2 Copyright (c) 2001, Loki software, inc.
5 Redistribution and use in source and binary forms, with or without modification,
6 are permitted provided that the following conditions are met:
8 Redistributions of source code must retain the above copyright notice, this list
9 of conditions and the following disclaimer.
11 Redistributions in binary form must reproduce the above copyright notice, this
12 list of conditions and the following disclaimer in the documentation and/or
13 other materials provided with the distribution.
15 Neither the name of Loki software nor the names of its contributors may be used
16 to endorse or promote products derived from this software without specific prior
19 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS''
20 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
22 DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
23 DIRECT,INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
24 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
25 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
26 ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
28 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 // Functions to load JPEG files from a buffer, based on jdatasrc.c
34 // Leonardo Zide (leo@lokigames.com)
49 #include "ifilesystem.h"
53 typedef unsigned char byte;
55 /* Expanded data source object for stdio input */
58 struct jpeg_source_mgr pub; /* public fields */
63 JOCTET *buffer; /* start of buffer */
64 boolean start_of_file; /* have we gotten any data yet? */
67 typedef my_source_mgr *my_src_ptr;
69 const int INPUT_BUF_SIZE = 4096; /* choose an efficiently fread'able size */
73 * Initialize source --- called by jpeg_read_header
74 * before any data is actually read.
77 static void my_init_source(j_decompress_ptr cinfo)
79 my_src_ptr src = (my_src_ptr) cinfo->src;
81 /* We reset the empty-input-file flag for each image,
82 * but we don't clear the input buffer.
83 * This is correct behavior for reading a series of images from one source.
85 src->start_of_file = TRUE;
90 * Fill the input buffer --- called whenever buffer is emptied.
92 * In typical applications, this should read fresh data into the buffer
93 * (ignoring the current state of next_input_byte & bytes_in_buffer),
94 * reset the pointer & count to the start of the buffer, and return TRUE
95 * indicating that the buffer has been reloaded. It is not necessary to
96 * fill the buffer entirely, only to obtain at least one more byte.
98 * There is no such thing as an EOF return. If the end of the file has been
99 * reached, the routine has a choice of ERREXIT() or inserting fake data into
100 * the buffer. In most cases, generating a warning message and inserting a
101 * fake EOI marker is the best course of action --- this will allow the
102 * decompressor to output however much of the image is there. However,
103 * the resulting error message is misleading if the real problem is an empty
104 * input file, so we handle that case specially.
106 * In applications that need to be able to suspend compression due to input
107 * not being available yet, a FALSE return indicates that no more data can be
108 * obtained right now, but more may be forthcoming later. In this situation,
109 * the decompressor will return to its caller (with an indication of the
110 * number of scanlines it has read, if any). The application should resume
111 * decompression after it has loaded more data into the input buffer. Note
112 * that there are substantial restrictions on the use of suspension --- see
115 * When suspending, the decompressor will back up to a convenient restart point
116 * (typically the start of the current MCU). next_input_byte & bytes_in_buffer
117 * indicate where the restart point will be if the current call returns FALSE.
118 * Data beyond this point must be rescanned after resumption, so move it to
119 * the front of the buffer rather than discarding it.
122 static boolean my_fill_input_buffer(j_decompress_ptr cinfo)
124 my_src_ptr src = (my_src_ptr) cinfo->src;
127 if (src->src_size > INPUT_BUF_SIZE) {
128 nbytes = INPUT_BUF_SIZE;
130 nbytes = src->src_size;
133 memcpy(src->buffer, src->src_buffer, nbytes);
134 src->src_buffer += nbytes;
135 src->src_size -= nbytes;
138 if (src->start_of_file) { /* Treat empty input file as fatal error */
139 ERREXIT(cinfo, JERR_INPUT_EMPTY);
141 WARNMS(cinfo, JWRN_JPEG_EOF);
142 /* Insert a fake EOI marker */
143 src->buffer[0] = (JOCTET) 0xFF;
144 src->buffer[1] = (JOCTET) JPEG_EOI;
148 src->pub.next_input_byte = src->buffer;
149 src->pub.bytes_in_buffer = nbytes;
150 src->start_of_file = FALSE;
157 * Skip data --- used to skip over a potentially large amount of
158 * uninteresting data (such as an APPn marker).
