--- /dev/null
+<?php
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * Classes for reading and writing Avro data to AvroIO objects.
+ *
+ * @package Avro
+ *
+ * @todo Implement JSON encoding, as is required by the Avro spec.
+ */
+
+/**
+ * Exceptions arising from writing or reading Avro data.
+ *
+ * @package Avro
+ */
+class AvroIOTypeException extends AvroException
+{
+ /**
+ * @param AvroSchema $expected_schema
+ * @param mixed $datum
+ */
+ public function __construct($expected_schema, $datum)
+ {
+ parent::__construct(sprintf('The datum %s is not an example of schema %s',
+ var_export($datum, true), $expected_schema));
+ }
+}
+
+/**
+ * Exceptions arising from incompatibility between
+ * reader and writer schemas.
+ *
+ * @package Avro
+ */
+class AvroIOSchemaMatchException extends AvroException
+{
+ /**
+ * @param AvroSchema $writers_schema
+ * @param AvroSchema $readers_schema
+ */
+ function __construct($writers_schema, $readers_schema)
+ {
+ parent::__construct(
+ sprintf("Writer's schema %s and Reader's schema %s do not match.",
+ $writers_schema, $readers_schema));
+ }
+}
+
+/**
+ * Handles schema-specific writing of data to the encoder.
+ *
+ * Ensures that each datum written is consistent with the writer's schema.
+ *
+ * @package Avro
+ */
+class AvroIODatumWriter
+{
+ /**
+ * Schema used by this instance to write Avro data.
+ * @var AvroSchema
+ */
+ private $writers_schema;
+
+ /**
+ * @param AvroSchema $writers_schema
+ */
+ function __construct($writers_schema=null)
+ {
+ $this->writers_schema = $writers_schema;
+ }
+
+ /**
+ * @param AvroSchema $writers_schema
+ * @param $datum
+ * @param AvroIOBinaryEncoder $encoder
+ * @returns mixed
+ *
+ * @throws AvroIOTypeException if $datum is invalid for $writers_schema
+ */
+ function write_data($writers_schema, $datum, $encoder)
+ {
+ if (!AvroSchema::is_valid_datum($writers_schema, $datum))
+ throw new AvroIOTypeException($writers_schema, $datum);
+
+ switch ($writers_schema->type())
+ {
+ case AvroSchema::NULL_TYPE:
+ return $encoder->write_null($datum);
+ case AvroSchema::BOOLEAN_TYPE:
+ return $encoder->write_boolean($datum);
+ case AvroSchema::INT_TYPE:
+ return $encoder->write_int($datum);
+ case AvroSchema::LONG_TYPE:
+ return $encoder->write_long($datum);
+ case AvroSchema::FLOAT_TYPE:
+ return $encoder->write_float($datum);
+ case AvroSchema::DOUBLE_TYPE:
+ return $encoder->write_double($datum);
+ case AvroSchema::STRING_TYPE:
+ return $encoder->write_string($datum);
+ case AvroSchema::BYTES_TYPE:
+ return $encoder->write_bytes($datum);
+ case AvroSchema::ARRAY_SCHEMA:
+ return $this->write_array($writers_schema, $datum, $encoder);
+ case AvroSchema::MAP_SCHEMA:
+ return $this->write_map($writers_schema, $datum, $encoder);
+ case AvroSchema::FIXED_SCHEMA:
+ return $this->write_fixed($writers_schema, $datum, $encoder);
+ case AvroSchema::ENUM_SCHEMA:
+ return $this->write_enum($writers_schema, $datum, $encoder);
+ case AvroSchema::RECORD_SCHEMA:
+ case AvroSchema::ERROR_SCHEMA:
+ case AvroSchema::REQUEST_SCHEMA:
+ return $this->write_record($writers_schema, $datum, $encoder);
+ case AvroSchema::UNION_SCHEMA:
+ return $this->write_union($writers_schema, $datum, $encoder);
+ default:
+ throw new AvroException(sprintf('Uknown type: %s',
+ $writers_schema->type));
+ }
+ }
+
+ /**
+ * @param $datum
+ * @param AvroIOBinaryEncoder $encoder
+ */
+ function write($datum, $encoder)
+ {
+ $this->write_data($this->writers_schema, $datum, $encoder);
