     \
+	DO(test_allocator_weird_alignments) \
+	DO(test_allocator_unreasonably_large_allocation_fails_gracefully)
+
+#endif
diff --git a/src/unit/greatest.h b/src/unit/greatest.h
new file mode 100644
index 0000000..af0c053
--- /dev/null
+++ b/src/unit/greatest.h
@@ -0,0 +1,1266 @@
+/*
+ * Copyright (c) 2011-2021 Scott Vokes <[email protected]>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifndef GREATEST_H
+#define GREATEST_H
+
+#if defined(__cplusplus) && !defined(GREATEST_NO_EXTERN_CPLUSPLUS)
+extern "C" {
+#endif
+
+/* 1.5.0 */
+#define GREATEST_VERSION_MAJOR 1
+#define GREATEST_VERSION_MINOR 5
+#define GREATEST_VERSION_PATCH 0
+
+/* A unit testing system for C, contained in 1 file.
+ * It doesn't use dynamic allocation or depend on anything
+ * beyond ANSI C89.
+ *
+ * An up-to-date version can be found at:
+ *     https://github.com/silentbicycle/greatest/
+ */
+
+
+/*********************************************************************
+ * Minimal test runner template
+ *********************************************************************/
+#if 0
+
+#include "greatest.h"
+
+TEST foo_should_foo(void) {
+    PASS();
+}
+
+static void setup_cb(void *data) {
+    printf("setup callback for each test case\n");
+}
+
+static void teardown_cb(void *data) {
+    printf("teardown callback for each test case\n");
+}
+
+SUITE(suite) {
+    /* Optional setup/teardown callbacks which will be run before/after
+     * every test case. If using a test suite, they will be cleared when
+     * the suite finishes. */
+    SET_SETUP(setup_cb, voidp_to_callback_data);
+    SET_TEARDOWN(teardown_cb, voidp_to_callback_data);
+
+    RUN_TEST(foo_should_foo);
+}
+
+/* Add definitions that need to be in the test runner's main file. */
+GREATEST_MAIN_DEFS();
+
+/* Set up, run suite(s) of tests, report pass/fail/skip stats. */
+int run_tests(void) {
+    GREATEST_INIT();            /* init. greatest internals */
+    /* List of suites to run (if any). */
+    RUN_SUITE(suite);
+
+    /* Tests can also be run directly, without using test suites. */
+    RUN_TEST(foo_should_foo);
+
+    GREATEST_PRINT_REPORT();          /* display results */
+    return greatest_all_passed();
+}
+
+/* main(), for a standalone command-line test runner.
+ * This replaces run_tests above, and adds command line option
+ * handling and exiting with a pass/fail status. */
+int main(int argc, char **argv) {
+    GREATEST_MAIN_BEGIN();      /* init & parse command-line args */
+    RUN_SUITE(suite);
+    GREATEST_MAIN_END();        /* display results */
+}
+
+#endif
+/*********************************************************************/
+
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <ctype.h>
+
+/***********
+ * Options *
+ ***********/
+
+/* Default column width for non-verbose output. */
+#ifndef GREATEST_DEFAULT_WIDTH
+#define GREATEST_DEFAULT_WIDTH 72
+#endif
+
+/* FILE *, for test logging. */
+#ifndef GREATEST_STDOUT
+#define GREATEST_STDOUT stdout
+#endif
+
+/* Remove GREATEST_ prefix from most commonly used symbols? */
+#ifndef GREATEST_USE_ABBREVS
+#define GREATEST_USE_ABBREVS 1
+#endif
+
+/* Set to 0 to disable all use of setjmp/longjmp. */
+#ifndef GREATEST_USE_LONGJMP
+#define GREATEST_USE_LONGJMP 0
+#endif
+
+/* Make it possible to replace fprintf with another
+ * function with the same interface. */
+#ifndef GREATEST_FPRINTF
+#define GREATEST_FPRINTF fprintf
+#endif
+
+#if GREATEST_USE_LONGJMP
+#include <setjmp.h>
+#endif
+
+/* Set to 0 to disable all use of time.h / clock(). */
+#ifndef GREATEST_USE_TIME
+#define GREATEST_USE_TIME 1
+#endif
+
+#if GREATEST_USE_TIME
+#include <time.h>
+#endif
+
+/* Floating point type, for ASSERT_IN_RANGE. */
+#ifndef GREATEST_FLOAT
+#define GREATEST_FLOAT double
+#define GREATEST_FLOAT_FMT "%g"
+#endif
+
+/* Size of buffer for test name + optional '_' separator and suffix */
+#ifndef GREATEST_TESTNAME_BUF_SIZE
+#define GREATEST_TESTNAME_BUF_SIZE 128
+#endif
+
+
+/*********
+ * Types *
+ *********/
+
+/* Info for the current running suite. */
+typedef struct greatest_suite_info {
+    unsigned int tests_run;
+    unsigned int passed;
+    unsigned int failed;
+    unsigned int skipped;
+
+#if GREATEST_USE_TIME
+    /* timers, pre/post running suite and individual tests */
+    clock_t pre_suite;
+    clock_t post_suite;
+    clock_t pre_test;
+    clock_t post_test;
+#endif
+} greatest_suite_info;
+
+/* Type for a suite function. */
+typedef void greatest_suite_cb(void);
+
+/* Types for setup/teardown callbacks. If non-NULL, these will be run
+ * and passed the pointer to their additional data. */
+typedef void greatest_setup_cb(void *udata);
+typedef void greatest_teardown_cb(void *udata);
+
+/* Type for an equality comparison between two pointers of the same type.
+ * Should return non-0 if equal, otherwise 0.
+ * UDATA is a closure value, passed through from ASSERT_EQUAL_T[m]. */
+typedef int greatest_equal_cb(const void *expd, const void *got, void *udata);
+
+/* Type for a callback that prints a value pointed to by T.
+ * Return value has the same meaning as printf's.
+ * UDATA is a closure value, passed through from ASSERT_EQUAL_T[m]. */
+typedef int greatest_printf_cb(const void *t, void *udata);
+
+/* Callbacks for an arbitrary type; needed for type-specific
+ * comparisons via GREATEST_ASSERT_EQUAL_T[m].*/
+typedef struct greatest_type_info {
+    greatest_equal_cb *equal;
+    greatest_printf_cb *print;
+} greatest_type_info;
+
+typedef struct greatest_memory_cmp_env {
+    const unsigned char *exp;
+    const unsigned char *got;
+    size_t size;
+} greatest_memory_cmp_env;
+
+/* Callbacks for string and raw memory types. */
+extern greatest_type_info greatest_type_info_string;
+extern greatest_type_info greatest_type_info_memory;
+
+typedef enum {
+    GREATEST_FLAG_FIRST_FAIL = 0x01,
+    GREATEST_FLAG_LIST_ONLY = 0x02,
+    GREATEST_FLAG_ABORT_ON_FAIL = 0x04
+} greatest_flag_t;
+
+/* Internal state for a PRNG, used to shuffle test order. */
+struct greatest_prng {
+    unsigned char random_order; /* use random ordering? */
+    unsigned char initialized;  /* is random ordering initialized? */
+    unsigned char pad_0[6];
+    unsigned long state;        /* PRNG state */
+    unsigned long count;        /* how many tests, this pass */
+    unsigned long count_ceil;   /* total number of tests */
+    unsigned long count_run;    /* total tests run */
+    unsigned long a;            /* LCG multiplier */
+    unsigned long c;            /* LCG increment */
+    unsigned long m;            /* LCG modulus, based on count_ceil */
+};
+
+/* Struct containing all test runner state. */
+typedef struct greatest_run_info {
+    unsigned char flags;
+    unsigned char verbosity;
+    unsigned char running_test; /* guard for nested RUN_TEST calls */
+    unsigned char exact_name_match;
+
+    unsigned int tests_run;     /* total test count */
+
+    /* currently running test suite */
+    greatest_suite_info suite;
+
+    /* overall pass/fail/skip counts */
+    unsigned int passed;
+    unsigned int failed;
+    unsigned int skipped;
+    unsigned int assertions;
+
+    /* info to print about the most recent failure */
+    unsigned int fail_line;
+    unsigned int pad_1;
+    const char *fail_file;
+    const char *msg;
+
+    /* current setup/teardown hooks and userdata */
+    greatest_setup_cb *setup;
+    void *setup_udata;
+    greatest_teardown_cb *teardown;
+    void *teardown_udata;
+
+    /* formatting info for ".....s...F"-style output */
+    unsigned int col;
+    unsigned int width;
+
+    /* only run a specific suite or test */
+    const char *suite_filter;
+    const char *test_filter;
+    const char *test_exclude;
+    const char *name_suffix;    /* print suffix with test name */
+    char name_buf[GREATEST_TESTNAME_BUF_SIZE];
+
+    struct greatest_prng prng[2]; /* 0: suites, 1: tests */
+
+#if GREATEST_USE_TIME
+    /* overall timers */
+    clock_t begin;
+    clock_t end;
+#endif
+
+#if GREATEST_USE_LONGJMP
+    int pad_jmp_buf;
+    unsigned char pad_2[4];
+    jmp_buf jump_dest;
+#endif
+} greatest_run_info;
+
+struct greatest_report_t {
+    /* overall pass/fail/skip counts */
+    unsigned int passed;
+    unsigned int failed;
+    unsigned int skipped;
+    unsigned int assertions;
+};
+
+/* Global var for the current testing context.
