From 958dfe2451f12ce25975aafbe1fc98105b49f673 Mon Sep 17 00:00:00 2001
From: Scott Wheeler <wheeler@kde.org>
Date: Fri, 1 Feb 2008 00:49:01 +0000
Subject: [PATCH] A couple of small bugs (the more significant ones were
already fixed) from Oskar Liljeblad
BUG:126010
git-svn-id: svn://anonsvn.kde.org/home/kde/trunk/kdesupport/taglib@769284 283d02a7-25f6-0310-bc7c-ecb5cbfe19da
---
taglib/mpeg/mpegfile.cpp | 48 ++++++++++++++++++++++++----------------
1 file changed, 29 insertions(+), 19 deletions(-)
diff --git a/taglib/mpeg/mpegfile.cpp b/taglib/mpeg/mpegfile.cpp
index 18dc75c0..221ccd6a 100644
--- a/taglib/mpeg/mpegfile.cpp
+++ b/taglib/mpeg/mpegfile.cpp
@@ -313,45 +313,55 @@ void MPEG::File::setID3v2FrameFactory(const ID3v2::FrameFactory *factory)
long MPEG::File::nextFrameOffset(long position)
{
- // TODO: This will miss syncs spanning buffer read boundaries.
+ bool foundLastSyncPattern = false;
- ByteVector buffer = readBlock(bufferSize());
-
- while(buffer.size() > 0) {
+ ByteVector buffer;
+
+ while(true) {
seek(position);
buffer = readBlock(bufferSize());
- for(int i = 0; i < int(buffer.size()) - 1; i++) {
+ if(buffer.size() <= 0)
+ return -1;
+
+ if(foundLastSyncPattern && secondSynchByte(buffer[0]))
+ return position - 1;
+
+ for(uint i = 0; i < buffer.size() - 1; i++) {
if(uchar(buffer[i]) == 0xff && secondSynchByte(buffer[i + 1]))
return position + i;
}
- position += bufferSize();
- }
- return -1;
+ foundLastSyncPattern = uchar(buffer[buffer.size() - 1]) == 0xff;
+ position += buffer.size();
+ }
}
long MPEG::File::previousFrameOffset(long position)
{
- // TODO: This will miss syncs spanning buffer read boundaries.
+ bool foundFirstSyncPattern = false;
+ ByteVector buffer;
- while(int(position - bufferSize()) > int(bufferSize())) {
- position -= bufferSize();
+ while (position > 0) {
+ long size = ulong(position) < bufferSize() ? position : bufferSize();
+ position -= size;
+
seek(position);
- ByteVector buffer = readBlock(bufferSize());
-
- // If the amount of data is smaller than an MPEG header (4 bytes) there's no
- // chance of this being valid.
-
- if(buffer.size() < 4)
- return -1;
+ buffer = readBlock(size);
+ if(buffer.size() <= 0)
+ break;
+
+ if(foundFirstSyncPattern && uchar(buffer[buffer.size() - 1]) == 0xff)
+ return position + buffer.size() - 1;
+
for(int i = buffer.size() - 2; i >= 0; i--) {
if(uchar(buffer[i]) == 0xff && secondSynchByte(buffer[i + 1]))
return position + i;
}
- }
+ foundFirstSyncPattern = secondSynchByte(buffer[0]);
+ }
return -1;
}