28 lines
1 KiB
JavaScript
28 lines
1 KiB
JavaScript
const alphabetByEncoding = {};
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const alphabetByValue = new Array(64);
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for (let i = 0, start = "A".charCodeAt(0), limit = "Z".charCodeAt(0); i + start <= limit; i++) {
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const char = String.fromCharCode(i + start);
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alphabetByEncoding[char] = i;
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alphabetByValue[i] = char;
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}
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for (let i = 0, start = "a".charCodeAt(0), limit = "z".charCodeAt(0); i + start <= limit; i++) {
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const char = String.fromCharCode(i + start);
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const index = i + 26;
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alphabetByEncoding[char] = index;
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alphabetByValue[index] = char;
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}
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for (let i = 0; i < 10; i++) {
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alphabetByEncoding[i.toString(10)] = i + 52;
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const char = i.toString(10);
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const index = i + 52;
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alphabetByEncoding[char] = index;
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alphabetByValue[index] = char;
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}
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alphabetByEncoding["+"] = 62;
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alphabetByValue[62] = "+";
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alphabetByEncoding["/"] = 63;
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alphabetByValue[63] = "/";
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const bitsPerLetter = 6;
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const bitsPerByte = 8;
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const maxLetterValue = 0b111111;
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export { alphabetByEncoding, alphabetByValue, bitsPerLetter, bitsPerByte, maxLetterValue };
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