+ * Initialized by GREATEST_MAIN_DEFS(). */
+extern greatest_run_info greatest_info;
+
+/* Type for ASSERT_ENUM_EQ's ENUM_STR argument. */
+typedef const char *greatest_enum_str_fun(int value);
+
+
+/**********************
+ * Exported functions *
+ **********************/
+
+/* These are used internally by greatest macros. */
+int greatest_test_pre(const char *name);
+void greatest_test_post(int res);
+int greatest_do_assert_equal_t(const void *expd, const void *got,
+    greatest_type_info *type_info, void *udata);
+void greatest_prng_init_first_pass(int id);
+int greatest_prng_init_second_pass(int id, unsigned long seed);
+void greatest_prng_step(int id);
+
+/* These are part of the public greatest API. */
+void GREATEST_SET_SETUP_CB(greatest_setup_cb *cb, void *udata);
+void GREATEST_SET_TEARDOWN_CB(greatest_teardown_cb *cb, void *udata);
+void GREATEST_INIT(void);
+void GREATEST_PRINT_REPORT(void);
+int greatest_all_passed(void);
+void greatest_set_suite_filter(const char *filter);
+void greatest_set_test_filter(const char *filter);
+void greatest_set_test_exclude(const char *filter);
+void greatest_set_exact_name_match(void);
+void greatest_stop_at_first_fail(void);
+void greatest_abort_on_fail(void);
+void greatest_list_only(void);
+void greatest_get_report(struct greatest_report_t *report);
+unsigned int greatest_get_verbosity(void);
+void greatest_set_verbosity(unsigned int verbosity);
+void greatest_set_flag(greatest_flag_t flag);
+void greatest_set_test_suffix(const char *suffix);
+
+
+/********************
+* Language Support *
+********************/
+
+/* If __VA_ARGS__ (C99) is supported, allow parametric testing
+* without needing to manually manage the argument struct. */
+#if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 19901L) ||        \
+    (defined(_MSC_VER) && _MSC_VER >= 1800)
+#define GREATEST_VA_ARGS
+#endif
+
+
+/**********
+ * Macros *
+ **********/
+
+/* Define a suite. (The duplication is intentional -- it eliminates
+ * a warning from -Wmissing-declarations.) */
+#define GREATEST_SUITE(NAME) void NAME(void); void NAME(void)
+
+/* Declare a suite, provided by another compilation unit. */
+#define GREATEST_SUITE_EXTERN(NAME) void NAME(void)
+
+/* Start defining a test function.
+ * The arguments are not included, to allow parametric testing. */
+#define GREATEST_TEST static enum greatest_test_res
+
+/* PASS/FAIL/SKIP result from a test. Used internally. */
+typedef enum greatest_test_res {
+    GREATEST_TEST_RES_PASS = 0,
+    GREATEST_TEST_RES_FAIL = -1,
+    GREATEST_TEST_RES_SKIP = 1
+} greatest_test_res;
+
+/* Run a suite. */
+#define GREATEST_RUN_SUITE(S_NAME) greatest_run_suite(S_NAME, #S_NAME)
+
+/* Run a test in the current suite. */
+#define GREATEST_RUN_TEST(TEST)                                         \
+    do {                                                                \
+        if (greatest_test_pre(#TEST) == 1) {                            \
+            enum greatest_test_res res = GREATEST_SAVE_CONTEXT();       \
+            if (res == GREATEST_TEST_RES_PASS) {                        \
+                res = TEST();                                           \
+            }                                                           \
+            greatest_test_post(res);                                    \
+        }                                                               \
+    } while (0)
+
+/* Ignore a test, don't warn about it being unused. */
+#define GREATEST_IGNORE_TEST(TEST) (void)TEST
+
+/* Run a test in the current suite with one void * argument,
+ * which can be a pointer to a struct with multiple arguments. */
+#define GREATEST_RUN_TEST1(TEST, ENV)                                   \
+    do {                                                                \
+        if (greatest_test_pre(#TEST) == 1) {                            \
+            enum greatest_test_res res = GREATEST_SAVE_CONTEXT();       \
+            if (res == GREATEST_TEST_RES_PASS) {                        \
+                res = TEST(ENV);                                        \
+            }                                                           \
+            greatest_test_post(res);                                    \
+        }                                                               \
+    } while (0)
+
+#ifdef GREATEST_VA_ARGS
+#define GREATEST_RUN_TESTp(TEST, ...)                                   \
+    do {                                                                \
+        if (greatest_test_pre(#TEST) == 1) {                            \
+            enum greatest_test_res res = GREATEST_SAVE_CONTEXT();       \
+            if (res == GREATEST_TEST_RES_PASS) {                        \
+                res = TEST(__VA_ARGS__);                                \
+            }                                                           \
+            greatest_test_post(res);                                    \
+        }                                                               \
+    } while (0)
+#endif
+
+
+/* Check if the test runner is in verbose mode. */
+#define GREATEST_IS_VERBOSE() ((greatest_info.verbosity) > 0)
+#define GREATEST_LIST_ONLY()                                            \
+    (greatest_info.flags & GREATEST_FLAG_LIST_ONLY)
+#define GREATEST_FIRST_FAIL()                                           \
+    (greatest_info.flags & GREATEST_FLAG_FIRST_FAIL)
+#define GREATEST_ABORT_ON_FAIL()                                        \
+    (greatest_info.flags & GREATEST_FLAG_ABORT_ON_FAIL)
+#define GREATEST_FAILURE_ABORT()                                        \
+    (GREATEST_FIRST_FAIL() &&                                           \
+        (greatest_info.suite.failed > 0 || greatest_info.failed > 0))
+
+/* Message-less forms of tests defined below. */
+#define GREATEST_PASS() GREATEST_PASSm(NULL)
+#define GREATEST_FAIL() GREATEST_FAILm(NULL)
+#define GREATEST_SKIP() GREATEST_SKIPm(NULL)
+#define GREATEST_ASSERT(COND)                                           \
+    GREATEST_ASSERTm(#COND, COND)
+#define GREATEST_ASSERT_OR_LONGJMP(COND)                                \
+    GREATEST_ASSERT_OR_LONGJMPm(#COND, COND)
+#define GREATEST_ASSERT_FALSE(COND)                                     \
+    GREATEST_ASSERT_FALSEm(#COND, COND)
+#define GREATEST_ASSERT_EQ(EXP, GOT)                                    \
+    GREATEST_ASSERT_EQm(#EXP " != " #GOT, EXP, GOT)
+#define GREATEST_ASSERT_NEQ(EXP, GOT)                                   \
+    GREATEST_ASSERT_NEQm(#EXP " == " #GOT, EXP, GOT)
+#define GREATEST_ASSERT_GT(EXP, GOT)                                    \
+    GREATEST_ASSERT_GTm(#EXP " <= " #GOT, EXP, GOT)
+#define GREATEST_ASSERT_GTE(EXP, GOT)                                   \
+    GREATEST_ASSERT_GTEm(#EXP " < " #GOT, EXP, GOT)
+#define GREATEST_ASSERT_LT(EXP, GOT)                                    \
+    GREATEST_ASSERT_LTm(#EXP " >= " #GOT, EXP, GOT)
+#define GREATEST_ASSERT_LTE(EXP, GOT)                                   \
+    GREATEST_ASSERT_LTEm(#EXP " > " #GOT, EXP, GOT)
+#define GREATEST_ASSERT_EQ_FMT(EXP, GOT, FMT)                           \
+    GREATEST_ASSERT_EQ_FMTm(#EXP " != " #GOT, EXP, GOT, FMT)
+#define GREATEST_ASSERT_IN_RANGE(EXP, GOT, TOL)                         \
+    GREATEST_ASSERT_IN_RANGEm(#EXP " != " #GOT " +/- " #TOL, EXP, GOT, TOL)
+#define GREATEST_ASSERT_EQUAL_T(EXP, GOT, TYPE_INFO, UDATA)             \
+    GREATEST_ASSERT_EQUAL_Tm(#EXP " != " #GOT, EXP, GOT, TYPE_INFO, UDATA)
+#define GREATEST_ASSERT_STR_EQ(EXP, GOT)                                \
+    GREATEST_ASSERT_STR_EQm(#EXP " != " #GOT, EXP, GOT)
+#define GREATEST_ASSERT_STRN_EQ(EXP, GOT, SIZE)                         \
+    GREATEST_ASSERT_STRN_EQm(#EXP " != " #GOT, EXP, GOT, SIZE)
+#define GREATEST_ASSERT_MEM_EQ(EXP, GOT, SIZE)                          \
+    GREATEST_ASSERT_MEM_EQm(#EXP " != " #GOT, EXP, GOT, SIZE)
+#define GREATEST_ASSERT_ENUM_EQ(EXP, GOT, ENUM_STR)                     \
+    GREATEST_ASSERT_ENUM_EQm(#EXP " != " #GOT, EXP, GOT, ENUM_STR)
+
+/* The following forms take an additional message argument first,
+ * to be displayed by the test runner. */
+
+/* Fail if a condition is not true, with message. */
+#define GREATEST_ASSERTm(MSG, COND)                                     \
+    do {                                                                \
+        greatest_info.assertions++;                                     \
+        if (!(COND)) { GREATEST_FAILm(MSG); }                           \
+    } while (0)
+
+/* Fail if a condition is not true, longjmping out of test. */
+#define GREATEST_ASSERT_OR_LONGJMPm(MSG, COND)                          \
+    do {                                                                \
+        greatest_info.assertions++;                                     \
+        if (!(COND)) { GREATEST_FAIL_WITH_LONGJMPm(MSG); }              \
+    } while (0)
+
+/* Fail if a condition is not false, with message. */
+#define GREATEST_ASSERT_FALSEm(MSG, COND)                               \
+    do {                                                                \
+        greatest_info.assertions++;                                     \
+        if ((COND)) { GREATEST_FAILm(MSG); }                            \
