aaac7fed
 liuqimichale
add
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var zero = '0'.charCodeAt(0);
var plus = '+'.charCodeAt(0);
var minus = '-'.charCodeAt(0);
function isWhitespace(code) {
return code <= 32;
}
function isDigit(code) {
return 48 <= code && code <= 57;
}
function isSign(code) {
return code === minus || code === plus;
}
module.exports = function (opts, a, b) {
var checkSign = opts.sign;
var ia = 0;
var ib = 0;
var ma = a.length;
var mb = b.length;
var ca, cb; // character code
var za, zb; // leading zero count
var na, nb; // number length
var sa, sb; // number sign
var ta, tb; // temporary
var bias;
while (ia < ma && ib < mb) {
ca = a.charCodeAt(ia);
cb = b.charCodeAt(ib);
za = zb = 0;
na = nb = 0;
sa = sb = true;
bias = 0;
// skip over leading spaces
while (isWhitespace(ca)) {
ia += 1;
ca = a.charCodeAt(ia);
}
while (isWhitespace(cb)) {
ib += 1;
cb = b.charCodeAt(ib);
}
// skip and save sign
if (checkSign) {
ta = a.charCodeAt(ia + 1);
if (isSign(ca) && isDigit(ta)) {
if (ca === minus) {
sa = false;
}
ia += 1;
ca = ta;
}
tb = b.charCodeAt(ib + 1);
if (isSign(cb) && isDigit(tb)) {
if (cb === minus) {
sb = false;
}
ib += 1;
cb = tb;
}
}
// compare digits with other symbols
if (isDigit(ca) && !isDigit(cb)) {
return -1;
}
if (!isDigit(ca) && isDigit(cb)) {
return 1;
}
// compare negative and positive
if (!sa && sb) {
return -1;
}
if (sa && !sb) {
return 1;
}
// count leading zeros
while (ca === zero) {
za += 1;
ia += 1;
ca = a.charCodeAt(ia);
}
while (cb === zero) {
zb += 1;
ib += 1;
cb = b.charCodeAt(ib);
}
// count numbers
while (isDigit(ca) || isDigit(cb)) {
if (isDigit(ca) && isDigit(cb) && bias === 0) {
if (sa) {
if (ca < cb) {
bias = -1;
} else if (ca > cb) {
bias = 1;
}
} else {
if (ca > cb) {
bias = -1;
} else if (ca < cb) {
bias = 1;
}
}
}
if (isDigit(ca)) {
ia += 1;
na += 1;
ca = a.charCodeAt(ia);
}
if (isDigit(cb)) {
ib += 1;
nb += 1;
cb = b.charCodeAt(ib);
}
}
// compare number length
if (sa) {
if (na < nb) {
return -1;
}
if (na > nb) {
return 1;
}
} else {
if (na > nb) {
return -1;
}
if (na < nb) {
return 1;
}
}
// compare numbers
if (bias) {
return bias;
}
// compare leading zeros
if (sa) {
if (za > zb) {
return -1;
}
if (za < zb) {
return 1;
}
} else {
if (za < zb) {
return -1;
}
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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