NS_IMETHODIMP nsCacheEntryDescriptor::
nsCompressOutputStreamWrapper::Write(const char * buf,
uint32_t count,
uint32_t * result)
{
int zerr = Z_OK;
nsresult rv = NS_OK;
if (!mStreamInitialized) {
rv = InitZstream();
if (NS_FAILED(rv)) {
return rv;
}
}
if (!mWriteBuffer) {
// Once allocated, this buffer is referenced by the zlib stream and
// cannot be grown. We use 2x(initial write request) to approximate
// a stream buffer size proportional to request buffers.
mWriteBufferLen = NS_MAX(count*2, (uint32_t)kMinCompressWriteBufLen);
mWriteBuffer = (unsigned char*)nsMemory::Alloc(mWriteBufferLen);
if (!mWriteBuffer) {
mWriteBufferLen = 0;
return NS_ERROR_OUT_OF_MEMORY;
}
mZstream.next_out = mWriteBuffer;
mZstream.avail_out = mWriteBufferLen;
}
// Compress (deflate) the requested buffer. Keep going
// until the entire buffer has been deflated.
mZstream.avail_in = count;
mZstream.next_in = (Bytef*)buf;
while (mZstream.avail_in > 0) {
zerr = deflate(&mZstream, Z_NO_FLUSH);
if (zerr == Z_STREAM_ERROR) {
deflateEnd(&mZstream);
mStreamInitialized = false;
return NS_ERROR_FAILURE;
}
// Note: Z_BUF_ERROR is non-fatal and sometimes expected here.
// If the compression stream output buffer is filled, write
// it out to the underlying stream wrapper.
if (mZstream.avail_out == 0) {
rv = WriteBuffer();
if (NS_FAILED(rv)) {
deflateEnd(&mZstream);
mStreamInitialized = false;
return rv;
}
}
}
*result = count;
mUncompressedCount += *result;
return NS_OK;
}
NS_INTERFACE_MAP_END_THREADSAFE
NS_IMETHODIMP nsCacheEntryDescriptor::
nsDecompressInputStreamWrapper::Read(char * buf,
uint32_t count,
uint32_t *countRead)
{
mozilla::MutexAutoLock lock(mLock);
int zerr = Z_OK;
nsresult rv = NS_OK;
if (!mStreamInitialized) {
rv = InitZstream();
if (NS_FAILED(rv)) {
return rv;
}
}
mZstream.next_out = (Bytef*)buf;
mZstream.avail_out = count;
if (mReadBufferLen < count) {
// Allocate a buffer for reading from the input stream. This will
// determine the max number of compressed bytes read from the
// input stream at one time. Making the buffer size proportional
// to the request size is not necessary, but helps minimize the
// number of read requests to the input stream.
uint32_t newBufLen = std::max(count, (uint32_t)kMinDecompressReadBufLen);
unsigned char* newBuf;
newBuf = (unsigned char*)nsMemory::Realloc(mReadBuffer,
newBufLen);
if (newBuf) {
mReadBuffer = newBuf;
mReadBufferLen = newBufLen;
}
if (!mReadBuffer) {
mReadBufferLen = 0;
return NS_ERROR_OUT_OF_MEMORY;
}
}
// read and inflate data until the output buffer is full, or
// there is no more data to read
while (NS_SUCCEEDED(rv) &&
zerr == Z_OK &&
mZstream.avail_out > 0 &&
count > 0) {
if (mZstream.avail_in == 0) {
rv = nsInputStreamWrapper::Read_Locked((char*)mReadBuffer,
mReadBufferLen,
&mZstream.avail_in);
if (NS_FAILED(rv) || !mZstream.avail_in) {
break;
}
mZstream.next_in = mReadBuffer;
}
zerr = inflate(&mZstream, Z_NO_FLUSH);
if (zerr == Z_STREAM_END) {
// The compressed data may have been stored in multiple
// chunks/streams. To allow for this case, re-initialize
// the inflate stream and continue decompressing from
// the next byte.
Bytef * saveNextIn = mZstream.next_in;
unsigned int saveAvailIn = mZstream.avail_in;
Bytef * saveNextOut = mZstream.next_out;
unsigned int saveAvailOut = mZstream.avail_out;
inflateReset(&mZstream);
mZstream.next_in = saveNextIn;
mZstream.avail_in = saveAvailIn;
mZstream.next_out = saveNextOut;
mZstream.avail_out = saveAvailOut;
zerr = Z_OK;
} else if (zerr != Z_OK) {
rv = NS_ERROR_INVALID_CONTENT_ENCODING;
}
}
if (NS_SUCCEEDED(rv)) {
*countRead = count - mZstream.avail_out;
}
return rv;
}
