/**
 * YMD5.cpp
 * This file is part of the YATE Project http://YATE.null.ro
 *
 * Authors: Colin Plumb, Constantin Bergemann
 * Adapted for YATE by Paul Chitescu
 *
 * Yet Another Telephony Engine - a fully featured software PBX and IVR
 * Copyright (C) 2004-2014 Null Team
 *
 * This software is distributed under multiple licenses;
 * see the COPYING file in the main directory for licensing
 * information for this specific distribution.
 *
 * This use of this software may be subject to additional restrictions.
 * See the LEGAL file in the main directory for details.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 */

#include "yateclass.h"

#include <stdlib.h>
#include <string.h>

#define MD5_HASHBYTES 16

typedef struct MD5Context {
    u_int32_t buf[4];
    u_int32_t bits[2];
    unsigned char in[64];
} MD5_CTX;


#if !(defined(WORDS_BIGENDIAN) || defined(BIGENDIAN))
#define byteReverse(buf, len)	/* Nothing */
#else

/*
 * Note: this code is harmless on little-endian machines.
 */
static void byteReverse(unsigned char *buf, unsigned longs)
{
    u_int32_t t;
    do {
	t = (u_int32_t) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
	    ((unsigned) buf[1] << 8 | buf[0]);
	*(u_int32_t *) buf = t;
	buf += 4;
    } while (--longs);
}
#endif

/* The four core functions - F1 is optimized somewhat */

/* #define F1(x, y, z) (x & y | ~x & z) */
#define F1(x, y, z) (z ^ (x & (y ^ z)))
#define F2(x, y, z) F1(z, x, y)
#define F3(x, y, z) (x ^ y ^ z)
#define F4(x, y, z) (y ^ (x | ~z))

/* This is the central step in the MD5 algorithm. */
#define MD5STEP(f, w, x, y, z, data, s) \
	( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )

/*
 * The core of the MD5 algorithm, this alters an existing MD5 hash to
 * reflect the addition of 16 longwords of new data.  MD5Update blocks
 * the data and converts bytes into longwords for this routine.
 */
static void MD5Transform(u_int32_t buf[4], u_int32_t const in[16])
{
    register u_int32_t a, b, c, d;

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

    MD5STEP(F1, a, b, c, d,  in[0] + 0xd76aa478,  7);
    MD5STEP(F1, d, a, b, c,  in[1] + 0xe8c7b756, 12);
    MD5STEP(F1, c, d, a, b,  in[2] + 0x242070db, 17);
    MD5STEP(F1, b, c, d, a,  in[3] + 0xc1bdceee, 22);
    MD5STEP(F1, a, b, c, d,  in[4] + 0xf57c0faf,  7);
    MD5STEP(F1, d, a, b, c,  in[5] + 0x4787c62a, 12);
    MD5STEP(F1, c, d, a, b,  in[6] + 0xa8304613, 17);
    MD5STEP(F1, b, c, d, a,  in[7] + 0xfd469501, 22);
    MD5STEP(F1, a, b, c, d,  in[8] + 0x698098d8,  7);
    MD5STEP(F1, d, a, b, c,  in[9] + 0x8b44f7af, 12);
    MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
    MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
    MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122,  7);
    MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
    MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
    MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);

    MD5STEP(F2, a, b, c, d,  in[1] + 0xf61e2562,  5);
    MD5STEP(F2, d, a, b, c,  in[6] + 0xc040b340,  9);
    MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
    MD5STEP(F2, b, c, d, a,  in[0] + 0xe9b6c7aa, 20);
    MD5STEP(F2, a, b, c, d,  in[5] + 0xd62f105d,  5);
    MD5STEP(F2, d, a, b, c, in[10] + 0x02441453,  9);
    MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
    MD5STEP(F2, b, c, d, a,  in[4] + 0xe7d3fbc8, 20);
    MD5STEP(F2, a, b, c, d,  in[9] + 0x21e1cde6,  5);
    MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6,  9);
    MD5STEP(F2, c, d, a, b,  in[3] + 0xf4d50d87, 14);
    MD5STEP(F2, b, c, d, a,  in[8] + 0x455a14ed, 20);
    MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905,  5);
    MD5STEP(F2, d, a, b, c,  in[2] + 0xfcefa3f8,  9);
    MD5STEP(F2, c, d, a, b,  in[7] + 0x676f02d9, 14);
    MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);

