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add md5 hash function
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Chris Dyer committed Sep 16, 2011
1 parent 9acb1f9 commit 445c624
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363 changes: 363 additions & 0 deletions utils/stringlib.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -90,3 +90,366 @@ void ProcessAndStripSGML(string* pline, map<string, string>* out) {
}
}

string SGMLOpenSegTag(const map<string, string>& attr) {
ostringstream os;
os << "<seg";
for (map<string,string>::const_iterator it = attr.begin(); it != attr.end(); ++it)
os << ' ' << it->first << '=' << '"' << it->second << '"';
os << '>';
return os.str();
}

class MD5 {
public:
typedef unsigned int size_type; // must be 32bit

MD5();
MD5(const std::string& text);
void update(const unsigned char *buf, size_type length);
void update(const char *buf, size_type length);
MD5& finalize();
std::string hexdigest() const;

private:
void init();
typedef unsigned char uint1; // 8bit
typedef unsigned int uint4; // 32bit
enum {blocksize = 64}; // VC6 won't eat a const static int here

void transform(const uint1 block[blocksize]);
static void decode(uint4 output[], const uint1 input[], size_type len);
static void encode(uint1 output[], const uint4 input[], size_type len);

bool finalized;
uint1 buffer[blocksize]; // bytes that didn't fit in last 64 byte chunk
uint4 count[2]; // 64bit counter for number of bits (lo, hi)
uint4 state[4]; // digest so far
uint1 digest[16]; // the result

// low level logic operations
static inline uint4 F(uint4 x, uint4 y, uint4 z);
static inline uint4 G(uint4 x, uint4 y, uint4 z);
static inline uint4 H(uint4 x, uint4 y, uint4 z);
static inline uint4 I(uint4 x, uint4 y, uint4 z);
static inline uint4 rotate_left(uint4 x, int n);
static inline void FF(uint4 &a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac);
static inline void GG(uint4 &a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac);
static inline void HH(uint4 &a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac);
static inline void II(uint4 &a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac);
};

// Constants for MD5Transform routine.
#define S11 7
#define S12 12
#define S13 17
#define S14 22
#define S21 5
#define S22 9
#define S23 14
#define S24 20
#define S31 4
#define S32 11
#define S33 16
#define S34 23
#define S41 6
#define S42 10
#define S43 15
#define S44 21

///////////////////////////////////////////////

// F, G, H and I are basic MD5 functions.
inline MD5::uint4 MD5::F(uint4 x, uint4 y, uint4 z) {
return (x&y) | (~x&z);
}

inline MD5::uint4 MD5::G(uint4 x, uint4 y, uint4 z) {
return (x&z) | (y&~z);
}

inline MD5::uint4 MD5::H(uint4 x, uint4 y, uint4 z) {
return x^y^z;
}

inline MD5::uint4 MD5::I(uint4 x, uint4 y, uint4 z) {
return y ^ (x | ~z);
}

// rotate_left rotates x left n bits.
inline MD5::uint4 MD5::rotate_left(uint4 x, int n) {
return (x << n) | (x >> (32-n));
}

// FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
// Rotation is separate from addition to prevent recomputation.
inline void MD5::FF(uint4 &a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac) {
a = rotate_left(a+ F(b,c,d) + x + ac, s) + b;
}

inline void MD5::GG(uint4 &a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac) {
a = rotate_left(a + G(b,c,d) + x + ac, s) + b;
}

inline void MD5::HH(uint4 &a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac) {
a = rotate_left(a + H(b,c,d) + x + ac, s) + b;
}

inline void MD5::II(uint4 &a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac) {
a = rotate_left(a + I(b,c,d) + x + ac, s) + b;
}

//////////////////////////////////////////////

// default ctor, just initailize
MD5::MD5()
{
init();
}

//////////////////////////////////////////////

// nifty shortcut ctor, compute MD5 for string and finalize it right away
MD5::MD5(const std::string &text)
{
init();
update(text.c_str(), text.length());
finalize();
}

//////////////////////////////

void MD5::init()
{
finalized=false;

count[0] = 0;
count[1] = 0;

