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function META () {
return {
name: "sha1Hash",
description: "SHA-1 Hash"
};
}
function str (x) {
warn(x);
if (x instanceof Object) {
warn('-> Node');
if (x.is_literal()) {
warn('-> literal');
warn(x.literal_value);
return x.literal_value;
} else if (x.is_resource()) {
warn('-> resource');
return x.uri_value;
} else {
warn('-> blank');
return x.blank_identifier;
}
} else {
warn('-> Non-Node');
return x;
}
}
function sha1Hash(msg)
{
msg = str(msg);
// constants [4.2.1]
var K = [0x5a827999, 0x6ed9eba1, 0x8f1bbcdc, 0xca62c1d6];
// PREPROCESSING
msg += String.fromCharCode(0x80); // add trailing '1' bit to string [5.1.1]
// convert string msg into 512-bit/16-integer blocks arrays of ints [5.2.1]
var l = Math.ceil(msg.length/4) + 2; // long enough to contain msg plus 2-word length
var N = Math.ceil(l/16); // in N 16-int blocks
var M = new Array(N);
for (var i=0; i<N; i++) {
M[i] = new Array(16);
for (var j=0; j<16; j++) { // encode 4 chars per integer, big-endian encoding
M[i][j] = (msg.charCodeAt(i*64+j*4)<<24) | (msg.charCodeAt(i*64+j*4+1)<<16) |
(msg.charCodeAt(i*64+j*4+2)<<8) | (msg.charCodeAt(i*64+j*4+3));
}
}
// add length (in bits) into final pair of 32-bit integers (big-endian) [5.1.1]
// note: most significant word would be ((len-1)*8 >>> 32, but since JS converts
// bitwise-op args to 32 bits, we need to simulate this by arithmetic operators
M[N-1][14] = ((msg.length-1)*8) / Math.pow(2, 32); M[N-1][14] = Math.floor(M[N-1][14])
M[N-1][15] = ((msg.length-1)*8) & 0xffffffff;
// set initial hash value [5.3.1]
var H0 = 0x67452301;
var H1 = 0xefcdab89;
var H2 = 0x98badcfe;
var H3 = 0x10325476;
var H4 = 0xc3d2e1f0;
// HASH COMPUTATION [6.1.2]
var W = new Array(80); var a, b, c, d, e;
for (var i=0; i<N; i++) {
// 1 - prepare message schedule 'W'
for (var t=0; t<16; t++) W[t] = M[i][t];
for (var t=16; t<80; t++) W[t] = ROTL(W[t-3] ^ W[t-8] ^ W[t-14] ^ W[t-16], 1);
// 2 - initialise five working variables a, b, c, d, e with previous hash value
a = H0; b = H1; c = H2; d = H3; e = H4;
// 3 - main loop
for (var t=0; t<80; t++) {
var s = Math.floor(t/20); // seq for blocks of 'f' functions and 'K' constants
var T = (ROTL(a,5) + f(s,b,c,d) + e + K[s] + W[t]) & 0xffffffff;
e = d;
d = c;
c = ROTL(b, 30);
b = a;
a = T;
}
// 4 - compute the new intermediate hash value
H0 = (H0+a) & 0xffffffff; // note 'addition modulo 2^32'
H1 = (H1+b) & 0xffffffff;
H2 = (H2+c) & 0xffffffff;
H3 = (H3+d) & 0xffffffff;
H4 = (H4+e) & 0xffffffff;
}
return H0.toHexStr() + H1.toHexStr() + H2.toHexStr() + H3.toHexStr() + H4.toHexStr();
}
//
// function 'f' [4.1.1]
//
function f(s, x, y, z)
{
switch (s) {
case 0: return (x & y) ^ (~x & z);
case 1: return x ^ y ^ z;
case 2: return (x & y) ^ (x & z) ^ (y & z);
case 3: return x ^ y ^ z;
}
}
//
// rotate left (circular left shift) value x by n positions [3.2.5]
//
function ROTL(x, n)
{
return (x<<n) | (x>>>(32-n));
}
//
// extend Number class with a tailored hex-string method
// (note toString(16) is implementation-dependant, and
// in IE returns signed numbers when used on full words)
//
Number.prototype.toHexStr = function()
{
var s="", v;
for (var i=7; i>=0; i--) { v = (this>>>(i*4)) & 0xf; s += v.toString(16); }
return s;
}
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