--- a/lib/Protobuf-PHP/library/DrSlump/Protobuf/Codec/Binary/Writer.php +++ b/lib/Protobuf-PHP/library/DrSlump/Protobuf/Codec/Binary/Writer.php @@ -1,1 +1,318 @@ - +<?php + +namespace DrSlump\Protobuf\Codec\Binary; + +/** + * Implements writing primitives for Protobuf binary streams + * + * @note Protobuf uses little-endian order + */ +class Writer +{ + /** @var resource */ + protected $_fd; + + + public function __construct() + { + $this->_fd = fopen('php://memory', 'wb'); + } + + public function __destruct() + { + fclose($this->_fd); + } + + /** + * Get the current bytes in the stream + * + * @return string + */ + public function getBytes() + { + fseek($this->_fd, 0, SEEK_SET); + return stream_get_contents($this->_fd); + } + + /** + * Store the given bytes in the stream + * + * @throws \RuntimeException + * @param string $bytes + * @param int $length + */ + public function write($bytes, $length = null) + { + if ($length === NULL) { + $length = strlen($bytes); + } + + $written = fwrite($this->_fd, $bytes, $length); + if ($written !== $length) { + throw new \RuntimeException('Failed to write ' . $length . ' bytes'); + } + } + + /** + * Store a single byte + * + * @param int $value + */ + public function byte($value) + { + $this->write(chr($value), 1); + } + + /** + * Store an integer encoded as varint + * + * @throws \OutOfBoundsException + * @param int $value + */ + public function varint($value) + { + // Small values do not need to be encoded + if ($value >= 0 && $value < 0x80) { + $this->byte($value); + return; + } + + // Build an array of bytes with the encoded values + if ($value > 0) { + $values = array(); + while ($value > 0) { + $values[] = 0x80 | ($value & 0x7f); + $value = $value >> 7; + } + } else if (function_exists('gmp_init')) { + $value = PHP_INT_SIZE < 8 + ? gmp_and($value, '0x0ffffffffffffffff') + : sprintf('%u', $value); + + $values = $this->varint_gmp($value); + } else if (PHP_INT_SIZE < 8) { + throw new \OutOfBoundsException( + "PHP versions compiled with 32bit integers can only support negative integer encoding with GMP extension ($value was given)" + ); + } else if (function_exists('bccomp')) { + $value = sprintf('%u', $value); + $values = $this->varint_bc($value); + } else { + throw new \OutOfBoundsException("Varints of negative integers are only supported with GMP or BC big integers PHP extensions ($value was given)"); + } + + // Remove the MSB flag from the last byte + $values[count($values)-1] &= 0x7f; + + // Convert the byte sized ints to actual bytes in a string + //$bytes = implode('', array_map('chr', $values)); + $bytes = call_user_func_array('pack', array_merge(array('C*'), $values));; + + $this->write($bytes); + } + + public function varint_gmp($value) + { + static $x00, $x7f, $x80; + + if (NULL === $x00) { + $x00 = \gmp_init(0x00); + $x7f = \gmp_init(0x7f); + $x80 = \gmp_init(0x80); + } + + $values = array(); + while (\gmp_cmp($value, $x00) > 0) { + $values[] = \gmp_intval(\gmp_and($value, $x7f)) | 0x80; + $value = \gmp_div_q($value, $x80); + } + + return $values; + } + + public function varint_bc($value) + { + $values = array(); + while (\bccomp($value, 0, 0) > 0) { + // Get the last 7bits of the number + $bin = ''; + $dec = $value; + do { + $rest = bcmod($dec, 2); + $dec = bcdiv($dec, 2, 0); + $bin = $rest . $bin; + } while ($dec > 0 && strlen($bin) < 7); + + // Pack as a decimal and apply the flag + $values[] = intval($bin, 2) | 0x80; + + $value = bcdiv($value, 0x80, 0); + } + + return $values; + } + + /** + * Encodes an integer with zigzag + * + * @param int $value + * @param int $base Either 32 or 64 bits + */ + public function zigzag($value, $base = 32) + { + $value = ($value << 1) ^ ($value >> $base-1); + $this->varint($value); + } + + /** + * Encode an integer as a fixed of 32bits with sign + * + * @param int $value + */ + public function sFixed32($value) + { + $bytes = pack('l*', $value); + if ($this->isBigEndian()) { + $bytes = strrev($bytes); + } + + $this->write($bytes, 4); + } + + /** + * Encode an integer as a fixed of 32bits without sign + * + * @param int $value + */ + public function fixed32($value) + { + $bytes = pack('V*', $value); + $this->write($bytes, 4); + } + + /** + * Encode an integer as a fixed of 64bits with sign + * + * @param int $value + */ + public function sFixed64($value) + { + if ($value >= 0) { + $this->fixed64($value); + } else if (function_exists('gmp_init')) { + $this->sFixed64_gmp($value); + } else if (function_exists('bcadd')) { + $this->sFixed64_bc($value); + } else { + throw new \OutOfBoundsException("The signed Fixed64 type with negative integers is only supported with GMP or BC big integers PHP extensions ($value was given)"); + } + } + + public function sFixed64_gmp($value) + { + static $xff, $x100; + + if (NULL === $xff) { + $xff = gmp_init(0xff); + $x100 = gmp_init(0x100); + } + + $value = PHP_INT_SIZE < 8 + ? gmp_and($value, '0x0ffffffffffffffff') + : gmp_init(sprintf('%u', $value)); + + $bytes = ''; + for ($i=0; $i<8; $i++) { + $bytes .= chr(gmp_intval(gmp_and($value, $xff))); + $value = gmp_div_q($value, $x100); + } + + $this->write($bytes); + } + + public function sFixed64_bc($value) + { + if (PHP_INT_SIZE < 8) { + throw new \OutOfBoundsException( + "PHP versions compiled with 32bit integers can only support negative integer encoding with GMP extension ($value was given)" + ); + } + + $value = sprintf('%u', $value); + + $bytes = ''; + for ($i=0; $i<8; $i++) { + // Get the last 8bits of the number + $bin = ''; + $dec = $value; + do { + $bin = bcmod($dec, 2) . $bin; + $dec = bcdiv($dec, 2, 0); + } while (strlen($bin) < 8); + + // Pack the byte + $bytes .= chr(intval($bin, 2)); + + $value = bcdiv($value, 0x100, 0); + } + + $this->write($bytes); + } + + /** + * Encode an integer as a fixed of 64bits without sign + * + * @param int $value + */ + public function fixed64($value) + { + $bytes = pack('V*', $value & 0xffffffff, $value / (0xffffffff+1)); + $this->write($bytes, 8); + } + + /** + * Encode a number as a 32bit float + * + * @param float $value + */ + public function float($value) + { + $bytes = pack('f*', $value); + if ($this->isBigEndian()) { + $bytes = strrev($bytes); + } + $this->write($bytes, 4); + } + + /** + * Encode a number as a 64bit double + * + * @param float $value + */ + public function double($value) + { + $bytes = pack('d*', $value); + if ($this->isBigEndian()) { + $bytes = strrev($bytes); + } + $this->write($bytes, 8); + } + + /** + * Checks if the current architecture is Big Endian + * + * @return bool + */ + public function isBigEndian() + { + static $endianness; + + if (NULL === $endianness) { + list(,$result) = unpack('L', pack('V', 1)); + $endianness = $result !== 1; + } + + return $endianness; + } +} +