/*
 * MD5C.C - RSA Data Security, Inc., MD5 message-digest algorithm
 *
 * Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All
 * rights reserved.
 *
 * License to copy and use this software is granted provided that it
 * is identified as the "RSA Data Security, Inc. MD5 Message-Digest
 * Algorithm" in all material mentioning or referencing this software
 * or this function.
 *
 * License is also granted to make and use derivative works provided
 * that such works are identified as "derived from the RSA Data
 * Security, Inc. MD5 Message-Digest Algorithm" in all material
 * mentioning or referencing the derived work.
 *
 * RSA Data Security, Inc. makes no representations concerning either
 * the merchantability of this software or the suitability of this
 * software for any particular purpose. It is provided "as is"
 * without express or implied warranty of any kind.
 *
 * These notices must be retained in any copies of any part of this
 * documentation and/or software.
 *
 * $FreeBSD: src/lib/libmd/md5c.c,v 1.11 1999/12/29 05:04:20 peter Exp $
 *
 * This code is the same as the code published by RSA Inc.  It has been
 * edited for clarity and style only.
 */
#ifndef TEST_MD5
#include <stdio.h>
#include <string.h>

#include "md5.h"

typedef unsigned int md5uint32;

static void MD5Transform(md5uint32 [4], const unsigned char [64]);

#ifdef i386
#define Encode memcpy
#define Decode memcpy
#else /* i386 */

/*
 * Encodes input (md5uint32) into output (unsigned char). Assumes len is
 * a multiple of 4.
 */

static void
Encode (unsigned char *output, md5uint32 *input, unsigned int len)
{
	unsigned int i, j;

	for (i = 0, j = 0; j < len; i++, j += 4) {
		output[j] = (unsigned char)(input[i] & 0xff);
		output[j+1] = (unsigned char)((input[i] >> 8) & 0xff);
		output[j+2] = (unsigned char)((input[i] >> 16) & 0xff);
		output[j+3] = (unsigned char)((input[i] >> 24) & 0xff);
	}
}

/*
 * Decodes input (unsigned char) into output (md5uint32). Assumes len is
 * a multiple of 4.
 */

static void
Decode (md5uint32 *output, const unsigned char *input, unsigned int len)
{
	unsigned int i, j;

	for (i = 0, j = 0; j < len; i++, j += 4)
		output[i] = ((md5uint32)input[j]) | (((md5uint32)input[j+1]) << 8) |
		    (((md5uint32)input[j+2]) << 16) | (((md5uint32)input[j+3]) << 24);
}
#endif /* i386 */

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
};

/* F, G, H and I are basic MD5 functions. */
#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define I(x, y, z) ((y) ^ ((x) | (~z)))

/* ROTATE_LEFT rotates x left n bits. */
#define ROTATE_LEFT(x, n) (((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.
 */
#define FF(a, b, c, d, x, s, ac) { \
	(a) += F ((b), (c), (d)) + (x) + (md5uint32)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
	}
#define GG(a, b, c, d, x, s, ac) { \
	(a) += G ((b), (c), (d)) + (x) + (md5uint32)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
	}
#define HH(a, b, c, d, x, s, ac) { \
	(a) += H ((b), (c), (d)) + (x) + (md5uint32)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
	}
#define II(a, b, c, d, x, s, ac) { \
	(a) += I ((b), (c), (d)) + (x) + (md5uint32)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
	}

/* MD5 initialization. Begins an MD5 operation, writing a new context. */

void
MD5Init (MD5_CTX *context)
{

	context->count[0] = context->count[1] = 0;

	/* Load magic initialization constants.  */
	context->state[0] = 0x67452301;
	context->state[1] = 0xefcdab89;
	context->state[2] = 0x98badcfe;
	context->state[3] = 0x10325476;
}

/* 
 * MD5 block update operation. Continues an MD5 message-digest
 * operation, processing another message block, and updating the
 * context.
 */

void
MD5Update (MD5_CTX *context, const unsigned char *input, unsigned int inputLen)
{
	unsigned int i, index, partLen;

	/* Compute number of bytes mod 64 */
	index = (unsigned int)((context->count[0] >> 3) & 0x3F);

	/* Update number of bits */
	if ((context->count[0] += ((md5uint32)inputLen << 3))
	    < ((md5uint32)inputLen << 3))
		context->count[1]++;
	context->count[1] += ((md5uint32)inputLen >> 29);

	partLen = 64 - index;

	/* Transform as many times as possible. */
	if (inputLen >= partLen) {
		memcpy((void *)&context->buffer[index], (const void *)input,
		    partLen);
		MD5Transform (context->state, context->buffer);

		for (i = partLen; i + 63 < inputLen; i += 64)
			MD5Transform (context->state, &input[i]);

		index = 0;
	}
	else
		i = 0;

	/* Buffer remaining input */
	memcpy ((void *)&context->buffer[index], (const void *)&input[i],
	    inputLen-i);
}

