def __init__(self, path, start=0, length=0):
self._block_compressed = False
self._decompress = False
self._sync_seen = False
self._value_class = None
self._key_class = None
self._codec = None
self._metadata = None
self._record = DataInputBuffer()
self._initialize(path, start, length)
def decompressInputStream(self, data):
return DataInputBuffer(self.decompress(data))
class Reader(object):
def __init__(self, path, start=0, length=0):
self._block_compressed = False
self._decompress = False
self._sync_seen = False
self._value_class = None
self._key_class = None
self._codec = None
self._metadata = None
self._record = DataInputBuffer()
self._initialize(path, start, length)
def getStream(self, path):
return DataInputStream(FileInputStream(path))
def close(self):
self._stream.close()
def getCompressionCodec(self):
return self._codec
def getKeyClass(self):
if not self._key_class:
self._key_class = hadoopClassFromName(self._key_class_name)
return self._key_class
def getKeyClassName(self):
return hadoopClassName(self.getKeyClass())
def getValueClass(self):
if not self._value_class:
self._value_class = hadoopClassFromName(self._value_class_name)
return self._value_class
def getValueClassName(self):
return hadoopClassName(self.getValueClass())
def getPosition(self):
return self._stream.getPos()
def getMetadata(self):
return self._metadata
def isBlockCompressed(self):
return self._block_compressed
def isCompressed(self):
return self._decompress
def nextRawKey(self):
if not self._block_compressed:
record_length = self._readRecordLength()
if record_length < 0:
return None
key_length = self._stream.readInt()
key = DataInputBuffer(self._stream.read(key_length))
self._record.reset(self._stream.read(record_length - key_length))
return key
else:
if hasattr(self, '_block_index') and \
self._block_index < self._record[0]:
self._sync_seen = False
records, keys_len, keys, values_len, values = self._record
key_length = readVInt(keys_len)
self._block_index += 1
return DataInputBuffer(keys.read(key_length))
if self._stream.getPos() >= self._end:
return None
# Read Sync
self._stream.readInt() # -1
sync_check = self._stream.read(SYNC_HASH_SIZE)
if sync_check != self._sync:
raise IOError("File is corrupt")
self._sync_seen = True
def _readBuffer():
length = readVInt(self._stream)
buf = self._stream.read(length)
return self._codec.decompressInputStream(buf)
records = readVInt(self._stream)
keys_len = _readBuffer()
keys = _readBuffer()
values_len = _readBuffer()
values = _readBuffer()
self._record = (records, keys_len, keys, values_len, values)
self._block_index = 1
key_length = readVInt(keys_len)
return DataInputBuffer(keys.read(key_length))
def nextKey(self, key):
buf = self.nextRawKey()
if not buf:
return False
key.readFields(buf)
return True
def nextRawValue(self):
if not self._block_compressed:
if self._decompress:
compress_data = self._record.read(self._record.size())
return self._codec.decompressInputStream(compress_data)
else:
return self._record
else:
records, keys_len, keys, values_len, values = self._record
value_length = readVInt(values_len)
return DataInputBuffer(values.read(value_length))
def next(self, key, value):
more = self.nextKey(key)
if more:
self._getCurrentValue(value)
return more
def seek(self, position):
self._stream.seek(position)
if self._block_compressed:
self._no_buffered_keys = 0
self._values_decompressed = True
def sync(self, position):
if (position + SYNC_SIZE) > self._end:
self.seek(self._end)
return
if position < self._header_end:
self._stream.seek(self._header_end)
self._sync_seen = True
return
self.seek(position + 4)
sync_check = [x for x in self._stream.read(SYNC_HASH_SIZE)]
i = 0
while self._stream.getPos() < self._end:
j = 0
while j < SYNC_HASH_SIZE:
if self._sync[j] != sync_check[(i + j) % SYNC_HASH_SIZE]:
break
j += 1
if j == SYNC_HASH_SIZE:
self._stream.seek(self._stream.getPos() - SYNC_SIZE)
return
sync_check[i % SYNC_HASH_SIZE] = chr(self._stream.readByte())
i += 1
def syncSeen(self):
return self._sync_seen
def _initialize(self, path, start, length):
self._stream = self.getStream(path)
if length == 0:
self._end = self._stream.getPos() + self._stream.length()
else:
self._end = self._stream.getPos() + length
# Parse Header
version_block = self._stream.read(len(VERSION))
if not version_block.startswith(VERSION_PREFIX):
raise VersionPrefixException(VERSION_PREFIX,
version_block[0:len(VERSION_PREFIX)])
self._version = version_block[len(VERSION_PREFIX)]
if self._version > VERSION[len(VERSION_PREFIX)]:
raise VersionMismatchException(VERSION[len(VERSION_PREFIX)],
self._version)
if self._version < BLOCK_COMPRESS_VERSION:
# Same as below, but with UTF8 Deprecated Class
raise NotImplementedError
else:
self._key_class_name = Text.readString(self._stream)
self._value_class_name = Text.readString(self._stream)
if ord(self._version) > 2:
self._decompress = self._stream.readBoolean()
else:
self._decompress = False
if self._version >= BLOCK_COMPRESS_VERSION:
self._block_compressed = self._stream.readBoolean()
else:
self._block_compressed = False
# setup compression codec
if self._decompress:
if self._version >= CUSTOM_COMPRESS_VERSION:
codec_class = Text.readString(self._stream)
self._codec = CodecPool().getDecompressor(codec_class)
else:
self._codec = CodecPool().getDecompressor()
self._metadata = Metadata()
if self._version >= VERSION_WITH_METADATA:
self._metadata.readFields(self._stream)
if self._version > 1:
self._sync = self._stream.read(SYNC_HASH_SIZE)
self._header_end = self._stream.getPos()
def _readRecordLength(self):
if self._stream.getPos() >= self._end:
return -1
length = self._stream.readInt()
if self._version > 1 and self._sync is not None and length == SYNC_ESCAPE:
sync_check = self._stream.read(SYNC_HASH_SIZE)
if sync_check != self._sync:
raise IOError("File is corrupt!")
self._sync_seen = True
if self._stream.getPos() >= self._end:
return -1
length = self._stream.readInt()
else:
self._sync_seen = False
return length
def _getCurrentValue(self, value):
try:
stream = self.nextRawValue()
value.readFields(stream)
if not self._block_compressed:
assert self._record.size() == 0
except:
pass