// load magic initialization constants.
state[0] = 0x67452301;
state[1] = 0xefcdab89;
state[2] = 0x98badcfe;
state[3] = 0x10325476;
}

//////////////////////////////

// decodes input (unsigned char) into output (uint4). Assumes len is a multiple of 4.
void MD5::decode(uint4 output[], const uint1 input[], size_type len)
{
for (unsigned int i = 0, j = 0; j < len; i++, j += 4)
output[i] = ((uint4)input[j]) | (((uint4)input[j+1]) << 8) |
(((uint4)input[j+2]) << 16) | (((uint4)input[j+3]) << 24);
}

//////////////////////////////

// encodes input (uint4) into output (unsigned char). Assumes len is
// a multiple of 4.
void MD5::encode(uint1 output[], const uint4 input[], size_type len)
{
for (size_type i = 0, j = 0; j < len; i++, j += 4) {
output[j] = input[i] & 0xff;
output[j+1] = (input[i] >> 8) & 0xff;
output[j+2] = (input[i] >> 16) & 0xff;
output[j+3] = (input[i] >> 24) & 0xff;
}
}

//////////////////////////////

// apply MD5 algo on a block
void MD5::transform(const uint1 block[blocksize])
{
uint4 a = state[0], b = state[1], c = state[2], d = state[3], x[16];
decode (x, block, blocksize);

/* Round 1 */
FF (a, b, c, d, x[ 0], S11, 0xd76aa478); /* 1 */
FF (d, a, b, c, x[ 1], S12, 0xe8c7b756); /* 2 */
FF (c, d, a, b, x[ 2], S13, 0x242070db); /* 3 */
FF (b, c, d, a, x[ 3], S14, 0xc1bdceee); /* 4 */
FF (a, b, c, d, x[ 4], S11, 0xf57c0faf); /* 5 */
FF (d, a, b, c, x[ 5], S12, 0x4787c62a); /* 6 */
FF (c, d, a, b, x[ 6], S13, 0xa8304613); /* 7 */
FF (b, c, d, a, x[ 7], S14, 0xfd469501); /* 8 */
FF (a, b, c, d, x[ 8], S11, 0x698098d8); /* 9 */
FF (d, a, b, c, x[ 9], S12, 0x8b44f7af); /* 10 */
FF (c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
FF (b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
FF (a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
FF (d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
FF (c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
FF (b, c, d, a, x[15], S14, 0x49b40821); /* 16 */

/* Round 2 */
GG (a, b, c, d, x[ 1], S21, 0xf61e2562); /* 17 */
GG (d, a, b, c, x[ 6], S22, 0xc040b340); /* 18 */
GG (c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aa); /* 20 */
GG (a, b, c, d, x[ 5], S21, 0xd62f105d); /* 21 */
GG (d, a, b, c, x[10], S22, 0x2441453); /* 22 */
GG (c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8); /* 24 */
GG (a, b, c, d, x[ 9], S21, 0x21e1cde6); /* 25 */
GG (d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
GG (c, d, a, b, x[ 3], S23, 0xf4d50d87); /* 27 */
GG (b, c, d, a, x[ 8], S24, 0x455a14ed); /* 28 */
GG (a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8); /* 30 */
GG (c, d, a, b, x[ 7], S23, 0x676f02d9); /* 31 */
GG (b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */

/* Round 3 */
HH (a, b, c, d, x[ 5], S31, 0xfffa3942); /* 33 */
HH (d, a, b, c, x[ 8], S32, 0x8771f681); /* 34 */
HH (c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
HH (b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
HH (a, b, c, d, x[ 1], S31, 0xa4beea44); /* 37 */
HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9); /* 38 */
HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60); /* 39 */
HH (b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
HH (a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
HH (d, a, b, c, x[ 0], S32, 0xeaa127fa); /* 42 */
HH (c, d, a, b, x[ 3], S33, 0xd4ef3085); /* 43 */
HH (b, c, d, a, x[ 6], S34, 0x4881d05); /* 44 */
HH (a, b, c, d, x[ 9], S31, 0xd9d4d039); /* 45 */
HH (d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
HH (c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
HH (b, c, d, a, x[ 2], S34, 0xc4ac5665); /* 48 */

