@zxing/text-encoding
Version:
Polyfill for the Encoding Living Standard's API.
119 lines • 3.85 kB
JavaScript
Object.defineProperty(exports, "__esModule", { value: true });
/**
* @param {number} a The number to test.
* @param {number} min The minimum value in the range, inclusive.
* @param {number} max The maximum value in the range, inclusive.
* @return {boolean} True if a >= min and a <= max.
*/
function inRange(a, min, max) {
return min <= a && a <= max;
}
exports.inRange = inRange;
/**
* @param {!Array.<*>} array The array to check.
* @param {*} item The item to look for in the array.
* @return {boolean} True if the item appears in the array.
*/
function includes(array, item) {
return array.indexOf(item) !== -1;
}
exports.includes = includes;
/**
* @param {*} o
* @return {Object}
*/
function ToDictionary(o) {
if (o === undefined || o === null)
return {};
if (o === Object(o))
return o;
throw TypeError('Could not convert argument to dictionary');
}
exports.ToDictionary = ToDictionary;
/**
* @param {string} string Input string of UTF-16 code units.
* @return {!Array.<number>} Code points.
*/
function stringToCodePoints(string) {
// https://heycam.github.io/webidl/#dfn-obtain-unicode
// 1. Let S be the DOMString value.
var s = String(string);
// 2. Let n be the length of S.
var n = s.length;
// 3. Initialize i to 0.
var i = 0;
// 4. Initialize U to be an empty sequence of Unicode characters.
var u = [];
// 5. While i < n:
while (i < n) {
// 1. Let c be the code unit in S at index i.
var c = s.charCodeAt(i);
// 2. Depending on the value of c:
// c < 0xD800 or c > 0xDFFF
if (c < 0xD800 || c > 0xDFFF) {
// Append to U the Unicode character with code point c.
u.push(c);
}
// 0xDC00 ≤ c ≤ 0xDFFF
else if (0xDC00 <= c && c <= 0xDFFF) {
// Append to U a U+FFFD REPLACEMENT CHARACTER.
u.push(0xFFFD);
}
// 0xD800 ≤ c ≤ 0xDBFF
else if (0xD800 <= c && c <= 0xDBFF) {
// 1. If i = n−1, then append to U a U+FFFD REPLACEMENT
// CHARACTER.
if (i === n - 1) {
u.push(0xFFFD);
}
// 2. Otherwise, i < n−1:
else {
// 1. Let d be the code unit in S at index i+1.
var d = s.charCodeAt(i + 1);
// 2. If 0xDC00 ≤ d ≤ 0xDFFF, then:
if (0xDC00 <= d && d <= 0xDFFF) {
// 1. Let a be c & 0x3FF.
var a = c & 0x3FF;
// 2. Let b be d & 0x3FF.
var b = d & 0x3FF;
// 3. Append to U the Unicode character with code point
// 2^16+2^10*a+b.
u.push(0x10000 + (a << 10) + b);
// 4. Set i to i+1.
i += 1;
}
// 3. Otherwise, d < 0xDC00 or d > 0xDFFF. Append to U a
// U+FFFD REPLACEMENT CHARACTER.
else {
u.push(0xFFFD);
}
}
}
// 3. Set i to i+1.
i += 1;
}
// 6. Return U.
return u;
}
exports.stringToCodePoints = stringToCodePoints;
/**
* @param {!Array.<number>} code_points Array of code points.
* @return {string} string String of UTF-16 code units.
*/
function codePointsToString(code_points) {
var s = '';
for (var i = 0; i < code_points.length; ++i) {
var cp = code_points[i];
if (cp <= 0xFFFF) {
s += String.fromCharCode(cp);
}
else {
cp -= 0x10000;
s += String.fromCharCode((cp >> 10) + 0xD800, (cp & 0x3FF) + 0xDC00);
}
}
return s;
}
exports.codePointsToString = codePointsToString;
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