SAMV71 Xplained Ultra Software Package 1.5

jdatadst.c

00001 /*
00002  * jdatadst.c
00003  *
00004  * Copyright (C) 1994-1996, Thomas G. Lane.
00005  * Modified 2009 by Guido Vollbeding.
00006  * This file is part of the Independent JPEG Group's software.
00007  * For conditions of distribution and use, see the accompanying README file.
00008  *
00009  * This file contains compression data destination routines for the case of
00010  * emitting JPEG data to memory or to a file (or any stdio stream).
00011  * While these routines are sufficient for most applications,
00012  * some will want to use a different destination manager.
00013  * IMPORTANT: we assume that fwrite() will correctly transcribe an array of
00014  * JOCTETs into 8-bit-wide elements on external storage.  If char is wider
00015  * than 8 bits on your machine, you may need to do some tweaking.
00016  */
00017 
00018 /* this is not a core library module, so it doesn't define JPEG_INTERNALS */
00019 #include "jinclude.h"
00020 #include "jpeglib.h"
00021 #include "jerror.h"
00022 
00023 #ifndef HAVE_STDLIB_H       /* <stdlib.h> should declare malloc(),free() */
00024 extern void * malloc JPP((size_t size));
00025 extern void free JPP((void *ptr));
00026 #endif
00027 
00028 #if 0
00029 
00030 /* Expanded data destination object for stdio output */
00031 
00032 typedef struct {
00033   struct jpeg_destination_mgr pub; /* public fields */
00034 
00035   FILE * outfile;       /* target stream */
00036   JOCTET * buffer;      /* start of buffer */
00037 } my_destination_mgr;
00038 
00039 typedef my_destination_mgr * my_dest_ptr;
00040 
00041 #define OUTPUT_BUF_SIZE  4096   /* choose an efficiently fwrite'able size */
00042 
00043 #endif // 0
00044 
00045 /* Expanded data destination object for memory output */
00046 
00047 typedef struct {
00048   struct jpeg_destination_mgr pub; /* public fields */
00049 
00050   unsigned char ** outbuffer;   /* target buffer */
00051   unsigned long * outsize;
00052   unsigned char * newbuffer;    /* newly allocated buffer */
00053   JOCTET * buffer;      /* start of buffer */
00054   size_t bufsize;
00055 } my_mem_destination_mgr;
00056 
00057 typedef my_mem_destination_mgr * my_mem_dest_ptr;
00058 
00059 /*
00060  * Initialize destination --- called by jpeg_start_compress
00061  * before any data is actually written.
00062  */
00063 
00064 METHODDEF(void)
00065 init_destination (j_compress_ptr cinfo)
00066 {
00067   my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
00068 
00069   /* Allocate the output buffer --- it will be released when done with image */
00070   dest->buffer = (JOCTET *)
00071       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
00072                   OUTPUT_BUF_SIZE * SIZEOF(JOCTET));
00073 
00074   dest->pub.next_output_byte = dest->buffer;
00075   dest->pub.free_in_buffer = OUTPUT_BUF_SIZE;
00076 }
00077 
00078 METHODDEF(void)
00079 init_mem_destination (j_compress_ptr cinfo)
00080 {
00081   /* no work necessary here */
00082 }
00083 
00084 
00085 /*
00086  * Empty the output buffer --- called whenever buffer fills up.
00087  *
00088  * In typical applications, this should write the entire output buffer
00089  * (ignoring the current state of next_output_byte & free_in_buffer),
00090  * reset the pointer & count to the start of the buffer, and return TRUE
00091  * indicating that the buffer has been dumped.
00092  *
00093  * In applications that need to be able to suspend compression due to output
00094  * overrun, a FALSE return indicates that the buffer cannot be emptied now.
00095  * In this situation, the compressor will return to its caller (possibly with
00096  * an indication that it has not accepted all the supplied scanlines).  The
00097  * application should resume compression after it has made more room in the
00098  * output buffer.  Note that there are substantial restrictions on the use of
00099  * suspension --- see the documentation.
00100  *
00101  * When suspending, the compressor will back up to a convenient restart point
00102  * (typically the start of the current MCU). next_output_byte & free_in_buffer
00103  * indicate where the restart point will be if the current call returns FALSE.
00104  * Data beyond this point will be regenerated after resumption, so do not
00105  * write it out when emptying the buffer externally.
00106  */
00107 
00108 #if 0
00109 METHODDEF(boolean)
00110 empty_output_buffer (j_compress_ptr cinfo)
00111 {
00112   my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
00113 
00114   if (JFWRITE(dest->outfile, dest->buffer, OUTPUT_BUF_SIZE) !=
00115       (size_t) OUTPUT_BUF_SIZE)
00116     ERREXIT(cinfo, JERR_FILE_WRITE);
00117 
00118   dest->pub.next_output_byte = dest->buffer;
00119   dest->pub.free_in_buffer = OUTPUT_BUF_SIZE;
00120 
00121   return TRUE;
00122 }
00123 #endif // 0
00124 
00125 METHODDEF(boolean)
00126 empty_mem_output_buffer (j_compress_ptr cinfo)
00127 {
00128   size_t nextsize;
00129   JOCTET * nextbuffer;
00130   my_mem_dest_ptr dest = (my_mem_dest_ptr) cinfo->dest;
00131 
00132   /* Try to allocate new buffer with double size */
00133   nextsize = dest->bufsize * 2;
00134   nextbuffer = malloc(nextsize);
00135 
00136   if (nextbuffer == NULL)
00137     ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, 10);
00138 
00139   MEMCOPY(nextbuffer, dest->buffer, dest->bufsize);
00140 
00141   if (dest->newbuffer != NULL)
00142     free(dest->newbuffer);
00143 
00144   dest->newbuffer = nextbuffer;
00145 
00146   dest->pub.next_output_byte = nextbuffer + dest->bufsize;
00147   dest->pub.free_in_buffer = dest->bufsize;
00148 
00149   dest->buffer = nextbuffer;
00150   dest->bufsize = nextsize;
00151 
00152   return TRUE;
00153 }
00154 
00155 
00156 /*
00157  * Terminate destination --- called by jpeg_finish_compress
00158  * after all data has been written.  Usually needs to flush buffer.