+ }
+
+ /**#@+
+ * @param AvroSchema $writers_schema
+ * @param null|boolean|int|float|string|array $datum item to be written
+ * @param AvroIOBinaryEncoder $encoder
+ */
+ private function write_array($writers_schema, $datum, $encoder)
+ {
+ $datum_count = count($datum);
+ if (0 < $datum_count)
+ {
+ $encoder->write_long($datum_count);
+ $items = $writers_schema->items();
+ foreach ($datum as $item)
+ $this->write_data($items, $item, $encoder);
+ }
+ return $encoder->write_long(0);
+ }
+
+ private function write_map($writers_schema, $datum, $encoder)
+ {
+ $datum_count = count($datum);
+ if ($datum_count > 0)
+ {
+ $encoder->write_long($datum_count);
+ foreach ($datum as $k => $v)
+ {
+ $encoder->write_string($k);
+ $this->write_data($writers_schema->values(), $v, $encoder);
+ }
+ }
+ $encoder->write_long(0);
+ }
+
+ private function write_union($writers_schema, $datum, $encoder)
+ {
+ $datum_schema_index = -1;
+ $datum_schema = null;
+ foreach ($writers_schema->schemas() as $index => $schema)
+ if (AvroSchema::is_valid_datum($schema, $datum))
+ {
+ $datum_schema_index = $index;
+ $datum_schema = $schema;
+ break;
+ }
+
+ if (is_null($datum_schema))
+ throw new AvroIOTypeException($writers_schema, $datum);
+
+ $encoder->write_long($datum_schema_index);
+ $this->write_data($datum_schema, $datum, $encoder);
+ }
+
+ private function write_enum($writers_schema, $datum, $encoder)
+ {
+ $datum_index = $writers_schema->symbol_index($datum);
+ return $encoder->write_int($datum_index);
+ }
+
+ private function write_fixed($writers_schema, $datum, $encoder)
+ {
+ /**
+ * NOTE Unused $writers_schema parameter included for consistency
+ * with other write_* methods.
+ */
+ return $encoder->write($datum);
+ }
+
+ private function write_record($writers_schema, $datum, $encoder)
+ {
+ foreach ($writers_schema->fields() as $field)
+ $this->write_data($field->type(), $datum[$field->name()], $encoder);
+ }
+
+ /**#@-*/
+}
+
+/**
+ * Encodes and writes Avro data to an AvroIO object using
+ * Avro binary encoding.
+ *
+ * @package Avro
+ */
+class AvroIOBinaryEncoder
+{
+ /**
+ * Performs encoding of the given float value to a binary string
+ *
+ * XXX: This is <b>not</b> endian-aware! The {@link Avro::check_platform()}
+ * called in {@link AvroIOBinaryEncoder::__construct()} should ensure the
+ * library is only used on little-endian platforms, which ensure the little-endian
+ * encoding required by the Avro spec.
+ *
+ * @param float $float
+ * @returns string bytes
+ * @see Avro::check_platform()
+ */
+ static function float_to_int_bits($float)
+ {
+ return pack('f', (float) $float);
+ }
+
+ /**
+ * Performs encoding of the given double value to a binary string
+ *
+ * XXX: This is <b>not</b> endian-aware! See comments in
+ * {@link AvroIOBinaryEncoder::float_to_int_bits()} for details.
+ *
+ * @param double $double
+ * @returns string bytes
+ */
+ static function double_to_long_bits($double)
+ {
+ return pack('d', (double) $double);
+ }
+
+ /**
+ * @param int|string $n
+ * @returns string long $n encoded as bytes
+ * @internal This relies on 64-bit PHP.
+ */
+ static public function encode_long($n)
+ {
+ $n = (int) $n;
+ $n = ($n << 1) ^ ($n >> 63);
+ $str = '';
+ while (0 != ($n & ~0x7F))
+ {
+ $str .= chr(($n & 0x7F) | 0x80);
+ $n >>= 7;
+ }
+ $str .= chr($n);
+ return $str;
+ }
+
+ /**
+ * @var AvroIO
+ */
+ private $io;
+
+ /**
+ * @param AvroIO $io object to which data is to be written.