+    } while (0)
+
+/* Internal macro for relational assertions */
+#define GREATEST__REL(REL, MSG, EXP, GOT)                               \
+    do {                                                                \
+        greatest_info.assertions++;                                     \
+        if (!((EXP) REL (GOT))) { GREATEST_FAILm(MSG); }                \
+    } while (0)
+
+/* Fail if EXP is not ==, !=, >, <, >=, or <= to GOT. */
+#define GREATEST_ASSERT_EQm(MSG,E,G) GREATEST__REL(==, MSG,E,G)
+#define GREATEST_ASSERT_NEQm(MSG,E,G) GREATEST__REL(!=, MSG,E,G)
+#define GREATEST_ASSERT_GTm(MSG,E,G) GREATEST__REL(>, MSG,E,G)
+#define GREATEST_ASSERT_GTEm(MSG,E,G) GREATEST__REL(>=, MSG,E,G)
+#define GREATEST_ASSERT_LTm(MSG,E,G) GREATEST__REL(<, MSG,E,G)
+#define GREATEST_ASSERT_LTEm(MSG,E,G) GREATEST__REL(<=, MSG,E,G)
+
+/* Fail if EXP != GOT (equality comparison by ==).
+ * Warning: FMT, EXP, and GOT will be evaluated more
+ * than once on failure. */
+#define GREATEST_ASSERT_EQ_FMTm(MSG, EXP, GOT, FMT)                     \
+    do {                                                                \
+        greatest_info.assertions++;                                     \
+        if ((EXP) != (GOT)) {                                           \
+            GREATEST_FPRINTF(GREATEST_STDOUT, "\nExpected: ");          \
+            GREATEST_FPRINTF(GREATEST_STDOUT, FMT, EXP);                \
+            GREATEST_FPRINTF(GREATEST_STDOUT, "\n     Got: ");          \
+            GREATEST_FPRINTF(GREATEST_STDOUT, FMT, GOT);                \
+            GREATEST_FPRINTF(GREATEST_STDOUT, "\n");                    \
+            GREATEST_FAILm(MSG);                                        \
+        }                                                               \
+    } while (0)
+
+/* Fail if EXP is not equal to GOT, printing enum IDs. */
+#define GREATEST_ASSERT_ENUM_EQm(MSG, EXP, GOT, ENUM_STR)               \
+    do {                                                                \
+        int greatest_EXP = (int)(EXP);                                  \
+        int greatest_GOT = (int)(GOT);                                  \
+        greatest_enum_str_fun *greatest_ENUM_STR = ENUM_STR;            \
+        if (greatest_EXP != greatest_GOT) {                             \
+            GREATEST_FPRINTF(GREATEST_STDOUT, "\nExpected: %s",         \
+                greatest_ENUM_STR(greatest_EXP));                       \
+            GREATEST_FPRINTF(GREATEST_STDOUT, "\n     Got: %s\n",       \
+                greatest_ENUM_STR(greatest_GOT));                       \
+            GREATEST_FAILm(MSG);                                        \
+        }                                                               \
+    } while (0)                                                         \
+
+/* Fail if GOT not in range of EXP +|- TOL. */
+#define GREATEST_ASSERT_IN_RANGEm(MSG, EXP, GOT, TOL)                   \
+    do {                                                                \
+        GREATEST_FLOAT greatest_EXP = (EXP);                            \
+        GREATEST_FLOAT greatest_GOT = (GOT);                            \
+        GREATEST_FLOAT greatest_TOL = (TOL);                            \
+        greatest_info.assertions++;                                     \
+        if ((greatest_EXP > greatest_GOT &&                             \
+                greatest_EXP - greatest_GOT > greatest_TOL) ||          \
+            (greatest_EXP < greatest_GOT &&                             \
+                greatest_GOT - greatest_EXP > greatest_TOL)) {          \
+            GREATEST_FPRINTF(GREATEST_STDOUT,                           \
+                "\nExpected: " GREATEST_FLOAT_FMT                       \
+                " +/- " GREATEST_FLOAT_FMT                              \
+                "\n     Got: " GREATEST_FLOAT_FMT                       \
+                "\n",                                                   \
+                greatest_EXP, greatest_TOL, greatest_GOT);              \
+            GREATEST_FAILm(MSG);                                        \
+        }                                                               \
+    } while (0)
+
+/* Fail if EXP is not equal to GOT, according to strcmp. */
+#define GREATEST_ASSERT_STR_EQm(MSG, EXP, GOT)                          \
+    do {                                                                \
+        GREATEST_ASSERT_EQUAL_Tm(MSG, EXP, GOT,                         \
+            &greatest_type_info_string, NULL);                          \
+    } while (0)                                                         \
+
+/* Fail if EXP is not equal to GOT, according to strncmp. */
+#define GREATEST_ASSERT_STRN_EQm(MSG, EXP, GOT, SIZE)                   \
+    do {                                                                \
+        size_t size = SIZE;                                             \
+        GREATEST_ASSERT_EQUAL_Tm(MSG, EXP, GOT,                         \
+            &greatest_type_info_string, &size);                         \
+    } while (0)                                                         \
+
+/* Fail if EXP is not equal to GOT, according to memcmp. */
+#define GREATEST_ASSERT_MEM_EQm(MSG, EXP, GOT, SIZE)                    \
+    do {                                                                \
+        greatest_memory_cmp_env env;                                    \
+        env.exp = (const unsigned char *)EXP;                           \
+        env.got = (const unsigned char *)GOT;                           \
+        env.size = SIZE;                                                \
+        GREATEST_ASSERT_EQUAL_Tm(MSG, env.exp, env.got,                 \
+            &greatest_type_info_memory, &env);                          \
+    } while (0)                                                         \
+
+/* Fail if EXP is not equal to GOT, according to a comparison
+ * callback in TYPE_INFO. If they are not equal, optionally use a
+ * print callback in TYPE_INFO to print them. */
+#define GREATEST_ASSERT_EQUAL_Tm(MSG, EXP, GOT, TYPE_INFO, UDATA)       \
+    do {                                                                \
+        greatest_type_info *type_info = (TYPE_INFO);                    \
+        greatest_info.assertions++;                                     \
+        if (!greatest_do_assert_equal_t(EXP, GOT,                       \
+                type_info, UDATA)) {                                    \
+            if (type_info == NULL || type_info->equal == NULL) {        \
+                GREATEST_FAILm("type_info->equal callback missing!");   \
+            } else {                                                    \
+                GREATEST_FAILm(MSG);                                    \
+            }                                                           \
+        }                                                               \
+    } while (0)                                                         \
+
+/* Pass. */
+#define GREATEST_PASSm(MSG)                                             \
+    do {                                                                \
+        greatest_info.msg = MSG;                                        \
+        return GREATEST_TEST_RES_PASS;                                  \
+    } while (0)
+
+/* Fail. */
+#define GREATEST_FAILm(MSG)                                             \
+    do {                                                                \
+        greatest_info.fail_file = __FILE__;                             \
+        greatest_info.fail_line = __LINE__;                             \
+        greatest_info.msg = MSG;                                        \
+        if (GREATEST_ABORT_ON_FAIL()) { abort(); }                      \
+        return GREATEST_TEST_RES_FAIL;                                  \
+    } while (0)
+
+/* Optional GREATEST_FAILm variant that longjmps. */
+#if GREATEST_USE_LONGJMP
+#define GREATEST_FAIL_WITH_LONGJMP() GREATEST_FAIL_WITH_LONGJMPm(NULL)
+#define GREATEST_FAIL_WITH_LONGJMPm(MSG)                                \
+    do {                                                                \
+        greatest_info.fail_file = __FILE__;                             \
+        greatest_info.fail_line = __LINE__;                             \
+        greatest_info.msg = MSG;                                        \
+        longjmp(greatest_info.jump_dest, GREATEST_TEST_RES_FAIL);       \
+    } while (0)
+#endif
+
+/* Skip the current test. */
+#define GREATEST_SKIPm(MSG)                                             \
+    do {                                                                \
+        greatest_info.msg = MSG;                                        \
+        return GREATEST_TEST_RES_SKIP;                                  \
+    } while (0)
+
+/* Check the result of a subfunction using ASSERT, etc. */
+#define GREATEST_CHECK_CALL(RES)                                        \
+    do {                                                                \
+        enum greatest_test_res greatest_RES = RES;                      \
