96 lines
2.5 KiB
JavaScript
96 lines
2.5 KiB
JavaScript
'use strict';
|
|
|
|
Ox.oshash = function (file, callback) {
|
|
|
|
// Needs to go via string to work for files > 2GB
|
|
var hash = fromString(file.size.toString());
|
|
|
|
read(0);
|
|
|
|
function add(A, B) {
|
|
var a, b, c, d;
|
|
d = A[3] + B[3];
|
|
c = A[2] + B[2] + (d >> 16);
|
|
d &= 0xffff;
|
|
b = A[1] + B[1] + (c >> 16);
|
|
c &= 0xffff;
|
|
a = A[0] + B[0] + (b >> 16);
|
|
b &= 0xffff;
|
|
// Cut off overflow
|
|
a &= 0xffff;
|
|
return [a, b, c, d];
|
|
}
|
|
|
|
function fromData(s, offset) {
|
|
offset = offset || 0;
|
|
return [
|
|
s.charCodeAt(offset + 6) + (s.charCodeAt(offset + 7) << 8),
|
|
s.charCodeAt(offset + 4) + (s.charCodeAt(offset + 5) << 8),
|
|
s.charCodeAt(offset + 2) + (s.charCodeAt(offset + 3) << 8),
|
|
s.charCodeAt(offset + 0) + (s.charCodeAt(offset + 1) << 8)
|
|
];
|
|
}
|
|
|
|
function fromString(str) {
|
|
var base = 10,
|
|
blen = 1,
|
|
i,
|
|
num,
|
|
pos,
|
|
r = [0, 0, 0, 0];
|
|
for (pos = 0; pos < str.length; pos++) {
|
|
num = parseInt(str.charAt(pos), base);
|
|
i = 0;
|
|
do {
|
|
while (i < blen) {
|
|
num += r[3 - i] * base;
|
|
r[3 - i++] = (num & 0xFFFF);
|
|
num >>>= 16;
|
|
}
|
|
if (num) {
|
|
blen++;
|
|
}
|
|
} while (num);
|
|
}
|
|
return r;
|
|
}
|
|
|
|
function pad(string, length, padding) {
|
|
padding = Ox.repeat(padding, length - string.length);
|
|
return (padding + string).slice(-length);
|
|
};
|
|
|
|
function hex(h) {
|
|
return (
|
|
pad(h[0].toString(16), 4, '0')
|
|
+ pad(h[1].toString(16), 4, '0')
|
|
+ pad(h[2].toString(16), 4, '0')
|
|
+ pad(h[3].toString(16), 4, '0')
|
|
).toLowerCase();
|
|
}
|
|
|
|
function read(offset, last) {
|
|
var blob,
|
|
block = 65536,
|
|
length = 8,
|
|
reader = new FileReader();
|
|
reader.onload = function(data) {
|
|
var s = data.target.result,
|
|
s_length = s.length - length,
|
|
i;
|
|
for (i = 0; i <= s_length; i += length) {
|
|
hash = add(hash, fromData(s, i));
|
|
}
|
|
if (file.size < block || last) {
|
|
callback(hex(hash));
|
|
} else {
|
|
read(file.size - block, true);
|
|
}
|
|
};
|
|
|
|
blob = file.slice(offset, offset + block);
|
|
reader.readAsBinaryString(blob);
|
|
}
|
|
|
|
};
|