/*
* jbufferdst.c
*
* This file contains compression data destination routines for the case of
* emitting JPEG data to a buffer.
*
*/
/* this is not a core library module, so it doesn't define JPEG_INTERNALS */
#include "..\ImgAlloc.h"
#include "jinclude.h"
#include "jpeglib.h"
#include "jerror.h"
/* Expanded data destination object for stdio output */
typedef struct {
struct jpeg_destination_mgr pub; /* public fields */
unsigned char ** outbuf; /* target buffer */
unsigned long * outsize;
JOCTET * buffer; /* start of buffer */
} my_destination_mgr;
typedef my_destination_mgr * my_dest_ptr;
#define OUTPUT_BUF_SIZE 4096 /* choose an efficiently remalloc'able size */
/*
* Initialize destination --- called by jpeg_start_compress
* before any data is actually written.
*/
METHODDEF(void)
init_destination (j_compress_ptr cinfo)
{
my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
//modified
if(*dest->outsize == 0)
{
*dest->outbuf = NULL;
*dest->outsize = 0;
}
//modified
/* Allocate the output buffer --- it will be released when done with image */
dest->buffer = (JOCTET *)
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
OUTPUT_BUF_SIZE * SIZEOF(JOCTET));
dest->pub.next_output_byte = dest->buffer;
dest->pub.free_in_buffer = OUTPUT_BUF_SIZE;
}
/*
* Empty the output buffer --- called whenever buffer fills up.
*
* In typical applications, this should write the entire output buffer
* (ignoring the current state of next_output_byte & free_in_buffer),
* reset the pointer & count to the start of the buffer, and return TRUE
* indicating that the buffer has been dumped.
*
* In applications that need to be able to suspend compression due to output
* overrun, a FALSE return indicates that the buffer cannot be emptied now.
* In this situation, the compressor will return to its caller (possibly with
* an indication that it has not accepted all the supplied scanlines). The
* application should resume compression after it has made more room in the
* output buffer. Note that there are substantial restrictions on the use of
* suspension --- see the documentation.
*
* When suspending, the compressor will back up to a convenient restart point
* (typically the start of the current MCU). next_output_byte & free_in_buffer
* indicate where the restart point will be if the current call returns FALSE.
* Data beyond this point will be regenerated after resumption, so do not
* write it out when emptying the buffer externally.
*/
METHODDEF(boolean)
empty_output_buffer (j_compress_ptr cinfo)
{
my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
//modified
unsigned long WriteSize = (OUTPUT_BUF_SIZE - dest->pub.free_in_buffer);
if((*dest->outbuf) == NULL)
(*dest->outbuf) = (unsigned char*) img_malloc(WriteSize);
else
(*dest->outbuf) = (unsigned char*) img_realloc(*dest->outbuf,*dest->outsize + WriteSize);
if(*dest->outbuf == NULL)
ERREXIT(cinfo,JERR_FILE_WRITE);
else
{
img_memcpy(&((*dest->outbuf)[(*dest->outsize)]),dest->buffer,WriteSize);
*dest->outsize += WriteSize;
}
//modified
dest->pub.next_output_byte = dest->buffer;
dest->pub.free_in_buffer = OUTPUT_BUF_SIZE;
return TRUE;
}
/*
* Terminate destination --- called by jpeg_finish_compress
* after all data has been written. Usually needs to flush buffer.
*
* NB: *not* called by jpeg_abort or jpeg_destroy; surrounding
* application must deal with any cleanup that should happen even
* for error exit.
*/
METHODDEF(void)
term_destination (j_compress_ptr cinfo)
{
my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
//modified
unsigned long WriteSize = (OUTPUT_BUF_SIZE - dest->pub.free_in_buffer);
if(WriteSize > 0)
{
if((*dest->outbuf) == NULL)
(*dest->outbuf) = (unsigned char*) img_malloc(WriteSize);
else
(*dest->outbuf) = (unsigned char*) img_realloc(*dest->outbuf,*dest->outsize + WriteSize);
if(*dest->outbuf == NULL)
ERREXIT(cinfo,JERR_FILE_WRITE);
else
{
img_memcpy(&((*dest->outbuf)[(*dest->outsize)]),dest->buffer,WriteSize);
*dest->outsize += WriteSize;
}
}
//modified
}
/*
* Prepare for output to a stdio stream.
* The caller must have already opened the stream, and is responsible
* for closing it after finishing compression.
*/
GLOBAL(void)
jpeg_buffer_dest (j_compress_ptr cinfo, unsigned char ** outbuf,unsigned long * outsize)
{
my_dest_ptr dest;
/* The destination object is made permanent so that multiple JPEG images
* can be written to the same file without re-executing jpeg_stdio_dest.
* This makes it dangerous to use this manager and a different destination
* manager serially with the same JPEG object, because their private object
* sizes may be different. Caveat programmer.
*/
if (cinfo->dest == NULL) { /* first time for this JPEG object? */
cinfo->dest = (struct jpeg_destination_mgr *)
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
SIZEOF(my_destination_mgr));
}
dest = (my_dest_ptr) cinfo->dest;
dest->pub.init_destination = init_destination;
dest->pub.empty_output_buffer = empty_output_buffer;
dest->pub.term_destination = term_destination;
dest->outbuf = outbuf;
dest->outsize = outsize;
}