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// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#include "bufferedinputstream.h"
#include <cstring>
#include <cstdint>
Fast_BufferedInputStream::Fast_BufferedInputStream(Fast_InputStream &in, size_t bufferSize)
: Fast_FilterInputStream(in),
_buffer(new char[bufferSize]),
_bufferSize((_buffer != nullptr) ? bufferSize : 0),
_bufferUsed(0),
_bufferRead(0),
_nextWillFail(false)
{
}
Fast_BufferedInputStream::~Fast_BufferedInputStream()
{
delete [] _buffer;
}
ssize_t
Fast_BufferedInputStream::Available()
{
return _in->Available() + _bufferUsed - _bufferRead;
}
bool
Fast_BufferedInputStream::Close()
{
return _in->Close();
}
ssize_t
Fast_BufferedInputStream::Skip(size_t skipNBytes)
{
ssize_t numBytesSkipped = 0;
if (_nextWillFail) {
_nextWillFail = false;
return -1;
}
if (skipNBytes > _bufferUsed - _bufferRead) {
// First, skip all bytes in buffer
numBytesSkipped = _bufferUsed - _bufferRead;
_bufferUsed = _bufferRead = 0;
// Skip rest of bytes in slave stream
ssize_t slaveSkipped = _in->Skip(skipNBytes - numBytesSkipped);
if (slaveSkipped < 0) {
if (numBytesSkipped > 0) {
_nextWillFail = true;
} else {
numBytesSkipped = slaveSkipped;
}
} else {
numBytesSkipped += slaveSkipped;
}
} else {
// Skip all skipNBytes in buffer
_bufferRead += skipNBytes;
if (_bufferRead == _bufferUsed) {
_bufferUsed = _bufferRead = 0;
}
numBytesSkipped = skipNBytes;
}
return numBytesSkipped;
}
ssize_t
Fast_BufferedInputStream::Read(void *targetBuffer, size_t length)
{
// This function will under no circumstance read more than once from
// its slave stream, in order to prevent blocking on input.
if (_nextWillFail) {
_nextWillFail = false;
return -1;
}
ssize_t numBytesRead = 0;
char* to = static_cast<char*>(targetBuffer);
size_t bufferRemain = _bufferUsed - _bufferRead;
if (length <= bufferRemain) {
memcpy(to, &_buffer[_bufferRead], length);
numBytesRead += length;
_bufferRead += length;
if (_bufferRead == _bufferUsed) {
_bufferRead = _bufferUsed = 0;
}
} else {
// Use the data currently in the buffer, then read from slave stream.
if (bufferRemain > 0) {
memcpy(to, &_buffer[_bufferRead], bufferRemain);
numBytesRead += bufferRemain;
length -= bufferRemain;
to += bufferRemain;
}
_bufferUsed = 0;
_bufferRead = 0;
ssize_t slaveRead;
// If remaining data to be read can fit in the buffer, put it
// there, otherwise read directly to receiver and empty the buffer.
if (length < _bufferSize) {
slaveRead = Fast_FilterInputStream::Read(_buffer, _bufferSize);
} else {
slaveRead = Fast_FilterInputStream::Read(to, length);
}
if (slaveRead > 0) {
if (length < _bufferSize) {
// We read to buffer, so copy from buffer to receiver.
if (length < static_cast<size_t>(slaveRead)) {
memcpy(to, _buffer, length);
numBytesRead += length;
_bufferUsed = slaveRead;
_bufferRead = length;
} else {
memcpy(to, _buffer, slaveRead);
numBytesRead += slaveRead;
}
} else {
// We read directly to receiver, no need to copy.
numBytesRead += slaveRead;
}
} else if (slaveRead == 0) {
// Do nothing
} else {
// slaveRead < 0, so an error occurred while reading from the
// slave. If there was data in the buffer, report success and
// fail on next operation instead.
if (numBytesRead > 0) {
_nextWillFail = true;
} else {
numBytesRead = slaveRead;
}
}
} // End of slave read
return numBytesRead;
}
ssize_t
Fast_BufferedInputStream::ReadBufferFullUntil(void *targetBuffer, size_t maxlength, char stopChar)
{
if (maxlength > _bufferSize)
maxlength = _bufferSize;
// This function will under no circumstance read more than once from
// its slave stream, in order to prevent blocking on input.
if (_nextWillFail) {
_nextWillFail = false;
return -1;
}
uint32_t offset = 0;
ssize_t numBytesRead = 0;
char* to = static_cast<char*>(targetBuffer);
size_t bufferRemain = _bufferUsed - _bufferRead;
// Check if we should scan for stopChar in buffer
if (bufferRemain > 0) {
for (offset = _bufferRead; offset < _bufferUsed; offset++) {
if(_buffer[offset] == stopChar) {
break;
}
}
// Found character in buffer
if (offset < _bufferUsed) {
maxlength = offset - _bufferRead + 1;
}
}
if (maxlength <= bufferRemain) {
memcpy(to, &_buffer[_bufferRead], maxlength);
numBytesRead += maxlength;
_bufferRead += maxlength;
if (_bufferRead == _bufferUsed) {
_bufferRead = _bufferUsed = 0;
}
} else {
// Use the data currently in the buffer, then read from slave stream.
if (bufferRemain > 0) {
memcpy(to, &_buffer[_bufferRead], bufferRemain);
numBytesRead += bufferRemain;
maxlength -= bufferRemain;
to += bufferRemain;
}
_bufferUsed = 0;
_bufferRead = 0;
ssize_t slaveRead;
slaveRead = Fast_FilterInputStream::Read(_buffer, _bufferSize);
if (slaveRead > 0) {
for (offset = 0; offset < static_cast<uint32_t>(slaveRead); offset++) {
if(_buffer[offset] == stopChar) {
break;
}
}
if (offset >= maxlength) {
// Discard data if character was not present
numBytesRead = -1;
} else {
// Found character in buffer
if (offset < static_cast<uint32_t>(slaveRead)) {
maxlength = offset + 1;
}
// We read to buffer, so copy from buffer to receiver.
if (maxlength < static_cast<size_t>(slaveRead)) {
memcpy(to, _buffer, maxlength);
numBytesRead += maxlength;
_bufferUsed = slaveRead;
_bufferRead = maxlength;
} else {
memcpy(to, _buffer, slaveRead);
numBytesRead += slaveRead;
}
}
} else if (slaveRead == 0) {
// Do nothing
} else {
// slaveRead < 0, so an error occurred while reading from the
// slave. If there was data in the buffer, report success and
// fail on next operation instead.
if (numBytesRead > 0) {
_nextWillFail = true;
} else {
numBytesRead = slaveRead;
}
}
} // End of slave read
return numBytesRead;
}
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