make WavPack library check the extent of the block that it is parsing so that it cannot run into the next block; also enhance the metadata code to handle the case of files with non-audio blocks at the beginning (which can happen if the source WAV file has lots of RIFF data)

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@28736 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 65 insertions, 43 deletions

diff --git a/apps/metadata/wavpack.c b/apps/metadata/wavpack.c
index bb181b8d3f..7d19435543 100644
--- a/apps/metadata/wavpack.c
+++ b/apps/metadata/wavpack.c
@@ -47,14 +47,16 @@ static const long wavpack_sample_rates [] =
  * now works with self-extrating WavPack files and also will scan the
  * metadata for non-standard sampling rates. This no longer fails on
  * WavPack files containing floating-point audio data because these are
- * now converted to standard Rockbox format in the decoder.
+ * now converted to standard Rockbox format in the decoder, and also
+ * handles the case where up to 15 non-audio blocks might occur at the
+ * beginning of the file.
  */
 
 bool get_wavpack_metadata(int fd, struct mp3entry* id3)
 {
     /* Use the trackname part of the id3 structure as a temporary buffer */
     unsigned char* buf = (unsigned char *)id3->path;
-    uint32_t totalsamples, blocksamples, flags;
+    uint32_t totalsamples = (uint32_t) -1;
     int i;
 
     for (i = 0; i < 256; ++i) {
@@ -78,66 +80,86 @@ bool get_wavpack_metadata(int fd, struct mp3entry* id3)
 
     id3->vbr = true;   /* All WavPack files are VBR */
     id3->filesize = filesize (fd);
-    totalsamples = get_long_le(&buf[12]);
-    blocksamples = get_long_le(&buf[20]);
-    flags = get_long_le(&buf[24]);
 
-    if (blocksamples) {
-        int srindx = ((buf [26] >> 7) & 1) + ((buf [27] << 1) & 14);
+    /* check up to 16 headers before we give up finding one with audio */
 
-        if (srindx == 15) {
-            uint32_t meta_bytes = buf [4] + (buf [5] << 8) + (buf [6] << 16) - 24;
-            uint32_t meta_size;
+    for (i = 0; i < 16; ++i) {
+        uint32_t trial_totalsamples = get_long_le(&buf[12]);
+        uint32_t blockindex = get_long_le(&buf[16]);
+        uint32_t blocksamples = get_long_le(&buf[20]);
+        uint32_t flags = get_long_le(&buf[24]);
 
-            id3->frequency = 44100;
+        if (totalsamples == (uint32_t) -1 && trial_totalsamples != (uint32_t) -1 && blockindex == 0)
+            totalsamples = trial_totalsamples;
 
-            while (meta_bytes >= 6) {
-                if (read(fd, buf, 2) < 2)
-                    break;
+        if (blocksamples) {
+            int srindx = ((buf [26] >> 7) & 1) + ((buf [27] << 1) & 14);
+
+            if (srindx == 15) {
+                uint32_t meta_bytes = buf [4] + (buf [5] << 8) + (buf [6] << 16) - 24;
+                uint32_t meta_size;
 
-                if (buf [0] & ID_LARGE) {
-                    if (read(fd, buf + 2, 2) < 2)
+                id3->frequency = 44100;
+
+                while (meta_bytes >= 6) {
+                    if (read(fd, buf, 2) < 2)
                         break;
 
-                    meta_size = (buf [1] << 1) + (buf [2] << 9) + (buf [3] << 17);
-                    meta_bytes -= meta_size + 4;
-                }
-                else {
-                    meta_size = buf [1] << 1;
-                    meta_bytes -= meta_size + 2;
+                    if (buf [0] & ID_LARGE) {
+                        if (read(fd, buf + 2, 2) < 2)
+                            break;
 
-                    if ((buf [0] & ID_UNIQUE) == ID_SAMPLE_RATE) {
-                        if (meta_size == 4 && read(fd, buf + 2, 4) == 4)
-                            id3->frequency = buf [2] + (buf [3] << 8) + (buf [4] << 16);
+                        meta_size = (buf [1] << 1) + (buf [2] << 9) + (buf [3] << 17);
+                        meta_bytes -= meta_size + 4;
+                    }
+                    else {
+                        meta_size = buf [1] << 1;
+                        meta_bytes -= meta_size + 2;
 
-                        break;
+                        if ((buf [0] & ID_UNIQUE) == ID_SAMPLE_RATE) {
+                            if (meta_size == 4 && read(fd, buf + 2, 4) == 4)
+                                id3->frequency = buf [2] + (buf [3] << 8) + (buf [4] << 16);
+
+                            break;
+                        }
                     }
-                }
 
-                if (meta_size > 0 && lseek(fd, meta_size, SEEK_CUR) < 0)
-                    break;
+                    if (meta_size > 0 && lseek(fd, meta_size, SEEK_CUR) < 0)
+                        break;
+                }
             }
-        }
-        else
-            id3->frequency = wavpack_sample_rates[srindx];
+            else
+                id3->frequency = wavpack_sample_rates[srindx];
+
+            /* if the total number of samples is still unknown, make a guess on the high side (for now) */
+
+            if (totalsamples == (uint32_t) -1) {
+                totalsamples = filesize (fd) * 3;
 
-        /* if the total number of samples is unknown, make a guess on the high side (for now) */
+                if (!(flags & HYBRID_FLAG))
+                    totalsamples /= 2;
 
-        if (totalsamples == (uint32_t) -1) {
-            totalsamples = filesize (fd) * 3;
+                if (!(flags & MONO_FLAG))
+                    totalsamples /= 2;
+            }
 
-            if (!(flags & HYBRID_FLAG))
-                totalsamples /= 2;
+            id3->length = ((int64_t) totalsamples * 1000) / id3->frequency;
+            id3->bitrate = filesize (fd) / (id3->length / 8);
 
-            if (!(flags & MONO_FLAG))
-                totalsamples /= 2;
+            read_ape_tags(fd, id3);
+            return true;
         }
+        else {   /* block did not contain audio, so seek to the end and see if there's another */
+            uint32_t meta_bytes = buf [4] + (buf [5] << 8) + (buf [6] << 16) - 24;
 
-        id3->length = ((int64_t) totalsamples * 1000) / id3->frequency;
-        id3->bitrate = filesize (fd) / (id3->length / 8);
+            if ((meta_bytes > 0 && lseek(fd, meta_bytes, SEEK_CUR) < 0) ||
+                read(fd, buf, 32) < 32)
+                    break;
 
-        read_ape_tags(fd, id3);
-        return true;
+            if (memcmp (buf, "wvpk", 4) != 0 || buf [9] != 4 ||
+                buf [8] < 2 || buf [8] > 0x10)
+                    break;
+        }
     }
 
     return false;