+        if (greatest_RES != GREATEST_TEST_RES_PASS) {                   \
+            return greatest_RES;                                        \
+        }                                                               \
+    } while (0)                                                         \
+
+#if GREATEST_USE_TIME
+#define GREATEST_SET_TIME(NAME)                                         \
+    NAME = clock();                                                     \
+    if (NAME == (clock_t) -1) {                                         \
+        GREATEST_FPRINTF(GREATEST_STDOUT,                               \
+            "clock error: %s\n", #NAME);                                \
+        exit(EXIT_FAILURE);                                             \
+    }
+
+#define GREATEST_CLOCK_DIFF(C1, C2)                                     \
+    GREATEST_FPRINTF(GREATEST_STDOUT, " (%lu ticks, %.3f sec)",         \
+        (long unsigned int) (C2) - (long unsigned int)(C1),             \
+        (double)((C2) - (C1)) / (1.0 * (double)CLOCKS_PER_SEC))
+#else
+#define GREATEST_SET_TIME(UNUSED)
+#define GREATEST_CLOCK_DIFF(UNUSED1, UNUSED2)
+#endif
+
+#if GREATEST_USE_LONGJMP
+#define GREATEST_SAVE_CONTEXT()                                         \
+        /* setjmp returns 0 (GREATEST_TEST_RES_PASS) on first call *    \
+         * so the test runs, then RES_FAIL from FAIL_WITH_LONGJMP. */   \
+        ((enum greatest_test_res)(setjmp(greatest_info.jump_dest)))
+#else
+#define GREATEST_SAVE_CONTEXT()                                         \
+    /*a no-op, since setjmp/longjmp aren't being used */                \
+    GREATEST_TEST_RES_PASS
+#endif
+
+/* Run every suite / test function run within BODY in pseudo-random
+ * order, seeded by SEED. (The top 3 bits of the seed are ignored.)
+ *
+ * This should be called like:
+ *     GREATEST_SHUFFLE_TESTS(seed, {
+ *         GREATEST_RUN_TEST(some_test);
+ *         GREATEST_RUN_TEST(some_other_test);
+ *         GREATEST_RUN_TEST(yet_another_test);
+ *     });
+ *
+ * Note that the body of the second argument will be evaluated
+ * multiple times. */
+#define GREATEST_SHUFFLE_SUITES(SD, BODY) GREATEST_SHUFFLE(0, SD, BODY)
+#define GREATEST_SHUFFLE_TESTS(SD, BODY) GREATEST_SHUFFLE(1, SD, BODY)
+#define GREATEST_SHUFFLE(ID, SD, BODY)                                  \
+    do {                                                                \
+        struct greatest_prng *prng = &greatest_info.prng[ID];           \
+        greatest_prng_init_first_pass(ID);                              \
+        do {                                                            \
+            prng->count = 0;                                            \
+            if (prng->initialized) { greatest_prng_step(ID); }          \
+            BODY;                                                       \
+            if (!prng->initialized) {                                   \
+                if (!greatest_prng_init_second_pass(ID, SD)) { break; } \
+            } else if (prng->count_run == prng->count_ceil) {           \
+                break;                                                  \
+            }                                                           \
+        } while (!GREATEST_FAILURE_ABORT());                            \
+        prng->count_run = prng->random_order = prng->initialized = 0;   \
+    } while(0)
+
+/* Include several function definitions in the main test file. */
+#define GREATEST_MAIN_DEFS()                                            \
+                                                                        \
+/* Is FILTER a subset of NAME? */                                       \
+static int greatest_name_match(const char *name, const char *filter,    \
+        int res_if_none) {                                              \
+    size_t offset = 0;                                                  \
+    size_t filter_len = filter ? strlen(filter) : 0;                    \
+    if (filter_len == 0) { return res_if_none; } /* no filter */        \
+    if (greatest_info.exact_name_match && strlen(name) != filter_len) { \
+        return 0; /* ignore substring matches */                        \
+    }                                                                   \
+    while (name[offset] != '\0') {                                      \
+        if (name[offset] == filter[0]) {                                \
+            if (0 == strncmp(&name[offset], filter, filter_len)) {      \
+                return 1;                                               \
+            }                                                           \
+        }                                                               \
+        offset++;                                                       \
+    }                                                                   \
+                                                                        \
+    return 0;                                                           \
+}                                                                       \
+                                                                        \
+static void greatest_buffer_test_name(const char *name) {               \
+    struct greatest_run_info *g = &greatest_info;                       \
+    size_t len = strlen(name), size = sizeof(g->name_buf);              \
+    memset(g->name_buf, 0x00, size);                                    \
+    (void)strncat(g->name_buf, name, size - 1);                         \
+    if (g->name_suffix && (len + 1 < size)) {                           \
+        g->name_buf[len] = '_';                                         \
+        strncat(&g->name_buf[len+1], g->name_suffix, size-(len+2));     \
+    }                                                                   \
+}                                                                       \
+                                                                        \
+/* Before running a test, check the name filtering and                  \
+ * test shuffling state, if applicable, and then call setup hooks. */   \
+int greatest_test_pre(const char *name) {                               \
+    struct greatest_run_info *g = &greatest_info;                       \
+    int match;                                                          \
+    greatest_buffer_test_name(name);                                    \
+    match = greatest_name_match(g->name_buf, g->test_filter, 1) &&      \
+      !greatest_name_match(g->name_buf, g->test_exclude, 0);            \
+    if (GREATEST_LIST_ONLY()) {   /* just listing test names */         \
+        if (match) {                                                    \
+            GREATEST_FPRINTF(GREATEST_STDOUT, "  %s\n", g->name_buf);   \
+        }                                                               \
+        goto clear;                                                     \
+    }                                                                   \
+    if (match && (!GREATEST_FIRST_FAIL() || g->suite.failed == 0)) {    \
+            struct greatest_prng *p = &g->prng[1];                      \
+        if (p->random_order) {                                          \
+            p->count++;                                                 \
+            if (!p->initialized || ((p->count - 1) != p->state)) {      \
+                goto clear;       /* don't run this test yet */         \
+            }                                                           \
+        }                                                               \
+        if (g->running_test) {                                          \
+            fprintf(stderr, "Error: Test run inside another test.\n");  \
+            return 0;                                                   \
+        }                                                               \
+        GREATEST_SET_TIME(g->suite.pre_test);                           \
+        if (g->setup) { g->setup(g->setup_udata); }                     \
+        p->count_run++;                                                 \
+        g->running_test = 1;                                            \
+        return 1;                 /* test should be run */              \
+    } else {                                                            \
+        goto clear;               /* skipped */                         \
+    }                                                                   \
+clear:                                                                  \
+    g->name_suffix = NULL;                                              \
+    return 0;                                                           \
+}                                                                       \
+                                                                        \
+static void greatest_do_pass(void) {                                    \
+    struct greatest_run_info *g = &greatest_info;                       \
+    if (GREATEST_IS_VERBOSE()) {                                        \
+        GREATEST_FPRINTF(GREATEST_STDOUT, "PASS %s: %s",                \
+            g->name_buf, g->msg ? g->msg : "");                         \
