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Member "quicktime4linux-2.3/jdatadst.c" (9 Jan 2007, 4284 Bytes) of package /linux/privat/old/quicktime4linux-2.3-src.tar.gz:


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    1 #include <stdio.h>
    2 #include <stdlib.h>
    3 #include "jpeg.h"
    4 #include "jpeglib.h"
    5 #include "jerror.h"
    6 
    7 
    8 /* Expanded data destination object for stdio output */
    9 
   10 typedef struct {
   11   struct jpeg_destination_mgr pub; /* public fields */
   12 
   13   JOCTET *buffer;       /* Pointer to buffer */
   14   mjpa_compress_engine *engine;
   15 } my_destination_mgr;
   16 
   17 typedef my_destination_mgr *my_dest_ptr;
   18 
   19 
   20 /*
   21  * Initialize destination --- called by jpeg_start_compress
   22  * before any data is actually written.
   23  */
   24 
   25 METHODDEF(void)
   26 init_destination (j_compress_ptr cinfo)
   27 {
   28   my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
   29 
   30 /* Set the pointer to the preallocated buffer */
   31   dest->buffer = dest->engine->output_buffer;
   32 
   33   dest->pub.next_output_byte = dest->buffer;
   34   dest->pub.free_in_buffer = dest->engine->output_allocated;
   35 }
   36 
   37 
   38 /*
   39  * Empty the output buffer --- called whenever buffer fills up.
   40  *
   41  * In typical applications, this should write the entire output buffer
   42  * (ignoring the current state of next_output_byte & free_in_buffer),
   43  * reset the pointer & count to the start of the buffer, and return TRUE
   44  * indicating that the buffer has been dumped.
   45  *
   46  * In applications that need to be able to suspend compression due to output
   47  * overrun, a FALSE return indicates that the buffer cannot be emptied now.
   48  * In this situation, the compressor will return to its caller (possibly with
   49  * an indication that it has not accepted all the supplied scanlines).  The
   50  * application should resume compression after it has made more room in the
   51  * output buffer.  Note that there are substantial restrictions on the use of
   52  * suspension --- see the documentation.
   53  *
   54  * When suspending, the compressor will back up to a convenient restart point
   55  * (typically the start of the current MCU). next_output_byte & free_in_buffer
   56  * indicate where the restart point will be if the current call returns FALSE.
   57  * Data beyond this point will be regenerated after resumption, so do not
   58  * write it out when emptying the buffer externally.
   59  */
   60 
   61 METHODDEF(boolean)
   62 empty_output_buffer (j_compress_ptr cinfo)
   63 {
   64 /* Allocate a bigger buffer. */
   65     my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
   66     char *new_buffer;
   67     int new_size, i;
   68     int offset = dest->engine->output_allocated;
   69 
   70     new_size = dest->engine->output_allocated * 2;
   71     new_buffer = malloc(new_size);
   72     for(i = 0; i < offset; i++)
   73         new_buffer[i] = dest->engine->output_buffer[i];
   74     free(dest->engine->output_buffer);
   75     dest->engine->output_buffer = new_buffer;
   76     dest->engine->output_allocated = new_size;
   77     dest->buffer = dest->engine->output_buffer;
   78 
   79     dest->pub.next_output_byte = dest->buffer + offset;
   80     dest->pub.free_in_buffer = dest->engine->output_allocated - offset;
   81 
   82     return TRUE;
   83 }
   84 
   85 
   86 /*
   87  * Terminate destination --- called by jpeg_finish_compress
   88  * after all data has been written.  Usually needs to flush buffer.
   89  *
   90  * NB: *not* called by jpeg_abort or jpeg_destroy; surrounding
   91  * application must deal with any cleanup that should happen even
   92  * for error exit.
   93  */
   94 
   95 METHODDEF(void)
   96 term_destination (j_compress_ptr cinfo)
   97 {
   98 /* Just get the length */
   99     my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
  100     dest->engine->output_size = dest->engine->output_allocated - dest->pub.free_in_buffer;
  101 }
  102 
  103 
  104 /*
  105  * Prepare for output to a stdio stream.
  106  * The caller must have already opened the stream, and is responsible
  107  * for closing it after finishing compression.
  108  */
  109 
  110 GLOBAL(void)
  111 jpeg_buffer_dest (j_compress_ptr cinfo, mjpa_compress_engine *engine)
  112 {
  113   my_dest_ptr dest;
  114 
  115   /* The destination object is made permanent so that multiple JPEG images
  116    * can be written to the same file without re-executing jpeg_stdio_dest.
  117    * This makes it dangerous to use this manager and a different destination
  118    * manager serially with the same JPEG object, because their private object
  119    * sizes may be different.  Caveat programmer.
  120    */
  121   if (cinfo->dest == NULL) {    /* first time for this JPEG object? */
  122     cinfo->dest = (struct jpeg_destination_mgr *)
  123       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
  124                   sizeof(my_destination_mgr));
  125   }
  126 
  127   dest = (my_dest_ptr) cinfo->dest;
  128   dest->pub.init_destination = init_destination;
  129   dest->pub.empty_output_buffer = empty_output_buffer;
  130   dest->pub.term_destination = term_destination;
  131   dest->engine = engine;
  132 }