+ *
+ */
+ function __construct($io)
+ {
+ Avro::check_platform();
+ $this->io = $io;
+ }
+
+ /**
+ * @param null $datum actual value is ignored
+ */
+ function write_null($datum) { return null; }
+
+ /**
+ * @param boolean $datum
+ */
+ function write_boolean($datum)
+ {
+ $byte = $datum ? chr(1) : chr(0);
+ $this->write($byte);
+ }
+
+ /**
+ * @param int $datum
+ */
+ function write_int($datum) { $this->write_long($datum); }
+
+ /**
+ * @param int $n
+ */
+ function write_long($n)
+ {
+ if (Avro::uses_gmp())
+ $this->write(AvroGMP::encode_long($n));
+ else
+ $this->write(self::encode_long($n));
+ }
+
+ /**
+ * @param float $datum
+ * @uses self::float_to_int_bits()
+ */
+ public function write_float($datum)
+ {
+ $this->write(self::float_to_int_bits($datum));
+ }
+
+ /**
+ * @param float $datum
+ * @uses self::double_to_long_bits()
+ */
+ public function write_double($datum)
+ {
+ $this->write(self::double_to_long_bits($datum));
+ }
+
+ /**
+ * @param string $str
+ * @uses self::write_bytes()
+ */
+ function write_string($str) { $this->write_bytes($str); }
+
+ /**
+ * @param string $bytes
+ */
+ function write_bytes($bytes)
+ {
+ $this->write_long(strlen($bytes));
+ $this->write($bytes);
+ }
+
+ /**
+ * @param string $datum
+ */
+ function write($datum) { $this->io->write($datum); }
+}
+
+/**
+ * Handles schema-specifc reading of data from the decoder.
+ *
+ * Also handles schema resolution between the reader and writer
+ * schemas (if a writer's schema is provided).
+ *
+ * @package Avro
+ */
+class AvroIODatumReader
+{
+ /**
+ *
+ * @param AvroSchema $writers_schema
+ * @param AvroSchema $readers_schema
+ * @returns boolean true if the schemas are consistent with
+ * each other and false otherwise.
+ */
+ static function schemas_match($writers_schema, $readers_schema)
+ {
+ $writers_schema_type = $writers_schema->type;
+ $readers_schema_type = $readers_schema->type;
+
+ if (AvroSchema::UNION_SCHEMA == $writers_schema_type
+ || AvroSchema::UNION_SCHEMA == $readers_schema_type)
+ return true;
+
+ if ($writers_schema_type == $readers_schema_type)
+ {
+ if (AvroSchema::is_primitive_type($writers_schema_type))
+ return true;
+
+ switch ($readers_schema_type)
+ {
+ case AvroSchema::MAP_SCHEMA:
+ return self::attributes_match($writers_schema->values(),
+ $readers_schema->values(),
+ array(AvroSchema::TYPE_ATTR));
+ case AvroSchema::ARRAY_SCHEMA:
+ return self::attributes_match($writers_schema->items(),
+ $readers_schema->items(),
+ array(AvroSchema::TYPE_ATTR));
+ case AvroSchema::ENUM_SCHEMA:
+ return self::attributes_match($writers_schema, $readers_schema,
+ array(AvroSchema::FULLNAME_ATTR));
+ case AvroSchema::FIXED_SCHEMA:
+ return self::attributes_match($writers_schema, $readers_schema,
+ array(AvroSchema::FULLNAME_ATTR,
+ AvroSchema::SIZE_ATTR));
+ case AvroSchema::RECORD_SCHEMA:
+ case AvroSchema::ERROR_SCHEMA:
+ return self::attributes_match($writers_schema, $readers_schema,
+ array(AvroSchema::FULLNAME_ATTR));
+ case AvroSchema::REQUEST_SCHEMA:
+ // XXX: This seems wrong
+ return true;
+ // XXX: no default
+ }
+
+ if (AvroSchema::INT_TYPE == $writers_schema_type
+ && in_array($readers_schema_type, array(AvroSchema::LONG_TYPE,
+ AvroSchema::FLOAT_TYPE,
+ AvroSchema::DOUBLE_TYPE)))
+ return true;
+
+ if (AvroSchema::LONG_TYPE == $writers_schema_type
+ && in_array($readers_schema_type, array(AvroSchema::FLOAT_TYPE,
+ AvroSchema::DOUBLE_TYPE)))
+ return true;
+
+ if (AvroSchema::FLOAT_TYPE == $writers_schema_type
+ && AvroSchema::DOUBLE_TYPE == $readers_schema_type)
+ return true;
+
+ return false;
+ }
+
+ }
+
+ /**
+ * Checks equivalence of the given attributes of the two given schemas.