160 * Writers of suspendable-input applications must note that skip_input_data
161 * is not granted the right to give a suspension return. If the skip extends
162 * beyond the data currently in the buffer, the buffer can be marked empty so
163 * that the next read will cause a fill_input_buffer call that can suspend.
164 * Arranging for additional bytes to be discarded before reloading the input
165 * buffer is the application writer's problem.
168 static void my_skip_input_data(j_decompress_ptr cinfo, long num_bytes)
170 my_src_ptr src = (my_src_ptr) cinfo->src;
172 /* Just a dumb implementation for now. Could use fseek() except
173 * it doesn't work on pipes. Not clear that being smart is worth
174 * any trouble anyway --- large skips are infrequent.
177 while (num_bytes > (long) src->pub.bytes_in_buffer) {
178 num_bytes -= (long) src->pub.bytes_in_buffer;
179 (void) my_fill_input_buffer(cinfo);
180 /* note we assume that fill_input_buffer will never return FALSE,
181 * so suspension need not be handled.
184 src->pub.next_input_byte += (size_t) num_bytes;
185 src->pub.bytes_in_buffer -= (size_t) num_bytes;
191 * An additional method that can be provided by data source modules is the
192 * resync_to_restart method for error recovery in the presence of RST markers.
193 * For the moment, this source module just uses the default resync method
194 * provided by the JPEG library. That method assumes that no backtracking
200 * Terminate source --- called by jpeg_finish_decompress
201 * after all data has been read. Often a no-op.
203 * NB: *not* called by jpeg_abort or jpeg_destroy; surrounding
204 * application must deal with any cleanup that should happen even
208 static void my_term_source(j_decompress_ptr cinfo)
210 /* no work necessary here */
215 * Prepare for input from a stdio stream.
216 * The caller must have already opened the stream, and is responsible
217 * for closing it after finishing decompression.
220 static void jpeg_buffer_src(j_decompress_ptr cinfo, void *buffer, int bufsize)
224 /* The source object and input buffer are made permanent so that a series
225 * of JPEG images can be read from the same file by calling jpeg_stdio_src
226 * only before the first one. (If we discarded the buffer at the end of
227 * one image, we'd likely lose the start of the next one.)
228 * This makes it unsafe to use this manager and a different source
229 * manager serially with the same JPEG object. Caveat programmer.
231 if (cinfo->src == NULL) { /* first time for this JPEG object? */
232 cinfo->src = (struct jpeg_source_mgr *)
233 (*cinfo->mem->alloc_small)((j_common_ptr) cinfo, JPOOL_PERMANENT,
234 sizeof(my_source_mgr));
235 src = (my_src_ptr) cinfo->src;
236 src->buffer = (JOCTET *)
237 (*cinfo->mem->alloc_small)((j_common_ptr) cinfo, JPOOL_PERMANENT,
238 INPUT_BUF_SIZE * sizeof(JOCTET));
241 src = (my_src_ptr) cinfo->src;
242 src->pub.init_source = my_init_source;
243 src->pub.fill_input_buffer = my_fill_input_buffer;
244 src->pub.skip_input_data = my_skip_input_data;
245 src->pub.resync_to_restart = jpeg_resync_to_restart; /* use default method */
246 src->pub.term_source = my_term_source;
247 src->src_buffer = (JOCTET *) buffer;
248 src->src_size = bufsize;
249 src->pub.bytes_in_buffer = 0; /* forces fill_input_buffer on first read */
250 src->pub.next_input_byte = NULL; /* until buffer loaded */
253 // =============================================================================
255 static char errormsg[JMSG_LENGTH_MAX];
257 typedef struct my_jpeg_error_mgr {
258 struct jpeg_error_mgr pub; // "public" fields
259 jmp_buf setjmp_buffer; // for return to caller