+    } else {                                                            \
+        GREATEST_FPRINTF(GREATEST_STDOUT, ".");                         \
+    }                                                                   \
+    g->suite.passed++;                                                  \
+}                                                                       \
+                                                                        \
+static void greatest_do_fail(void) {                                    \
+    struct greatest_run_info *g = &greatest_info;                       \
+    if (GREATEST_IS_VERBOSE()) {                                        \
+        GREATEST_FPRINTF(GREATEST_STDOUT,                               \
+            "FAIL %s: %s (%s:%u)", g->name_buf,                         \
+            g->msg ? g->msg : "", g->fail_file, g->fail_line);          \
+    } else {                                                            \
+        GREATEST_FPRINTF(GREATEST_STDOUT, "F");                         \
+        g->col++;  /* add linebreak if in line of '.'s */               \
+        if (g->col != 0) {                                              \
+            GREATEST_FPRINTF(GREATEST_STDOUT, "\n");                    \
+            g->col = 0;                                                 \
+        }                                                               \
+        GREATEST_FPRINTF(GREATEST_STDOUT, "FAIL %s: %s (%s:%u)\n",      \
+            g->name_buf, g->msg ? g->msg : "",                          \
+            g->fail_file, g->fail_line);                                \
+    }                                                                   \
+    g->suite.failed++;                                                  \
+}                                                                       \
+                                                                        \
+static void greatest_do_skip(void) {                                    \
+    struct greatest_run_info *g = &greatest_info;                       \
+    if (GREATEST_IS_VERBOSE()) {                                        \
+        GREATEST_FPRINTF(GREATEST_STDOUT, "SKIP %s: %s",                \
+            g->name_buf, g->msg ? g->msg : "");                         \
+    } else {                                                            \
+        GREATEST_FPRINTF(GREATEST_STDOUT, "s");                         \
+    }                                                                   \
+    g->suite.skipped++;                                                 \
+}                                                                       \
+                                                                        \
+void greatest_test_post(int res) {                                      \
+    GREATEST_SET_TIME(greatest_info.suite.post_test);                   \
+    if (greatest_info.teardown) {                                       \
+        void *udata = greatest_info.teardown_udata;                     \
+        greatest_info.teardown(udata);                                  \
+    }                                                                   \
+                                                                        \
+    greatest_info.running_test = 0;                                     \
+    if (res <= GREATEST_TEST_RES_FAIL) {                                \
+        greatest_do_fail();                                             \
+    } else if (res >= GREATEST_TEST_RES_SKIP) {                         \
+        greatest_do_skip();                                             \
+    } else if (res == GREATEST_TEST_RES_PASS) {                         \
+        greatest_do_pass();                                             \
+    }                                                                   \
+    greatest_info.name_suffix = NULL;                                   \
+    greatest_info.suite.tests_run++;                                    \
+    greatest_info.col++;                                                \
+    if (GREATEST_IS_VERBOSE()) {                                        \
+        GREATEST_CLOCK_DIFF(greatest_info.suite.pre_test,               \
+            greatest_info.suite.post_test);                             \
+        GREATEST_FPRINTF(GREATEST_STDOUT, "\n");                        \
+    } else if (greatest_info.col % greatest_info.width == 0) {          \
+        GREATEST_FPRINTF(GREATEST_STDOUT, "\n");                        \
+        greatest_info.col = 0;                                          \
+    }                                                                   \
+    fflush(GREATEST_STDOUT);                                            \
+}                                                                       \
+                                                                        \
+static void report_suite(void) {                                        \
+    if (greatest_info.suite.tests_run > 0) {                            \
+        GREATEST_FPRINTF(GREATEST_STDOUT,                               \
+            "\n%u test%s - %u passed, %u failed, %u skipped",           \
+            greatest_info.suite.tests_run,                              \
+            greatest_info.suite.tests_run == 1 ? "" : "s",              \
+            greatest_info.suite.passed,                                 \
+            greatest_info.suite.failed,                                 \
+            greatest_info.suite.skipped);                               \
+        GREATEST_CLOCK_DIFF(greatest_info.suite.pre_suite,              \
+            greatest_info.suite.post_suite);                            \
+        GREATEST_FPRINTF(GREATEST_STDOUT, "\n");                        \
+    }                                                                   \
+}                                                                       \
+                                                                        \
+static void update_counts_and_reset_suite(void) {                       \
+    greatest_info.setup = NULL;                                         \
+    greatest_info.setup_udata = NULL;                                   \
+    greatest_info.teardown = NULL;                                      \
+    greatest_info.teardown_udata = NULL;                                \
+    greatest_info.passed += greatest_info.suite.passed;                 \
+    greatest_info.failed += greatest_info.suite.failed;                 \
+    greatest_info.skipped += greatest_info.suite.skipped;               \
+    greatest_info.tests_run += greatest_info.suite.tests_run;           \
+    memset(&greatest_info.suite, 0, sizeof(greatest_info.suite));       \
+    greatest_info.col = 0;                                              \
+}                                                                       \
+                                                                        \
+static int greatest_suite_pre(const char *suite_name) {                 \
+    struct greatest_prng *p = &greatest_info.prng[0];                   \
+    if (!greatest_name_match(suite_name, greatest_info.suite_filter, 1) \
+        || (GREATEST_FAILURE_ABORT())) { return 0; }                    \
+    if (p->random_order) {                                              \
+        p->count++;                                                     \
+        if (!p->initialized || ((p->count - 1) != p->state)) {          \
+            return 0; /* don't run this suite yet */                    \
+        }                                                               \
+    }                                                                   \
+    p->count_run++;                                                     \
+    update_counts_and_reset_suite();                                    \
+    GREATEST_FPRINTF(GREATEST_STDOUT, "\n* Suite %s:\n", suite_name);   \
+    GREATEST_SET_TIME(greatest_info.suite.pre_suite);                   \
+    return 1;                                                           \
+}                                                                       \
+                                                                        \
+static void greatest_suite_post(void) {                                 \
+    GREATEST_SET_TIME(greatest_info.suite.post_suite);                  \
+    report_suite();                                                     \
+}                                                                       \
+                                                                        \
+static void greatest_run_suite(greatest_suite_cb *suite_cb,             \
+                               const char *suite_name) {                \
+    if (greatest_suite_pre(suite_name)) {                               \
+        suite_cb();                                                     \
+        greatest_suite_post();                                          \
+    }                                                                   \
+}                                                                       \
+                                                                        \
