//SHA1.cpp
#include <string>
std::string SHA1(std::string s)
{
const char HEX_CHAR[]={'0', '1', '2', '3', '4', '5', '6', '7',
'8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
const unsigned long K[] = {0x5A827999, 0x6ED9EBA1, 0x8F1BBCDC, 0xCA62C1D6};
//擴展成K*512位
unsigned long *data;
int l;
l = s.length()*8;
data = new unsigned long[((l/512)+1)*512];
memset(data, 0, sizeof(data[0])*((l/512)+1)*512);
for(unsigned int i = 0; i < s.length(); ++i){
data[i / 4] |= s[i] << 8*(3 - (i % 4));
}
data[s.length() / 4] |= 0x80 << 8*(3-(s.length()%4));
data[((l/512)+1)*512/32-1]=l;
l = (l/512)+1;
//開始計算
unsigned long H[5], G[5];
H[0] = G[0] = 0x67452301;
H[1] = G[1] = 0xEFCDAB89;
H[2] = G[2] = 0x98BADCFE;
H[3] = G[3] = 0x10325476;
H[4] = G[4] = 0xC3D2E1F0;
for(int i = 0; i<l; ++i){
unsigned long W[80];
int t;
for(t = 0; t<16; ++t)
W[t] = data[i*16+t];
for(t = 16; t<80; ++t){
unsigned long tmp = W[t-3] ^ W[t-8] ^ W[t-14] ^ W[t-16];
W[t] = (tmp << 1)|(tmp >> 31);
}
unsigned long tmp;
for(t = 0; t<5; ++t)
H[t] = G[t];
for(t = 0; t<20; ++t){
tmp = ((H[0] << 5) | (H[0] >> 27)) + ((H[1] & H[2]) | (~ H[1] & H[3])) + H[4] + W[t] + K[0];
H[4] = H[3]; H[3] = H[2]; H[2] = (H[1]<<30)|(H[1] >> 2); H[1] = H[0]; H[0] = tmp;
}
for(t = 20; t<40; ++t){
tmp = ((H[0] << 5) | (H[0] >> 27)) + (H[1] ^ H[2] ^ H[3]) + H[4] + W[t] + K[1];
H[4] = H[3]; H[3] = H[2]; H[2] = (H[1]<<30)|(H[1] >> 2); H[1] = H[0]; H[0] = tmp;
}
for(t = 40; t<60; ++t){
tmp = ((H[0] << 5) | (H[0] >> 27)) + ((H[1] & H[2])|(H[2] & H[3])|(H[1] & H[3])) + H[4] + W[t] + K[2];
H[4] = H[3]; H[3] = H[2]; H[2] = (H[1]<<30)|(H[1] >> 2); H[1] = H[0]; H[0] = tmp;
}
for(t = 60; t<80; ++t){
tmp = ((H[0] << 5) | (H[0] >> 27)) + (H[1] ^ H[2] ^ H[3]) + H[4] + W[t] + K[3];
H[4] = H[3]; H[3] = H[2]; H[2] = (H[1]<<30)|(H[1] >> 2); H[1] = H[0]; H[0] = tmp;
}
for(t = 0; t<5; ++t)
G[t] += H[t];
}
delete data;
char buf[41];
for(int i = 0; i<40; ++i){
buf[i] = HEX_CHAR[(G[i / 8] >> (4*(7- (i % 8))))&0xf];
}
buf[40] = '\0';
return std::string(buf);
}
//Test
//#include <iostream>
//using namespace std;
//int main(int argc, char* argv[])
//{
// char s[100];
// while(true){
// scanf("%s", s);
// cout << SHA1(s)<< endl;
// }
// return 0;
//}