262 static void my_jpeg_error_exit(j_common_ptr cinfo)
264 my_jpeg_error_mgr *myerr = (bt_jpeg_error_mgr *) cinfo->err;
266 (*cinfo->err->format_message)(cinfo, errormsg);
268 longjmp(myerr->setjmp_buffer, 1);
272 static void j_putRGBScanline(unsigned char *jpegline, int widthPix, unsigned char *outBuf, int row)
274 int offset = row * widthPix * 4;
277 for (count = 0; count < widthPix; count++) {
278 unsigned char iRed, iBlu, iGrn;
279 unsigned char *oRed, *oBlu, *oGrn, *oAlp;
281 iRed = *(jpegline + count * 3 + 0);
282 iGrn = *(jpegline + count * 3 + 1);
283 iBlu = *(jpegline + count * 3 + 2);
285 oRed = outBuf + offset + count * 4 + 0;
286 oGrn = outBuf + offset + count * 4 + 1;
287 oBlu = outBuf + offset + count * 4 + 2;
288 oAlp = outBuf + offset + count * 4 + 3;
298 static void j_putRGBAScanline(unsigned char *jpegline, int widthPix, unsigned char *outBuf, int row)
300 int offset = row * widthPix * 4;
303 for (count = 0; count < widthPix; count++) {
304 unsigned char iRed, iBlu, iGrn, iAlp;
305 unsigned char *oRed, *oBlu, *oGrn, *oAlp;
307 iRed = *(jpegline + count * 4 + 0);
308 iGrn = *(jpegline + count * 4 + 1);
309 iBlu = *(jpegline + count * 4 + 2);
310 iAlp = *(jpegline + count * 4 + 3);
312 oRed = outBuf + offset + count * 4 + 0;
313 oGrn = outBuf + offset + count * 4 + 1;
314 oBlu = outBuf + offset + count * 4 + 2;
315 oAlp = outBuf + offset + count * 4 + 3;
321 //!\todo fix jpeglib, it leaves alpha channel uninitialised
331 // stash a gray scanline
332 static void j_putGrayScanlineToRGB(unsigned char *jpegline, int widthPix, unsigned char *outBuf, int row)
334 int offset = row * widthPix * 4;
337 for (count = 0; count < widthPix; count++) {
339 unsigned char *oRed, *oBlu, *oGrn, *oAlp;
341 // get our grayscale value
342 iGray = *(jpegline + count);
344 oRed = outBuf + offset + count * 4;
345 oGrn = outBuf + offset + count * 4 + 1;
346 oBlu = outBuf + offset + count * 4 + 2;
347 oAlp = outBuf + offset + count * 4 + 3;
356 static Image *LoadJPGBuff_(const void *src_buffer, int src_size)
358 struct jpeg_decompress_struct cinfo;
359 struct my_jpeg_error_mgr jerr;
361 cinfo.err = jpeg_std_error(&jerr.pub);
362 jerr.pub.error_exit = my_jpeg_error_exit;
364 if (setjmp(jerr.setjmp_buffer)) { //< TODO: use c++ exceptions instead of setjmp/longjmp to handle errors
365 globalErrorStream() << "WARNING: JPEG library error: " << errormsg << "\n";
366 jpeg_destroy_decompress(&cinfo);
370 jpeg_create_decompress(&cinfo);
371 jpeg_buffer_src(&cinfo, const_cast<void *>( src_buffer ), src_size);
372 jpeg_read_header(&cinfo, TRUE);
373 jpeg_start_decompress(&cinfo);
375 int row_stride = cinfo.output_width * cinfo.output_components;
377 RGBAImage *image = new RGBAImage(cinfo.output_width, cinfo.output_height);
379 JSAMPARRAY buffer = (*cinfo.mem->alloc_sarray)((j_common_ptr) &cinfo, JPOOL_IMAGE, row_stride, 1);
381 while (cinfo.output_scanline < cinfo.output_height) {
382 jpeg_read_scanlines(&cinfo, buffer, 1);
384 if (cinfo.out_color_components == 4) {
385 j_putRGBAScanline(buffer[0], cinfo.output_width, image->getRGBAPixels(), cinfo.output_scanline - 1);
386 } else if (cinfo.out_color_components == 3) {
387 j_putRGBScanline(buffer[0], cinfo.output_width, image->getRGBAPixels(), cinfo.output_scanline - 1);
388 } else if (cinfo.out_color_components == 1) {
389 j_putGrayScanlineToRGB(buffer[0], cinfo.output_width, image->getRGBAPixels(), cinfo.output_scanline - 1);
393 jpeg_finish_decompress(&cinfo);
394 jpeg_destroy_decompress(&cinfo);
399 Image *LoadJPG(ArchiveFile &file)
401 ScopedArchiveBuffer buffer(file);
402 return LoadJPGBuff_(buffer.buffer, static_cast<int>( buffer.length ));