+int greatest_do_assert_equal_t(const void *expd, const void *got,       \
+        greatest_type_info *type_info, void *udata) {                   \
+    int eq = 0;                                                         \
+    if (type_info == NULL || type_info->equal == NULL) { return 0; }    \
+    eq = type_info->equal(expd, got, udata);                            \
+    if (!eq) {                                                          \
+        if (type_info->print != NULL) {                                 \
+            GREATEST_FPRINTF(GREATEST_STDOUT, "\nExpected: ");          \
+            (void)type_info->print(expd, udata);                        \
+            GREATEST_FPRINTF(GREATEST_STDOUT, "\n     Got: ");          \
+            (void)type_info->print(got, udata);                         \
+            GREATEST_FPRINTF(GREATEST_STDOUT, "\n");                    \
+        }                                                               \
+    }                                                                   \
+    return eq;                                                          \
+}                                                                       \
+                                                                        \
+static void greatest_usage(const char *name) {                          \
+    GREATEST_FPRINTF(GREATEST_STDOUT,                                   \
+        "Usage: %s [-hlfavex] [-s SUITE] [-t TEST] [-x EXCLUDE]\n"      \
+        "  -h, --help  print this Help\n"                               \
+        "  -l          List suites and tests, then exit (dry run)\n"    \
+        "  -f          Stop runner after first failure\n"               \
+        "  -a          Abort on first failure (implies -f)\n"           \
+        "  -v          Verbose output\n"                                \
+        "  -s SUITE    only run suites containing substring SUITE\n"    \
+        "  -t TEST     only run tests containing substring TEST\n"      \
+        "  -e          only run exact name match for -s or -t\n"        \
+        "  -x EXCLUDE  exclude tests containing substring EXCLUDE\n",   \
+        name);                                                          \
+}                                                                       \
+                                                                        \
+static void greatest_parse_options(int argc, char **argv) {             \
+    int i = 0;                                                          \
+    for (i = 1; i < argc; i++) {                                        \
+        if (argv[i][0] == '-') {                                        \
+            char f = argv[i][1];                                        \
+            if ((f == 's' || f == 't' || f == 'x') && argc <= i + 1) {  \
+                greatest_usage(argv[0]); exit(EXIT_FAILURE);            \
+            }                                                           \
+            switch (f) {                                                \
+            case 's': /* suite name filter */                           \
+                greatest_set_suite_filter(argv[i + 1]); i++; break;     \
+            case 't': /* test name filter */                            \
+                greatest_set_test_filter(argv[i + 1]); i++; break;      \
+            case 'x': /* test name exclusion */                         \
+                greatest_set_test_exclude(argv[i + 1]); i++; break;     \
+            case 'e': /* exact name match */                            \
+                greatest_set_exact_name_match(); break;                 \
+            case 'f': /* first fail flag */                             \
+                greatest_stop_at_first_fail(); break;                   \
+            case 'a': /* abort() on fail flag */                        \
+                greatest_abort_on_fail(); break;                        \
+            case 'l': /* list only (dry run) */                         \
+                greatest_list_only(); break;                            \
+            case 'v': /* first fail flag */                             \
+                greatest_info.verbosity++; break;                       \
+            case 'h': /* help */                                        \
+                greatest_usage(argv[0]); exit(EXIT_SUCCESS);            \
+            default:                                                    \
+            case '-':                                                   \
+                if (0 == strncmp("--help", argv[i], 6)) {               \
+                    greatest_usage(argv[0]); exit(EXIT_SUCCESS);        \
+                } else if (0 == strcmp("--", argv[i])) {                \
+                    return; /* ignore following arguments */            \
+                }                                                       \
+                GREATEST_FPRINTF(GREATEST_STDOUT,                       \
+                    "Unknown argument '%s'\n", argv[i]);                \
+                greatest_usage(argv[0]);                                \
+                exit(EXIT_FAILURE);                                     \
+            }                                                           \
+        }                                                               \
+    }                                                                   \
+}                                                                       \
+                                                                        \
+int greatest_all_passed(void) { return (greatest_info.failed == 0); }   \
+                                                                        \
+void greatest_set_test_filter(const char *filter) {                     \
+    greatest_info.test_filter = filter;                                 \
+}                                                                       \
+                                                                        \
+void greatest_set_test_exclude(const char *filter) {                    \
+    greatest_info.test_exclude = filter;                                \
+}                                                                       \
+                                                                        \
+void greatest_set_suite_filter(const char *filter) {                    \
+    greatest_info.suite_filter = filter;                                \
+}                                                                       \
+                                                                        \
+void greatest_set_exact_name_match(void) {                              \
+    greatest_info.exact_name_match = 1;                                 \
+}                                                                       \
+                                                                        \
+void greatest_stop_at_first_fail(void) {                                \
+    greatest_set_flag(GREATEST_FLAG_FIRST_FAIL);                        \
+}                                                                       \
+                                                                        \
+void greatest_abort_on_fail(void) {                                     \
+    greatest_set_flag(GREATEST_FLAG_ABORT_ON_FAIL);                     \
+}                                                                       \
+                                                                        \
+void greatest_list_only(void) {                                         \
+    greatest_set_flag(GREATEST_FLAG_LIST_ONLY);                         \
+}                                                                       \
+                                                                        \
+void greatest_get_report(struct greatest_report_t *report) {            \
+    if (report) {                                                       \
+        report->passed = greatest_info.passed;                          \
+        report->failed = greatest_info.failed;                          \
+        report->skipped = greatest_info.skipped;                        \
+        report->assertions = greatest_info.assertions;                  \
+    }                                                                   \
+}                                                                       \
+                                                                        \
+unsigned int greatest_get_verbosity(void) {                             \
+    return greatest_info.verbosity;                                     \
+}                                                                       \
+                                                                        \
+void greatest_set_verbosity(unsigned int verbosity) {                   \
+    greatest_info.verbosity = (unsigned char)verbosity;                 \
+}                                                                       \
+                                                                        \
+void greatest_set_flag(greatest_flag_t flag) {                          \
+    greatest_info.flags = (unsigned char)(greatest_info.flags | flag);  \
