NET-Web-API-w-Angular/my-app/node_modules/hdr-histogram-js/dist/ZigZagEncoding.js

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2024-02-09 00:38:41 +00:00
"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
const { pow, floor } = Math;
const TWO_POW_7 = pow(2, 7);
const TWO_POW_14 = pow(2, 14);
const TWO_POW_21 = pow(2, 21);
const TWO_POW_28 = pow(2, 28);
const TWO_POW_35 = pow(2, 35);
const TWO_POW_42 = pow(2, 42);
const TWO_POW_49 = pow(2, 49);
const TWO_POW_56 = pow(2, 56);
/**
* 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).
*/
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, value) {
if (value >= 0) {
value = value * 2;
}
else {
value = -value * 2 - 1;
}
if (value < TWO_POW_7) {
buffer.put(value);
}
else {
buffer.put(value | 0x80);
if (value < TWO_POW_14) {
buffer.put(floor(value / TWO_POW_7));
}
else {
buffer.put(floor(value / TWO_POW_7) | 0x80);
if (value < TWO_POW_21) {
buffer.put(floor(value / TWO_POW_14));
}
else {
buffer.put(floor(value / TWO_POW_14) | 0x80);
if (value < TWO_POW_28) {
buffer.put(floor(value / TWO_POW_21));
}
else {
buffer.put(floor(value / TWO_POW_21) | 0x80);
if (value < TWO_POW_35) {
buffer.put(floor(value / TWO_POW_28));
}
else {
buffer.put(floor(value / TWO_POW_28) | 0x80);
if (value < TWO_POW_42) {
buffer.put(floor(value / TWO_POW_35));
}
else {
buffer.put(floor(value / TWO_POW_35) | 0x80);
if (value < TWO_POW_49) {
buffer.put(floor(value / TWO_POW_42));
}
else {
buffer.put(floor(value / TWO_POW_42) | 0x80);
if (value < TWO_POW_56) {
buffer.put(floor(value / TWO_POW_49));
}
else {
// should not happen
buffer.put(floor(value / TWO_POW_49) + 0x80);
buffer.put(floor(value / TWO_POW_56));
}
}
}
}
}
}
}
}
}
/**
* 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) {
let v = buffer.get();
let value = v & 0x7f;
if ((v & 0x80) != 0) {
v = buffer.get();
value += (v & 0x7f) * TWO_POW_7;
if ((v & 0x80) != 0) {
v = buffer.get();
value += (v & 0x7f) * TWO_POW_14;
if ((v & 0x80) != 0) {
v = buffer.get();
value += (v & 0x7f) * TWO_POW_21;
if ((v & 0x80) != 0) {
v = buffer.get();
value += (v & 0x7f) * TWO_POW_28;
if ((v & 0x80) != 0) {
v = buffer.get();
value += (v & 0x7f) * TWO_POW_35;
if ((v & 0x80) != 0) {
v = buffer.get();
value += (v & 0x7f) * TWO_POW_42;
if ((v & 0x80) != 0) {
v = buffer.get();
value += (v & 0x7f) * TWO_POW_49;
if ((v & 0x80) != 0) {
v = buffer.get();
value += (v & 0x7f) * TWO_POW_56;
}
}
}
}
}
}
}
}
if (value % 2 === 0) {
value = value / 2;
}
else {
value = -(value + 1) / 2;
}
return value;
}
}
exports.default = ZigZagEncoding;
//# sourceMappingURL=ZigZagEncoding.js.map