modules/bpg.c

   1 // This file is part of Deark.
   2 // Copyright (C) 2016 Jason Summers
   3 // See the file COPYING for terms of use.
   4
   5 // BPG
   6
   7 #include <deark-config.h>
   8 #include <deark-private.h>
   9 #include <deark-fmtutil.h>
  10 DE_DECLARE_MODULE(de_module_bpg);
  11
  12 typedef struct localctx_struct {
  13         i64 width, height;
  14
  15         u8 pixel_format;
  16         u8 alpha_flag;
  17         i64 bit_depth;
  18
  19         u8 color_space;
  20         u8 extension_present_flag;
  21         u8 alpha2_flag;
  22         u8 limited_range_flag;
  23
  24         i64 picture_data_len;
  25         i64 extension_data_len;
  26
  27 } lctx;
  28
  29 static i64 get_ue7(deark *c, i64 *pos)
  30 {
  31         u8 b;
  32         i64 val = 0;
  33         int bytecount = 0;
  34
  35         // TODO: Better error handling
  36         while(1) {
  37                 b = de_getbyte(*pos);
  38                 (*pos)++;
  39                 bytecount++;
  40
  41                 // A quick hack to prevent 64-bit integer overflow.
  42                 // 5 bytes are enough for 35 bits, and none of the fields in
  43                 // BPG v0.9.4.1 require more than 32.
  44                 if(bytecount<=5)
  45                         val = (val<<7)|(b&0x7f);
  46
  47                 if(b<0x80) {
  48                         break;
  49                 }
  50         }
  51         return val;
  52 }
  53
  54 static void do_exif(deark *c, lctx *d, i64 pos1, i64 len1)
  55 {
  56         u8 buf[3];
  57         i64 pos = pos1;
  58         i64 len = len1;
  59
  60         if(len1<8) return;
  61         de_read(buf, pos1, 3);
  62         if(buf[0]==0 && (buf[1]=='M' || buf[1]=='I') && buf[2]==buf[1]) {
  63                 de_warn(c, "Ignoring initial NUL byte in Exif data (libbpg bug?)");
  64                 pos++;
  65                 len--;
  66         }
  67         fmtutil_handle_exif(c, pos, len);
  68 }
  69
  70 static void do_extensions(deark *c, lctx *d, i64 pos)
  71 {
  72         i64 endpos;
  73         i64 tag;
  74         i64 payload_len;
  75
  76         endpos = pos + d->extension_data_len;
  77
  78         while(pos < endpos) {
  79                 tag = get_ue7(c, &pos);
  80                 payload_len = get_ue7(c, &pos);
  81                 if(pos+payload_len>endpos) break;
  82
  83                 switch(tag) {
  84                 case 1: // Exif
  85                         do_exif(c, d, pos, payload_len);
  86                         break;
  87                 case 2: // ICC profile
  88                         dbuf_create_file_from_slice(c->infile, pos, payload_len, "icc", NULL, DE_CREATEFLAG_IS_AUX);
  89                         break;
  90                 case 3: // XMP
  91                         dbuf_create_file_from_slice(c->infile, pos, payload_len, "xmp", NULL, DE_CREATEFLAG_IS_AUX);
  92                         break;
  93                 case 4: // Thumbnail
  94                         dbuf_create_file_from_slice(c->infile, pos, payload_len, "thumb.bpg", NULL, DE_CREATEFLAG_IS_AUX);
  95                         break;
  96                 default:
  97                         de_dbg(c, "unrecognized extension type: %d", (int)tag);
  98                 }
  99
 100                 pos += payload_len;
 101         }
 102 }
 103
 104 static void do_hevc_file(deark *c, lctx *d)
 105 {
 106         i64 pos;
 107         u8 b;
 108
 109         pos = 4;
 110         b = de_getbyte(pos);
 111         pos++;
 112         d->pixel_format = b>>5;
 113         d->alpha_flag = (b>>4)&0x01;
 114         d->bit_depth = (i64)(b&0x0f) +8;
 115         de_dbg(c, "pixel format: %d", (int)d->pixel_format);
 116         de_dbg(c, "alpha flag: %d", (int)d->alpha_flag);
 117         de_dbg(c, "bit depth: %d", (int)d->bit_depth);
 118
 119         b = de_getbyte(pos);
 120         pos++;
 121         d->color_space = b>>4;
 122         d->extension_present_flag = (b>>3)&0x01;
 123         d->alpha2_flag = (b>>2)&0x01;
 124         d->limited_range_flag = (b>>1)&0x01;
 125         de_dbg(c, "color_space: %d", (int)d->color_space);
 126         de_dbg(c, "extension_present_flag: %d", (int)d->extension_present_flag);
 127         de_dbg(c, "alpha2_flag: %d", (int)d->alpha2_flag);
 128         de_dbg(c, "limited_range_flag: %d", (int)d->limited_range_flag);
 129
 130         d->width = get_ue7(c, &pos);
 131         d->height = get_ue7(c, &pos);
 132         de_dbg_dimensions(c, d->width, d->height);
 133
 134
 135         d->picture_data_len = get_ue7(c, &pos);
 136         de_dbg(c, "picture_data_len: %d%s", (int)d->picture_data_len,
 137                 (d->picture_data_len==0)?" (= to EOF)":"");
 138
 139         if(d->extension_present_flag) {
 140                 d->extension_data_len = get_ue7(c, &pos);
 141                 de_dbg(c, "extension data len: %d", (int)d->extension_data_len);
 142         }
 143
 144         if(d->extension_present_flag) {
 145                 do_extensions(c, d, pos);
 146                 pos += d->extension_data_len;
 147         }
 148
 149         de_dbg(c, "hevc_header_and_data begins at %d", (int)pos);
 150 }
 151
 152 static void de_run_bpg(deark *c, de_module_params *mparams)
 153 {
 154         lctx *d = NULL;
 155
 156         d = de_malloc(c, sizeof(lctx));
 157
 158         do_hevc_file(c, d);
 159
 160         de_free(c, d);
 161 }
 162
 163 static int de_identify_bpg(deark *c)
 164 {
 165         if(!dbuf_memcmp(c->infile, 0, "\x42\x50\x47\xfb", 4)) {
 166                 return 100;
 167         }
 168         return 0;
 169 }
 170
 171 void de_module_bpg(deark *c, struct deark_module_info *mi)
 172 {
 173         mi->id = "bpg";
 174         mi->desc = "BPG (Better Portable Graphics)";
 175         mi->desc2 = "resources only";
 176         mi->run_fn = de_run_bpg;
 177         mi->identify_fn = de_identify_bpg;
 178 }