split up the metadata parser

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@13637 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 122 insertions, 0 deletions

diff --git a/apps/metadata/flac.c b/apps/metadata/flac.c
new file mode 100644
index 0000000..5b3644e
--- /dev/null
+++ b/apps/metadata/flac.c
@@ -0,0 +1,122 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2005 Dave Chapman
+ *
+ * All files in this archive are subject to the GNU General Public License.
+ * See the file COPYING in the source tree root for full license agreement.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <inttypes.h>
+
+#include "system.h"
+#include "id3.h"
+#include "metadata_common.h"
+#include "logf.h"
+
+bool get_flac_metadata(int fd, struct mp3entry* id3)
+{
+    /* A simple parser to read vital metadata from a FLAC file - length,
+     * frequency, bitrate etc. This code should either be moved to a 
+     * seperate file, or discarded in favour of the libFLAC code.
+     * The FLAC stream specification can be found at 
+     * http://flac.sourceforge.net/format.html#stream
+     */
+
+    /* Use the trackname part of the id3 structure as a temporary buffer */
+    unsigned char* buf = (unsigned char *)id3->path;
+    bool rc = false;
+
+    if (!skip_id3v2(fd, id3) || (read(fd, buf, 4) < 4))
+    {
+        return rc;
+    }
+    
+    if (memcmp(buf, "fLaC", 4) != 0) 
+    {
+        return rc;
+    }
+
+    while (true) 
+    {
+        long i;
+        
+        if (read(fd, buf, 4) < 0)
+        {
+            return rc;
+        }
+        
+        /* The length of the block */
+        i = (buf[1] << 16) | (buf[2] << 8) | buf[3];
+
+        if ((buf[0] & 0x7f) == 0)       /* 0 is the STREAMINFO block */
+        {
+            unsigned long totalsamples;
+
+            /* FIXME: Don't trust the value of i */
+            if (read(fd, buf, i) < 0)
+            {
+                return rc;
+            }
+          
+            id3->vbr = true;   /* All FLAC files are VBR */
+            id3->filesize = filesize(fd);
+            id3->frequency = (buf[10] << 12) | (buf[11] << 4) 
+                | ((buf[12] & 0xf0) >> 4);
+            rc = true;  /* Got vital metadata */
+
+            /* totalsamples is a 36-bit field, but we assume <= 32 bits are used */
+            totalsamples = get_long_be(&buf[14]);
+
+            /* Calculate track length (in ms) and estimate the bitrate (in kbit/s) */
+            id3->length = ((int64_t) totalsamples * 1000) / id3->frequency;
+        
+            if (id3->length <= 0)
+            {
+                logf("flac length invalid!");
+                return false;
+            }
+
+            id3->bitrate = (id3->filesize * 8) / id3->length;
+        } 
+        else if ((buf[0] & 0x7f) == 4)  /* 4 is the VORBIS_COMMENT block */
+        {
+            /* The next i bytes of the file contain the VORBIS COMMENTS. */
+            if (!read_vorbis_tags(fd, id3, i))
+            {
+                return rc;
+            }
+        } 
+        else 
+        {
+            if (buf[0] & 0x80) 
+            {
+                /* If we have reached the last metadata block, abort. */
+                break;
+            }
+            else
+            {
+                /* Skip to next metadata block */
+                if (lseek(fd, i, SEEK_CUR) < 0)
+                {
+                    return rc;
+                }
+            }
+        }
+    }
+    
+    return true;
+}