    MD5STEP(F3, a, b, c, d,  in[5] + 0xfffa3942,  4);
    MD5STEP(F3, d, a, b, c,  in[8] + 0x8771f681, 11);
    MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
    MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
    MD5STEP(F3, a, b, c, d,  in[1] + 0xa4beea44,  4);
    MD5STEP(F3, d, a, b, c,  in[4] + 0x4bdecfa9, 11);
    MD5STEP(F3, c, d, a, b,  in[7] + 0xf6bb4b60, 16);
    MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
    MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6,  4);
    MD5STEP(F3, d, a, b, c,  in[0] + 0xeaa127fa, 11);
    MD5STEP(F3, c, d, a, b,  in[3] + 0xd4ef3085, 16);
    MD5STEP(F3, b, c, d, a,  in[6] + 0x04881d05, 23);
    MD5STEP(F3, a, b, c, d,  in[9] + 0xd9d4d039,  4);
    MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
    MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
    MD5STEP(F3, b, c, d, a,  in[2] + 0xc4ac5665, 23);

    MD5STEP(F4, a, b, c, d,  in[0] + 0xf4292244,  6);
    MD5STEP(F4, d, a, b, c,  in[7] + 0x432aff97, 10);
    MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
    MD5STEP(F4, b, c, d, a,  in[5] + 0xfc93a039, 21);
    MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3,  6);
    MD5STEP(F4, d, a, b, c,  in[3] + 0x8f0ccc92, 10);
    MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
    MD5STEP(F4, b, c, d, a,  in[1] + 0x85845dd1, 21);
    MD5STEP(F4, a, b, c, d,  in[8] + 0x6fa87e4f,  6);
    MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
    MD5STEP(F4, c, d, a, b,  in[6] + 0xa3014314, 15);
    MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
    MD5STEP(F4, a, b, c, d,  in[4] + 0xf7537e82,  6);
    MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
    MD5STEP(F4, c, d, a, b,  in[2] + 0x2ad7d2bb, 15);
    MD5STEP(F4, b, c, d, a,  in[9] + 0xeb86d391, 21);

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

/*
 * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
 * initialization constants.
 */
void MD5_Init(MD5_CTX *ctx)
{
    ctx->buf[0] = 0x67452301;
    ctx->buf[1] = 0xefcdab89;
    ctx->buf[2] = 0x98badcfe;
    ctx->buf[3] = 0x10325476;

    ctx->bits[0] = 0;
    ctx->bits[1] = 0;
}

/*
 * Update context to reflect the concatenation of another buffer full
 * of bytes.
 */
static void MD5_Update(MD5_CTX *ctx, unsigned char const *buf, unsigned len)
{
    u_int32_t t;

    /* Update bitcount */

    t = ctx->bits[0];
    if ((ctx->bits[0] = t + ((u_int32_t) len << 3)) < t)
	ctx->bits[1]++;		/* Carry from low to high */
    ctx->bits[1] += len >> 29;

    t = (t >> 3) & 0x3f;	/* Bytes already in shsInfo->data */

    /* Handle any leading odd-sized chunks */

    if (t) {
	unsigned char *p = (unsigned char *) ctx->in + t;

	t = 64 - t;
	if (len < t) {
	    memcpy(p, buf, len);
	    return;
	}
	memcpy(p, buf, t);
	byteReverse(ctx->in, 16);
	MD5Transform(ctx->buf, (u_int32_t *) ctx->in);
	buf += t;
	len -= t;
    }
    /* Process data in 64-byte chunks */

    while (len >= 64) {
	memcpy(ctx->in, buf, 64);
	byteReverse(ctx->in, 16);
	MD5Transform(ctx->buf, (u_int32_t *) ctx->in);
	buf += 64;
	len -= 64;
    }

