/*
 *  FIPS-180-2 compliant SHA-256 implementation
 *
 *  Copyright (C) 2003-2006  Christophe Devine
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License, version 2.1 as published by the Free Software Foundation.
 *
 *  This library 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.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 *  MA  02110-1301  USA
 */
/*
 *  The SHA-256 standard was published by NIST in 2002.
 *
 *  http://csrc.nist.gov/publications/fips/fips180-2/fips180-2.pdf
 */

#ifndef _CRT_SECURE_NO_DEPRECATE
#define _CRT_SECURE_NO_DEPRECATE 1
#endif

#include <string.h>
#include <stdio.h>

#include "sha2.h"
#include "filesys.h"
#include "../shared/shared.h"

/**
 * 32-bit integer manipulation macros (big endian)
 */
#ifndef GET_UINT32_BE
#define GET_UINT32_BE(n,b,i)                    \
{                                               \
    (n) = ( (uint64_t) (b)[(i)    ] << 24 )        \
        | ( (uint64_t) (b)[(i) + 1] << 16 )        \
        | ( (uint64_t) (b)[(i) + 2] <<  8 )        \
        | ( (uint64_t) (b)[(i) + 3]       );       \
}
#endif
#ifndef PUT_UINT32_BE
#define PUT_UINT32_BE(n,b,i)                    \
{                                               \
    (b)[(i)    ] = (byte) ( (n) >> 24 );       \
    (b)[(i) + 1] = (byte) ( (n) >> 16 );       \
    (b)[(i) + 2] = (byte) ( (n) >>  8 );       \
    (b)[(i) + 3] = (byte) ( (n)       );       \
}
#endif

/*
 * Core SHA-256 functions
 */
void Com_SHA2Starts (sha2_context *ctx)
{
	ctx->total[0] = 0;
	ctx->total[1] = 0;

	ctx->state[0] = 0x6A09E667;
	ctx->state[1] = 0xBB67AE85;
	ctx->state[2] = 0x3C6EF372;
	ctx->state[3] = 0xA54FF53A;
	ctx->state[4] = 0x510E527F;
	ctx->state[5] = 0x9B05688C;
	ctx->state[6] = 0x1F83D9AB;
	ctx->state[7] = 0x5BE0CD19;
}

static void Com_SHA2Process (sha2_context *ctx, const byte data[64])
{
	uint64_t temp1, temp2, W[64];
	uint64_t A, B, C, D, E, F, G, H;

	GET_UINT32_BE(W[0], data, 0);
	GET_UINT32_BE(W[1], data, 4);
	GET_UINT32_BE(W[2], data, 8);
	GET_UINT32_BE(W[3], data, 12);
	GET_UINT32_BE(W[4], data, 16);
	GET_UINT32_BE(W[5], data, 20);
	GET_UINT32_BE(W[6], data, 24);
	GET_UINT32_BE(W[7], data, 28);
	GET_UINT32_BE(W[8], data, 32);
	GET_UINT32_BE(W[9], data, 36);
	GET_UINT32_BE(W[10], data, 40);
	GET_UINT32_BE(W[11], data, 44);
	GET_UINT32_BE(W[12], data, 48);
	GET_UINT32_BE(W[13], data, 52);
	GET_UINT32_BE(W[14], data, 56);
	GET_UINT32_BE(W[15], data, 60);

#define  SHR(x,n) ((x & 0xFFFFFFFF) >> n)
#define ROTR(x,n) (SHR(x,n) | (x << (32 - n)))

#define S0(x) (ROTR(x, 7) ^ ROTR(x,18) ^  SHR(x, 3))
#define S1(x) (ROTR(x,17) ^ ROTR(x,19) ^  SHR(x,10))

#define S2(x) (ROTR(x, 2) ^ ROTR(x,13) ^ ROTR(x,22))
#define S3(x) (ROTR(x, 6) ^ ROTR(x,11) ^ ROTR(x,25))

#define F0(x,y,z) ((x & y) | (z & (x | y)))
#define F1(x,y,z) (z ^ (x & (y ^ z)))

#define R(t)                                    \
(                                               \
    W[t] = S1(W[t -  2]) + W[t -  7] +          \
           S0(W[t - 15]) + W[t - 16]            \
)

#define P(a,b,c,d,e,f,g,h,x,K)                  \
{                                               \
    temp1 = h + S3(e) + F1(e,f,g) + K + x;      \
    temp2 = S2(a) + F0(a,b,c);                  \
    d += temp1; h = temp1 + temp2;              \
}

	A = ctx->state[0];
	B = ctx->state[1];
	C = ctx->state[2];
	D = ctx->state[3];
	E = ctx->state[4];
	F = ctx->state[5];
	G = ctx->state[6];
	H = ctx->state[7];

