35 lines
1.5 KiB
TypeScript
35 lines
1.5 KiB
TypeScript
|
import ByteBuffer from "./ByteBuffer";
|
||
|
|
/**
|
||
|
|
* This class provides encoding and decoding methods for writing and reading
|
||
|
|
* ZigZag-encoded LEB128-64b9B-variant (Little Endian Base 128) values to/from a
|
||
|
|
* {@link ByteBuffer}. LEB128's variable length encoding provides for using a
|
||
|
|
* smaller nuber of bytes for smaller values, and the use of ZigZag encoding
|
||
|
|
* allows small (closer to zero) negative values to use fewer bytes. Details
|
||
|
|
* on both LEB128 and ZigZag can be readily found elsewhere.
|
||
|
|
*
|
||
|
|
* The LEB128-64b9B-variant encoding used here diverges from the "original"
|
||
|
|
* LEB128 as it extends to 64 bit values: In the original LEB128, a 64 bit
|
||
|
|
* value can take up to 10 bytes in the stream, where this variant's encoding
|
||
|
|
* of a 64 bit values will max out at 9 bytes.
|
||
|
|
*
|
||
|
|
* As such, this encoder/decoder should NOT be used for encoding or decoding
|
||
|
|
* "standard" LEB128 formats (e.g. Google Protocol Buffers).
|
||
|
|
*/
|
||
|
|
declare class ZigZagEncoding {
|
||
|
|
/**
|
||
|
|
* Writes a long value to the given buffer in LEB128 ZigZag encoded format
|
||
|
|
* (negative numbers not supported)
|
||
|
|
* @param buffer the buffer to write to
|
||
|
|
* @param value the value to write to the buffer
|
||
|
|
*/
|
||
|
|
static encode(buffer: ByteBuffer, value: number): void;
|
||
|
|
/**
|
||
|
|
* Read an LEB128-64b9B ZigZag encoded long value from the given buffer
|
||
|
|
* (negative numbers not supported)
|
||
|
|
* @param buffer the buffer to read from
|
||
|
|
* @return the value read from the buffer
|
||
|
|
*/
|
||
|
|
static decode(buffer: ByteBuffer): number;
|
||
|
|
}
|
||
|
|
export default ZigZagEncoding;
|