aaac7fed
 liuqimichale
add
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module.exports = function bufferIndexOf(buff, search, offset, encoding){
if (!Buffer.isBuffer(buff)) {
throw TypeError('buffer is not a buffer');
}
// allow optional offset when providing an encoding
if (encoding === undefined && typeof offset === 'string') {
encoding = offset;
offset = undefined;
}
if (typeof search === 'string') {
search = new Buffer(search, encoding || 'utf8');
} else if (typeof search === 'number' && !isNaN(search)) {
search = new Buffer([search])
} else if (!Buffer.isBuffer(search)) {
throw TypeError('search is not a bufferable object');
}
if (search.length === 0) {
return -1;
}
if (offset === undefined || (typeof offset === 'number' && isNaN(offset))) {
offset = 0;
} else if (typeof offset !== 'number') {
throw TypeError('offset is not a number');
}
if (offset < 0) {
offset = buff.length + offset
}
if (offset < 0) {
offset = 0;
}
var m = 0;
var s = -1;
for (var i = offset; i < buff.length ; ++i) {
if(buff[i] != search[m]){
s = -1;
// <-- go back
// match abc to aabc
// 'aabc'
// 'aab'
// ^ no match
// a'abc'
// ^ set index here now and look at these again.
// 'abc' yay!
i -= m-1
m = 0;
}
if(buff[i] == search[m]) {
if(s == -1) {
s = i;
}
++m;
if(m == search.length) {
break;
}
}
}
if (s > -1 && buff.length - s < search.length) {
return -1;
}
return s;
}
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