/*
This file is derived from the RSA Data Security, Inc.
MD5 Message-Digest Algorithm as implemented originally by Dr. Ron Rivest.
Original copyright notice follows:
*/

/* 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.
 */

#include "md5.h"
#include "xxmalloc.h"

#include <fcntl.h>
#include <unistd.h>

#include <sys/mman.h>
#include <sys/stat.h>

#include <errno.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>

#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

static const uint8_t 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) + (uint32_t)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }
#define GG(a, b, c, d, x, s, ac) { \
 (a) += G ((b), (c), (d)) + (x) + (uint32_t)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }
#define HH(a, b, c, d, x, s, ac) { \
 (a) += H ((b), (c), (d)) + (x) + (uint32_t)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }
#define II(a, b, c, d, x, s, ac) { \
 (a) += I ((b), (c), (d)) + (x) + (uint32_t)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }

/* MD5 initialization. Begins an MD5 operation, writing a new context.
 */
void md5_init(context)
	 md5_context_t *context;	/* 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;
}

/* Encodes input (uint32_t) into output (unsigned char). Assumes len is
  a multiple of 4.
 */
static void Encode(output, input, len)
	 uint8_t *output;
	 uint32_t *input;
	 size_t len;
{
	size_t i, j;

	for(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);
	}
}

/* Decodes input (unsigned char) into output (uint32_t). Assumes len is
  a multiple of 4.
 */
static void Decode(output, input, len)
	 uint32_t *output;
	 uint8_t *input;
	 size_t len;
{
	size_t i, j;

	for(i = 0, j = 0; j < len; i++, j += 4)
		output[i] = ((uint32_t) input[j]) | (((uint32_t) input[j + 1]) << 8) | (((uint32_t) input[j + 2]) << 16) | (((uint32_t) input[j + 3]) << 24);
}

/* MD5 basic transformation. Transforms state based on block.
 */
static void MD5Transform(state, block)
	 uint32_t state[4];
	 uint8_t block[64];
{
	uint32_t a = state[0], b = state[1], c = state[2], d = state[3], x[16];

	Decode(x, block, 64);

	/* 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, and updating the
  context.
 */
void md5_update(context, input, inputLen)
	 md5_context_t *context;	/* context */
	 const void *input;	/* input block */
	 size_t inputLen;	/* length of input block */
{
	size_t i, index, partLen;

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

	/* Update number of bits */
	if((context->count[0] += ((uint32_t) inputLen << 3))
	   < ((uint32_t) inputLen << 3))
		context->count[1]++;
	context->count[1] += ((uint32_t) inputLen >> 29);

	partLen = 64 - index;

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

		for(i = partLen; i + 63 < inputLen; i += 64)
			MD5Transform(context->state, (uint8_t *)input+i);

		index = 0;
	} else
		i = 0;

	/* Buffer remaining input */
	memcpy(&context->buffer[index], (uint8_t *)input+i, inputLen - i);
}

/* MD5 finalization. Ends an MD5 message-digest operation, writing the
  the message digest and zeroizing the context.
 */
void md5_final(digest, context)
	 unsigned char digest[16];	/* message digest */
	 md5_context_t *context;	/* context */
{
	uint8_t bits[8];
	size_t 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);
	md5_update(context, PADDING, padLen);

	/* Append length (before padding) */
	md5_update(context, bits, 8);

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

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

void md5_buffer(const void *buffer, size_t length, unsigned char digest[16])
{
	md5_context_t context;

	md5_init(&context);
	md5_update(&context, (const unsigned char *) buffer, length);
	md5_final(digest, &context);
}

#if defined(CCTOOLS_OPSYS_DARWIN) || defined(CCTOOLS_OPSYS_CYGWIN) || defined (CCTOOLS_OPSYS_FREEBSD)
#define stat64 stat
#endif

#define BUFFER_SIZE (1<<20)
int md5_file(const char *filename, unsigned char digest[20])
{
	int fd;
	struct stat buf;
	md5_context_t context;
	md5_init(&context);

	fd = open(filename, O_RDONLY);
	if (fd == -1)
		return 0;

	if (fstat(fd, &buf) == -1) {
		close(fd);
		return 0;
	}

	void *data = mmap(NULL, buf.st_size, PROT_READ, MAP_SHARED, fd, 0);
	if (data == MAP_FAILED) {
		void *buffer = xxmalloc(BUFFER_SIZE);
		ssize_t n;
		while ((n = read(fd, buffer, BUFFER_SIZE)) > 0) {
			md5_update(&context, buffer, n);
		}
		free(buffer);
		close(fd);
	} else {
		close(fd);
		posix_madvise(data, buf.st_size, POSIX_MADV_SEQUENTIAL);
		md5_update(&context, data, buf.st_size);
		munmap(data, buf.st_size);
	}

	md5_final(digest, &context);

	return 1;
}

const char *md5_string(unsigned char digest[16])
{
	static char str[33];
	int i;
	for(i = 0; i < 16; i++) {
		sprintf(&str[i * 2], "%02x", (unsigned) digest[i]);
	}
	str[32] = 0;
	return str;
}

char *md5_cal(const char *s) {
	unsigned char digest[MD5_DIGEST_LENGTH_HEX];
	md5_context_t context;
	char *p = NULL;

	p = malloc(sizeof(char) * (MD5_DIGEST_LENGTH_HEX+1));
	if(!p) {
		return NULL;
	}

	md5_init(&context);
	md5_update(&context, (const unsigned char *)s, strlen(s));
	md5_final(digest, &context);
	sprintf(p, "%s", md5_string(digest));
	return p;
}

/* vim: set noexpandtab tabstop=4: */
