media/libjpeg/jdatadst.c

   1 /*
   2  * jdatadst.c
   3  *
   4  * This file was part of the Independent JPEG Group's software:
   5  * Copyright (C) 1994-1996, Thomas G. Lane.
   6  * Modified 2009-2012 by Guido Vollbeding.
   7  * libjpeg-turbo Modifications:
   8  * Copyright (C) 2013, 2016, 2022, D. R. Commander.
   9  * For conditions of distribution and use, see the accompanying README.ijg
  10  * file.
  11  *
  12  * This file contains compression data destination routines for the case of
  13  * emitting JPEG data to memory or to a file (or any stdio stream).
  14  * While these routines are sufficient for most applications,
  15  * some will want to use a different destination manager.
  16  * IMPORTANT: we assume that fwrite() will correctly transcribe an array of
  17  * JOCTETs into 8-bit-wide elements on external storage.  If char is wider
  18  * than 8 bits on your machine, you may need to do some tweaking.
  19  */
  20
  21 /* this is not a core library module, so it doesn't define JPEG_INTERNALS */
  22 #include "jinclude.h"
  23 #include "jpeglib.h"
  24 #include "jerror.h"
  25
  26
  27 /* Expanded data destination object for stdio output */
  28
  29 typedef struct {
  30   struct jpeg_destination_mgr pub; /* public fields */
  31
  32   FILE *outfile;                /* target stream */
  33   JOCTET *buffer;               /* start of buffer */
  34 } my_destination_mgr;
  35
  36 typedef my_destination_mgr *my_dest_ptr;
  37
  38 #define OUTPUT_BUF_SIZE  4096   /* choose an efficiently fwrite'able size */
  39
  40
  41 #if JPEG_LIB_VERSION >= 80 || defined(MEM_SRCDST_SUPPORTED)
  42 /* Expanded data destination object for memory output */
  43
  44 typedef struct {
  45   struct jpeg_destination_mgr pub; /* public fields */
  46
  47   unsigned char **outbuffer;    /* target buffer */
  48   unsigned long *outsize;
  49   unsigned char *newbuffer;     /* newly allocated buffer */
  50   JOCTET *buffer;               /* start of buffer */
  51   size_t bufsize;
  52 } my_mem_destination_mgr;
  53
  54 typedef my_mem_destination_mgr *my_mem_dest_ptr;
  55 #endif
  56
  57
  58 /*
  59  * Initialize destination --- called by jpeg_start_compress
  60  * before any data is actually written.
  61  */
  62
  63 METHODDEF(void)
  64 init_destination(j_compress_ptr cinfo)
  65 {
  66   my_dest_ptr dest = (my_dest_ptr)cinfo->dest;
  67
  68   /* Allocate the output buffer --- it will be released when done with image */
  69   dest->buffer = (JOCTET *)
  70     (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE,
  71                                 OUTPUT_BUF_SIZE * sizeof(JOCTET));
  72
  73   dest->pub.next_output_byte = dest->buffer;
  74   dest->pub.free_in_buffer = OUTPUT_BUF_SIZE;
  75 }
  76
  77 #if JPEG_LIB_VERSION >= 80 || defined(MEM_SRCDST_SUPPORTED)
  78 METHODDEF(void)
  79 init_mem_destination(j_compress_ptr cinfo)
  80 {
  81   /* no work necessary here */
  82 }
  83 #endif
  84
  85
  86 /*
  87  * Empty the output buffer --- called whenever buffer fills up.
  88  *
  89  * In typical applications, this should write the entire output buffer
  90  * (ignoring the current state of next_output_byte & free_in_buffer),
  91  * reset the pointer & count to the start of the buffer, and return TRUE
  92  * indicating that the buffer has been dumped.
  93  *
  94  * In applications that need to be able to suspend compression due to output
  95  * overrun, a FALSE return indicates that the buffer cannot be emptied now.
  96  * In this situation, the compressor will return to its caller (possibly with
  97  * an indication that it has not accepted all the supplied scanlines).  The
  98  * application should resume compression after it has made more room in the
  99  * output buffer.  Note that there are substantial restrictions on the use of
 100  * suspension --- see the documentation.
