flatbuffers
Version:
Memory Efficient Serialization Library
124 lines (123 loc) • 4.65 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.validateOffset = validateOffset;
exports.readInt = readInt;
exports.readUInt = readUInt;
exports.readFloat = readFloat;
exports.indirect = indirect;
exports.keyIndex = keyIndex;
exports.diffKeys = diffKeys;
exports.keyForIndex = keyForIndex;
const bit_width_util_js_1 = require("./bit-width-util.js");
const bit_width_js_1 = require("./bit-width.js");
const flexbuffers_util_js_1 = require("./flexbuffers-util.js");
function validateOffset(dataView, offset, width) {
if (dataView.byteLength <= offset + width ||
(offset & ((0, bit_width_util_js_1.toByteWidth)(width) - 1)) !== 0) {
throw 'Bad offset: ' + offset + ', width: ' + width;
}
}
function readInt(dataView, offset, width) {
if (width < 2) {
if (width < 1) {
return dataView.getInt8(offset);
}
else {
return dataView.getInt16(offset, true);
}
}
else {
if (width < 3) {
return dataView.getInt32(offset, true);
}
else {
if (dataView.setBigInt64 === undefined) {
return (BigInt(dataView.getUint32(offset, true)) +
(BigInt(dataView.getUint32(offset + 4, true)) << BigInt(32)));
}
return dataView.getBigInt64(offset, true);
}
}
}
function readUInt(dataView, offset, width) {
if (width < 2) {
if (width < 1) {
return dataView.getUint8(offset);
}
else {
return dataView.getUint16(offset, true);
}
}
else {
if (width < 3) {
return dataView.getUint32(offset, true);
}
else {
if (dataView.getBigUint64 === undefined) {
return (BigInt(dataView.getUint32(offset, true)) +
(BigInt(dataView.getUint32(offset + 4, true)) << BigInt(32)));
}
return dataView.getBigUint64(offset, true);
}
}
}
function readFloat(dataView, offset, width) {
if (width < bit_width_js_1.BitWidth.WIDTH32) {
throw 'Bad width: ' + width;
}
if (width === bit_width_js_1.BitWidth.WIDTH32) {
return dataView.getFloat32(offset, true);
}
return dataView.getFloat64(offset, true);
}
function indirect(dataView, offset, width) {
const step = readUInt(dataView, offset, width);
return offset - step;
}
function keyIndex(key, dataView, offset, parentWidth, byteWidth, length) {
const input = (0, flexbuffers_util_js_1.toUTF8Array)(key);
const keysVectorOffset = indirect(dataView, offset, parentWidth) - byteWidth * 3;
const bitWidth = (0, bit_width_util_js_1.fromByteWidth)(byteWidth);
const indirectOffset = keysVectorOffset - Number(readUInt(dataView, keysVectorOffset, bitWidth));
const _byteWidth = Number(readUInt(dataView, keysVectorOffset + byteWidth, bitWidth));
let low = 0;
let high = length - 1;
while (low <= high) {
const mid = (high + low) >> 1;
const dif = diffKeys(input, mid, dataView, indirectOffset, _byteWidth);
if (dif === 0)
return mid;
if (dif < 0) {
high = mid - 1;
}
else {
low = mid + 1;
}
}
return null;
}
function diffKeys(input, index, dataView, offset, width) {
const keyOffset = offset + index * width;
const keyIndirectOffset = keyOffset - Number(readUInt(dataView, keyOffset, (0, bit_width_util_js_1.fromByteWidth)(width)));
for (let i = 0; i < input.length; i++) {
const dif = input[i] - dataView.getUint8(keyIndirectOffset + i);
if (dif !== 0) {
return dif;
}
}
return dataView.getUint8(keyIndirectOffset + input.length) === 0 ? 0 : -1;
}
function keyForIndex(index, dataView, offset, parentWidth, byteWidth) {
const keysVectorOffset = indirect(dataView, offset, parentWidth) - byteWidth * 3;
const bitWidth = (0, bit_width_util_js_1.fromByteWidth)(byteWidth);
const indirectOffset = keysVectorOffset - Number(readUInt(dataView, keysVectorOffset, bitWidth));
const _byteWidth = Number(readUInt(dataView, keysVectorOffset + byteWidth, bitWidth));
const keyOffset = indirectOffset + index * _byteWidth;
const keyIndirectOffset = keyOffset -
Number(readUInt(dataView, keyOffset, (0, bit_width_util_js_1.fromByteWidth)(_byteWidth)));
let length = 0;
while (dataView.getUint8(keyIndirectOffset + length) !== 0) {
length++;
}
return (0, flexbuffers_util_js_1.fromUTF8Array)(new Uint8Array(dataView.buffer, keyIndirectOffset, length));
}