/*
 * $Id: sha1.c, implementation of sha1 in c,
 *	originally By Steve Reid <steve@edmweb.com>
 */

#include "sk.h"
#include "sha1.h"
#include "strasm.h"

void    SHA1Transform(ulong state[5], uchar buffer[64])
{
	ulong   a, b, c, d, e;
	typedef union {
		uchar   c[64];
		ulong   l[16];
	} CHAR64LONG16;
	CHAR64LONG16 *block;
#ifdef SHA1HANDSOFF
	static uchar workspace[64];
	block = (CHAR64LONG16 *) workspace;
	memcpy(block, buffer, 64);
#else
	block = (CHAR64LONG16 *) buffer;
#endif
	/* Copy context->state[] to working vars */
	a = state[0];
	b = state[1];
	c = state[2];
	d = state[3];
	e = state[4];
	/* 4 rounds of 20 operations each. Loop unrolled. */
	R0(a, b, c, d, e, 0);
	R0(e, a, b, c, d, 1);
	R0(d, e, a, b, c, 2);
	R0(c, d, e, a, b, 3);
	R0(b, c, d, e, a, 4);
	R0(a, b, c, d, e, 5);
	R0(e, a, b, c, d, 6);
	R0(d, e, a, b, c, 7);
	R0(c, d, e, a, b, 8);
	R0(b, c, d, e, a, 9);
	R0(a, b, c, d, e, 10);
	R0(e, a, b, c, d, 11);
	R0(d, e, a, b, c, 12);
	R0(c, d, e, a, b, 13);
	R0(b, c, d, e, a, 14);
	R0(a, b, c, d, e, 15);
	R1(e, a, b, c, d, 16);
	R1(d, e, a, b, c, 17);
	R1(c, d, e, a, b, 18);
	R1(b, c, d, e, a, 19);
	R2(a, b, c, d, e, 20);
	R2(e, a, b, c, d, 21);
	R2(d, e, a, b, c, 22);
	R2(c, d, e, a, b, 23);
	R2(b, c, d, e, a, 24);
	R2(a, b, c, d, e, 25);
	R2(e, a, b, c, d, 26);
	R2(d, e, a, b, c, 27);
	R2(c, d, e, a, b, 28);
	R2(b, c, d, e, a, 29);
	R2(a, b, c, d, e, 30);
	R2(e, a, b, c, d, 31);
	R2(d, e, a, b, c, 32);
	R2(c, d, e, a, b, 33);
	R2(b, c, d, e, a, 34);
	R2(a, b, c, d, e, 35);
	R2(e, a, b, c, d, 36);
	R2(d, e, a, b, c, 37);
	R2(c, d, e, a, b, 38);
	R2(b, c, d, e, a, 39);
	R3(a, b, c, d, e, 40);
	R3(e, a, b, c, d, 41);
	R3(d, e, a, b, c, 42);
	R3(c, d, e, a, b, 43);
	R3(b, c, d, e, a, 44);
	R3(a, b, c, d, e, 45);
	R3(e, a, b, c, d, 46);
	R3(d, e, a, b, c, 47);
	R3(c, d, e, a, b, 48);
	R3(b, c, d, e, a, 49);
	R3(a, b, c, d, e, 50);
	R3(e, a, b, c, d, 51);
	R3(d, e, a, b, c, 52);
	R3(c, d, e, a, b, 53);
	R3(b, c, d, e, a, 54);
	R3(a, b, c, d, e, 55);
	R3(e, a, b, c, d, 56);
	R3(d, e, a, b, c, 57);
	R3(c, d, e, a, b, 58);
	R3(b, c, d, e, a, 59);
	R4(a, b, c, d, e, 60);
	R4(e, a, b, c, d, 61);
	R4(d, e, a, b, c, 62);
	R4(c, d, e, a, b, 63);
	R4(b, c, d, e, a, 64);
	R4(a, b, c, d, e, 65);
	R4(e, a, b, c, d, 66);
	R4(d, e, a, b, c, 67);
	R4(c, d, e, a, b, 68);
	R4(b, c, d, e, a, 69);
	R4(a, b, c, d, e, 70);
	R4(e, a, b, c, d, 71);
	R4(d, e, a, b, c, 72);
	R4(c, d, e, a, b, 73);
	R4(b, c, d, e, a, 74);
	R4(a, b, c, d, e, 75);
	R4(e, a, b, c, d, 76);
	R4(d, e, a, b, c, 77);
	R4(c, d, e, a, b, 78);
	R4(b, c, d, e, a, 79);
	/* Add the working vars back into context.state[] */
	state[0] += a;
	state[1] += b;
	state[2] += c;
	state[3] += d;
	state[4] += e;
	/* Wipe variables */
	a = b = c = d = e = 0;
}


/* SHA1Init - Initialize new context */
void    SHA1Init(SHA1_CTX * context)
{
	/* SHA1 initialization constants */
	context->state[0] = 0x67452301;
	context->state[1] = 0xEFCDAB89;
	context->state[2] = 0x98BADCFE;
	context->state[3] = 0x10325476;
	context->state[4] = 0xC3D2E1F0;
	context->count[0] = context->count[1] = 0;
}


/* Run your data through this. */
void    SHA1Update(SHA1_CTX * context, uchar * data, ulong len)
{
	ulong   i, j;

	j = (context->count[0] >> 3) & 63;
	if ((context->count[0] += len << 3) < (len << 3))
		context->count[1]++;
	context->count[1] += (len >> 29);
	if ((j + len) > 63) {
		memcpy(&context->buffer[j], data, (i = 64 - j));
		SHA1Transform(context->state, context->buffer);
		for (; i + 63 < len; i += 64) {
			SHA1Transform(context->state, &data[i]);
		}
		j = 0;
	} else
		i = 0;
	memcpy(&context->buffer[j], &data[i], len - i);
}


/* Add padding and return the message digest. */
void    SHA1Final(uchar digest[20], SHA1_CTX * context)
{
	ulong   i, j;
	uchar   finalcount[8];

	for (i = 0; i < 8; i++) {
		finalcount[i] = (uchar) ((context->count[(i >= 4 ? 0 : 1)]
					  >> ((3 - (i & 3)) * 8)) & 255);
	}
	SHA1Update(context, (uchar *) "\200", 1);
	while ((context->count[0] & 504) != 448) {
		SHA1Update(context, (uchar *) "\0", 1);
	}
	SHA1Update(context, finalcount, 8);
	for (i = 0; i < 20; i++) {
		digest[i] = (uchar)
		    ((context->state[i >> 2] >> ((3 - (i & 3)) * 8)) & 255);
	}
	/* Wipe variables */
	i = j = 0;
	memset(context->buffer, 0, 64);
	memset(context->state, 0, 20);
	memset(context->count, 0, 8);
	memset(&finalcount, 0, 8);
#ifdef SHA1HANDSOFF
	SHA1Transform(context->state, context->buffer);
#endif
}