 101  *
 102  * When suspending, the compressor will back up to a convenient restart point
 103  * (typically the start of the current MCU). next_output_byte & free_in_buffer
 104  * indicate where the restart point will be if the current call returns FALSE.
 105  * Data beyond this point will be regenerated after resumption, so do not
 106  * write it out when emptying the buffer externally.
 107  */
 108
 109 METHODDEF(boolean)
 110 empty_output_buffer(j_compress_ptr cinfo)
 111 {
 112   my_dest_ptr dest = (my_dest_ptr)cinfo->dest;
 113
 114   if (fwrite(dest->buffer, 1, OUTPUT_BUF_SIZE, dest->outfile) !=
 115       (size_t)OUTPUT_BUF_SIZE)
 116     ERREXIT(cinfo, JERR_FILE_WRITE);
 117
 118   dest->pub.next_output_byte = dest->buffer;
 119   dest->pub.free_in_buffer = OUTPUT_BUF_SIZE;
 120
 121   return TRUE;
 122 }
 123
 124 #if JPEG_LIB_VERSION >= 80 || defined(MEM_SRCDST_SUPPORTED)
 125 METHODDEF(boolean)
 126 empty_mem_output_buffer(j_compress_ptr cinfo)
 127 {
 128   size_t nextsize;
 129   JOCTET *nextbuffer;
 130   my_mem_dest_ptr dest = (my_mem_dest_ptr)cinfo->dest;
 131
 132   /* Try to allocate new buffer with double size */
 133   nextsize = dest->bufsize * 2;
 134   nextbuffer = (JOCTET *)malloc(nextsize);
 135
 136   if (nextbuffer == NULL)
 137     ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, 10);
 138
 139   memcpy(nextbuffer, dest->buffer, dest->bufsize);
 140
 141   free(dest->newbuffer);
 142
 143   dest->newbuffer = nextbuffer;
 144
 145   dest->pub.next_output_byte = nextbuffer + dest->bufsize;
 146   dest->pub.free_in_buffer = dest->bufsize;
 147
 148   dest->buffer = nextbuffer;
 149   dest->bufsize = nextsize;
 150
 151   return TRUE;
 152 }
 153 #endif
 154
 155
 156 /*
 157  * Terminate destination --- called by jpeg_finish_compress
 158  * after all data has been written.  Usually needs to flush buffer.
 159  *
 160  * NB: *not* called by jpeg_abort or jpeg_destroy; surrounding
 161  * application must deal with any cleanup that should happen even
 162  * for error exit.
 163  */
 164
 165 METHODDEF(void)
 166 term_destination(j_compress_ptr cinfo)
 167 {
 168   my_dest_ptr dest = (my_dest_ptr)cinfo->dest;
 169   size_t datacount = OUTPUT_BUF_SIZE - dest->pub.free_in_buffer;
 170
 171   /* Write any data remaining in the buffer */
 172   if (datacount > 0) {
 173     if (fwrite(dest->buffer, 1, datacount, dest->outfile) != datacount)
 174       ERREXIT(cinfo, JERR_FILE_WRITE);
 175   }
 176   fflush(dest->outfile);
 177   /* Make sure we wrote the output file OK */
 178   if (ferror(dest->outfile))
 179     ERREXIT(cinfo, JERR_FILE_WRITE);
 180 }
 181
 182 #if JPEG_LIB_VERSION >= 80 || defined(MEM_SRCDST_SUPPORTED)
 183 METHODDEF(void)
 184 term_mem_destination(j_compress_ptr cinfo)
 185 {
 186   my_mem_dest_ptr dest = (my_mem_dest_ptr)cinfo->dest;
 187
 188   *dest->outbuffer = dest->buffer;
 189   *dest->outsize = (unsigned long)(dest->bufsize - dest->pub.free_in_buffer);
 190 }
 191 #endif
 192
 193
 194 /*
 195  * Prepare for output to a stdio stream.
 196  * The caller must have already opened the stream, and is responsible
 197  * for closing it after finishing compression.