+ *
+ * @param AvroSchema $schema_one
+ * @param AvroSchema $schema_two
+ * @param string[] $attribute_names array of string attribute names to compare
+ *
+ * @returns boolean true if the attributes match and false otherwise.
+ */
+ static function attributes_match($schema_one, $schema_two, $attribute_names)
+ {
+ foreach ($attribute_names as $attribute_name)
+ if ($schema_one->attribute($attribute_name)
+ != $schema_two->attribute($attribute_name))
+ return false;
+ return true;
+ }
+
+ /**
+ * @var AvroSchema
+ */
+ private $writers_schema;
+
+ /**
+ * @var AvroSchema
+ */
+ private $readers_schema;
+
+ /**
+ * @param AvroSchema $writers_schema
+ * @param AvroSchema $readers_schema
+ */
+ function __construct($writers_schema=null, $readers_schema=null)
+ {
+ $this->writers_schema = $writers_schema;
+ $this->readers_schema = $readers_schema;
+ }
+
+ /**
+ * @param AvroSchema $readers_schema
+ */
+ public function set_writers_schema($readers_schema)
+ {
+ $this->writers_schema = $readers_schema;
+ }
+
+ /**
+ * @param AvroIOBinaryDecoder $decoder
+ * @returns string
+ */
+ public function read($decoder)
+ {
+ if (is_null($this->readers_schema))
+ $this->readers_schema = $this->writers_schema;
+ return $this->read_data($this->writers_schema, $this->readers_schema,
+ $decoder);
+ }
+
+ /**#@+
+ * @param AvroSchema $writers_schema
+ * @param AvroSchema $readers_schema
+ * @param AvroIOBinaryDecoder $decoder
+ */
+ /**
+ * @returns mixed
+ */
+ public function read_data($writers_schema, $readers_schema, $decoder)
+ {
+ if (!self::schemas_match($writers_schema, $readers_schema))
+ throw new AvroIOSchemaMatchException($writers_schema, $readers_schema);
+
+ // Schema resolution: reader's schema is a union, writer's schema is not
+ if (AvroSchema::UNION_SCHEMA == $readers_schema->type()
+ && AvroSchema::UNION_SCHEMA != $writers_schema->type())
+ {
+ foreach ($readers_schema->schemas() as $schema)
+ if (self::schemas_match($writers_schema, $schema))
+ return $this->read_data($writers_schema, $schema, $decoder);
+ throw new AvroIOSchemaMatchException($writers_schema, $readers_schema);
+ }
+
+ switch ($writers_schema->type())
+ {
+ case AvroSchema::NULL_TYPE:
+ return $decoder->read_null();
+ case AvroSchema::BOOLEAN_TYPE:
+ return $decoder->read_boolean();
+ case AvroSchema::INT_TYPE:
+ return $decoder->read_int();
+ case AvroSchema::LONG_TYPE:
+ return $decoder->read_long();
+ case AvroSchema::FLOAT_TYPE:
+ return $decoder->read_float();
+ case AvroSchema::DOUBLE_TYPE:
+ return $decoder->read_double();
+ case AvroSchema::STRING_TYPE:
+ return $decoder->read_string();
+ case AvroSchema::BYTES_TYPE:
+ return $decoder->read_bytes();
+ case AvroSchema::ARRAY_SCHEMA:
+ return $this->read_array($writers_schema, $readers_schema, $decoder);
+ case AvroSchema::MAP_SCHEMA:
+ return $this->read_map($writers_schema, $readers_schema, $decoder);
+ case AvroSchema::UNION_SCHEMA:
+ return $this->read_union($writers_schema, $readers_schema, $decoder);
+ case AvroSchema::ENUM_SCHEMA:
+ return $this->read_enum($writers_schema, $readers_schema, $decoder);
+ case AvroSchema::FIXED_SCHEMA:
+ return $this->read_fixed($writers_schema, $readers_schema, $decoder);
+ case AvroSchema::RECORD_SCHEMA:
+ case AvroSchema::ERROR_SCHEMA:
+ case AvroSchema::REQUEST_SCHEMA:
