com.twitter.finagle.util.BufReader.scala Maven / Gradle / Ivy
package com.twitter.finagle.util
import com.twitter.io.Buf
import java.lang.{Double => JDouble, Float => JFloat}
/**
* A [[BufReader]] provides a stateful API to extract bytes from a
* [[Buf]]. This conveniently allows codec implementations to
* decode frames, specifically when they need to decode and interpret
* the bytes as a numeric value. Unless otherwise stated, [[BufReader]]
* implementations are not thread safe.
*/
private[finagle] trait BufReader {
/**
* The remainder of bytes that the reader is capable of reading.
*/
def remaining: Int
/**
* Extract 8 bits and interpret as a signed integer, advancing the byte cursor by 1.
*/
def readByte(): Byte
/**
* Extract 8 bits and interpret as an unsigned integer, advancing the byte cursor by 1.
*/
def readUnsignedByte(): Short
/**
* Extract 16 bits and interpret as a big endian integer, advancing the byte cursor by 2.
*/
def readShortBE(): Short
/**
* Extract 16 bits and interpret as a little endian integer, advancing the byte cursor by 2.
*/
def readShortLE(): Short
/**
* Extract 16 bits and interpret as a big endian unsigned integer, advancing the byte cursor by 2.
*/
def readUnsignedShortBE(): Int
/**
* Extract 16 bits and interpret as a little endian unsigned integer, advancing the byte cursor by 2.
*/
def readUnsignedShortLE(): Int
/**
* Extract 24 bits and interpret as a big endian integer, advancing the byte cursor by 3.
*/
def readMediumBE(): Int
/**
* Extract 24 bits and interpret as a little endian integer, advancing the byte cursor by 3.
*/
def readMediumLE(): Int
/**
* Extract 24 bits and interpret as a big endian unsigned integer, advancing the byte cursor by 3.
*/
def readUnsignedMediumBE(): Int
/**
* Extract 24 bits and interpret as a little endian unsigned integer, advancing the byte cursor by 3.
*/
def readUnsignedMediumLE(): Int
/**
* Extract 32 bits and interpret as a big endian integer, advancing the byte cursor by 4.
*/
def readIntBE(): Int
/**
* Extract 32 bits and interpret as a little endian int, advancing the byte cursor by 4.
*/
def readIntLE(): Int
/**
* Extract 32 bits and interpret as a big endian unsigned integer, advancing the byte cursor by 4.
*/
def readUnsignedIntBE(): Long
/**
* Extract 32 bits and interpret as a little endian unsigned integer, advancing the byte cursor by 4.
*/
def readUnsignedIntLE(): Long
/**
* Extract 64 bits and interpret as a big endian integer, advancing the byte cursor by 8.
*/
def readLongBE(): Long
/**
* Extract 64 bits and interpret as a little endian integer, advancing the byte cursor by 8.
*/
def readLongLE(): Long
/**
* Extract 32 bits and interpret as a big endian floating point, advancing the byte cursor by 4.
*/
def readFloatBE(): Float
/**
* Extract 32 bits and interpret as a little endian floating point, advancing the byte cursor by 4.
*/
def readFloatLE(): Float
/**
* Extract 64 bits and interpret as a big endian floating point, advancing the byte cursor by 4.
*/
def readDoubleBE(): Double
/**
* Extract 64 bits and interpret as a little endian floating point, advancing the byte cursor by 4.
*/
def readDoubleLE(): Double
/**
* Returns a new buffer representing a slice of this buffer, delimited
* by the indices `[cursor, remaining)`. Out of bounds indices are truncated.
* Negative indices are not accepted.
*/
def readBytes(n: Int): Buf
/**
* Skip over the next `n` bytes.
*
* @throws UnderflowException if there are < `n` bytes available
*/
def skip(n: Int): Unit
/**
* Like `read`, but extracts the remainder of bytes from cursor
* to the length. Note, this advances the cursor to the end of
* the buf.
