336 lines
11 KiB
JavaScript
336 lines
11 KiB
JavaScript
"use strict";
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module.exports = factory(factory);
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/**
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* Reads / writes floats / doubles from / to buffers.
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* @name util.float
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* @namespace
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*/
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/**
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* Writes a 32 bit float to a buffer using little endian byte order.
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* @name util.float.writeFloatLE
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* @function
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* @param {number} val Value to write
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* @param {Uint8Array} buf Target buffer
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* @param {number} pos Target buffer offset
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* @returns {undefined}
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*/
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/**
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* Writes a 32 bit float to a buffer using big endian byte order.
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* @name util.float.writeFloatBE
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* @function
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* @param {number} val Value to write
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* @param {Uint8Array} buf Target buffer
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* @param {number} pos Target buffer offset
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* @returns {undefined}
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*/
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/**
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* Reads a 32 bit float from a buffer using little endian byte order.
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* @name util.float.readFloatLE
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* @function
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* @param {Uint8Array} buf Source buffer
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* @param {number} pos Source buffer offset
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* @returns {number} Value read
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*/
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/**
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* Reads a 32 bit float from a buffer using big endian byte order.
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* @name util.float.readFloatBE
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* @function
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* @param {Uint8Array} buf Source buffer
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* @param {number} pos Source buffer offset
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* @returns {number} Value read
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*/
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/**
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* Writes a 64 bit double to a buffer using little endian byte order.
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* @name util.float.writeDoubleLE
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* @function
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* @param {number} val Value to write
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* @param {Uint8Array} buf Target buffer
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* @param {number} pos Target buffer offset
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* @returns {undefined}
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*/
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/**
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* Writes a 64 bit double to a buffer using big endian byte order.
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* @name util.float.writeDoubleBE
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* @function
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* @param {number} val Value to write
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* @param {Uint8Array} buf Target buffer
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* @param {number} pos Target buffer offset
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* @returns {undefined}
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*/
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/**
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* Reads a 64 bit double from a buffer using little endian byte order.
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* @name util.float.readDoubleLE
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* @function
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* @param {Uint8Array} buf Source buffer
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* @param {number} pos Source buffer offset
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* @returns {number} Value read
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*/
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/**
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* Reads a 64 bit double from a buffer using big endian byte order.
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* @name util.float.readDoubleBE
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* @function
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* @param {Uint8Array} buf Source buffer
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* @param {number} pos Source buffer offset
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* @returns {number} Value read
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*/
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// Factory function for the purpose of node-based testing in modified global environments
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function factory(exports) {
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// float: typed array
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if (typeof Float32Array !== "undefined") (function() {
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var f32 = new Float32Array([ -0 ]),
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f8b = new Uint8Array(f32.buffer),
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le = f8b[3] === 128;
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function writeFloat_f32_cpy(val, buf, pos) {
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f32[0] = val;
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buf[pos ] = f8b[0];
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buf[pos + 1] = f8b[1];
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buf[pos + 2] = f8b[2];
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buf[pos + 3] = f8b[3];
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}
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function writeFloat_f32_rev(val, buf, pos) {
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f32[0] = val;
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buf[pos ] = f8b[3];
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buf[pos + 1] = f8b[2];
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buf[pos + 2] = f8b[1];
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buf[pos + 3] = f8b[0];
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}
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/* istanbul ignore next */
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exports.writeFloatLE = le ? writeFloat_f32_cpy : writeFloat_f32_rev;
