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<?php
namespace Protobuf\Binary;
use Protobuf\Binary\Platform\BigEndian;
use Protobuf\MessageInterface;
use Protobuf\Configuration;
use Protobuf\WireFormat;
use Protobuf\Unknown;
use Protobuf\Stream;
use RuntimeException;
/**
* Implements reading primitives for Protobuf binary streams.
*
* @author Iván Montes <drslump@pollinimini.net>
* @author Fabio B. Silva <fabio.bat.silva@gmail.com>
*/
class StreamReader
{
/**
* @var \Protobuf\Configuration
*/
protected $config;
/**
* @var \Protobuf\Stream
*/
protected $stream;
/**
* @var bool
*/
protected $isBigEndian;
/**
* Constructor
*
* @param \Protobuf\Configuration $config
*/
public function __construct(Configuration $config)
{
$this->config = $config;
$this->isBigEndian = BigEndian::isBigEndian();
}
/**
* Reads a byte.
*
* @param \Protobuf\Stream $stream
*
* @return integer
*/
public function readByte(Stream $stream)
{
$char = $stream->read(1);
$byte = ord($char);
return $byte;
}
/**
* Decode a varint.
*
* @param \Protobuf\Stream $stream
*
* @return integer
*/
public function readVarint(Stream $stream)
{
// Optimize common case (single byte varints)
$byte = $this->readByte($stream);
if ($byte < 0x80) {
return $byte;
}
$length = $stream->getSize();
$offset = $stream->tell();
$result = $byte & 0x7f;
$shift = 7;
// fastpath 32bit varints (5bytes) by unrolling the loop
if ($length - $offset >= 4) {
// 2
$byte = $this->readByte($stream);
$result |= ($byte & 0x7f) << 7;
if ($byte < 0x80) {
return $result;
}
// 3
$byte = $this->readByte($stream);
$result |= ($byte & 0x7f) << 14;
if ($byte < 0x80) {
return $result;
}
// 4
$byte = $this->readByte($stream);
$result |= ($byte & 0x7f) << 21;
if ($byte < 0x80) {
return $result;
}
// 5
$byte = $this->readByte($stream);
$result |= ($byte & 0x7f) << 28;
if ($byte < 0x80) {
return $result;
}
$shift = 35;
}
// If we're just at the end of the buffer or handling a 64bit varint
do {
$byte = $this->readByte($stream);
$result |= ($byte & 0x7f) << $shift;
$shift += 7;
} while ($byte > 0x7f);
return $result;
}
/**
* Decodes a zigzag integer of the given bits.
*
* @param \Protobuf\Stream $stream
*
* @return integer
*/
public function readZigzag(Stream $stream)
{
$number = $this->readVarint($stream);
$zigzag = ($number >> 1) ^ (-($number & 1));
return $zigzag;
}
/**
* Decode a fixed 32bit integer with sign.
*
* @param \Protobuf\Stream $stream
*
* @return integer
*/
public function readSFixed32(Stream $stream)
{
$bytes = $stream->read(4);
if ($this->isBigEndian) {
$bytes = strrev($bytes);
}
list(, $result) = unpack('l', $bytes);
return $result;
}
/**
* Decode a fixed 32bit integer without sign.
*
* @param \Protobuf\Stream $stream
*
* @return integer
*/
public function readFixed32(Stream $stream)
{
$bytes = $stream->read(4);
if (PHP_INT_SIZE < 8) {
list(, $lo, $hi) = unpack('v*', $bytes);
return $hi << 16 | $lo;
}
list(, $result) = unpack('V*', $bytes);
return $result;
}
/**
* Decode a fixed 64bit integer with sign.
*
* @param \Protobuf\Stream $stream
*
* @return integer
*/
public function readSFixed64(Stream $stream)
{
$bytes = $stream->read(8);
list(, $lo0, $lo1, $hi0, $hi1) = unpack('v*', $bytes);
return ($hi1 << 16 | $hi0) << 32 | ($lo1 << 16 | $lo0);
}
/**
* Decode a fixed 64bit integer without sign.
*
* @param \Protobuf\Stream $stream
*
* @return integer
*/
public function readFixed64(Stream $stream)
{
return $this->readSFixed64($stream);
}
/**
* Decode a 32bit float.
*
* @param \Protobuf\Stream $stream
*
* @return float
*/
public function readFloat(Stream $stream)
{
$bytes = $stream->read(4);
if ($this->isBigEndian) {
$bytes = strrev($bytes);
}
list(, $result) = unpack('f', $bytes);
return $result;
}
/**
* Decode a 64bit double.
*
* @param \Protobuf\Stream $stream
*
* @return float
*/
public function readDouble(Stream $stream)
{
$bytes = $stream->read(8);
if ($this->isBigEndian) {
$bytes = strrev($bytes);
}
list(, $result) = unpack('d', $bytes);
return $result;
}
/**
* Decode a bool.
*
* @param \Protobuf\Stream $stream
*
* @return bool
*/
public function readBool(Stream $stream)
{
return (bool) $this->readVarint($stream);
}
/**
* Decode a string.
*
* @param \Protobuf\Stream $stream
*
* @return string
*/
public function readString(Stream $stream)
{
$length = $this->readVarint($stream);
$string = $stream->read($length);
return $string;
}
/**
* Decode a stream of bytes.
*
* @param \Protobuf\Stream $stream
*
* @return \Protobuf\Stream
*/
public function readByteStream(Stream $stream)
{
$length = $this->readVarint($stream);
$value = $stream->readStream($length);
return $value;
}
/**
* Read unknown scalar value.
*
* @param \Protobuf\Stream $stream
* @param integer $wire
*
* @return scalar
*/
public function readUnknown(Stream $stream, $wire)
{
if ($wire === WireFormat::WIRE_VARINT) {
return $this->readVarint($stream);
}
if ($wire === WireFormat::WIRE_LENGTH) {
return $this->readString($stream);
}
if ($wire === WireFormat::WIRE_FIXED32) {
return $this->readFixed32($stream);
}
if ($wire === WireFormat::WIRE_FIXED64) {
return $this->readFixed64($stream);
}
if ($wire === WireFormat::WIRE_GROUP_START || $wire === WireFormat::WIRE_GROUP_END) {
throw new RuntimeException('Groups are deprecated in Protocol Buffers and unsupported.');
}
throw new RuntimeException("Unsupported wire type '$wire' while reading unknown field.");
}
}