+ return $this->read_record($writers_schema, $readers_schema, $decoder);
+ default:
+ throw new AvroException(sprintf("Cannot read unknown schema type: %s",
+ $writers_schema->type()));
+ }
+ }
+
+ /**
+ * @returns array
+ */
+ public function read_array($writers_schema, $readers_schema, $decoder)
+ {
+ $items = array();
+ $block_count = $decoder->read_long();
+ while (0 != $block_count)
+ {
+ if ($block_count < 0)
+ {
+ $block_count = -$block_count;
+ $block_size = $decoder->read_long(); // Read (and ignore) block size
+ }
+ for ($i = 0; $i < $block_count; $i++)
+ $items []= $this->read_data($writers_schema->items(),
+ $readers_schema->items(),
+ $decoder);
+ $block_count = $decoder->read_long();
+ }
+ return $items;
+ }
+
+ /**
+ * @returns array
+ */
+ public function read_map($writers_schema, $readers_schema, $decoder)
+ {
+ $items = array();
+ $pair_count = $decoder->read_long();
+ while (0 != $pair_count)
+ {
+ if ($pair_count < 0)
+ {
+ $pair_count = -$pair_count;
+ // Note: we're not doing anything with block_size other than skipping it
+ $block_size = $decoder->read_long();
+ }
+
+ for ($i = 0; $i < $pair_count; $i++)
+ {
+ $key = $decoder->read_string();
+ $items[$key] = $this->read_data($writers_schema->values(),
+ $readers_schema->values(),
+ $decoder);
+ }
+ $pair_count = $decoder->read_long();
+ }
+ return $items;
+ }
+
+ /**
+ * @returns mixed
+ */
+ public function read_union($writers_schema, $readers_schema, $decoder)
+ {
+ $schema_index = $decoder->read_long();
+ $selected_writers_schema = $writers_schema->schema_by_index($schema_index);
+ return $this->read_data($selected_writers_schema, $readers_schema, $decoder);
+ }
+
+ /**
+ * @returns string
+ */
+ public function read_enum($writers_schema, $readers_schema, $decoder)
+ {
+ $symbol_index = $decoder->read_int();
+ $symbol = $writers_schema->symbol_by_index($symbol_index);
+ if (!$readers_schema->has_symbol($symbol))
+ null; // FIXME: unset wrt schema resolution
+ return $symbol;
+ }
+
+ /**
+ * @returns string
+ */
+ public function read_fixed($writers_schema, $readers_schema, $decoder)
+ {
+ return $decoder->read($writers_schema->size());
+ }
+
+ /**
+ * @returns array
+ */
+ public function read_record($writers_schema, $readers_schema, $decoder)
+ {
+ $readers_fields = $readers_schema->fields_hash();
+ $record = array();
+ foreach ($writers_schema->fields() as $writers_field)
+ {
+ $type = $writers_field->type();
+ if (isset($readers_fields[$writers_field->name()]))
+ $record[$writers_field->name()]
+ = $this->read_data($type,
+ $readers_fields[$writers_field->name()]->type(),
+ $decoder);
+ else
+ $this->skip_data($type, $decoder);
+ }
+ // Fill in default values
+ if (count($readers_fields) > count($record))
+ {
+ $writers_fields = $writers_schema->fields_hash();
+ foreach ($readers_fields as $field_name => $field)
+ {
+ if (!isset($writers_fields[$field_name]))
+ {
+ if ($field->has_default_value())
+ $record[$field->name()]
+ = $this->read_default_value($field->type(),
+ $field->default_value());
+ else
+ null; // FIXME: unset
+ }
+ }
+ }
+
+ return $record;
+ }
+ /**#@-*/
+
+ /**
+ * @param AvroSchema $field_schema
+ * @param null|boolean|int|float|string|array $default_value
+ * @returns null|boolean|int|float|string|array
+ *
+ * @throws AvroException if $field_schema type is unknown.