*/
def readAll(): Buf
}
private[finagle] trait ProxyBufReader extends BufReader {
protected def reader: BufReader
def remaining: Int = reader.remaining
def readByte(): Byte = reader.readByte()
def readUnsignedByte(): Short = reader.readUnsignedByte()
def readShortBE(): Short = reader.readShortBE()
def readShortLE(): Short = reader.readShortLE()
def readUnsignedShortBE(): Int = reader.readUnsignedShortBE()
def readUnsignedShortLE(): Int = reader.readUnsignedShortLE()
def readMediumBE(): Int = reader.readMediumBE()
def readMediumLE(): Int = reader.readMediumLE()
def readUnsignedMediumBE(): Int = reader.readUnsignedMediumBE()
def readUnsignedMediumLE(): Int = reader.readUnsignedMediumLE()
def readIntBE(): Int = reader.readIntBE()
def readIntLE(): Int = reader.readIntLE()
def readUnsignedIntBE(): Long = reader.readUnsignedIntBE()
def readUnsignedIntLE(): Long = reader.readUnsignedIntLE()
def readLongBE(): Long = reader.readLongBE()
def readLongLE(): Long = reader.readLongLE()
def readFloatBE(): Float = reader.readFloatBE()
def readFloatLE(): Float = reader.readFloatLE()
def readDoubleBE(): Double = reader.readDoubleBE()
def readDoubleLE(): Double = reader.readDoubleLE()
def readBytes(n: Int): Buf = reader.readBytes(n)
def skip(n: Int): Unit = reader.skip(n)
def readAll(): Buf = reader.readAll()
}
private[finagle] object BufReader {
/**
* Creates a [[BufReader]] that is capable of extracting
* numeric values in big endian order.
*/
def apply(buf: Buf): BufReader = new BufReaderImpl(buf)
/**
* Indicates there aren't sufficient bytes to be read.
*/
class UnderflowException(msg: String) extends Exception(msg)
/**
* The max value of a signed 24 bit "medium" integer
*/
private[util] val SignedMediumMax = 0x800000
}
private class BufReaderImpl(underlying: Buf) extends BufReader {
import BufReader._
// stores a reference to the remainder `underlying`.
private[this] var buf: Buf = underlying
// temporarily stores numeric values which can be extracted
// from `buf` via the `read*` methods.
private[this] val nums = new Array[Byte](8)
def remaining: Int = buf.length
def readByte(): Byte = {
if (remaining < 1) {
throw new UnderflowException(
s"tried to read a byte when remaining bytes was ${remaining}")
}
readBytes(1).write(nums, 0)
nums(0)
}
def readUnsignedByte(): Short = (readByte() & 0xff).toShort
// - Short -
def readShortBE(): Short = {
if (remaining < 2) {
throw new UnderflowException(
s"tried to read 2 bytes when remaining bytes was ${remaining}")
}
readBytes(2).write(nums, 0)
(((nums(0) & 0xff) << 8) |
((nums(1) & 0xff) )).toShort
}
def readShortLE(): Short = {
if (remaining < 2) {
throw new UnderflowException(
s"tried to read 2 bytes when remaining bytes was ${remaining}")
}
readBytes(2).write(nums, 0)
(((nums(0) & 0xff) ) |
((nums(1) & 0xff) << 8)).toShort
}
def readUnsignedShortBE(): Int = readShortBE() & 0xffff
def readUnsignedShortLE(): Int = readShortLE() & 0xffff
// - Medium -
def readMediumBE(): Int = {
val unsigned = readUnsignedMediumBE()
if (unsigned > SignedMediumMax) {
unsigned | 0xff000000
