From 66ebc35c557e27401799e542a6fee8c824364bb2 Mon Sep 17 00:00:00 2001
From: Yoshihisa Uchida <uchida@rockbox.org>
Date: Tue, 2 Mar 2010 10:59:46 +0000
Subject: Wave/Wave64/vox metadata parser: optimize just a little.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@24992 a1c6a512-1295-4272-9138-f99709370657
---
 apps/metadata/aiff.c | 51 +++++++++++++++------------------------------------
 1 file changed, 15 insertions(+), 36 deletions(-)

(limited to 'apps/metadata/aiff.c')

diff --git a/apps/metadata/aiff.c b/apps/metadata/aiff.c
index aba327f8c8..063e5d56af 100644
--- a/apps/metadata/aiff.c
+++ b/apps/metadata/aiff.c
@@ -38,35 +38,25 @@ bool get_aiff_metadata(int fd, struct mp3entry* id3)
     unsigned char* buf = (unsigned char *)id3->path;
     unsigned long numChannels = 0;
     unsigned long numSampleFrames = 0;
-    unsigned long sampleSize = 0;
-    unsigned long sampleRate = 0;
     unsigned long numbytes = 0;
     int read_bytes;
     int i;
     bool is_aifc = false;
 
-    if ((lseek(fd, 0, SEEK_SET) < 0) 
-        || ((read_bytes = read(fd, buf, sizeof(id3->path))) < 54))
+    if ((lseek(fd, 0, SEEK_SET) < 0) ||
+        ((read_bytes = read(fd, buf, sizeof(id3->path))) < 54) ||
+        (memcmp(buf, "FORM", 4) != 0) || (memcmp(buf + 8, "AIF", 3) != 0) ||
+        (!(is_aifc = (buf[11] == 'C')) && buf[11] != 'F'))
     {
         return false;
     }
-    
-    if (memcmp(buf, "FORM",4) != 0)
-        return false;
-
-    if (memcmp(&buf[8], "AIFF", 4) != 0)
-    {
-        if (memcmp(&buf[8], "AIFC", 4) != 0)
-            return false;
-
-        is_aifc = true;
-    }
-
-    buf += 12;
-    read_bytes -= 12;
 
+    i = 12;
     while ((numbytes == 0) && (read_bytes >= 8)) 
     {
+        buf        += i;
+        read_bytes -= i;
+
         /* chunkSize */
         i = get_long_be(&buf[4]);
         
@@ -76,20 +66,17 @@ bool get_aiff_metadata(int fd, struct mp3entry* id3)
             numChannels = ((buf[8]<<8)|buf[9]);
             /* numSampleFrames */
             numSampleFrames = get_long_be(&buf[10]);
-            /* sampleSize */
-            sampleSize = ((buf[14]<<8)|buf[15]);
             /* sampleRate */
-            sampleRate = get_long_be(&buf[18]);
-            sampleRate = sampleRate >> (16+14-buf[17]);
+            id3->frequency = get_long_be(&buf[18]);
+            id3->frequency >>= (16+14-buf[17]);
             /* save format infos */
-            id3->bitrate = (sampleSize * numChannels * sampleRate) / 1000;
-            id3->frequency = sampleRate;
+            id3->bitrate = (((buf[14]<<8)|buf[15]) * numChannels * id3->frequency) / 1000;
             if (!is_aifc || memcmp(&buf[26], AIFC_FORMAT_QT_IMA_ADPCM, 4) != 0)
                 id3->length = ((int64_t) numSampleFrames * 1000) / id3->frequency;
             else
             {
                 /* QuickTime IMA ADPCM is 1block = 64 data for each channel */
-                id3->length = (int64_t)(numSampleFrames * 64000LL) / id3->frequency;
+                id3->length = ((int64_t) numSampleFrames * 64000LL) / id3->frequency;
             }
 
             id3->vbr = false;   /* AIFF files are CBR */
@@ -100,17 +87,9 @@ bool get_aiff_metadata(int fd, struct mp3entry* id3)
             numbytes = i - 8;
         }
 
-        if (i & 0x01)
-        {
-            i++;  /* odd chunk sizes must be padded */
-        }
-        buf += i + 8;
-        read_bytes -= i + 8;
+        /* odd chunk sizes must be padded */
+        i += 8 + (i & 0x01);
     }
 
-    if ((numbytes == 0) || (numChannels == 0)) 
-    {
-        return false;
-    }
-    return true;
+    return ((numbytes != 0) && (numChannels != 0));
 }
-- 
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