/* Round 4 */
II (a, b, c, d, x[ 0], S41, 0xf4292244); /* 49 */
II (d, a, b, c, x[ 7], S42, 0x432aff97); /* 50 */
II (c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
II (b, c, d, a, x[ 5], S44, 0xfc93a039); /* 52 */
II (a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
II (d, a, b, c, x[ 3], S42, 0x8f0ccc92); /* 54 */
II (c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
II (b, c, d, a, x[ 1], S44, 0x85845dd1); /* 56 */
II (a, b, c, d, x[ 8], S41, 0x6fa87e4f); /* 57 */
II (d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
II (c, d, a, b, x[ 6], S43, 0xa3014314); /* 59 */
II (b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
II (a, b, c, d, x[ 4], S41, 0xf7537e82); /* 61 */
II (d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb); /* 63 */
II (b, c, d, a, x[ 9], S44, 0xeb86d391); /* 64 */

state[0] += a;
state[1] += b;
state[2] += c;
state[3] += d;

// Zeroize sensitive information.
memset(x, 0, sizeof x);
}

//////////////////////////////

// MD5 block update operation. Continues an MD5 message-digest
// operation, processing another message block
void MD5::update(const unsigned char input[], size_type length)
{
// compute number of bytes mod 64
size_type index = count[0] / 8 % blocksize;

// Update number of bits
if ((count[0] += (length << 3)) < (length << 3))
count[1]++;
count[1] += (length >> 29);

// number of bytes we need to fill in buffer
size_type firstpart = 64 - index;

size_type i;

// transform as many times as possible.
if (length >= firstpart)
{
// fill buffer first, transform
memcpy(&buffer[index], input, firstpart);
transform(buffer);

// transform chunks of blocksize (64 bytes)
for (i = firstpart; i + blocksize <= length; i += blocksize)
transform(&input[i]);

index = 0;
}
else
i = 0;

// buffer remaining input
memcpy(&buffer[index], &input[i], length-i);
}

//////////////////////////////

// for convenience provide a verson with signed char
void MD5::update(const char input[], size_type length)
{
update((const unsigned char*)input, length);
}

//////////////////////////////

// MD5 finalization. Ends an MD5 message-digest operation, writing the
// the message digest and zeroizing the context.
MD5& MD5::finalize()
{
static unsigned char padding[64] = {
0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};

if (!finalized) {
// Save number of bits
unsigned char bits[8];
encode(bits, count, 8);

// pad out to 56 mod 64.
size_type index = count[0] / 8 % 64;
size_type padLen = (index < 56) ? (56 - index) : (120 - index);
update(padding, padLen);

// Append length (before padding)
update(bits, 8);

// Store state in digest
encode(digest, state, 16);

// Zeroize sensitive information.
memset(buffer, 0, sizeof buffer);
memset(count, 0, sizeof count);

finalized=true;
}

return *this;
}

//////////////////////////////

// return hex representation of digest as string
std::string MD5::hexdigest() const
{
if (!finalized)
return "";

char buf[33];
for (int i=0; i<16; i++)
sprintf(buf+i*2, "%02x", digest[i]);
buf[32]=0;

return std::string(buf);
}

//////////////////////////////

std::string md5(const std::string& str) {
MD5 md5 = MD5(str);
return md5.hexdigest();
}

3 changes: 3 additions & 0 deletions utils/stringlib.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -249,6 +249,7 @@ inline void SplitCommandAndParam(const std::string& in, std::string* cmd, std::s
}

void ProcessAndStripSGML(std::string* line, std::map<std::string, std::string>* out);
std::string SGMLOpenSegTag(const std::map<std::string, std::string>& attr);

// given the first character of a UTF8 block, find out how wide it is
// see http://en.wikipedia.org/wiki/UTF-8 for more info
Expand All @@ -260,4 +261,6 @@ inline unsigned int UTF8Len(unsigned char x) {
else return 0;
}

std::string md5(const std::string& in);

#endif
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