} else {
unsigned
}
}
def readMediumLE(): Int = {
val unsigned = readUnsignedMediumLE()
if (unsigned > SignedMediumMax) {
unsigned | 0xff000000
} else {
unsigned
}
}
def readUnsignedMediumBE(): Int = {
if (remaining < 3) {
throw new UnderflowException(
s"tried to read 3 bytes when remaining bytes was ${remaining}")
}
readBytes(3).write(nums, 0)
((nums(0) & 0xff) << 16) |
((nums(1) & 0xff) << 8) |
((nums(2) & 0xff) )
}
def readUnsignedMediumLE(): Int = {
if (remaining < 3) {
throw new UnderflowException(
s"tried to read 3 bytes when remaining bytes was ${remaining}")
}
readBytes(3).write(nums, 0)
((nums(0) & 0xff) ) |
((nums(1) & 0xff) << 8) |
((nums(2) & 0xff) << 16)
}
// - Int -
def readIntBE(): Int = {
if (remaining < 4) {
throw new UnderflowException(
s"tried to read 4 bytes when remaining bytes was ${remaining}")
}
readBytes(4).write(nums, 0)
((nums(0) & 0xff) << 24) |
((nums(1) & 0xff) << 16) |
((nums(2) & 0xff) << 8) |
((nums(3) & 0xff) )
}
def readIntLE(): Int = {
if (remaining < 4) {
throw new UnderflowException(
s"tried to read 4 bytes when remaining bytes was ${remaining}")
}
readBytes(4).write(nums, 0)
((nums(0) & 0xff) ) |
((nums(1) & 0xff) << 8) |
((nums(2) & 0xff) << 16) |
((nums(3) & 0xff) << 24)
}
def readUnsignedIntBE(): Long = readIntBE() & 0xffffffffL
def readUnsignedIntLE(): Long = readIntLE() & 0xffffffffL
// - Long -
def readLongBE(): Long = {
if (remaining < 8) {
throw new UnderflowException(
s"tried to read 8 bytes when remaining bytes was ${remaining}")
}
readBytes(8).write(nums, 0)
((nums(0) & 0xff).toLong << 56) |
((nums(1) & 0xff).toLong << 48) |
((nums(2) & 0xff).toLong << 40) |
((nums(3) & 0xff).toLong << 32) |
((nums(4) & 0xff).toLong << 24) |
((nums(5) & 0xff).toLong << 16) |
((nums(6) & 0xff).toLong << 8) |
((nums(7) & 0xff).toLong )
}
def readLongLE(): Long = {
if (remaining < 8) {
throw new UnderflowException(
s"tried to read 8 bytes when remaining bytes was ${remaining}")
}
readBytes(8).write(nums, 0)
((nums(0) & 0xff).toLong ) |
((nums(1) & 0xff).toLong << 8) |
((nums(2) & 0xff).toLong << 16) |
((nums(3) & 0xff).toLong << 24) |
((nums(4) & 0xff).toLong << 32) |
((nums(5) & 0xff).toLong << 40) |
((nums(6) & 0xff).toLong << 48) |
((nums(7) & 0xff).toLong << 56)
}
// - Floating Point -
def readFloatBE(): Float = JFloat.intBitsToFloat(readIntBE())
def readDoubleBE(): Double = JDouble.longBitsToDouble(readLongBE())
def readFloatLE(): Float = JFloat.intBitsToFloat(readIntLE())
def readDoubleLE(): Double = JDouble.longBitsToDouble(readLongLE())
def readBytes(n: Int): Buf = {
val b = buf.slice(0, n)
buf = buf.slice(n, buf.length)
b
}
def skip(n: Int): Unit = {
if (n < 0) {
throw new IllegalArgumentException(s"Invalid number of bytes to skip: $n. Must be >= 0")
}
if (remaining < n) {
throw new UnderflowException(
s"Tried to skip $n bytes when remaining bytes was $remaining")
}
if (n > 0) {
buf = buf.slice(n, buf.length)
}
}
def readAll(): Buf = {
val b = buf.slice(0, buf.length)
buf = Buf.Empty
b
}
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