modules/flac.c

   1 // This file is part of Deark.
   2 // Copyright (C) 2018 Jason Summers
   3 // See the file COPYING for terms of use.
   4
   5 // FLAC audio
   6
   7 #include <deark-config.h>
   8 #include <deark-private.h>
   9 #include <deark-fmtutil.h>
  10 DE_DECLARE_MODULE(de_module_flac);
  11
  12 typedef struct localctx_struct {
  13         int reserved;
  14 } lctx;
  15
  16 static const char *get_mdblk_name(u8 blktype)
  17 {
  18         const char *name = NULL;
  19         switch(blktype) {
  20         case 0: name="STREAMINFO"; break;
  21         case 1: name="PADDING"; break;
  22         case 2: name="APPLICATION"; break;
  23         case 3: name="SEEKTABLE"; break;
  24         case 4: name="VORBIS_COMMENT"; break;
  25         case 5: name="CUESHEET"; break;
  26         case 6: name="PICTURE"; break;
  27         }
  28         return name?name:"?";
  29 }
  30
  31 static void do_metadata_block_vorbiscomment(deark *c, lctx *d, i64 pos1, i64 len)
  32 {
  33         de_dbg(c, "vorbis comment block at %"I64_FMT, pos1);
  34         de_dbg_indent(c, 1);
  35         de_run_module_by_id_on_slice2(c, "ogg", "C", c->infile, pos1, len);
  36         de_dbg_indent(c, -1);
  37 }
  38
  39 static void do_metadata_block_picture(deark *c, lctx *d, i64 pos1, i64 len)
  40 {
  41         de_dbg(c, "picture at %"I64_FMT, pos1);
  42         de_dbg_indent(c, 1);
  43         de_run_module_by_id_on_slice2(c, "id3", "F", c->infile, pos1, len);
  44         de_dbg_indent(c, -1);
  45 }
  46
  47 static void do_metadata_block(deark *c, lctx *d, u8 blktype, i64 pos1, i64 len)
  48 {
  49         switch(blktype) {
  50         case 4:
  51                 do_metadata_block_vorbiscomment(c, d, pos1, len);
  52                 break;
  53         case 6:
  54                 do_metadata_block_picture(c, d, pos1, len);
  55                 break;
  56         }
  57 }
  58
  59 static void run_flac_internal(deark *c, lctx *d, i64 pos1, i64 len)
  60 {
  61         i64 pos = pos1;
  62         int saved_indent_level;
  63
  64         de_dbg(c, "signature at %"I64_FMT, pos);
  65         pos += 4;
  66
  67         de_dbg_indent_save(c, &saved_indent_level);
  68         while(1) {
  69                 u8 b;
  70                 i64 blklen;
  71                 u8 blktype;
  72                 const char *blkname;
  73                 u8 is_last;
  74
  75                 if(pos >= pos1+len) goto done;
  76                 de_dbg(c, "metadata block at %"I64_FMT, pos);
  77                 de_dbg_indent(c, 1);
  78                 b = de_getbyte_p(&pos);
  79                 is_last = (b&0x80)!=0;
  80                 de_dbg(c, "is-last: %u", (unsigned int)is_last);
  81                 blktype = (b&0x7f);
  82                 blkname = get_mdblk_name(blktype);
  83                 de_dbg(c, "block type: %u (%s)", (unsigned int)blktype, blkname);
  84                 blklen = dbuf_getint_ext(c->infile, pos, 3, 0, 0);
  85                 pos += 3;
  86                 de_dbg(c, "block len: %u", (unsigned int)blklen);
  87                 do_metadata_block(c, d, blktype, pos, blklen);
  88                 pos += blklen;
  89                 de_dbg_indent(c, -1);
  90                 if(is_last) break;
  91         }
  92
  93         de_dbg(c, "frames start at %"I64_FMT, pos);
  94
  95 done:
  96         de_dbg_indent_restore(c, saved_indent_level);
  97 }
  98
  99 static void de_run_flac(deark *c, de_module_params *mparams)
 100 {
 101         lctx *d = NULL;
 102         struct de_id3info id3i;
 103
 104         d = de_malloc(c, sizeof(lctx));
 105         fmtutil_handle_id3(c, c->infile, &id3i, 0);
 106         run_flac_internal(c, d, id3i.main_start, id3i.main_end-id3i.main_start);
 107         de_free(c, d);
 108 }
 109
 110 static int de_identify_flac(deark *c)
 111 {
 112         i64 pos = 0;
 113
 114         if(!c->detection_data->id3.detection_attempted) {
 115                 de_err(c, "flac detection requires id3 module");
 116                 return 0;
 117         }
 118
 119         if(c->detection_data->id3.has_id3v2) {
 120                 pos = (i64)c->detection_data->id3.bytes_at_start;
 121         }
 122
 123         if(!dbuf_memcmp(c->infile, pos, "fLaC", 4))
 124                 return 100;
 125
 126         return 0;
 127 }
 128
 129 void de_module_flac(deark *c, struct deark_module_info *mi)
 130 {
 131         mi->id = "flac";
 132         mi->desc = "FLAC";
 133         mi->run_fn = de_run_flac;
 134         mi->identify_fn = de_identify_flac;
 135 }