mirror of
https://github.com/titanscouting/tra-analysis.git
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106 lines
3.2 KiB
JavaScript
106 lines
3.2 KiB
JavaScript
"use strict";
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/**
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* A minimal UTF8 implementation for number arrays.
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* @memberof util
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* @namespace
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*/
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var utf8 = exports;
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/**
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* Calculates the UTF8 byte length of a string.
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* @param {string} string String
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* @returns {number} Byte length
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*/
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utf8.length = function utf8_length(string) {
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var len = 0,
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c = 0;
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for (var i = 0; i < string.length; ++i) {
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c = string.charCodeAt(i);
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if (c < 128)
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len += 1;
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else if (c < 2048)
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len += 2;
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else if ((c & 0xFC00) === 0xD800 && (string.charCodeAt(i + 1) & 0xFC00) === 0xDC00) {
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++i;
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len += 4;
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} else
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len += 3;
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}
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return len;
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};
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/**
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* Reads UTF8 bytes as a string.
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* @param {Uint8Array} buffer Source buffer
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* @param {number} start Source start
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* @param {number} end Source end
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* @returns {string} String read
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*/
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utf8.read = function utf8_read(buffer, start, end) {
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var len = end - start;
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if (len < 1)
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return "";
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var parts = null,
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chunk = [],
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i = 0, // char offset
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t; // temporary
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while (start < end) {
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t = buffer[start++];
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if (t < 128)
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chunk[i++] = t;
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else if (t > 191 && t < 224)
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chunk[i++] = (t & 31) << 6 | buffer[start++] & 63;
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else if (t > 239 && t < 365) {
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t = ((t & 7) << 18 | (buffer[start++] & 63) << 12 | (buffer[start++] & 63) << 6 | buffer[start++] & 63) - 0x10000;
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chunk[i++] = 0xD800 + (t >> 10);
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chunk[i++] = 0xDC00 + (t & 1023);
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} else
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chunk[i++] = (t & 15) << 12 | (buffer[start++] & 63) << 6 | buffer[start++] & 63;
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if (i > 8191) {
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(parts || (parts = [])).push(String.fromCharCode.apply(String, chunk));
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i = 0;
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}
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}
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if (parts) {
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if (i)
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parts.push(String.fromCharCode.apply(String, chunk.slice(0, i)));
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return parts.join("");
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}
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return String.fromCharCode.apply(String, chunk.slice(0, i));
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};
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/**
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* Writes a string as UTF8 bytes.
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* @param {string} string Source string
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* @param {Uint8Array} buffer Destination buffer
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* @param {number} offset Destination offset
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* @returns {number} Bytes written
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*/
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utf8.write = function utf8_write(string, buffer, offset) {
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var start = offset,
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c1, // character 1
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c2; // character 2
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for (var i = 0; i < string.length; ++i) {
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c1 = string.charCodeAt(i);
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if (c1 < 128) {
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buffer[offset++] = c1;
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} else if (c1 < 2048) {
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buffer[offset++] = c1 >> 6 | 192;
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buffer[offset++] = c1 & 63 | 128;
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} else if ((c1 & 0xFC00) === 0xD800 && ((c2 = string.charCodeAt(i + 1)) & 0xFC00) === 0xDC00) {
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c1 = 0x10000 + ((c1 & 0x03FF) << 10) + (c2 & 0x03FF);
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++i;
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buffer[offset++] = c1 >> 18 | 240;
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buffer[offset++] = c1 >> 12 & 63 | 128;
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buffer[offset++] = c1 >> 6 & 63 | 128;
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buffer[offset++] = c1 & 63 | 128;
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} else {
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buffer[offset++] = c1 >> 12 | 224;
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buffer[offset++] = c1 >> 6 & 63 | 128;
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buffer[offset++] = c1 & 63 | 128;
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}
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}
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return offset - start;
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};
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