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