+}                                                                       \
+                                                                        \
+void greatest_set_test_suffix(const char *suffix) {                     \
+    greatest_info.name_suffix = suffix;                                 \
+}                                                                       \
+                                                                        \
+void GREATEST_SET_SETUP_CB(greatest_setup_cb *cb, void *udata) {        \
+    greatest_info.setup = cb;                                           \
+    greatest_info.setup_udata = udata;                                  \
+}                                                                       \
+                                                                        \
+void GREATEST_SET_TEARDOWN_CB(greatest_teardown_cb *cb, void *udata) {  \
+    greatest_info.teardown = cb;                                        \
+    greatest_info.teardown_udata = udata;                               \
+}                                                                       \
+                                                                        \
+static int greatest_string_equal_cb(const void *expd, const void *got,  \
+    void *udata) {                                                      \
+    size_t *size = (size_t *)udata;                                     \
+    return (size != NULL                                                \
+        ? (0 == strncmp((const char *)expd, (const char *)got, *size))  \
+        : (0 == strcmp((const char *)expd, (const char *)got)));        \
+}                                                                       \
+                                                                        \
+static int greatest_string_printf_cb(const void *t, void *udata) {      \
+    (void)udata; /* note: does not check \0 termination. */             \
+    return GREATEST_FPRINTF(GREATEST_STDOUT, "%s", (const char *)t);    \
+}                                                                       \
+                                                                        \
+greatest_type_info greatest_type_info_string = {                        \
+    greatest_string_equal_cb, greatest_string_printf_cb,                \
+};                                                                      \
+                                                                        \
+static int greatest_memory_equal_cb(const void *expd, const void *got,  \
+    void *udata) {                                                      \
+    greatest_memory_cmp_env *env = (greatest_memory_cmp_env *)udata;    \
+    return (0 == memcmp(expd, got, env->size));                         \
+}                                                                       \
+                                                                        \
+/* Hexdump raw memory, with differences highlighted */                  \
+static int greatest_memory_printf_cb(const void *t, void *udata) {      \
+    greatest_memory_cmp_env *env = (greatest_memory_cmp_env *)udata;    \
+    const unsigned char *buf = (const unsigned char *)t;                \
+    unsigned char diff_mark = ' ';                                      \
+    FILE *out = GREATEST_STDOUT;                                        \
+    size_t i, line_i, line_len = 0;                                     \
+    int len = 0;   /* format hexdump with differences highlighted */    \
+    for (i = 0; i < env->size; i+= line_len) {                          \
+        diff_mark = ' ';                                                \
+        line_len = env->size - i;                                       \
+        if (line_len > 16) { line_len = 16; }                           \
+        for (line_i = i; line_i < i + line_len; line_i++) {             \
+            if (env->exp[line_i] != env->got[line_i]) diff_mark = 'X';  \
+        }                                                               \
+        len += GREATEST_FPRINTF(out, "\n%04x %c ",                      \
+            (unsigned int)i, diff_mark);                                \
+        for (line_i = i; line_i < i + line_len; line_i++) {             \
+            int m = env->exp[line_i] == env->got[line_i]; /* match? */  \
+            len += GREATEST_FPRINTF(out, "%02x%c",                      \
+                buf[line_i], m ? ' ' : '<');                            \
+        }                                                               \
+        for (line_i = 0; line_i < 16 - line_len; line_i++) {            \
+            len += GREATEST_FPRINTF(out, "   ");                        \
+        }                                                               \
+        GREATEST_FPRINTF(out, " ");                                     \
+        for (line_i = i; line_i < i + line_len; line_i++) {             \
+            unsigned char c = buf[line_i];                              \
+            len += GREATEST_FPRINTF(out, "%c", isprint(c) ? c : '.');   \
+        }                                                               \
+    }                                                                   \
+    len += GREATEST_FPRINTF(out, "\n");                                 \
+    return len;                                                         \
+}                                                                       \
+                                                                        \
+void greatest_prng_init_first_pass(int id) {                            \
+    greatest_info.prng[id].random_order = 1;                            \
+    greatest_info.prng[id].count_run = 0;                               \
+}                                                                       \
+                                                                        \
+int greatest_prng_init_second_pass(int id, unsigned long seed) {        \
+    struct greatest_prng *p = &greatest_info.prng[id];                  \
+    if (p->count == 0) { return 0; }                                    \
+    p->count_ceil = p->count;                                           \
+    for (p->m = 1; p->m < p->count; p->m <<= 1) {}                      \
+    p->state = seed & 0x1fffffff;     /* only use lower 29 bits */      \
+    p->a = 4LU * p->state;            /* to avoid overflow when */      \
+    p->a = (p->a ? p->a : 4) | 1;            /* multiplied by 4 */      \
+    p->c = 2147483647;        /* and so p->c ((2 ** 31) - 1) is */      \
+    p->initialized = 1;     /* always relatively prime to p->a. */      \
+    fprintf(stderr, "init_second_pass: a %lu, c %lu, state %lu\n",      \
+        p->a, p->c, p->state);                                          \
+    return 1;                                                           \
+}                                                                       \
+                                                                        \
+/* Step the pseudorandom number generator until its state reaches       \
+ * another test ID between 0 and the test count.                        \
+ * This use a linear congruential pseudorandom number generator,        \
+ * with the power-of-two ceiling of the test count as the modulus, the  \
+ * masked seed as the multiplier, and a prime as the increment. For     \
+ * each generated value < the test count, run the corresponding test.   \
+ * This will visit all IDs 0 <= X < mod once before repeating,          \
+ * with a starting position chosen based on the initial seed.           \
+ * For details, see: Knuth, The Art of Computer Programming             \
+ * Volume. 2, section 3.2.1. */                                         \
+void greatest_prng_step(int id) {                                       \
+    struct greatest_prng *p = &greatest_info.prng[id];                  \
+    do {                                                                \
+        p->state = ((p->a * p->state) + p->c) & (p->m - 1);             \
+    } while (p->state >= p->count_ceil);                                \
+}                                                                       \
+                                                                        \
+void GREATEST_INIT(void) {                                              \
+    /* Suppress unused function warning if features aren't used */      \
+    (void)greatest_run_suite;                                           \
+    (void)greatest_parse_options;                                       \
+    (void)greatest_prng_step;                                           \
+    (void)greatest_prng_init_first_pass;                                \
+    (void)greatest_prng_init_second_pass;                               \
+    (void)greatest_set_test_suffix;                                     \
+                                                                        \
+    memset(&greatest_info, 0, sizeof(greatest_info));                   \
+    greatest_info.width = GREATEST_DEFAULT_WIDTH;                       \
+    GREATEST_SET_TIME(greatest_info.begin);                             \
+}                                                                       \