	P(A, B, C, D, E, F, G, H, W[0], 0x428A2F98);
	P(H, A, B, C, D, E, F, G, W[1], 0x71374491);
	P(G, H, A, B, C, D, E, F, W[2], 0xB5C0FBCF);
	P(F, G, H, A, B, C, D, E, W[3], 0xE9B5DBA5);
	P(E, F, G, H, A, B, C, D, W[4], 0x3956C25B);
	P(D, E, F, G, H, A, B, C, W[5], 0x59F111F1);
	P(C, D, E, F, G, H, A, B, W[6], 0x923F82A4);
	P(B, C, D, E, F, G, H, A, W[7], 0xAB1C5ED5);
	P(A, B, C, D, E, F, G, H, W[8], 0xD807AA98);
	P(H, A, B, C, D, E, F, G, W[9], 0x12835B01);
	P(G, H, A, B, C, D, E, F, W[10], 0x243185BE);
	P(F, G, H, A, B, C, D, E, W[11], 0x550C7DC3);
	P(E, F, G, H, A, B, C, D, W[12], 0x72BE5D74);
	P(D, E, F, G, H, A, B, C, W[13], 0x80DEB1FE);
	P(C, D, E, F, G, H, A, B, W[14], 0x9BDC06A7);
	P(B, C, D, E, F, G, H, A, W[15], 0xC19BF174);
	P(A, B, C, D, E, F, G, H, R(16), 0xE49B69C1);
	P(H, A, B, C, D, E, F, G, R(17), 0xEFBE4786);
	P(G, H, A, B, C, D, E, F, R(18), 0x0FC19DC6);
	P(F, G, H, A, B, C, D, E, R(19), 0x240CA1CC);
	P(E, F, G, H, A, B, C, D, R(20), 0x2DE92C6F);
	P(D, E, F, G, H, A, B, C, R(21), 0x4A7484AA);
	P(C, D, E, F, G, H, A, B, R(22), 0x5CB0A9DC);
	P(B, C, D, E, F, G, H, A, R(23), 0x76F988DA);
	P(A, B, C, D, E, F, G, H, R(24), 0x983E5152);
	P(H, A, B, C, D, E, F, G, R(25), 0xA831C66D);
	P(G, H, A, B, C, D, E, F, R(26), 0xB00327C8);
	P(F, G, H, A, B, C, D, E, R(27), 0xBF597FC7);
	P(E, F, G, H, A, B, C, D, R(28), 0xC6E00BF3);
	P(D, E, F, G, H, A, B, C, R(29), 0xD5A79147);
	P(C, D, E, F, G, H, A, B, R(30), 0x06CA6351);
	P(B, C, D, E, F, G, H, A, R(31), 0x14292967);
	P(A, B, C, D, E, F, G, H, R(32), 0x27B70A85);
	P(H, A, B, C, D, E, F, G, R(33), 0x2E1B2138);
	P(G, H, A, B, C, D, E, F, R(34), 0x4D2C6DFC);
	P(F, G, H, A, B, C, D, E, R(35), 0x53380D13);
	P(E, F, G, H, A, B, C, D, R(36), 0x650A7354);
	P(D, E, F, G, H, A, B, C, R(37), 0x766A0ABB);
	P(C, D, E, F, G, H, A, B, R(38), 0x81C2C92E);
	P(B, C, D, E, F, G, H, A, R(39), 0x92722C85);
	P(A, B, C, D, E, F, G, H, R(40), 0xA2BFE8A1);
	P(H, A, B, C, D, E, F, G, R(41), 0xA81A664B);
	P(G, H, A, B, C, D, E, F, R(42), 0xC24B8B70);
	P(F, G, H, A, B, C, D, E, R(43), 0xC76C51A3);
	P(E, F, G, H, A, B, C, D, R(44), 0xD192E819);
	P(D, E, F, G, H, A, B, C, R(45), 0xD6990624);
	P(C, D, E, F, G, H, A, B, R(46), 0xF40E3585);
	P(B, C, D, E, F, G, H, A, R(47), 0x106AA070);
	P(A, B, C, D, E, F, G, H, R(48), 0x19A4C116);
	P(H, A, B, C, D, E, F, G, R(49), 0x1E376C08);
	P(G, H, A, B, C, D, E, F, R(50), 0x2748774C);
	P(F, G, H, A, B, C, D, E, R(51), 0x34B0BCB5);
	P(E, F, G, H, A, B, C, D, R(52), 0x391C0CB3);
	P(D, E, F, G, H, A, B, C, R(53), 0x4ED8AA4A);
	P(C, D, E, F, G, H, A, B, R(54), 0x5B9CCA4F);
	P(B, C, D, E, F, G, H, A, R(55), 0x682E6FF3);
	P(A, B, C, D, E, F, G, H, R(56), 0x748F82EE);
	P(H, A, B, C, D, E, F, G, R(57), 0x78A5636F);
	P(G, H, A, B, C, D, E, F, R(58), 0x84C87814);
	P(F, G, H, A, B, C, D, E, R(59), 0x8CC70208);
	P(E, F, G, H, A, B, C, D, R(60), 0x90BEFFFA);
	P(D, E, F, G, H, A, B, C, R(61), 0xA4506CEB);
	P(C, D, E, F, G, H, A, B, R(62), 0xBEF9A3F7);
	P(B, C, D, E, F, G, H, A, R(63), 0xC67178F2);