 198  */
 199
 200 GLOBAL(void)
 201 jpeg_stdio_dest(j_compress_ptr cinfo, FILE *outfile)
 202 {
 203   my_dest_ptr dest;
 204
 205   /* The destination object is made permanent so that multiple JPEG images
 206    * can be written to the same file without re-executing jpeg_stdio_dest.
 207    */
 208   if (cinfo->dest == NULL) {    /* first time for this JPEG object? */
 209     cinfo->dest = (struct jpeg_destination_mgr *)
 210       (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_PERMANENT,
 211                                   sizeof(my_destination_mgr));
 212   } else if (cinfo->dest->init_destination != init_destination) {
 213     /* It is unsafe to reuse the existing destination manager unless it was
 214      * created by this function.  Otherwise, there is no guarantee that the
 215      * opaque structure is the right size.  Note that we could just create a
 216      * new structure, but the old structure would not be freed until
 217      * jpeg_destroy_compress() was called.
 218      */
 219     ERREXIT(cinfo, JERR_BUFFER_SIZE);
 220   }
 221
 222   dest = (my_dest_ptr)cinfo->dest;
 223   dest->pub.init_destination = init_destination;
 224   dest->pub.empty_output_buffer = empty_output_buffer;
 225   dest->pub.term_destination = term_destination;
 226   dest->outfile = outfile;
 227 }
 228
 229
 230 #if JPEG_LIB_VERSION >= 80 || defined(MEM_SRCDST_SUPPORTED)
 231 /*
 232  * Prepare for output to a memory buffer.
 233  * The caller may supply an own initial buffer with appropriate size.
 234  * Otherwise, or when the actual data output exceeds the given size,
 235  * the library adapts the buffer size as necessary.
 236  * The standard library functions malloc/free are used for allocating
 237  * larger memory, so the buffer is available to the application after
 238  * finishing compression, and then the application is responsible for
 239  * freeing the requested memory.
 240  * Note:  An initial buffer supplied by the caller is expected to be
 241  * managed by the application.  The library does not free such buffer
 242  * when allocating a larger buffer.
 243  */
 244
 245 GLOBAL(void)
 246 jpeg_mem_dest(j_compress_ptr cinfo, unsigned char **outbuffer,
 247               unsigned long *outsize)
 248 {
 249   my_mem_dest_ptr dest;
 250
 251   if (outbuffer == NULL || outsize == NULL)     /* sanity check */
 252     ERREXIT(cinfo, JERR_BUFFER_SIZE);
 253
 254   /* The destination object is made permanent so that multiple JPEG images
 255    * can be written to the same buffer without re-executing jpeg_mem_dest.
 256    */
 257   if (cinfo->dest == NULL) {    /* first time for this JPEG object? */
 258     cinfo->dest = (struct jpeg_destination_mgr *)
 259       (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_PERMANENT,
 260                                   sizeof(my_mem_destination_mgr));
 261   } else if (cinfo->dest->init_destination != init_mem_destination) {
 262     /* It is unsafe to reuse the existing destination manager unless it was
 263      * created by this function.
 264      */
 265     ERREXIT(cinfo, JERR_BUFFER_SIZE);
 266   }
 267
 268   dest = (my_mem_dest_ptr)cinfo->dest;
 269   dest->pub.init_destination = init_mem_destination;
 270   dest->pub.empty_output_buffer = empty_mem_output_buffer;
 271   dest->pub.term_destination = term_mem_destination;
 272   dest->outbuffer = outbuffer;
 273   dest->outsize = outsize;
 274   dest->newbuffer = NULL;
 275
 276   if (*outbuffer == NULL || *outsize == 0) {
 277     /* Allocate initial buffer */
 278     dest->newbuffer = *outbuffer = (unsigned char *)malloc(OUTPUT_BUF_SIZE);
 279     if (dest->newbuffer == NULL)
 280       ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, 10);
 281     *outsize = OUTPUT_BUF_SIZE;
 282   }
 283
 284   dest->pub.next_output_byte = dest->buffer = *outbuffer;
 285   dest->pub.free_in_buffer = dest->bufsize = *outsize;
 286 }
 287 #endif