1 files changed, 193 insertions, 0 deletions

diff --git a/lib/rbcodec/metadata/mp3.c b/lib/rbcodec/metadata/mp3.c
new file mode 100644
index 0000000000..feb1a52f77
--- /dev/null
+++ b/lib/rbcodec/metadata/mp3.c
@@ -0,0 +1,193 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2002 by Daniel Stenberg
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+/*
+ * Parts of this code has been stolen from the Ample project and was written
+ * by David H�deman. It has since been extended and enhanced pretty much by
+ * all sorts of friendly Rockbox people.
+ *
+ */
+
+ /* tagResolver and associated code copyright 2003 Thomas Paul Diffenbach
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdbool.h>
+#include "string-extra.h"
+#include "config.h"
+#include "file.h"
+#include "logf.h"
+
+#include "system.h"
+#include "metadata.h"
+#include "mp3data.h"
+#include "metadata_common.h"
+#include "metadata_parsers.h"
+
+/*
+ * Calculates the length (in milliseconds) of an MP3 file.
+ *
+ * Modified to only use integers.
+ *
+ * Arguments: file - the file to calculate the length upon
+ *            entry - the entry to update with the length
+ *
+ * Returns: the song length in milliseconds,
+ *          0 means that it couldn't be calculated
+ */
+static int getsonglength(int fd, struct mp3entry *entry)
+{
+    unsigned long filetime = 0;
+    struct mp3info info;
+    long bytecount;
+
+    /* Start searching after ID3v2 header */
+    if(-1 == lseek(fd, entry->id3v2len, SEEK_SET))
+        return 0;
+
+    bytecount = get_mp3file_info(fd, &info);
+
+    logf("Space between ID3V2 tag and first audio frame: 0x%lx bytes",
+           bytecount);
+
+    if(bytecount < 0)
+        return -1;
+
+    bytecount += entry->id3v2len;
+
+    /* Validate byte count, in case the file has been edited without
+     * updating the header.
+     */
+    if (info.byte_count)
+    {
+        const unsigned long expected = entry->filesize - entry->id3v1len
+            - entry->id3v2len;
+        const unsigned long diff = MAX(10240, info.byte_count / 20);
+
+        if ((info.byte_count > expected + diff)
+            || (info.byte_count < expected - diff))
+        {
+            logf("Note: info.byte_count differs from expected value by "
+                 "%ld bytes", labs((long) (expected - info.byte_count)));
+            info.byte_count = 0;
+            info.frame_count = 0;
+            info.file_time = 0;
+            info.enc_padding = 0;
+
+            /* Even if the bitrate was based on "known bad" values, it
+             * should still be better for VBR files than using the bitrate
+             * of the first audio frame.
+             */
+        }
+    }
+
+    entry->bitrate   = info.bitrate;
+    entry->frequency = info.frequency;
+    entry->layer     = info.layer;
+    switch(entry->layer) {
+#if CONFIG_CODEC==SWCODEC
+        case 0:
+            entry->codectype=AFMT_MPA_L1;
+            break;
+#endif
+        case 1:
+            entry->codectype=AFMT_MPA_L2;
+            break;
+        case 2:
+            entry->codectype=AFMT_MPA_L3;
+            break;
+    }
+
+    /* If the file time hasn't been established, this may be a fixed
+       rate MP3, so just use the default formula */
+
+    filetime = info.file_time;
+
+    if(filetime == 0)
+    {
+        /* Prevent a division by zero */
+        if (info.bitrate < 8)
+            filetime = 0;
+        else
+            filetime = (entry->filesize - bytecount) / (info.bitrate / 8);
+        /* bitrate is in kbps so this delivers milliseconds. Doing bitrate / 8
+         * instead of filesize * 8 is exact, because mpeg audio bitrates are
+         * always multiples of 8, and it avoids overflows. */
+    }
+
+    entry->frame_count = info.frame_count;
+
+    entry->vbr = info.is_vbr;
+    entry->has_toc = info.has_toc;
+
+#if CONFIG_CODEC==SWCODEC
+    if (!entry->lead_trim)
+        entry->lead_trim = info.enc_delay;
+    if (!entry->tail_trim)
+        entry->tail_trim = info.enc_padding;
+#endif
+
+    memcpy(entry->toc, info.toc, sizeof(info.toc));
+
+    /* Update the seek point for the first playable frame */
+    entry->first_frame_offset = bytecount;
+    logf("First frame is at %lx", entry->first_frame_offset);
+
+    return filetime;
+}
+
+/*
+ * Checks all relevant information (such as ID3v1 tag, ID3v2 tag, length etc)
+ * about an MP3 file and updates it's entry accordingly.
+ *
+  Note, that this returns true for successful, false for error! */
+bool get_mp3_metadata(int fd, struct mp3entry *entry)
+{
+    entry->title = NULL;
+    entry->filesize = filesize(fd);
+    entry->id3v2len = getid3v2len(fd);
+    entry->tracknum = 0;
+    entry->discnum = 0;
+
+    if (entry->id3v2len)
+        setid3v2title(fd, entry);
+    int len = getsonglength(fd, entry);
+    if (len < 0)
+        return false;
+    entry->length = len;
+
+    /* Subtract the meta information from the file size to get
+       the true size of the MP3 stream */
+    entry->filesize -= entry->first_frame_offset;
+
+    /* only seek to end of file if no id3v2 tags were found */
+    if (!entry->id3v2len) {
+        setid3v1title(fd, entry);
+    }
+
+    if(!entry->length || (entry->filesize < 8 ))
+        /* no song length or less than 8 bytes is hereby considered to be an
+           invalid mp3 and won't be played by us! */
+        return false;
+
+    return true;
+}