/* Part of XPCE --- The SWI-Prolog GUI toolkit Author: Jan Wielemaker and Anjo Anjewierden E-mail: jan@swi.psy.uva.nl WWW: http://www.swi.psy.uva.nl/projects/xpce/ Copyright (c) 2000-2011, University of Amsterdam All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - This module is a modified version of jdatadst.c from the jpeg library. It is modified to use our IOSTREAM package rather then the stdio.h routines. Such modification is explicitly adviced in the library's programing instructions, so we can be pretty sure not to run into compatibility issues. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ /* * jdatadst.c * * Copyright (C) 1994-1996, Thomas G. Lane. * 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 compression data destination routines for the case of * emitting JPEG data to a file (or any stdio stream). While these routines * are sufficient for most applications, some will want to use a different * destination manager. * IMPORTANT: we assume that fwrite() will correctly transcribe an array of * JOCTETs into 8-bit-wide elements on external storage. If char is wider * than 8 bits on your machine, you may need to do some tweaking. */ #define METHODDEF(type) static type /* this is not a core library module, so it doesn't define JPEG_INTERNALS */ #include #include #include #include #include #ifndef SIZEOF #define SIZEOF(t) sizeof(t) #endif #ifndef JOCTET #define JOCTET unsigned char #endif #define JFWRITE(file,buf,sizeofbuf) \ ((size_t) Sfwrite((void *) (buf), (size_t) 1, (size_t) (sizeofbuf), (file))) /* Expanded data destination object for stdio output */ typedef struct { struct jpeg_destination_mgr pub; /* public fields */ IOSTREAM * outfile; /* target stream */ JOCTET * buffer; /* start of buffer */ } my_destination_mgr; typedef my_destination_mgr * my_dest_ptr; #define OUTPUT_BUF_SIZE 4096 /* choose an efficiently fwrite'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; /* 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; if (JFWRITE(dest->outfile, dest->buffer, OUTPUT_BUF_SIZE) != (size_t) OUTPUT_BUF_SIZE) ERREXIT(cinfo, JERR_FILE_WRITE); 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; size_t datacount = OUTPUT_BUF_SIZE - dest->pub.free_in_buffer; /* Write any data remaining in the buffer */ if (datacount > 0) { if (JFWRITE(dest->outfile, dest->buffer, datacount) != datacount) ERREXIT(cinfo, JERR_FILE_WRITE); } Sflush(dest->outfile); /* Make sure we wrote the output file OK */ if (Sferror(dest->outfile)) ERREXIT(cinfo, JERR_FILE_WRITE); } /* * 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_iostream_dest (j_compress_ptr cinfo, IOSTREAM * outfile) { 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->outfile = outfile; }