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/* istanbul ignore next */
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exports.writeFloatBE = le ? writeFloat_f32_rev : writeFloat_f32_cpy;
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function readFloat_f32_cpy(buf, pos) {
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f8b[0] = buf[pos ];
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f8b[1] = buf[pos + 1];
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f8b[2] = buf[pos + 2];
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f8b[3] = buf[pos + 3];
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return f32[0];
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}
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function readFloat_f32_rev(buf, pos) {
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f8b[3] = buf[pos ];
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f8b[2] = buf[pos + 1];
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f8b[1] = buf[pos + 2];
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f8b[0] = buf[pos + 3];
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return f32[0];
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}
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/* istanbul ignore next */
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exports.readFloatLE = le ? readFloat_f32_cpy : readFloat_f32_rev;
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/* istanbul ignore next */
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exports.readFloatBE = le ? readFloat_f32_rev : readFloat_f32_cpy;
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// float: ieee754
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})(); else (function() {
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function writeFloat_ieee754(writeUint, val, buf, pos) {
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var sign = val < 0 ? 1 : 0;
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if (sign)
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val = -val;
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if (val === 0)
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writeUint(1 / val > 0 ? /* positive */ 0 : /* negative 0 */ 2147483648, buf, pos);
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else if (isNaN(val))
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writeUint(2143289344, buf, pos);
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else if (val > 3.4028234663852886e+38) // +-Infinity
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writeUint((sign << 31 | 2139095040) >>> 0, buf, pos);
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else if (val < 1.1754943508222875e-38) // denormal
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writeUint((sign << 31 | Math.round(val / 1.401298464324817e-45)) >>> 0, buf, pos);
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else {
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var exponent = Math.floor(Math.log(val) / Math.LN2),
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mantissa = Math.round(val * Math.pow(2, -exponent) * 8388608) & 8388607;
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writeUint((sign << 31 | exponent + 127 << 23 | mantissa) >>> 0, buf, pos);
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}
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}
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exports.writeFloatLE = writeFloat_ieee754.bind(null, writeUintLE);
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exports.writeFloatBE = writeFloat_ieee754.bind(null, writeUintBE);
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function readFloat_ieee754(readUint, buf, pos) {
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var uint = readUint(buf, pos),
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sign = (uint >> 31) * 2 + 1,
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exponent = uint >>> 23 & 255,
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mantissa = uint & 8388607;
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return exponent === 255
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? mantissa
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? NaN
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: sign * Infinity
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: exponent === 0 // denormal
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? sign * 1.401298464324817e-45 * mantissa
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: sign * Math.pow(2, exponent - 150) * (mantissa + 8388608);
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}
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exports.readFloatLE = readFloat_ieee754.bind(null, readUintLE);
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exports.readFloatBE = readFloat_ieee754.bind(null, readUintBE);
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})();
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// double: typed array
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if (typeof Float64Array !== "undefined") (function() {
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var f64 = new Float64Array([-0]),
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f8b = new Uint8Array(f64.buffer),
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le = f8b[7] === 128;
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function writeDouble_f64_cpy(val, buf, pos) {
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f64[0] = val;
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buf[pos ] = f8b[0];
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buf[pos + 1] = f8b[1];
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buf[pos + 2] = f8b[2];
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buf[pos + 3] = f8b[3];
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buf[pos + 4] = f8b[4];
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buf[pos + 5] = f8b[5];
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buf[pos + 6] = f8b[6];
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buf[pos + 7] = f8b[7];
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}
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function writeDouble_f64_rev(val, buf, pos) {
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f64[0] = val;
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buf[pos ] = f8b[7];
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buf[pos + 1] = f8b[6];
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buf[pos + 2] = f8b[5];
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buf[pos + 3] = f8b[4];
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buf[pos + 4] = f8b[3];
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buf[pos + 5] = f8b[2];
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buf[pos + 6] = f8b[1];
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buf[pos + 7] = f8b[0];
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}
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/* istanbul ignore next */
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exports.writeDoubleLE = le ? writeDouble_f64_cpy : writeDouble_f64_rev;
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/* istanbul ignore next */
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exports.writeDoubleBE = le ? writeDouble_f64_rev : writeDouble_f64_cpy;
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function readDouble_f64_cpy(buf, pos) {
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f8b[0] = buf[pos ];
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f8b[1] = buf[pos + 1];
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f8b[2] = buf[pos + 2];
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f8b[3] = buf[pos + 3];
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f8b[4] = buf[pos + 4];
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f8b[5] = buf[pos + 5];
