dhewm3/neo/renderer/jpeg_memory_src.cpp
dhewg 035dcbcd46 Move jpeg_memory_src()
Found another copy in renderer/Cinematic.cpp. Move the
newer implementation from renderer/Image_files.cpp in its
own file and use the libjpeg v8c license blob (which is where
this code comes from).

Adapt README too with the v8c license.
2012-01-07 20:57:07 +01:00

93 lines
3 KiB
C++

/*
* Copyright (C) 1994-1996, Thomas G. Lane.
* Modified 2009-2010 by Guido Vollbeding.
* This file is part of the Independent JPEG Group's software.
* For conditions of distribution and use, see the accompanying README file.
*
* This file contains decompression data source routines for the case of
* reading JPEG data from memory or from a file (or any stdio stream).
* While these routines are sufficient for most applications,
* some will want to use a different source manager.
* IMPORTANT: we assume that fread() will correctly transcribe an array of
* JOCTETs from 8-bit-wide elements on external storage. If char is wider
* than 8 bits on your machine, you may need to do some tweaking.
*/
#include "sys/platform.h"
#include "renderer/jpeg_memory_src.h"
#ifdef HAVE_JPEG_MEM_SRC
void jpeg_memory_src(j_decompress_ptr cinfo, unsigned char *inbuffer, unsigned long insize) {
jpeg_mem_src(cinfo, inbuffer, insize);
}
#else
static void init_mem_source(j_decompress_ptr cinfo) {
/* no work necessary here */
}
static boolean fill_mem_input_buffer(j_decompress_ptr cinfo) {
static JOCTET mybuffer[4];
/* The whole JPEG data is expected to reside in the supplied memory
* buffer, so any request for more data beyond the given buffer size
* is treated as an error.
*/
WARNMS(cinfo, JWRN_JPEG_EOF);
/* Insert a fake EOI marker */
mybuffer[0] = (JOCTET) 0xFF;
mybuffer[1] = (JOCTET) JPEG_EOI;
cinfo->src->next_input_byte = mybuffer;
cinfo->src->bytes_in_buffer = 2;
return TRUE;
}
static void skip_input_data(j_decompress_ptr cinfo, long num_bytes) {
struct jpeg_source_mgr *src = cinfo->src;
if (num_bytes > 0) {
while (num_bytes > (long)src->bytes_in_buffer) {
num_bytes -= (long)src->bytes_in_buffer;
(void)(*src->fill_input_buffer) (cinfo);
/* note we assume that fill_input_buffer will never return FALSE,
* so suspension need not be handled.
*/
}
src->next_input_byte += (size_t)num_bytes;
src->bytes_in_buffer -= (size_t)num_bytes;
}
}
static void term_source(j_decompress_ptr cinfo)
{
/* no work necessary here */
}
void jpeg_memory_src(j_decompress_ptr cinfo, unsigned char *inbuffer, unsigned long insize) {
struct jpeg_source_mgr *src;
if (inbuffer == NULL || insize == 0) /* Treat empty input as fatal error */
ERREXIT(cinfo, JERR_INPUT_EMPTY);
/* The source object is made permanent so that a series of JPEG images
* can be read from the same buffer by calling jpeg_mem_src only before
* the first one.
*/
if (cinfo->src == NULL) { /* first time for this JPEG object? */
cinfo->src = (struct jpeg_source_mgr *)
(*cinfo->mem->alloc_small)((j_common_ptr)cinfo, JPOOL_PERMANENT,
sizeof(struct jpeg_source_mgr));
}
src = cinfo->src;
src->init_source = init_mem_source;
src->fill_input_buffer = fill_mem_input_buffer;
src->skip_input_data = skip_input_data;
src->resync_to_restart = jpeg_resync_to_restart; /* use default method */
src->term_source = term_source;
src->bytes_in_buffer = (size_t)insize;
src->next_input_byte = (JOCTET *)inbuffer;
}
#endif