+ */
+ public function read_default_value($field_schema, $default_value)
+ {
+ switch($field_schema->type())
+ {
+ case AvroSchema::NULL_TYPE:
+ return null;
+ case AvroSchema::BOOLEAN_TYPE:
+ return $default_value;
+ case AvroSchema::INT_TYPE:
+ case AvroSchema::LONG_TYPE:
+ return (int) $default_value;
+ case AvroSchema::FLOAT_TYPE:
+ case AvroSchema::DOUBLE_TYPE:
+ return (float) $default_value;
+ case AvroSchema::STRING_TYPE:
+ case AvroSchema::BYTES_TYPE:
+ return $default_value;
+ case AvroSchema::ARRAY_SCHEMA:
+ $array = array();
+ foreach ($default_value as $json_val)
+ {
+ $val = $this->read_default_value($field_schema->items(), $json_val);
+ $array []= $val;
+ }
+ return $array;
+ case AvroSchema::MAP_SCHEMA:
+ $map = array();
+ foreach ($default_value as $key => $json_val)
+ $map[$key] = $this->read_default_value($field_schema->values(),
+ $json_val);
+ return $map;
+ case AvroSchema::UNION_SCHEMA:
+ return $this->read_default_value($field_schema->schema_by_index(0),
+ $default_value);
+ case AvroSchema::ENUM_SCHEMA:
+ case AvroSchema::FIXED_SCHEMA:
+ return $default_value;
+ case AvroSchema::RECORD_SCHEMA:
+ $record = array();
+ foreach ($field_schema->fields() as $field)
+ {
+ $field_name = $field->name();
+ if (!$json_val = $default_value[$field_name])
+ $json_val = $field->default_value();
+
+ $record[$field_name] = $this->read_default_value($field->type(),
+ $json_val);
+ }
+ return $record;
+ default:
+ throw new AvroException(sprintf('Unknown type: %s', $field_schema->type()));
+ }
+ }
+
+ /**
+ * @param AvroSchema $writers_schema
+ * @param AvroIOBinaryDecoder $decoder
+ */
+ private function skip_data($writers_schema, $decoder)
+ {
+ switch ($writers_schema->type())
+ {
+ case AvroSchema::NULL_TYPE:
+ return $decoder->skip_null();
+ case AvroSchema::BOOLEAN_TYPE:
+ return $decoder->skip_boolean();
+ case AvroSchema::INT_TYPE:
+ return $decoder->skip_int();
+ case AvroSchema::LONG_TYPE:
+ return $decoder->skip_long();
+ case AvroSchema::FLOAT_TYPE:
+ return $decoder->skip_float();
+ case AvroSchema::DOUBLE_TYPE:
+ return $decoder->skip_double();
+ case AvroSchema::STRING_TYPE:
+ return $decoder->skip_string();
+ case AvroSchema::BYTES_TYPE:
+ return $decoder->skip_bytes();
+ case AvroSchema::ARRAY_SCHEMA:
+ return $decoder->skip_array($writers_schema, $decoder);
+ case AvroSchema::MAP_SCHEMA:
+ return $decoder->skip_map($writers_schema, $decoder);
+ case AvroSchema::UNION_SCHEMA:
+ return $decoder->skip_union($writers_schema, $decoder);
+ case AvroSchema::ENUM_SCHEMA:
+ return $decoder->skip_enum($writers_schema, $decoder);
+ case AvroSchema::FIXED_SCHEMA:
+ return $decoder->skip_fixed($writers_schema, $decoder);
+ case AvroSchema::RECORD_SCHEMA:
+ case AvroSchema::ERROR_SCHEMA:
+ case AvroSchema::REQUEST_SCHEMA:
+ return $decoder->skip_record($writers_schema, $decoder);
+ default:
+ throw new AvroException(sprintf('Uknown schema type: %s',
+ $writers_schema->type()));
+ }
+ }
+}
+
+/**
+ * Decodes and reads Avro data from an AvroIO object encoded using
+ * Avro binary encoding.
+ *
+ * @package Avro
+ */
+class AvroIOBinaryDecoder
+{
+
+ /**
+ * @param int[] array of byte ascii values
+ * @returns long decoded value
+ * @internal Requires 64-bit platform
+ */
+ public static function decode_long_from_array($bytes)
+ {
+ $b = array_shift($bytes);
+ $n = $b & 0x7f;
+ $shift = 7;
+ while (0 != ($b & 0x80))
+ {
+ $b = array_shift($bytes);
+ $n |= (($b & 0x7f) << $shift);
+ $shift += 7;
+ }
+ return (($n >> 1) ^ -($n & 1));
+ }
+
+ /**
+ * Performs decoding of the binary string to a float value.
