/*
 * GPS Navigation ---An open source GPS navigation core software
 *
 *
 * Copyright (c) 2016  Hitachi, Ltd.
 *
 * This program is dual licensed under GPL version 2 or a commercial license.
 * See the LICENSE file distributed with this source file.
 */

/**
 * @file
 * @brief MD5ダイジェスト計算クラス(MUM_Cmn_Md5.cpp)
 * @date 20120515
 */
#include "SMCComCMNInternal.h"

/* MD5 のアルゴリズムは、 RFC1321(http://www.ietf.org/rfc/rfc1321.txt)を使用 */

#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 void Transform(UINT32 aState[4], UINT8 aBlock[64]);
static void Encode(UINT8 *apOutput, UINT32 *apInput, UINT32 aLen);
static void Decode(UINT32 *aOutput, UINT8 *apInput, UINT32 aLen);

static UINT8 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)(ac); \
			(a) = ROTATE_LEFT ((a), (s)); \
			(a) += (b); \
		}
#define GG(a, b, c, d, x, s, ac) { \
			(a) += G ((b), (c), (d)) + (x) + (UINT32)(ac); \
			(a) = ROTATE_LEFT ((a), (s)); \
			(a) += (b); \
		}
#define HH(a, b, c, d, x, s, ac) { \
			(a) += H ((b), (c), (d)) + (x) + (UINT32)(ac); \
			(a) = ROTATE_LEFT ((a), (s)); \
			(a) += (b); \
		}
#define II(a, b, c, d, x, s, ac) { \
			(a) += I ((b), (c), (d)) + (x) + (UINT32)(ac); \
			(a) = ROTATE_LEFT ((a), (s)); \
			(a) += (b); \
		}

/**
 * @brief 初期化処理
 * @param　[out]apContext　コンテキスト
 * @retval なし
 */
void CC_MD5_Init(T_CC_CMN_MD5_CTX *apContext)
{
	apContext->count[0] = 0;
	apContext->count[1] = 0;

	apContext->state[0] = 0x67452301;
	apContext->state[1] = 0xefcdab89;
	apContext->state[2] = 0x98badcfe;
	apContext->state[3] = 0x10325476;
}

/**
 * @brief MD5ダイジェスト更新
 * @param　[in/out]apContext　コンテキスト
 * @param  [int]apInput　　入力文字列
 * @param  [int]aInputLen　入力文字列長
 * @retval なし
 * @warning 元データのサイズが大きい場合はこれを複数回に分けて実行すること
 */
void CC_MD5_Update(T_CC_CMN_MD5_CTX *apContext, UINT8 *apInput, UINT32 aInputLen)
{
	UINT32 i;
	UINT32 index;
	UINT32 partLen;

	if (0 == aInputLen) {
		return;
	}

	/* Compute number of bytes mod 64 */
	index = (UINT32)((apContext->count[0] >> 3) & 0x3F);

	/* Update number of bits */
	if ((apContext->count[0] += ((UINT32)aInputLen << 3)) < ((UINT32)aInputLen << 3)) {
		apContext->count[1]++;
	}
	apContext->count[1] += ((UINT32)aInputLen >> 29);

	partLen = 64 - index;

	/* Transform as many times as possible. */
	if (aInputLen >= partLen) {
		memcpy((UINT8 *)&apContext->buffer[index], (UINT8 *)apInput, partLen);
		Transform(apContext->state, apContext->buffer);

		for (i = partLen; i + 63 < aInputLen; i += 64) {
			Transform(apContext->state, (UINT8 *)&apInput[i]);
		}

		index = 0;
	} else {
		i = 0;
	}

	if ((sizeof(apContext->buffer) - index) >= (aInputLen - i)) {
		memcpy((UINT8 *)&apContext->buffer[index], (UINT8 *)&apInput[i], aInputLen - i);
	}
}

/**
 * @brief 終了化処理
 * @param  [out]aDigest　　MD5ダイジェスト値
 * @param　[in]apContext　コンテキスト
 * @retval なし
 * @note MD5ダイジェストを取得する
 */
void CC_MD5_Final(UINT8 *aDigest, T_CC_CMN_MD5_CTX *apContext)
{
	UINT8 bits[8];
	UINT32 index;
	UINT32 padLen;

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

	/* Pad out to 56 mod 64. */
	index = (UINT32)((apContext->count[0] >> 3) & 0x3f);
	padLen = (index < 56) ? (56 - index) : (120 - index);
	CC_MD5_Update(apContext, PADDING, padLen);

	/* Append length (before padding) */
	CC_MD5_Update(apContext, bits, 8);

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

	memset((UINT8 *)apContext, 0, sizeof(*apContext));
}

/**
 * @brief MD5 basic transformation
 * @param  [in/out]aState
 * @param　[in/out]aBlock
 * @retval なし
 */
void Transform(UINT32 aState[4], UINT8 aBlock[64])
{
	UINT32 a = aState[0];
	UINT32 b = aState[1];
	UINT32 c = aState[2];
	UINT32 d = aState[3];
	UINT32 x[16];

	Decode(x, aBlock, 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 */

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

	memset((UINT8 *)x, 0, sizeof (x));
}

/**
 * @brief Encodes input (UINT32) into output (UINT8)
 * @param  [out]apOutput
 * @param　[in]apInput
 * @param  [in]aLen
 * @retval なし
 */
void Encode(UINT8 *apOutput, UINT32 *apInput, UINT32 aLen)
{
	UINT32 i;
	UINT32 j;

	for (i = 0, j = 0; j < aLen; i++, j += 4) {
		apOutput[j] = (UINT8)(apInput[i] & 0xff);
		apOutput[j+1] = (UINT8)((apInput[i] >> 8) & 0xff);
		apOutput[j+2] = (UINT8)((apInput[i] >> 16) & 0xff);
		apOutput[j+3] = (UINT8)((apInput[i] >> 24) & 0xff);
	}
}

/**
 * @brief Decodes input (UINT8) into output (UINT32)
 * @param  [out]apOutput
 * @param　[in]apInput
 * @param  [in]aLen
 * @retval なし
 */
void Decode(UINT32 *apOutput, UINT8 *apInput, UINT32 aLen)
{
	UINT32 i;
	UINT32 j;

	for (i = 0, j = 0; j < aLen; i++, j += 4) {
		apOutput[i] = ((UINT32)apInput[j]) | (((UINT32)apInput[j+1]) << 8) |
					  (((UINT32)apInput[j+2]) << 16) | (((UINT32)apInput[j+3]) << 24);
	}
}
