hexo/node_modules/@webassemblyjs/utf8/lib/decoder.js

74 lines
1.5 KiB
JavaScript

"use strict";
Object.defineProperty(exports, "__esModule", {
value: true
});
exports.decode = decode;
function con(b) {
if ((b & 0xc0) === 0x80) {
return b & 0x3f;
} else {
throw new Error("invalid UTF-8 encoding");
}
}
function code(min, n) {
if (n < min || 0xd800 <= n && n < 0xe000 || n >= 0x10000) {
throw new Error("invalid UTF-8 encoding");
} else {
return n;
}
}
function decode(bytes) {
return _decode(bytes).map(function (x) {
return String.fromCharCode(x);
}).join("");
}
function _decode(bytes) {
var result = [];
while (bytes.length > 0) {
var b1 = bytes[0];
if (b1 < 0x80) {
result.push(code(0x0, b1));
bytes = bytes.slice(1);
continue;
}
if (b1 < 0xc0) {
throw new Error("invalid UTF-8 encoding");
}
var b2 = bytes[1];
if (b1 < 0xe0) {
result.push(code(0x80, ((b1 & 0x1f) << 6) + con(b2)));
bytes = bytes.slice(2);
continue;
}
var b3 = bytes[2];
if (b1 < 0xf0) {
result.push(code(0x800, ((b1 & 0x0f) << 12) + (con(b2) << 6) + con(b3)));
bytes = bytes.slice(3);
continue;
}
var b4 = bytes[3];
if (b1 < 0xf8) {
result.push(code(0x10000, (((b1 & 0x07) << 18) + con(b2) << 12) + (con(b3) << 6) + con(b4)));
bytes = bytes.slice(4);
continue;
}
throw new Error("invalid UTF-8 encoding");
}
return result;
}