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Copy pathioapi_mem.c
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164 lines (136 loc) · 4.47 KB
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/* ioapi_mem.h -- IO base function header for compress/uncompress .zip
files using zlib + zip or unzip API
This version of ioapi is designed to access memory rather than files.
We do use a region of memory to put data in to and take it out of. We do
not have auto-extending buffers and do not inform anyone else that the
data has been written. It is really intended for accessing a zip archive
embedded in an application such that I can write an installer with no
external files. Creation of archives has not been attempted, although
parts of the framework are present.
Based on Unzip ioapi.c version 0.22, May 19th, 2003
Copyright (C) 1998-2003 Gilles Vollant
(C) 2003 Justin Fletcher
This file is under the same license as the Unzip tool it is distributed
with.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "zlib.h"
#include "ioapi.h"
#include "ioapi_mem.h"
#ifndef IOMEM_BUFFERSIZE
# define IOMEM_BUFFERSIZE (UINT16_MAX)
#endif
voidpf ZCALLBACK fopen_mem_func(voidpf opaque, const char *filename, int mode)
{
ourmemory_t *mem = (ourmemory_t *)opaque;
if (mem == NULL)
return NULL; /* Mem structure passed in was null */
if (mode & ZLIB_FILEFUNC_MODE_CREATE)
{
if (mem->grow)
{
mem->size = IOMEM_BUFFERSIZE;
mem->base = (char *)malloc(mem->size);
}
mem->limit = 0; /* When writing we start with 0 bytes written */
}
else
mem->limit = mem->size;
mem->cur_offset = 0;
return mem;
}
voidpf ZCALLBACK fopendisk_mem_func(voidpf opaque, voidpf stream, uint32_t number_disk, int mode)
{
/* Not used */
return NULL;
}
uint32_t ZCALLBACK fread_mem_func(voidpf opaque, voidpf stream, void *buf, uint32_t size)
{
ourmemory_t *mem = (ourmemory_t *)stream;
if (size > mem->size - mem->cur_offset)
size = mem->size - mem->cur_offset;
memcpy(buf, mem->base + mem->cur_offset, size);
mem->cur_offset += size;
return size;
}
uint32_t ZCALLBACK fwrite_mem_func(voidpf opaque, voidpf stream, const void *buf, uint32_t size)
{
ourmemory_t *mem = (ourmemory_t *)stream;
uint32_t newmemsize = 0;
char *newbase = NULL;
if (size > mem->size - mem->cur_offset)
{
if (mem->grow)
{
newmemsize = mem->size;
if (size < IOMEM_BUFFERSIZE)
newmemsize += IOMEM_BUFFERSIZE;
else
newmemsize += size;
newbase = (char *)malloc(newmemsize);
memcpy(newbase, mem->base, mem->size);
free(mem->base);
mem->base = newbase;
mem->size = newmemsize;
}
else
size = mem->size - mem->cur_offset;
}
memcpy(mem->base + mem->cur_offset, buf, size);
mem->cur_offset += size;
if (mem->cur_offset > mem->limit)
mem->limit = mem->cur_offset;
return size;
}
long ZCALLBACK ftell_mem_func(voidpf opaque, voidpf stream)
{
ourmemory_t *mem = (ourmemory_t *)stream;
return mem->cur_offset;
}
long ZCALLBACK fseek_mem_func(voidpf opaque, voidpf stream, uint32_t offset, int origin)
{
ourmemory_t *mem = (ourmemory_t *)stream;
uint32_t new_pos = 0;
switch (origin)
{
case ZLIB_FILEFUNC_SEEK_CUR:
new_pos = mem->cur_offset + offset;
break;
case ZLIB_FILEFUNC_SEEK_END:
new_pos = mem->limit + offset;
break;
case ZLIB_FILEFUNC_SEEK_SET:
new_pos = offset;
break;
default:
return -1;
}
if (new_pos > mem->size)
return 1; /* Failed to seek that far */
mem->cur_offset = new_pos;
return 0;
}
int ZCALLBACK fclose_mem_func(voidpf opaque, voidpf stream)
{
/* Even with grow = 1, caller must always free() memory */
return 0;
}
int ZCALLBACK ferror_mem_func(voidpf opaque, voidpf stream)
{
/* We never return errors */
return 0;
}
void fill_memory_filefunc(zlib_filefunc_def *pzlib_filefunc_def, ourmemory_t *ourmem)
{
pzlib_filefunc_def->zopen_file = fopen_mem_func;
pzlib_filefunc_def->zopendisk_file = fopendisk_mem_func;
pzlib_filefunc_def->zread_file = fread_mem_func;
pzlib_filefunc_def->zwrite_file = fwrite_mem_func;
pzlib_filefunc_def->ztell_file = ftell_mem_func;
pzlib_filefunc_def->zseek_file = fseek_mem_func;
pzlib_filefunc_def->zclose_file = fclose_mem_func;
pzlib_filefunc_def->zerror_file = ferror_mem_func;
pzlib_filefunc_def->opaque = ourmem;
}