	ctx->state[0] += A;
	ctx->state[1] += B;
	ctx->state[2] += C;
	ctx->state[3] += D;
	ctx->state[4] += E;
	ctx->state[5] += F;
	ctx->state[6] += G;
	ctx->state[7] += H;
}

void Com_SHA2Update (sha2_context *ctx, const byte* input, uint32_t length)
{
	if (!length)
		return;

	uint64_t left = ctx->total[0] & 0x3F;
	const uint64_t fill = 64 - left;

	ctx->total[0] += length;
	ctx->total[0] &= 0xFFFFFFFF;

	if (ctx->total[0] < length)
		ctx->total[1]++;

	if (left && length >= fill) {
		memcpy((void*) (ctx->buffer + left), (const void*) input, fill);
		Com_SHA2Process(ctx, ctx->buffer);
		length -= fill;
		input += fill;
		left = 0;
	}

	while (length >= 64) {
		Com_SHA2Process(ctx, input);
		length -= 64;
		input += 64;
	}

	if (length) {
		memcpy((void*) (ctx->buffer + left), (const void*) input, length);
	}
}

static const byte sha2_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 };

void Com_SHA2Finish (sha2_context *ctx, byte digest[32])
{
	byte msglen[8];

	const uint64_t high = (ctx->total[0] >> 29) | (ctx->total[1] << 3);
	const uint64_t low = (ctx->total[0] << 3);

	PUT_UINT32_BE(high, msglen, 0);
	PUT_UINT32_BE(low, msglen, 4);

	const uint64_t last = ctx->total[0] & 0x3F;
	const uint64_t padn = (last < 56) ? (56 - last) : (120 - last);

	Com_SHA2Update(ctx, sha2_padding, padn);
	Com_SHA2Update(ctx, msglen, 8);

	PUT_UINT32_BE(ctx->state[0], digest, 0);
	PUT_UINT32_BE(ctx->state[1], digest, 4);
	PUT_UINT32_BE(ctx->state[2], digest, 8);
	PUT_UINT32_BE(ctx->state[3], digest, 12);
	PUT_UINT32_BE(ctx->state[4], digest, 16);
	PUT_UINT32_BE(ctx->state[5], digest, 20);
	PUT_UINT32_BE(ctx->state[6], digest, 24);
	PUT_UINT32_BE(ctx->state[7], digest, 28);
}

bool Com_SHA2File (const char* filename, byte digest[32])
{
	ScopedFile f;
	const int filelen = FS_OpenFile(filename, &f, FILE_READ);
	if (filelen < 1)
		return false;

	sha2_context ctx;
	Com_SHA2Starts(&ctx);

	byte buf[1024];
	for (;;) {
		const int n = FS_Read(buf, sizeof(buf), &f);
		if (n < 1)
			break;
		Com_SHA2Update(&ctx, buf, (uint32_t) n);
	}

	Com_SHA2Finish(&ctx, digest);
	return true;
}

void Com_SHA2Csum (const byte* buf, uint32_t buflen, byte digest[32])
{
	sha2_context ctx;

	Com_SHA2Starts(&ctx);
	Com_SHA2Update(&ctx, buf, buflen);
	Com_SHA2Finish(&ctx, digest);
}

void Com_SHA2ToHex (const byte digest[32], char final[65])
{
	final[0] = '\0';
	for (int i = 0; i < 32; i++)
		Q_strcat(final, 65, "%02x", digest[i]);
}

void Com_SHA2Hmac (const byte* buf, uint32_t buflen, const byte* key, uint32_t keylen, byte digest[32])
{
	uint32_t i;
	sha2_context ctx;
	byte k_ipad[64];
	byte k_opad[64];
	byte tmpbuf[32];

	memset(k_ipad, 0x36, 64);
	memset(k_opad, 0x5C, 64);

	for (i = 0; i < keylen; i++) {
		if (i >= 64)
			break;

		k_ipad[i] ^= key[i];
		k_opad[i] ^= key[i];
	}

	Com_SHA2Starts(&ctx);
	Com_SHA2Update(&ctx, k_ipad, 64);
	Com_SHA2Update(&ctx, buf, buflen);
	Com_SHA2Finish(&ctx, tmpbuf);

	Com_SHA2Starts(&ctx);
	Com_SHA2Update(&ctx, k_opad, 64);
	Com_SHA2Update(&ctx, tmpbuf, 32);
	Com_SHA2Finish(&ctx, digest);

	memset(k_ipad, 0, 64);
	memset(k_opad, 0, 64);
	memset(tmpbuf, 0, 32);
	memset(&ctx, 0, sizeof(sha2_context));
}