/*
** iksemel (XML Parser for Jabber)
** Copyright (C) 2000-2001 Gurer Ozen <palpa@jabber.org>
**
** This code is free software; you can redistribute it and/or
** modify it under the terms of GNU Lesser General Public License.
**
** SHA1 Secure Hash Algorithm
*/

#include "common.h"
#include "iksemel.h"

static void sha_buffer(iksha *sha, const unsigned char *data, int len);
static void sha_calculate(iksha *sha);


iksha *iks_sha_new(void)
{
	iksha *sha;

	sha = malloc(sizeof(iksha));
	if(!sha) return(NULL);
	iks_sha_reset(sha);
	return sha;
}


void iks_sha_reset(iksha *sha)
{
	memset(sha, 0, sizeof(iksha));
	sha->hash[0] = 0x67452301L;
	sha->hash[1] = 0xefcdab89L;
	sha->hash[2] = 0x98badcfeL;
	sha->hash[3] = 0x10325476L;
	sha->hash[4] = 0xc3d2e1f0L;
}


void iks_sha_hash(iksha *sha, const unsigned char *data, int len, int finish)
{
	unsigned char pad[8];
	unsigned char padc;

	if(data && len != 0) sha_buffer(sha, data, len);
	if(!finish) return;

	pad[0] = (unsigned char)((sha->lenhi >> 24) & 0xff);
	pad[1] = (unsigned char)((sha->lenhi >> 16) & 0xff);
	pad[2] = (unsigned char)((sha->lenhi >> 8) & 0xff);
	pad[3] = (unsigned char)(sha->lenhi & 0xff);
	pad[4] = (unsigned char)((sha->lenlo >> 24) & 0xff);
	pad[5] = (unsigned char)((sha->lenlo >> 16) & 0xff);
	pad[6] = (unsigned char)((sha->lenlo >> 8) & 0xff);
	pad[7] = (unsigned char)(sha->lenlo & 255);

	padc = 0x80;
	sha_buffer(sha, &padc, 1);

	padc = 0x00;
	while(sha->blen != 56)
		sha_buffer(sha, &padc, 1);

	sha_buffer(sha, pad, 8);
}


void iks_sha_print(iksha *sha, char *hash)
{
	int i;

	for(i=0; i<5; i++)
	{
		sprintf(hash, "%08lX", sha->hash[i]);
		hash += 8;
	}
}


void iks_sha_delete(iksha *sha)
{
	free(sha);
}


void iks_sha(const char *data, char *hash)
{
	iksha *sha;

	sha = iks_sha_new();
	iks_sha_hash(sha, data, strlen(data), 1);
	iks_sha_print(sha, hash);
	free(sha);
}


static void sha_buffer(iksha *sha, const unsigned char *data, int len)
{
	int i;

	for(i=0; i<len; i++)
	{
		sha->buf[sha->blen / 4] <<= 8;
		sha->buf[sha->blen / 4] |= (unsigned long)data[i];
		if((++sha->blen) % 64 == 0)
		{
			sha_calculate(sha);
			sha->blen = 0;
		}
		sha->lenlo += 8;
		sha->lenhi += (sha->lenlo < 8);
	}
}


#define SRL(x,y) (((x) << (y)) | ((x) >> (32-(y))))
#define SHA(a,b,f,c) \
	for(i= (a) ; i<= (b) ; i++) \
	{ \
		TMP = SRL(A,5) + ( (f) ) + E + sha->buf[i] + (c) ; \
		E = D; \
		D = C; \
		C = SRL(B,30); \
		B = A; \
		A = TMP; \
	}

static void sha_calculate(iksha *sha)
{
	int i;
	unsigned long A, B, C, D, E, TMP;

	for(i=16; i<80; i++)
		sha->buf[i] = SRL(sha->buf[i-3] ^ sha->buf[i-8] ^ sha->buf[i-14] ^ sha->buf[i-16], 1);

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

	SHA(0,  19, ((C^D)&B)^D,     0x5a827999L);
	SHA(20, 39, B^C^D,           0x6ed9eba1L);
	SHA(40, 59, (B&C)|(D&(B|C)), 0x8f1bbcdcL);
	SHA(60, 79, B^C^D,           0xca62c1d6L);

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