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f8b[6] = buf[pos + 6];
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f8b[7] = buf[pos + 7];
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return f64[0];
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}
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function readDouble_f64_rev(buf, pos) {
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f8b[7] = buf[pos ];
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f8b[6] = buf[pos + 1];
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f8b[5] = buf[pos + 2];
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f8b[4] = buf[pos + 3];
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f8b[3] = buf[pos + 4];
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f8b[2] = buf[pos + 5];
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f8b[1] = buf[pos + 6];
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f8b[0] = buf[pos + 7];
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return f64[0];
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}
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/* istanbul ignore next */
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exports.readDoubleLE = le ? readDouble_f64_cpy : readDouble_f64_rev;
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/* istanbul ignore next */
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exports.readDoubleBE = le ? readDouble_f64_rev : readDouble_f64_cpy;
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// double: ieee754
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})(); else (function() {
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function writeDouble_ieee754(writeUint, off0, off1, val, buf, pos) {
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var sign = val < 0 ? 1 : 0;
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if (sign)
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val = -val;
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if (val === 0) {
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writeUint(0, buf, pos + off0);
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writeUint(1 / val > 0 ? /* positive */ 0 : /* negative 0 */ 2147483648, buf, pos + off1);
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} else if (isNaN(val)) {
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writeUint(0, buf, pos + off0);
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writeUint(2146959360, buf, pos + off1);
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} else if (val > 1.7976931348623157e+308) { // +-Infinity
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writeUint(0, buf, pos + off0);
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writeUint((sign << 31 | 2146435072) >>> 0, buf, pos + off1);
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} else {
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var mantissa;
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if (val < 2.2250738585072014e-308) { // denormal
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mantissa = val / 5e-324;
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writeUint(mantissa >>> 0, buf, pos + off0);
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writeUint((sign << 31 | mantissa / 4294967296) >>> 0, buf, pos + off1);
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} else {
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var exponent = Math.floor(Math.log(val) / Math.LN2);
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if (exponent === 1024)
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exponent = 1023;
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mantissa = val * Math.pow(2, -exponent);
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writeUint(mantissa * 4503599627370496 >>> 0, buf, pos + off0);
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writeUint((sign << 31 | exponent + 1023 << 20 | mantissa * 1048576 & 1048575) >>> 0, buf, pos + off1);
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}
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}
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}
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exports.writeDoubleLE = writeDouble_ieee754.bind(null, writeUintLE, 0, 4);
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exports.writeDoubleBE = writeDouble_ieee754.bind(null, writeUintBE, 4, 0);
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function readDouble_ieee754(readUint, off0, off1, buf, pos) {
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var lo = readUint(buf, pos + off0),
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hi = readUint(buf, pos + off1);
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var sign = (hi >> 31) * 2 + 1,
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exponent = hi >>> 20 & 2047,
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mantissa = 4294967296 * (hi & 1048575) + lo;
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return exponent === 2047
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? mantissa
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? NaN
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: sign * Infinity
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: exponent === 0 // denormal
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? sign * 5e-324 * mantissa
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: sign * Math.pow(2, exponent - 1075) * (mantissa + 4503599627370496);
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}
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exports.readDoubleLE = readDouble_ieee754.bind(null, readUintLE, 0, 4);
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exports.readDoubleBE = readDouble_ieee754.bind(null, readUintBE, 4, 0);
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})();
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return exports;
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}
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// uint helpers
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function writeUintLE(val, buf, pos) {
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buf[pos ] = val & 255;
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buf[pos + 1] = val >>> 8 & 255;
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buf[pos + 2] = val >>> 16 & 255;
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buf[pos + 3] = val >>> 24;
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}
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function writeUintBE(val, buf, pos) {
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buf[pos ] = val >>> 24;
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buf[pos + 1] = val >>> 16 & 255;
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buf[pos + 2] = val >>> 8 & 255;
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buf[pos + 3] = val & 255;
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}
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function readUintLE(buf, pos) {
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return (buf[pos ]
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| buf[pos + 1] << 8
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| buf[pos + 2] << 16
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| buf[pos + 3] << 24) >>> 0;
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}
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function readUintBE(buf, pos) {
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return (buf[pos ] << 24
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| buf[pos + 1] << 16
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| buf[pos + 2] << 8
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| buf[pos + 3]) >>> 0;
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}
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