Add mem allocator, remove listpool.

1 files changed, 232 insertions, 0 deletions

diff --git a/mem/test/mem_test.c b/mem/test/mem_test.c
new file mode 100644
index 0000000..6ab4c7c
--- /dev/null
+++ b/mem/test/mem_test.c
@@ -0,0 +1,232 @@
+#include "mem.h"
+
+#include "test.h"
+
+#define NUM_BLOCKS 10
+
+DEF_MEM(test_mem, int, NUM_BLOCKS);
+
+static int count(test_mem* mem) {
+  int count = 0;
+  mem_foreach(mem, n, { count++; });
+  return count;
+}
+
+static int sum(test_mem* mem) {
+  int sum = 0;
+  mem_foreach(mem, n, { sum += *n; });
+  return sum;
+}
+
+// Create a statically-backed allocator.
+TEST_CASE(mem_create) {
+  test_mem mem;
+  mem_make(&mem);
+}
+
+// Create a dynamically-backed allocator.
+TEST_CASE(mem_create_dyn) {
+  DEF_MEM_DYN(dyn_mem, int);
+  
+  dyn_mem mem;
+  mem_make_dyn(&mem, NUM_BLOCKS, sizeof(int));
+}
+
+// Allocate N chunks of 1 block each.
+TEST_CASE(mem_fully_allocate) {
+  test_mem mem;
+  mem_make(&mem);
+
+  for (int i = 0; i < NUM_BLOCKS; ++i) {
+    const int* block = mem_alloc(&mem, 1);
+    TEST_TRUE(block != 0);
+  }
+}
+
+// Allocate N chunks of 1 block each, then free them.
+TEST_CASE(mem_fill_then_free) {
+  test_mem mem;
+  mem_make(&mem);
+
+  int* blocks[NUM_BLOCKS] = {0};
+  for (int i = 0; i < NUM_BLOCKS; i++) {
+    blocks[i] = mem_alloc(&mem, 1);
+    TEST_TRUE(blocks[i] != 0);
+  }
+
+  for (int i = 0; i < NUM_BLOCKS; i++) {
+    mem_free(&mem, &blocks[i]);
+    TEST_EQUAL(blocks[i], 0); // Pointer should be set to 0 on free.
+  }
+
+  TEST_EQUAL(count(&mem), 0);
+}
+
+// Attempt to allocate blocks past the maximum allocator size.
+// The allocator should handle the failed allocations gracefully.
+TEST_CASE(mem_allocate_beyond_max_size) {
+  test_mem mem;
+  mem_make(&mem);
+
+  // Fully allocate the mem.
+  for (int i = 0; i < NUM_BLOCKS; ++i) {
+    TEST_TRUE(mem_alloc(&mem, 1) != 0);
+  }
+
+  // Past the end.
+  for (int i = 0; i < NUM_BLOCKS; ++i) {
+    TEST_EQUAL(mem_alloc(&mem, 1), 0);
+  }
+}
+
+// Free blocks should always remain zeroed out.
+// This tests the invariant right after creating the allocator.
+TEST_CASE(mem_zero_free_blocks_after_creation) {
+  test_mem mem;
+  mem_make(&mem);
+
+  const int zero = 0;
+  for (int i = 0; i < NUM_BLOCKS; ++i) {
+    const int* block = (const int*)(mem.blocks) + i;
+    TEST_EQUAL(memcmp(block, &zero, sizeof(int)), 0);
+  }
+}
+
+// Free blocks should always remain zeroed out.
+// This tests the invariant after freeing a block.
+TEST_CASE(mem_zero_free_block_after_free) {
+  test_mem mem;
+  mem_make(&mem);
+
+  int* val = mem_alloc(&mem, 1);
+  TEST_TRUE(val != 0);
+  *val = 177;
+
+  int* old_val = val;
+  mem_free(&mem, &val);    // val pointer is set to 0.
+  TEST_EQUAL(*old_val, 0); // Block is zeroed out after free.
+}
+
+// Traverse an empty allocator.
+TEST_CASE(mem_traverse_empty) {
+  test_mem mem;
+  mem_make(&mem);
+
+  TEST_EQUAL(count(&mem), 0);
+}
+
+// Traverse a partially full allocator.
