eBookReaderSwitch/mupdf/source/fitz/pool.c

111 lines
2.3 KiB
C

#include "mupdf/fitz.h"
#include <string.h>
#include <stdio.h>
typedef struct fz_pool_node_s fz_pool_node;
#define POOL_SIZE (4<<10) /* default size of pool blocks */
#define POOL_SELF (1<<10) /* size where allocs are put into their own blocks */
struct fz_pool_s
{
size_t size;
fz_pool_node *head, *tail;
char *pos, *end;
};
struct fz_pool_node_s
{
fz_pool_node *next;
char mem[1];
};
fz_pool *fz_new_pool(fz_context *ctx)
{
fz_pool *pool;
fz_pool_node *node = NULL;
pool = fz_malloc_struct(ctx, fz_pool);
fz_try(ctx)
{
node = Memento_label(fz_calloc(ctx, offsetof(fz_pool_node, mem) + POOL_SIZE, 1), "fz_pool_block");
pool->head = pool->tail = node;
pool->pos = node->mem;
pool->end = node->mem + POOL_SIZE;
}
fz_catch(ctx)
{
fz_free(ctx, pool);
fz_rethrow(ctx);
}
return pool;
}
static void *fz_pool_alloc_oversize(fz_context *ctx, fz_pool *pool, size_t size)
{
fz_pool_node *node;
/* link in memory at the head of the list */
node = Memento_label(fz_calloc(ctx, offsetof(fz_pool_node, mem) + size, 1), "fz_pool_oversize");
node->next = pool->head;
pool->head = node;
pool->size += offsetof(fz_pool_node, mem) + size;
return node->mem;
}
void *fz_pool_alloc(fz_context *ctx, fz_pool *pool, size_t size)
{
char *ptr;
if (size >= POOL_SELF)
return fz_pool_alloc_oversize(ctx, pool, size);
/* round size to pointer alignment (we don't expect to use doubles) */
size = ((size + sizeof(void*) - 1) / sizeof(void*)) * sizeof(void*);
if (pool->pos + size > pool->end)
{
fz_pool_node *node = Memento_label(fz_calloc(ctx, offsetof(fz_pool_node, mem) + POOL_SIZE, 1), "fz_pool_block");
pool->tail = pool->tail->next = node;
pool->pos = node->mem;
pool->end = node->mem + POOL_SIZE;
pool->size += offsetof(fz_pool_node, mem) + POOL_SIZE;
}
ptr = pool->pos;
pool->pos += size;
return ptr;
}
char *fz_pool_strdup(fz_context *ctx, fz_pool *pool, const char *s)
{
size_t n = strlen(s) + 1;
char *p = fz_pool_alloc(ctx, pool, n);
memcpy(p, s, n);
return p;
}
size_t fz_pool_size(fz_context *ctx, fz_pool *pool)
{
return pool ? pool->size : 0;
}
void fz_drop_pool(fz_context *ctx, fz_pool *pool)
{
fz_pool_node *node;
if (!pool)
return;
node = pool->head;
while (node)
{
fz_pool_node *next = node->next;
fz_free(ctx, node);
node = next;
}
fz_free(ctx, pool);
}