/*
 * MD5 padding. Adds padding followed by original length.
 */

void
MD5Pad (MD5_CTX *context)
{
	unsigned char bits[8];
	unsigned int index, padLen;

	/* Save number of bits */
	Encode (bits, context->count, 8);

	/* Pad out to 56 mod 64. */
	index = (unsigned int)((context->count[0] >> 3) & 0x3f);
	padLen = (index < 56) ? (56 - index) : (120 - index);
	MD5Update (context, PADDING, padLen);

	/* Append length (before padding) */
	MD5Update (context, bits, 8);
}

/*
 * MD5 finalization. Ends an MD5 message-digest operation, writing the
 * the message digest and zeroizing the context.
 */

void
MD5Final (unsigned char digest[16],MD5_CTX *context)
{
	/* Do padding. */
	MD5Pad (context);

	/* Store state in digest */
	Encode (digest, context->state, 16);

	/* Zeroize sensitive information. */
	memset ((void *)context, 0, sizeof (*context));
}

/* MD5 basic transformation. Transforms state based on block. */

static void
MD5Transform (md5uint32 state[4], const unsigned char block[64])
{
	md5uint32 a = state[0], b = state[1], c = state[2], d = state[3], x[16];

	Decode (x, block, 64);

	/* Round 1 */
#define S11 7
#define S12 12
#define S13 17
#define S14 22
	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 */
#define S21 5
#define S22 9
#define S23 14
#define S24 20
	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 */
#define S31 4
#define S32 11
#define S33 16
#define S34 23
	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 */
#define S41 6
#define S42 10
#define S43 15
#define S44 21
	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 ((void *)x, 0, sizeof (x));
}

/*************** Convenience  / utilities */
void MD5Final(string &digest, MD5_CTX *context)
{
    unsigned char d[16];
    MD5Final (d, context);
    digest.assign((const char *)d, 16);
}

string& MD5String(const string& data, string& digest)
{
    MD5_CTX ctx;
    MD5Init(&ctx);
    MD5Update(&ctx, (const unsigned char*)data.c_str(), data.length());
    MD5Final(digest, &ctx);
    return digest;
}

string& MD5HexPrint(const string& digest, string &out)
{
    out.erase();
    out.reserve(33);
    static const char hex[]="0123456789abcdef";
    const unsigned char *hash = (const unsigned char *)digest.c_str();
    for (int i = 0; i < 16; i++) {
	out.append(1, hex[hash[i] >> 4]);
	out.append(1, hex[hash[i] & 0x0f]);
    }
    return out;
}
string& MD5HexScan(const string& xdigest, string& digest)
{
    digest.erase();
    if (xdigest.length() != 32) {
	return digest;
    }
    for (unsigned int i = 0; i < 16; i++) {
	unsigned int val;
	if (sscanf(xdigest.c_str() + 2*i, "%2x", &val) != 1) {
	    digest.erase();
	    return digest;
	}
	digest.append(1, (unsigned char)val);
    }
    return digest;
}

#include "readfile.h"
class FileScanMd5 : public FileScanDo {
public:
    FileScanMd5(string& d) : digest(d) {}
    virtual bool init(unsigned int size, string *reason) 
    {
	MD5Init(&ctx);
	return true;
    }
    virtual bool data(const char *buf, int cnt, string* reason) 
    {
	MD5Update(&ctx, (const unsigned char*)buf, cnt);
	return true;
    }
    string &digest;
    MD5_CTX ctx;
};
bool MD5File(const string& filename, string &digest, string *reason)
{
    FileScanMd5 md5er(digest);
    if (!file_scan(filename, &md5er, reason))
	return false;
    // We happen to know that digest and md5er.digest are the same object
    MD5Final(md5er.digest, &md5er.ctx);
    return true;
}
#else

// Test driver
#include <stdlib.h>

#include <string>
#include <iostream>
#include "md5.h"

using namespace std;

static const char *thisprog;
static char usage [] =
"trmd5 filename\n\n"
;
static void
Usage(void)
{
    fprintf(stderr, "%s: usage:\n%s", thisprog, usage);
    exit(1);
}

int main(int argc, const char **argv)
{
    thisprog = argv[0];
    argc--; argv++;

  if (argc != 1)
    Usage();
  string filename =  *argv++;argc--;

  string reason, digest;
  if (!MD5File(filename, digest, &reason)) {
      cerr << reason << endl;
      exit(1);
  } else {
      string hex;
      cout <<  "MD5 (" << filename << ") = " << MD5HexPrint(digest, hex) << endl;

      string digest1;
      MD5HexScan(hex, digest1);
      if (digest1.compare(digest)) {
	  cout << "MD5HexScan Failure" << endl;
	  cout <<  MD5HexPrint(digest, hex) << " " << digest.length() << " -> " 
	       << MD5HexPrint(digest1, hex) << " " << digest1.length() << endl;
	  exit(1);
      }

  }
  exit(0);
}

#endif