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#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include "cmark-gfm.h"
#include "cmark-gfm-extension_api.h"
static struct arena_chunk {
size_t sz, used;
uint8_t push_point;
void *ptr;
struct arena_chunk *prev;
} *A = NULL;
static struct arena_chunk *alloc_arena_chunk(size_t sz, struct arena_chunk *prev) {
struct arena_chunk *c = (struct arena_chunk *)calloc(1, sizeof(*c));
if (!c)
abort();
c->sz = sz;
c->ptr = calloc(1, sz);
if (!c->ptr)
abort();
c->prev = prev;
return c;
}
void cmark_arena_push(void) {
if (!A)
return;
A->push_point = 1;
A = alloc_arena_chunk(10240, A);
}
int cmark_arena_pop(void) {
if (!A)
return 0;
while (A && !A->push_point) {
free(A->ptr);
struct arena_chunk *n = A->prev;
free(A);
A = n;
}
if (A)
A->push_point = 0;
return 1;
}
static void init_arena(void) {
A = alloc_arena_chunk(4 * 1048576, NULL);
}
void cmark_arena_reset(void) {
while (A) {
free(A->ptr);
struct arena_chunk *n = A->prev;
free(A);
A = n;
}
}
static void *arena_calloc(size_t nmem, size_t size) {
if (!A)
init_arena();
size_t sz = nmem * size + sizeof(size_t);
// Round allocation sizes to largest integer size to
// ensure returned memory is correctly aligned
const size_t align = sizeof(size_t) - 1;
sz = (sz + align) & ~align;
struct arena_chunk *chunk;
if (sz > A->sz) {
A->prev = chunk = alloc_arena_chunk(sz, A->prev);
} else if (sz > A->sz - A->used) {
A = chunk = alloc_arena_chunk(A->sz + A->sz / 2, A);
} else {
chunk = A;
}
void *ptr = (uint8_t *) chunk->ptr + chunk->used;
chunk->used += sz;
*((size_t *) ptr) = sz - sizeof(size_t);
return (uint8_t *) ptr + sizeof(size_t);
}
static void *arena_realloc(void *ptr, size_t size) {
if (!A)
init_arena();
void *new_ptr = arena_calloc(1, size);
if (ptr)
memcpy(new_ptr, ptr, ((size_t *) ptr)[-1]);
return new_ptr;
}
static void arena_free(void *ptr) {
(void) ptr;
/* no-op */
}
cmark_mem CMARK_ARENA_MEM_ALLOCATOR = {arena_calloc, arena_realloc, arena_free};
cmark_mem *cmark_get_arena_mem_allocator(void) {
return &CMARK_ARENA_MEM_ALLOCATOR;
}
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