jpeg.c

   1 /*
   2     fbv  --  simple image viewer for the linux framebuffer
   3     Copyright (C) 2000, 2001, 2003  Mateusz Golicz
   4
   5     This program is free software; you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation; either version 2 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License
  16     along with this program; if not, write to the Free Software
  17     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18 */
  19 #include "config.h"
  20 #ifdef FBV_SUPPORT_JPEG
  21 #include <stdio.h>
  22 #include <sys/types.h>
  23 #include <sys/stat.h>
  24 #include <fcntl.h>
  25 #include <jpeglib.h>
  26 #include <setjmp.h>
  27 #include <unistd.h>
  28 #include <string.h>
  29 #include "fbv.h"
  30
  31 struct r_jpeg_error_mgr
  32 {
  33     struct jpeg_error_mgr pub;
  34     jmp_buf envbuffer;
  35 };
  36
  37
  38 int fh_jpeg_id(char *name)
  39 {
  40     int fd;
  41     unsigned char id[10];
  42     fd=open(name,O_RDONLY); if(fd==-1) return(0);
  43     read(fd,id,10);
  44     close(fd);
  45     if(id[6]=='J' && id[7]=='F' && id[8]=='I' && id[9]=='F') return(1);
  46     if(id[0]==0xff && id[1]==0xd8 && id[2]==0xff) return(1);
  47     return(0);
  48 }
  49
  50
  51 void jpeg_cb_error_exit(j_common_ptr cinfo)
  52 {
  53     struct r_jpeg_error_mgr *mptr;
  54     mptr=(struct r_jpeg_error_mgr*) cinfo->err;
  55     (*cinfo->err->output_message) (cinfo);
  56     longjmp(mptr->envbuffer,1);
  57 }
  58
  59 int fh_jpeg_load(char *filename,unsigned char *buffer, unsigned char ** alpha, int x,int y)
  60 {
  61     struct jpeg_decompress_struct cinfo;
  62     struct jpeg_decompress_struct *ciptr;
  63     struct r_jpeg_error_mgr emgr;
  64     unsigned char *bp;
  65     int px,py,c;
  66     FILE *fh;
  67     JSAMPLE *lb;
  68
  69     ciptr=&cinfo;
  70     if(!(fh=fopen(filename,"rb"))) return(FH_ERROR_FILE);
  71     ciptr->err=jpeg_std_error(&emgr.pub);
  72     emgr.pub.error_exit=jpeg_cb_error_exit;
  73     if(setjmp(emgr.envbuffer)==1)
  74     {
  75         // FATAL ERROR - Free the object and return...
  76         jpeg_destroy_decompress(ciptr);
  77         fclose(fh);
  78         return(FH_ERROR_FORMAT);
  79     }
  80
  81     jpeg_create_decompress(ciptr);
  82     jpeg_stdio_src(ciptr,fh);
  83     jpeg_read_header(ciptr,TRUE);
  84     ciptr->out_color_space=JCS_RGB;
  85     jpeg_start_decompress(ciptr);
  86
  87     px=ciptr->output_width; py=ciptr->output_height;
  88     c=ciptr->output_components;
  89
  90
  91     if(c==3)
  92     {
  93         lb=(*ciptr->mem->alloc_small)((j_common_ptr) ciptr,JPOOL_PERMANENT,c*px);
  94         bp=buffer;
  95         while (ciptr->output_scanline < ciptr->output_height)
  96         {
  97             jpeg_read_scanlines(ciptr, &lb, 1);
  98             memcpy(bp,lb,px*c);
  99             bp+=px*c;
 100         }
 101
 102     }
 103     jpeg_finish_decompress(ciptr);
 104     jpeg_destroy_decompress(ciptr);
 105     fclose(fh);
 106     return(FH_ERROR_OK);
 107 }
 108
 109 int fh_jpeg_getsize(char *filename,int *x,int *y)
 110 {
 111     struct jpeg_decompress_struct cinfo;
 112     struct jpeg_decompress_struct *ciptr;
 113     struct r_jpeg_error_mgr emgr;
 114     int px,py,c;
 115     FILE *fh;
 116
 117     ciptr=&cinfo;
 118     if(!(fh=fopen(filename,"rb"))) return(FH_ERROR_FILE);
 119
 120     ciptr->err=jpeg_std_error(&emgr.pub);
 121     emgr.pub.error_exit=jpeg_cb_error_exit;
 122     if(setjmp(emgr.envbuffer)==1)
 123     {
 124         // FATAL ERROR - Free the object and return...
 125         jpeg_destroy_decompress(ciptr);
 126         fclose(fh);
 127         return(FH_ERROR_FORMAT);
 128     }
 129
 130     jpeg_create_decompress(ciptr);
 131     jpeg_stdio_src(ciptr,fh);
 132     jpeg_read_header(ciptr,TRUE);
 133     ciptr->out_color_space=JCS_RGB;
 134     jpeg_start_decompress(ciptr);
 135     px=ciptr->output_width; py=ciptr->output_height;
 136     c=ciptr->output_components;
 137     *x=px; *y=py;
 138     jpeg_destroy_decompress(ciptr);
 139     fclose(fh);
 140     return(FH_ERROR_OK);
 141 }
 142 #endif