+                                                                        \
+/* Report passes, failures, skipped tests, the number of                \
+ * assertions, and the overall run time. */                             \
+void GREATEST_PRINT_REPORT(void) {                                      \
+    if (!GREATEST_LIST_ONLY()) {                                        \
+        update_counts_and_reset_suite();                                \
+        GREATEST_SET_TIME(greatest_info.end);                           \
+        GREATEST_FPRINTF(GREATEST_STDOUT,                               \
+            "\nTotal: %u test%s",                                       \
+            greatest_info.tests_run,                                    \
+            greatest_info.tests_run == 1 ? "" : "s");                   \
+        GREATEST_CLOCK_DIFF(greatest_info.begin,                        \
+            greatest_info.end);                                         \
+        GREATEST_FPRINTF(GREATEST_STDOUT, ", %u assertion%s\n",         \
+            greatest_info.assertions,                                   \
+            greatest_info.assertions == 1 ? "" : "s");                  \
+        GREATEST_FPRINTF(GREATEST_STDOUT,                               \
+            "Pass: %u, fail: %u, skip: %u.\n",                          \
+            greatest_info.passed,                                       \
+            greatest_info.failed, greatest_info.skipped);               \
+    }                                                                   \
+}                                                                       \
+                                                                        \
+greatest_type_info greatest_type_info_memory = {                        \
+    greatest_memory_equal_cb, greatest_memory_printf_cb,                \
+};                                                                      \
+                                                                        \
+greatest_run_info greatest_info
+
+/* Handle command-line arguments, etc. */
+#define GREATEST_MAIN_BEGIN()                                           \
+    do {                                                                \
+        GREATEST_INIT();                                                \
+        greatest_parse_options(argc, argv);                             \
+    } while (0)
+
+/* Report results, exit with exit status based on results. */
+#define GREATEST_MAIN_END()                                             \
+    do {                                                                \
+        GREATEST_PRINT_REPORT();                                        \
+        return (greatest_all_passed() ? EXIT_SUCCESS : EXIT_FAILURE);   \
+    } while (0)
+
+/* Make abbreviations without the GREATEST_ prefix for the
+ * most commonly used symbols. */
+#if GREATEST_USE_ABBREVS
+#define TEST           GREATEST_TEST
+#define SUITE          GREATEST_SUITE
+#define SUITE_EXTERN   GREATEST_SUITE_EXTERN
+#define RUN_TEST       GREATEST_RUN_TEST
+#define RUN_TEST1      GREATEST_RUN_TEST1
+#define RUN_SUITE      GREATEST_RUN_SUITE
+#define IGNORE_TEST    GREATEST_IGNORE_TEST
+#define ASSERT         GREATEST_ASSERT
+#define ASSERTm        GREATEST_ASSERTm
+#define ASSERT_FALSE   GREATEST_ASSERT_FALSE
+#define ASSERT_EQ      GREATEST_ASSERT_EQ
+#define ASSERT_NEQ     GREATEST_ASSERT_NEQ
+#define ASSERT_GT      GREATEST_ASSERT_GT
+#define ASSERT_GTE     GREATEST_ASSERT_GTE
+#define ASSERT_LT      GREATEST_ASSERT_LT
+#define ASSERT_LTE     GREATEST_ASSERT_LTE
+#define ASSERT_EQ_FMT  GREATEST_ASSERT_EQ_FMT
+#define ASSERT_IN_RANGE GREATEST_ASSERT_IN_RANGE
+#define ASSERT_EQUAL_T GREATEST_ASSERT_EQUAL_T
+#define ASSERT_STR_EQ  GREATEST_ASSERT_STR_EQ
+#define ASSERT_STRN_EQ GREATEST_ASSERT_STRN_EQ
+#define ASSERT_MEM_EQ  GREATEST_ASSERT_MEM_EQ
+#define ASSERT_ENUM_EQ GREATEST_ASSERT_ENUM_EQ
+#define ASSERT_FALSEm  GREATEST_ASSERT_FALSEm
+#define ASSERT_EQm     GREATEST_ASSERT_EQm
+#define ASSERT_NEQm    GREATEST_ASSERT_NEQm
+#define ASSERT_GTm     GREATEST_ASSERT_GTm
+#define ASSERT_GTEm    GREATEST_ASSERT_GTEm
+#define ASSERT_LTm     GREATEST_ASSERT_LTm
+#define ASSERT_LTEm    GREATEST_ASSERT_LTEm
+#define ASSERT_EQ_FMTm GREATEST_ASSERT_EQ_FMTm
+#define ASSERT_IN_RANGEm GREATEST_ASSERT_IN_RANGEm
+#define ASSERT_EQUAL_Tm GREATEST_ASSERT_EQUAL_Tm
+#define ASSERT_STR_EQm GREATEST_ASSERT_STR_EQm
+#define ASSERT_STRN_EQm GREATEST_ASSERT_STRN_EQm
+#define ASSERT_MEM_EQm GREATEST_ASSERT_MEM_EQm
+#define ASSERT_ENUM_EQm GREATEST_ASSERT_ENUM_EQm
+#define PASS           GREATEST_PASS
+#define FAIL           GREATEST_FAIL
+#define SKIP           GREATEST_SKIP
+#define PASSm          GREATEST_PASSm
+#define FAILm          GREATEST_FAILm
+#define SKIPm          GREATEST_SKIPm
+#define SET_SETUP      GREATEST_SET_SETUP_CB
+#define SET_TEARDOWN   GREATEST_SET_TEARDOWN_CB
+#define CHECK_CALL     GREATEST_CHECK_CALL
+#define SHUFFLE_TESTS  GREATEST_SHUFFLE_TESTS
+#define SHUFFLE_SUITES GREATEST_SHUFFLE_SUITES
+
+#ifdef GREATEST_VA_ARGS
+#define RUN_TESTp      GREATEST_RUN_TESTp
+#endif
+
+#if GREATEST_USE_LONGJMP
+#define ASSERT_OR_LONGJMP  GREATEST_ASSERT_OR_LONGJMP
+#define ASSERT_OR_LONGJMPm GREATEST_ASSERT_OR_LONGJMPm
+#define FAIL_WITH_LONGJMP  GREATEST_FAIL_WITH_LONGJMP
+#define FAIL_WITH_LONGJMPm GREATEST_FAIL_WITH_LONGJMPm
+#endif
+
+#endif /* USE_ABBREVS */
+
+#if defined(__cplusplus) && !defined(GREATEST_NO_EXTERN_CPLUSPLUS)
+}
+#endif
+
+#endif
diff --git a/src/unit/main.c b/src/unit/main.c
new file mode 100644
index 0000000..32df795
--- /dev/null
+++ b/src/unit/main.c
@@ -0,0 +1,17 @@
+#include "greatest.h"
+
+SUITE_EXTERN(std_allocator);
+SUITE_EXTERN(arena_allocator);
+SUITE_EXTERN(page_allocator);
+
+GREATEST_MAIN_DEFS();
+
+int main(int argc, char **argv) {
+    GREATEST_MAIN_BEGIN();
+
+    RUN_SUITE(std_allocator);
+    RUN_SUITE(arena_allocator);
+    RUN_SUITE(page_allocator);
+
+    GREATEST_MAIN_END();        /* display results */
+}
diff --git a/src/unit/test_arena_allocator.c b/src/unit/test_arena_allocator.c
new file mode 100644
index 0000000..5a6e3d8
--- /dev/null
+++ b/src/unit/test_arena_allocator.c
@@ -0,0 +1,21 @@
+#include "../core/allocator.h"
+#include "../core/arena_allocator.h"
+#include "../core/std_allocator.h"
+#include "./allocator_utils.h"
+
+#include "greatest.h"
+
+SUITE(arena_allocator) {
+#define RUN_WITH_ARENA(test)                                              \
+	do {                                                              \
+		SandAllocator parent = sand_new_std_allocator();          \
+		SandArena arena = sand_create_arena(&parent);             \
+		SandAllocator a = sand_get_allocator_for_arena(&arena);   \
+		RUN_TEST1(test, &a);                                      \
+		sand_destroy_arena(&arena);                               \
+	} while (0);
+
+
+	RUN_ALLOCATOR_TESTS(RUN_WITH_ARENA);
+#undef X
+}
diff --git a/src/unit/test_page_allocator.c b/src/unit/test_page_allocator.c
new file mode 100644
index 0000000..ea90355
--- /dev/null
+++ b/src/unit/test_page_allocator.c
@@ -0,0 +1,59 @@
+#include "../core/allocator.h"
+#include "../core/page_allocator.h"
+#include "./allocator_utils.h"
+
+#include "greatest.h"
+#include <unistd.h>
+
+TEST larger_than_page_size(void) {
+	SandAllocator *a = sand_get_page_allocator();
+
+	long page_size = sysconf(_SC_PAGESIZE);
+	if (page_size < 0) {
+		FAILm("Failed to get page size!?");
+	}
+
+	size_t size = page_size + 128;
+	unsigned char *ptr = sand_allocate(a, size);
+
+	for (size_t i = 0; i < size; ++i) { // This will crash under ASAN if invalid memory is returned.
+		ptr[i] = 0xFE;
+	}
+
+	sand_deallocate(a, ptr, size);
+	PASS();
+}
+
+TEST five_page_allocation(void) {
+	SandAllocator *a = sand_get_page_allocator();
+
+	long page_size = sysconf(_SC_PAGESIZE);
+	if (page_size < 0) {
+		FAILm("Failed to get page size!?");
+	}
+
+	size_t size = 5 * page_size;
+	unsigned char *ptr = sand_allocate(a, size);
+	ASSERT_NEQm("Allocating 5 pqgs should not fail", ptr, NULL);
+
+	for (size_t i = 0; i < size; ++i) { // This will crash under ASAN if invalid memory is returned.
+		ptr[i] = 0xFE;
+	}
+
+	sand_deallocate(a, ptr, size);
+	PASS();
+}
+
+SUITE(page_allocator) {
+#define RUN_WITH_PAGE_ALLOC(test)                             \
+	do {                                                  \
+		SandAllocator *a = sand_get_page_allocator(); \
+		RUN_TEST1(test, a);                           \
+	} while (0);
+
+	RUN_ALLOCATOR_TESTS(RUN_WITH_PAGE_ALLOC);
+#undef X
+
+	RUN_TEST(larger_than_page_size);
+	RUN_TEST(five_page_allocation);
+}
diff --git a/src/unit/test_std_allocator.c b/src/unit/test_std_allocator.c
new file mode 100644
index 0000000..e115952
--- /dev/null
+++ b/src/unit/test_std_allocator.c
@@ -0,0 +1,16 @@
+#include "../core/allocator.h"
+#include "../core/std_allocator.h"
+#include "./allocator_utils.h"
+
+#include "greatest.h"
+
+SUITE(std_allocator) {
+#define RUN_WITH_STD_ALLOCATOR(test)                           \
+	do {                                                   \
+		SandAllocator a = sand_new_std_allocator();    \
+		RUN_TEST1(test, &a);                           \
+	} while(0);
+
+	RUN_ALLOCATOR_TESTS(RUN_WITH_STD_ALLOCATOR);
+#undef RUN_WITH_STD_ALLOCATOR
+}