/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis, 
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is SHA 180-1 Reference Implementation (Compact version).
 *
 * The Initial Developer of the Original Code is
 * Paul Kocher of Cryptography Research.
 * Portions created by the Initial Developer are Copyright (C) 1995-9
 * the Initial Developer. All Rights Reserved.
 * 
 * Contributor(s):
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), 
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#include "commonheaders.h"

#define SHA_ROTL(X, n) (((X) << (n)) | ((X) >> (32-(n))))

static void shaHashBlock(mir_sha1_ctx *ctx)
{
	int t;
	unsigned long A, B, C, D, E, TEMP;

	for (t = 16; t <= 79; t++)
		ctx->W[t] =
		SHA_ROTL(ctx->W[t-3] ^ ctx->W[t-8] ^ ctx->W[t-14] ^ ctx->W[t-16], 1);

	A = ctx->H[0];
	B = ctx->H[1];
	C = ctx->H[2];
	D = ctx->H[3];
	E = ctx->H[4];

	for (t = 0; t <= 19; t++) {
		TEMP = SHA_ROTL(A, 5) + (((C^D)&B)^D)     + E + ctx->W[t] + 0x5a827999L;
		E = D; D = C; C = SHA_ROTL(B, 30); B = A; A = TEMP;
	}
	for (t = 20; t <= 39; t++) {
		TEMP = SHA_ROTL(A, 5) + (B^C^D)           + E + ctx->W[t] + 0x6ed9eba1L;
		E = D; D = C; C = SHA_ROTL(B, 30); B = A; A = TEMP;
	}
	for (t = 40; t <= 59; t++) {
		TEMP = SHA_ROTL(A, 5) + ((B&C)|(D&(B|C))) + E + ctx->W[t] + 0x8f1bbcdcL;
		E = D; D = C; C = SHA_ROTL(B, 30); B = A; A = TEMP;
	}
	for (t = 60; t <= 79; t++) {
		TEMP = SHA_ROTL(A, 5) + (B^C^D)           + E + ctx->W[t] + 0xca62c1d6L;
		E = D; D = C; C = SHA_ROTL(B, 30); B = A; A = TEMP;
	}

	ctx->H[0] += A;
	ctx->H[1] += B;
	ctx->H[2] += C;
	ctx->H[3] += D;
	ctx->H[4] += E;
}

MIR_CORE_DLL(void) mir_sha1_init(mir_sha1_ctx *ctx)
{
	ctx->lenW = 0;
	ctx->sizeHi = ctx->sizeLo = 0;

	/* Initialize H with the magic constants (see FIPS180 for constants)
	*/
	ctx->H[0] = 0x67452301L;
	ctx->H[1] = 0xefcdab89L;
	ctx->H[2] = 0x98badcfeL;
	ctx->H[3] = 0x10325476L;
	ctx->H[4] = 0xc3d2e1f0L;

	for (int i = 0; i < 80; i++)
		ctx->W[i] = 0;
}

MIR_CORE_DLL(void) mir_sha1_append(mir_sha1_ctx *ctx, const BYTE *dataIn, int len)
{
	/* Read the data into W and process blocks as they get full
	*/
	for (int i = 0; i < len; i++) {
		ctx->W[ctx->lenW / 4] <<= 8;
		ctx->W[ctx->lenW / 4] |= (unsigned long)dataIn[i];
		if ((++ctx->lenW) % 64 == 0) {
			shaHashBlock(ctx);
			ctx->lenW = 0;
		}
		ctx->sizeLo += 8;
		ctx->sizeHi += (ctx->sizeLo < 8);
	}
}

MIR_CORE_DLL(void) mir_sha1_finish(mir_sha1_ctx *ctx, BYTE hashout[20])
{
	unsigned char pad0x80 = 0x80;
	unsigned char pad0x00 = 0x00;
	unsigned char padlen[8];
	int i;

	/* Pad with a binary 1 (e.g. 0x80), then zeroes, then length
	*/
	padlen[0] = (unsigned char)((ctx->sizeHi >> 24) & 255);
	padlen[1] = (unsigned char)((ctx->sizeHi >> 16) & 255);
	padlen[2] = (unsigned char)((ctx->sizeHi >> 8) & 255);
	padlen[3] = (unsigned char)((ctx->sizeHi >> 0) & 255);
	padlen[4] = (unsigned char)((ctx->sizeLo >> 24) & 255);
	padlen[5] = (unsigned char)((ctx->sizeLo >> 16) & 255);
	padlen[6] = (unsigned char)((ctx->sizeLo >> 8) & 255);
	padlen[7] = (unsigned char)((ctx->sizeLo >> 0) & 255);
	mir_sha1_append(ctx, &pad0x80, 1);
	while (ctx->lenW != 56)
		mir_sha1_append(ctx, &pad0x00, 1);
	mir_sha1_append(ctx, padlen, 8);

	/* Output hash
	*/
	for (i = 0; i < 20; i++) {
		hashout[i] = (unsigned char)(ctx->H[i / 4] >> 24);
		ctx->H[i / 4] <<= 8;
	}

	/*
	*  Re-initialize the context (also zeroizes contents)
	*/
	mir_sha1_init(ctx); 
}

MIR_CORE_DLL(void) mir_sha1_hash(BYTE *dataIn, int len, BYTE hashout[20])
{
	mir_sha1_ctx ctx;

	mir_sha1_init(&ctx);
	mir_sha1_append(&ctx, dataIn, len);
	mir_sha1_finish(&ctx, hashout);
}

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

MIR_CORE_DLL(void) mir_hmac_sha1(BYTE hashout[MIR_SHA1_HASH_SIZE], const BYTE *key, size_t keylen, const BYTE *text, size_t textlen)
{
	const unsigned SHA_BLOCKSIZE = 64;

	BYTE mdkey[MIR_SHA1_HASH_SIZE], k_ipad[SHA_BLOCKSIZE], k_opad[SHA_BLOCKSIZE];
	mir_sha1_ctx ctx;

	if (keylen > SHA_BLOCKSIZE) {
		mir_sha1_init(&ctx);
		mir_sha1_append(&ctx, key, (int)keylen);
		mir_sha1_finish(&ctx, mdkey);
		keylen = 20;
		key = mdkey;
	}

	memcpy(k_ipad, key, keylen);
	memcpy(k_opad, key, keylen);
	memset(k_ipad+keylen, 0x36, SHA_BLOCKSIZE - keylen);
	memset(k_opad+keylen, 0x5c, SHA_BLOCKSIZE - keylen);

	for (unsigned i = 0; i < keylen; i++) {
		k_ipad[i] ^= 0x36;
		k_opad[i] ^= 0x5c;
	}

	mir_sha1_init(&ctx);
	mir_sha1_append(&ctx, k_ipad, SHA_BLOCKSIZE);
	mir_sha1_append(&ctx, text, (int)textlen);
	mir_sha1_finish(&ctx, hashout);

	mir_sha1_init(&ctx);
	mir_sha1_append(&ctx, k_opad, SHA_BLOCKSIZE);
	mir_sha1_append(&ctx, hashout, MIR_SHA1_HASH_SIZE);
	mir_sha1_finish(&ctx, hashout);
}