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Code Issues Releases Wiki Activity

Alpha 1.0.10: unpinning converted chat on demand.

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If we want to pin a chat and we have reached the limit we now check
for a deactivated (converted to supergroup) chat that is pinned and
is not in the chats list and just silently unpin it if it is found.

Also possible UB fix for a waveform encoding and decoding.
This commit is contained in:
John Preston
2017-02-16 19:47:50 +03:00
parent 8d354382a4
commit 7adfe93a8d
12 changed files with 103 additions and 32 deletions
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50
Telegram/SourceFiles/structs.cpp
View File

@@ -1659,20 +1659,54 @@ void DocumentData::notifyLayoutChanged() const {
}
VoiceWaveform documentWaveformDecode(const QByteArray &encoded5bit) {
VoiceWaveform result((encoded5bit.size() * 8) / 5, 0);
for (int32 i = 0, l = result.size(); i < l; ++i) { // read each 5 bit of encoded5bit as 0-31 unsigned char
int32 byte = (i * 5) / 8, shift = (i * 5) % 8;
result[i] = (((*(uint16*)(encoded5bit.constData() + byte)) >> shift) & 0x1F);
auto bitsCount = static_cast<int>(encoded5bit.size() * 8);
auto valuesCount = bitsCount / 5;
if (!valuesCount) {
return VoiceWaveform();
}
// Read each 5 bit of encoded5bit as 0-31 unsigned char.
// We count the index of the byte in which the desired 5-bit sequence starts.
// And then we read a uint16 starting from that byte to guarantee to get all of those 5 bits.
//
// BUT! if it is the last byte we have, we're not allowed to read a uint16 starting with it.
// Because it will be an overflow (we'll access one byte after the available memory).
// We see, that only the last 5 bits could start in the last available byte and be problematic.
// So we read in a general way all the entries in a general way except the last one.
auto result = VoiceWaveform(valuesCount, 0);
auto bitsData = encoded5bit.constData();
for (auto i = 0, l = valuesCount - 1; i != l; ++i) {
auto byteIndex = (i * 5) / 8;
auto bitShift = (i * 5) % 8;
auto value = *reinterpret_cast<const uint16*>(bitsData + byteIndex);
result[i] = static_cast<char>((value >> bitShift) & 0x1F);
}
auto lastByteIndex = ((valuesCount - 1) * 5) / 8;
auto lastBitShift = ((valuesCount - 1) * 5) % 8;
auto lastValue = (lastByteIndex == encoded5bit.size() - 1)
? static_cast<uint16>(*reinterpret_cast<const uchar*>(bitsData + lastByteIndex))
: *reinterpret_cast<const uint16*>(bitsData + lastByteIndex);
result[valuesCount - 1] = static_cast<char>((lastValue >> lastBitShift) & 0x1F);
return result;
}
QByteArray documentWaveformEncode5bit(const VoiceWaveform &waveform) {
QByteArray result((waveform.size() * 5 + 7) / 8, 0);
for (int32 i = 0, l = waveform.size(); i < l; ++i) { // write each 0-31 unsigned char as 5 bit to result
int32 byte = (i * 5) / 8, shift = (i * 5) % 8;
(*(uint16*)(result.data() + byte)) |= (uint16(waveform.at(i) & 0x1F) << shift);
auto bitsCount = waveform.size() * 5;
auto bytesCount = (bitsCount + 7) / 8;
auto result = QByteArray(bytesCount + 1, 0);
auto bitsData = result.data();
// Write each 0-31 unsigned char as 5 bit to result.
// We reserve one extra byte to be able to dereference any of required bytes
// as a uint16 without overflowing, even the byte with index "bytesCount - 1".
for (auto i = 0, l = waveform.size(); i < l; ++i) {
auto byteIndex = (i * 5) / 8;
auto bitShift = (i * 5) % 8;
auto value = (static_cast<uint16>(waveform[i]) & 0x1F) << bitShift;
*reinterpret_cast<uint16*>(bitsData + byteIndex) |= value;
}
result.resize(bytesCount);
return result;
}