+ *
+ * XXX: This is <b>not</b> endian-aware! See comments in
+ * {@link AvroIOBinaryEncoder::float_to_int_bits()} for details.
+ *
+ * @param string $bits
+ * @returns float
+ */
+ static public function int_bits_to_float($bits)
+ {
+ $float = unpack('f', $bits);
+ return (float) $float[1];
+ }
+
+ /**
+ * Performs decoding of the binary string to a double value.
+ *
+ * XXX: This is <b>not</b> endian-aware! See comments in
+ * {@link AvroIOBinaryEncoder::float_to_int_bits()} for details.
+ *
+ * @param string $bits
+ * @returns float
+ */
+ static public function long_bits_to_double($bits)
+ {
+ $double = unpack('d', $bits);
+ return (double) $double[1];
+ }
+
+ /**
+ * @var AvroIO
+ */
+ private $io;
+
+ /**
+ * @param AvroIO $io object from which to read.
+ */
+ public function __construct($io)
+ {
+ Avro::check_platform();
+ $this->io = $io;
+ }
+
+ /**
+ * @returns string the next byte from $this->io.
+ * @throws AvroException if the next byte cannot be read.
+ */
+ private function next_byte() { return $this->read(1); }
+
+ /**
+ * @returns null
+ */
+ public function read_null() { return null; }
+
+ /**
+ * @returns boolean
+ */
+ public function read_boolean()
+ {
+ return (boolean) (1 == ord($this->next_byte()));
+ }
+
+ /**
+ * @returns int
+ */
+ public function read_int() { return (int) $this->read_long(); }
+
+ /**
+ * @returns long
+ */
+ public function read_long()
+ {
+ $byte = ord($this->next_byte());
+ $bytes = array($byte);
+ while (0 != ($byte & 0x80))
+ {
+ $byte = ord($this->next_byte());
+ $bytes []= $byte;
+ }
+
+ if (Avro::uses_gmp())
+ return AvroGMP::decode_long_from_array($bytes);
+
+ return self::decode_long_from_array($bytes);
+ }
+
+ /**
+ * @returns float
+ */
+ public function read_float()
+ {
+ return self::int_bits_to_float($this->read(4));
+ }
+
+ /**
+ * @returns double
+ */
+ public function read_double()
+ {
+ return self::long_bits_to_double($this->read(8));
+ }
+
+ /**
+ * A string is encoded as a long followed by that many bytes
+ * of UTF-8 encoded character data.
+ * @returns string
+ */
+ public function read_string() { return $this->read_bytes(); }
+
+ /**
+ * @returns string
+ */
+ public function read_bytes() { return $this->read($this->read_long()); }
+
+ /**
+ * @param int $len count of bytes to read
+ * @returns string
+ */
+ public function read($len) { return $this->io->read($len); }
+
+ public function skip_null() { return null; }
+
+ public function skip_boolean() { return $this->skip(1); }
+
+ public function skip_int() { return $this->skip_long(); }
+
+ protected function skip_long()
+ {
+ $b = $this->next_byte();
+ while (0 != ($b & 0x80))
+ $b = $this->next_byte();
+ }
+
+ public function skip_float() { return $this->skip(4); }
+
+ public function skip_double() { return $this->skip(8); }
+
+ public function skip_bytes() { return $this->skip($this->read_long()); }
+
+ public function skip_string() { return $this->skip_bytes(); }
+
+ /**
+ * @param int $len count of bytes to skip
+ * @uses AvroIO::seek()
+ */
+ public function skip($len) { $this->seek($len, AvroIO::SEEK_CUR); }
+
+ /**
+ * @returns int position of pointer in AvroIO instance
+ * @uses AvroIO::tell()
+ */
+ private function tell() { return $this->io->tell(); }
+
+ /**
+ * @param int $offset
+ * @param int $whence
+ * @returns boolean true upon success
+ * @uses AvroIO::seek()
+ */
+ private function seek($offset, $whence)
+ {
+ return $this->io->seek($offset, $whence);
+ }
+}
+
scripts.mit.edu / autoinstallsdev / mediawiki.git / blobdiff