    /* Handle any remaining bytes of data. */

    memcpy(ctx->in, buf, len);
}

/*
 * Final wrapup - pad to 64-byte boundary with the bit pattern
 * 1 0* (64-bit count of bits processed, MSB-first)
 */
static void MD5_Final(unsigned char digest[16], MD5_CTX *ctx)
{
    unsigned count;
    unsigned char *p;

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

    /* Set the first char of padding to 0x80.  This is safe since there is
       always at least one byte free */
    p = ctx->in + count;
    *p++ = 0x80;

    /* Bytes of padding needed to make 64 bytes */
    count = 64 - 1 - count;

    /* Pad out to 56 mod 64 */
    if (count < 8) {
	/* Two lots of padding:  Pad the first block to 64 bytes */
	memset(p, 0, count);
	byteReverse(ctx->in, 16);
	MD5Transform(ctx->buf, (u_int32_t *) ctx->in);

	/* Now fill the next block with 56 bytes */
	memset(ctx->in, 0, 56);
    } else {
	/* Pad block to 56 bytes */
	memset(p, 0, count - 8);
    }
    byteReverse(ctx->in, 14);

    /* Append length in bits and transform */
    uint32_t* ctxIn = (uint32_t*)ctx->in;
    ctxIn[14] = ctx->bits[0];
    ctxIn[15] = ctx->bits[1];

    MD5Transform(ctx->buf, (u_int32_t *) ctx->in);
    byteReverse((unsigned char *) ctx->buf, 4);
    memcpy(digest, ctx->buf, 16);
    memset((char *) ctx, 0, sizeof(ctx));	/* In case it's sensitive */
}

// Yate's C++ wrapper routines start here

using namespace TelEngine;

MD5::MD5()
{
}

MD5::MD5(const void* buf, unsigned int len)
{
    update(buf,len);
}

MD5::MD5(const DataBlock& data)
{
    update(data);
}

MD5::MD5(const String& str)
{
    update(str);
}

MD5::MD5(const MD5& original)
{
    m_hex = original.m_hex;
    ::memcpy(m_bin,original.m_bin,sizeof(m_bin));
    if (original.m_private) {
	m_private = ::malloc(sizeof(MD5_CTX));
	::memcpy(m_private,original.m_private,sizeof(MD5_CTX));
    }
}

MD5::~MD5()
{
    clear();
}

MD5& MD5::operator=(const MD5& original)
{
    clear();
    m_hex = original.m_hex;
    ::memcpy(m_bin,original.m_bin,sizeof(m_bin));
    if (original.m_private) {
	m_private = ::malloc(sizeof(MD5_CTX));
	::memcpy(m_private,original.m_private,sizeof(MD5_CTX));
    }
    return *this;
}

void MD5::clear()
{
    if (m_private) {
	::free(m_private);
	m_private = 0;
    }
    m_hex.clear();
    ::memset(m_bin,0,sizeof(m_bin));
}

void MD5::init()
{
    if (m_private)
	return;
    clear();
    m_private = ::malloc(sizeof(MD5_CTX));
    MD5_Init((MD5_CTX*)m_private);
}

void MD5::finalize()
{
    static char hexa[] = "0123456789abcdef";
    if (m_hex)
	return;
    init();
    MD5_Final(m_bin, (MD5_CTX*)m_private);
    char buf[2*sizeof(m_bin)+1];
    char *p = buf;
    for (unsigned int i = 0; i < sizeof(m_bin); i++) {
	*p++ = hexa[m_bin[i] >> 4];
	*p++ = hexa[m_bin[i] & 15];
    }
    *p++ = '\0';
    m_hex = buf;
}

bool MD5::updateInternal(const void* buf, unsigned int len)
{
    // Don't update an already finalized digest
    if (m_hex)
	return false;
    if (!len)
	return true;
    if (!buf)
	return false;
    init();
    MD5_Update((MD5_CTX*)m_private, (unsigned char const*)buf, len);
    return true;
}

const unsigned char* MD5::rawDigest()
{
    finalize();
    return m_bin;
}

/* vi: set ts=8 sw=4 sts=4 noet: */
