var zero = '0'.charCodeAt(0);
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var plus = '+'.charCodeAt(0);
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var minus = '-'.charCodeAt(0);
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function isWhitespace(code) {
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return code <= 32;
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}
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function isDigit(code) {
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return 48 <= code && code <= 57;
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}
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function isSign(code) {
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return code === minus || code === plus;
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}
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module.exports = function (opts, a, b) {
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var checkSign = opts.sign;
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var ia = 0;
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var ib = 0;
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var ma = a.length;
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var mb = b.length;
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var ca, cb; // character code
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var za, zb; // leading zero count
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var na, nb; // number length
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var sa, sb; // number sign
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var ta, tb; // temporary
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var bias;
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while (ia < ma && ib < mb) {
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ca = a.charCodeAt(ia);
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cb = b.charCodeAt(ib);
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za = zb = 0;
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na = nb = 0;
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sa = sb = true;
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bias = 0;
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// skip over leading spaces
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while (isWhitespace(ca)) {
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ia += 1;
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ca = a.charCodeAt(ia);
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}
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while (isWhitespace(cb)) {
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ib += 1;
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cb = b.charCodeAt(ib);
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}
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// skip and save sign
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if (checkSign) {
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ta = a.charCodeAt(ia + 1);
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if (isSign(ca) && isDigit(ta)) {
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if (ca === minus) {
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sa = false;
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}
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ia += 1;
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ca = ta;
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}
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tb = b.charCodeAt(ib + 1);
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if (isSign(cb) && isDigit(tb)) {
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if (cb === minus) {
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sb = false;
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}
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ib += 1;
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cb = tb;
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}
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}
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// compare digits with other symbols
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if (isDigit(ca) && !isDigit(cb)) {
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return -1;
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}
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if (!isDigit(ca) && isDigit(cb)) {
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return 1;
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}
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// compare negative and positive
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if (!sa && sb) {
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return -1;
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}
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if (sa && !sb) {
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return 1;
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}
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// count leading zeros
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while (ca === zero) {
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za += 1;
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ia += 1;
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ca = a.charCodeAt(ia);
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}
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while (cb === zero) {
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zb += 1;
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ib += 1;
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cb = b.charCodeAt(ib);
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}
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// count numbers
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while (isDigit(ca) || isDigit(cb)) {
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if (isDigit(ca) && isDigit(cb) && bias === 0) {
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if (sa) {
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if (ca < cb) {
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bias = -1;
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} else if (ca > cb) {
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bias = 1;
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}
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} else {
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if (ca > cb) {
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bias = -1;
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} else if (ca < cb) {
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bias = 1;
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}
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}
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}
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if (isDigit(ca)) {
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ia += 1;
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na += 1;
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ca = a.charCodeAt(ia);
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}
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if (isDigit(cb)) {
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ib += 1;
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nb += 1;
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cb = b.charCodeAt(ib);
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}
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}
|
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// compare number length
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if (sa) {
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if (na < nb) {
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return -1;
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}
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if (na > nb) {
|
return 1;
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}
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} else {
|
if (na > nb) {
|
return -1;
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}
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if (na < nb) {
|
return 1;
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}
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}
|
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// compare numbers
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if (bias) {
|
return bias;
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}
|
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// compare leading zeros
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if (sa) {
|
if (za > zb) {
|
return -1;
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}
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if (za < zb) {
|
return 1;
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}
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} else {
|
if (za < zb) {
|
return -1;
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}
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if (za > zb) {
|
return 1;
|
}
|
}
|
|
// compare ascii codes
|
if (ca < cb) {
|
return -1;
|
}
|
if (ca > cb) {
|
return 1;
|
}
|
|
ia += 1;
|
ib += 1;
|
}
|
|
// compare length
|
if (ma < mb) {
|
return -1;
|
}
|
if (ma > mb) {
|
return 1;
|
}
|
};
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