Implement ta_realloc

2 files changed, 40 insertions, 0 deletions

diff --git a/tinyalloc.c b/tinyalloc.c
index eb9fa3f..67e6220 100644
--- a/tinyalloc.c
+++ b/tinyalloc.c
@@ -253,6 +253,45 @@ static size_t count_blocks(Block *ptr) {
     return num;
 }
 
+static Block *find(void *ptr)
+{
+    Block *block = heap->used;
+    while (block != NULL) {
+        if (ptr == block->addr)
+            return block;
+        block = block->next;
+    }
+
+    return NULL;
+}
+
+void *ta_realloc(void *ptr, size_t n) {
+    if (!ptr)
+        return ta_alloc(n);
+
+    Block *prev = find(ptr);
+
+    if (!ptr)
+        return NULL;
+    else if (n <= prev->size)
+    {
+        prev->size = n;
+        return prev->addr;
+    }
+
+    char *const new = ta_alloc(n), *p = new;
+    const char *src = prev->addr;
+
+    if (!new)
+        return NULL;
+
+    for (size_t i = 0; i < prev->size; i++)
+        *p++ = *src++;
+
+    ta_free(prev->addr);
+    return new;
+}
+
 size_t ta_num_free() {
     return count_blocks(heap->free);
 }
diff --git a/tinyalloc.h b/tinyalloc.h
index 113f147..628b4d8 100644
--- a/tinyalloc.h
+++ b/tinyalloc.h
@@ -7,6 +7,7 @@ extern "C" {
 
 bool ta_init(const void *base, const void *limit, const size_t heap_blocks, const size_t split_thresh, const size_t alignment);
 void *ta_alloc(size_t num);
+void *ta_realloc(void *ptr, size_t n);
 void *ta_calloc(size_t num, size_t size);
 bool ta_free(void *ptr);