00159  *
00160  * NB: *not* called by jpeg_abort or jpeg_destroy; surrounding
00161  * application must deal with any cleanup that should happen even
00162  * for error exit.
00163  */
00164 
00165 METHODDEF(void)
00166 term_destination (j_compress_ptr cinfo)
00167 {
00168   my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
00169   size_t datacount = OUTPUT_BUF_SIZE - dest->pub.free_in_buffer;
00170 
00171   /* Write any data remaining in the buffer */
00172   if (datacount > 0) {
00173     if (JFWRITE(dest->outfile, dest->buffer, datacount) != datacount)
00174       ERREXIT(cinfo, JERR_FILE_WRITE);
00175   }
00176   fflush(dest->outfile);
00177   /* Make sure we wrote the output file OK */
00178   if (ferror(dest->outfile))
00179     ERREXIT(cinfo, JERR_FILE_WRITE);
00180 }
00181 
00182 METHODDEF(void)
00183 term_mem_destination (j_compress_ptr cinfo)
00184 {
00185   my_mem_dest_ptr dest = (my_mem_dest_ptr) cinfo->dest;
00186 
00187   *dest->outbuffer = dest->buffer;
00188   *dest->outsize = dest->bufsize - dest->pub.free_in_buffer;
00189 }
00190 
00191 /*
00192  * Prepare for output to a stdio stream.
00193  * The caller must have already opened the stream, and is responsible
00194  * for closing it after finishing compression.
00195  */
00196 
00197 GLOBAL(void)
00198 jpeg_stdio_dest (j_compress_ptr cinfo, FILE * outfile)
00199 {
00200   my_dest_ptr dest;
00201 
00202   /* The destination object is made permanent so that multiple JPEG images
00203    * can be written to the same file without re-executing jpeg_stdio_dest.
00204    * This makes it dangerous to use this manager and a different destination
00205    * manager serially with the same JPEG object, because their private object
00206    * sizes may be different.  Caveat programmer.
00207    */
00208   if (cinfo->dest == NULL) {    /* first time for this JPEG object? */
00209     cinfo->dest = (struct jpeg_destination_mgr *)
00210       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
00211                   SIZEOF(my_destination_mgr));
00212   }
00213 
00214   dest = (my_dest_ptr) cinfo->dest;
00215   dest->pub.init_destination = init_destination;
00216   dest->pub.empty_output_buffer = empty_output_buffer;
00217   dest->pub.term_destination = term_destination;
00218   dest->outfile = outfile;
00219 }
00220 #endif // 0
00221 
00222 /*
00223  * Prepare for output to a memory buffer.
00224  * The caller may supply an own initial buffer with appropriate size.
00225  * Otherwise, or when the actual data output exceeds the given size,
00226  * the library adapts the buffer size as necessary.
00227  * The standard library functions malloc/free are used for allocating
00228  * larger memory, so the buffer is available to the application after
00229  * finishing compression, and then the application is responsible for
00230  * freeing the requested memory.
00231  */
00232 
00233 GLOBAL(void)
00234 jpeg_mem_dest (j_compress_ptr cinfo,
00235            unsigned char ** outbuffer, unsigned long * outsize)
00236 {
00237   my_mem_dest_ptr dest;
00238 
00239   if (outbuffer == NULL || outsize == NULL) /* sanity check */
00240     ERREXIT(cinfo, JERR_BUFFER_SIZE);
00241 
00242   /* The destination object is made permanent so that multiple JPEG images
00243    * can be written to the same buffer without re-executing jpeg_mem_dest.
00244    */
00245   if (cinfo->dest == NULL) {    /* first time for this JPEG object? */
00246     cinfo->dest = (struct jpeg_destination_mgr *)
00247       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
00248                   SIZEOF(my_mem_destination_mgr));
00249   }
00250 
00251   dest = (my_mem_dest_ptr) cinfo->dest;
00252   dest->pub.init_destination = init_mem_destination;
00253   dest->pub.empty_output_buffer = empty_mem_output_buffer;
00254   dest->pub.term_destination = term_mem_destination;
00255   dest->outbuffer = outbuffer;
00256   dest->outsize = outsize;
00257   dest->newbuffer = NULL;
00258 
00259   if (*outbuffer == NULL || *outsize == 0) {
00260     /* Allocate initial buffer */
00261     dest->newbuffer = *outbuffer = malloc(OUTPUT_BUF_SIZE);
00262     if (dest->newbuffer == NULL)
00263       ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, 10);
00264     *outsize = OUTPUT_BUF_SIZE;
00265   }
00266 
00267   dest->pub.next_output_byte = dest->buffer = *outbuffer;
00268   dest->pub.free_in_buffer = dest->bufsize = *outsize;
00269 }
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