jmemdst.c
Go to the documentation of this file.
00001 /*
00002  * jmemdst.c
00003  *
00004  * Copyright (C) 1994-1996, Toshihiro Matsui, Electrotechnical Laboratory
00005  */
00006 
00007 #include <stdio.h>
00008 #include <jpeglib.h>
00009 #include <jerror.h>
00010 
00011 /* Expanded data destination object for stdio output */
00012 
00013 typedef struct {
00014   struct jpeg_destination_mgr pub; /* public fields */
00015   JOCTET * buffer;              /* start of buffer */
00016   long   * data_count_ptr;
00017 } my_destination_mgr;
00018 
00019 typedef my_destination_mgr * my_dest_ptr;
00020 
00021 /*
00022  * Initialize destination --- called by jpeg_start_compress
00023  * before any data is actually written.
00024  */
00025 
00026 
00027 METHODDEF(void)
00028 init_destination (j_compress_ptr cinfo)
00029 {
00030   my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
00031 
00032   dest->pub.next_output_byte = dest->buffer;
00033   dest->pub.free_in_buffer = *dest->data_count_ptr;
00034 }
00035 
00036 /*
00037  * Empty the output buffer --- called whenever buffer fills up.
00038  *
00039  * In typical applications, this should write the entire output buffer
00040  * (ignoring the current state of next_output_byte & free_in_buffer),
00041  * reset the pointer & count to the start of the buffer, and return TRUE
00042  * indicating that the buffer has been dumped.
00043  *
00044  * In applications that need to be able to suspend compression due to output
00045  * overrun, a FALSE return indicates that the buffer cannot be emptied now.
00046  * In this situation, the compressor will return to its caller (possibly with
00047  * an indication that it has not accepted all the supplied scanlines).  The
00048  * application should resume compression after it has made more room in the
00049  * output buffer.  Note that there are substantial restrictions on the use of
00050  * suspension --- see the documentation.
00051  *
00052  * When suspending, the compressor will back up to a convenient restart point
00053  * (typically the start of the current MCU). next_output_byte & free_in_buffer
00054  * indicate where the restart point will be if the current call returns FALSE.
00055  * Data beyond this point will be regenerated after resumption, so do not
00056  * write it out when emptying the buffer externally.
00057  */
00058 
00059 METHODDEF(boolean)
00060 empty_output_buffer (j_compress_ptr cinfo)
00061 {
00062   my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
00063 
00064   
00065   fprintf(stderr, " : jpeg compression buffer overflow >%ld\n",
00066           *dest->data_count_ptr);
00067 
00068   dest->pub.next_output_byte = dest->buffer;
00069   dest->pub.free_in_buffer = *dest->data_count_ptr;
00070 
00071   return TRUE;
00072 }
00073 
00074 /*
00075  * Terminate destination --- called by jpeg_finish_compress
00076  * after all data has been written.  Usually needs to flush buffer.
00077  *
00078  * NB: *not* called by jpeg_abort or jpeg_destroy; surrounding
00079  * application must deal with any cleanup that should happen even
00080  * for error exit.
00081  */
00082 
00083 METHODDEF(void)
00084 term_destination (j_compress_ptr cinfo)
00085 {
00086   my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
00087   size_t datacount = *dest->data_count_ptr - dest->pub.free_in_buffer;
00088 
00089   *dest->data_count_ptr = datacount;
00090   }
00091 
00092 
00093 GLOBAL(void)
00094 jpeg_memio_dest (j_compress_ptr cinfo, JOCTET *jpegimgbuf, long *size)
00095 {
00096   my_dest_ptr dest;
00097 
00098   /* RGB image (provided by the main) is compressed into jpegimgbuf
00099    * and the size of the resulted JPEG data appears in the size.
00100    * The size should hold the maximum size of the jpegimgbuf at the beginning.
00101    */
00102 
00103   if (cinfo->dest == NULL) {    /* first time for this JPEG object? */
00104     cinfo->dest = (struct jpeg_destination_mgr *)
00105       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
00106                                   sizeof(my_destination_mgr));
00107   }
00108 
00109   dest = (my_dest_ptr) cinfo->dest;
00110   dest->pub.init_destination = init_destination;
00111   dest->pub.empty_output_buffer = empty_output_buffer;
00112   dest->pub.term_destination = term_destination;
00113   dest->buffer = jpegimgbuf;
00114   dest->data_count_ptr = size;
00115 }


euslisp
Author(s): Toshihiro Matsui
autogenerated on Thu Jun 6 2019 18:05:53