+TEST_CASE(mem_traverse_partially_full) {
+  const int N = NUM_BLOCKS / 2;
+
+  test_mem mem;
+  mem_make(&mem);
+
+  for (int i = 0; i < N; ++i) {
+    int* val = mem_alloc(&mem, 1);
+    TEST_TRUE(val != 0);
+    *val = i + 1;
+  }
+
+  TEST_EQUAL(sum(&mem), (N) * (N + 1) / 2);
+}
+
+// Traverse a full allocator.
+TEST_CASE(mem_traverse_full) {
+  test_mem mem;
+  mem_make(&mem);
+
+  for (int i = 0; i < NUM_BLOCKS; ++i) {
+    int* val = mem_alloc(&mem, 1);
+    TEST_TRUE(val != 0);
+    *val = i + 1;
+  }
+
+  TEST_EQUAL(sum(&mem), (NUM_BLOCKS) * (NUM_BLOCKS + 1) / 2);
+}
+
+// Get the ith (allocated) chunk.
+TEST_CASE(mem_get_block) {
+  test_mem mem;
+  mem_make(&mem);
+
+  for (int i = 0; i < NUM_BLOCKS; ++i) {
+    int* block = mem_alloc(&mem, 1);
+    TEST_TRUE(block != 0);
+    *block = i;
+    TEST_EQUAL(mem_get_chunk_handle(&mem, block), (size_t)i);
+  }
+
+  for (int i = 0; i < NUM_BLOCKS; ++i) {
+    TEST_EQUAL(*mem_get_chunk(&mem, i), i);
+  }
+}
+
+// Test merging.
+// 1. Allocate chunks of variable sizes.
+// 2. Free them in a different order.
+// 3. Then we should be able to allocate 1 chunk of N blocks.
+TEST_CASE(mem_fragmentation) {
+  test_mem mem;
+  mem_make(&mem);
+
+  int* blocks[NUM_BLOCKS] = {0};
+  int  next_block         = 0;
+
+#define ALLOC(num_blocks)                           \
+  blocks[next_block] = mem_alloc(&mem, num_blocks); \
+  TEST_TRUE(blocks[next_block] != 0);               \
+  next_block++;
+
+#define FREE(block_idx) mem_free(&mem, &blocks[block_idx])
+
+  // 5 total allocations of variable chunk sizes.
+  ALLOC(2); // 2;  idx = 0
+  ALLOC(3); // 5;  idx = 1
+  ALLOC(1); // 6;  idx = 2
+  ALLOC(3); // 9;  idx = 3
+  ALLOC(1); // 10; idx = 4
+
+  // Free the 5 allocations in a different order.
+  FREE(1);
+  FREE(3);
+  FREE(4);
+  FREE(2);
+  FREE(0);
+
+  // Should be able to allocate 1 chunk of N blocks.
+  const void* chunk = mem_alloc(&mem, NUM_BLOCKS);
+  TEST_TRUE(chunk != 0);
+}
+
+// Clear and re-use an allocator.
+TEST_CASE(mem_clear_then_reuse) {
+  test_mem mem;
+  mem_make(&mem);
+
+  // Allocate chunks, contents not important.
+  for (int i = 0; i < NUM_BLOCKS; ++i) {
+    int* chunk = mem_alloc(&mem, 1);
+    TEST_TRUE(chunk != 0);
+  }
+
+  mem_clear(&mem);
+
+  // Allocate chunks and assign values 0..N.
+  for (int i = 0; i < NUM_BLOCKS; ++i) {
+    int* chunk = mem_alloc(&mem, 1);
+    TEST_TRUE(chunk != 0);
+    *chunk = i + 1;
+  }
+
+  TEST_EQUAL(sum(&mem), NUM_BLOCKS * (NUM_BLOCKS + 1) / 2);
+}
+
+// Stress test.
+//
+// 1. Allocate the mem, either fully or partially. If fully, attempt to
+//    allocate some items past the end.
+//
+// 2. Free all allocated items in some random order.
+
+int main() { return 0; }