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/*
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 * Copyright (C) 2007 Michael Niedermayer <michaelni@gmx.at>
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 * based on public domain SHA-1 code by Steve Reid <steve@edmweb.com>
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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#include "common.h"
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#include "bswap.h"
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#include "sha1.h"
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typedef struct AVSHA1 {
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    uint64_t count;
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    uint8_t buffer[64];
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    uint32_t state[5];
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} AVSHA1;
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const int av_sha1_size = sizeof(AVSHA1);
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#define rol(value, bits) (((value) << (bits)) | ((value) >> (32 - (bits))))
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/* (R0+R1), R2, R3, R4 are the different operations used in SHA1 */
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#define blk0(i) (block[i] = be2me_32(((const uint32_t*)buffer)[i]))
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#define blk(i) (block[i] = rol(block[i-3]^block[i-8]^block[i-14]^block[i-16],1))
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#define R0(v,w,x,y,z,i) z+=((w&(x^y))^y)    +blk0(i)+0x5A827999+rol(v,5);w=rol(w,30);
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#define R1(v,w,x,y,z,i) z+=((w&(x^y))^y)    +blk (i)+0x5A827999+rol(v,5);w=rol(w,30);
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#define R2(v,w,x,y,z,i) z+=( w^x     ^y)    +blk (i)+0x6ED9EBA1+rol(v,5);w=rol(w,30);
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#define R3(v,w,x,y,z,i) z+=(((w|x)&y)|(w&x))+blk (i)+0x8F1BBCDC+rol(v,5);w=rol(w,30);
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#define R4(v,w,x,y,z,i) z+=( w^x     ^y)    +blk (i)+0xCA62C1D6+rol(v,5);w=rol(w,30);
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/* Hash a single 512-bit block. This is the core of the algorithm. */
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static void transform(uint32_t state[5], const uint8_t buffer[64]){
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    uint32_t block[80];
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    unsigned int i, a, b, c, d, e;
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    a = state[0];
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    b = state[1];
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    c = state[2];
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    d = state[3];
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    e = state[4];
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#ifdef CONFIG_SMALL
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    for(i=0; i<80; i++){
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        int t;
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        if(i<16) t= be2me_32(((uint32_t*)buffer)[i]);
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        else     t= rol(block[i-3]^block[i-8]^block[i-14]^block[i-16],1);
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        block[i]= t;
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        t+= e+rol(a,5);
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        if(i<40){
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            if(i<20)    t+= ((b&(c^d))^d)    +0x5A827999;
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            else        t+= ( b^c     ^d)    +0x6ED9EBA1;
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        }else{
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            if(i<60)    t+= (((b|c)&d)|(b&c))+0x8F1BBCDC;
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            else        t+= ( b^c     ^d)    +0xCA62C1D6;
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        }
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        e= d;
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        d= c;
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        c= rol(b,30);
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        b= a;
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        a= t;
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    }
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#else
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    for(i=0; i<15; i+=5){
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        R0(a,b,c,d,e,0+i); R0(e,a,b,c,d,1+i); R0(d,e,a,b,c,2+i); R0(c,d,e,a,b,3+i); R0(b,c,d,e,a,4+i);
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    }
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    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);
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    for(i=20; i<40; i+=5){
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        R2(a,b,c,d,e,0+i); R2(e,a,b,c,d,1+i); R2(d,e,a,b,c,2+i); R2(c,d,e,a,b,3+i); R2(b,c,d,e,a,4+i);
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    }
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    for(; i<60; i+=5){
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        R3(a,b,c,d,e,0+i); R3(e,a,b,c,d,1+i); R3(d,e,a,b,c,2+i); R3(c,d,e,a,b,3+i); R3(b,c,d,e,a,4+i);
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    }
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    for(; i<80; i+=5){
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        R4(a,b,c,d,e,0+i); R4(e,a,b,c,d,1+i); R4(d,e,a,b,c,2+i); R4(c,d,e,a,b,3+i); R4(b,c,d,e,a,4+i);
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    }
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#endif
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    state[0] += a;
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    state[1] += b;
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    state[2] += c;
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    state[3] += d;
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    state[4] += e;
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}
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void av_sha1_init(AVSHA1* ctx){
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    ctx->state[0] = 0x67452301;
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    ctx->state[1] = 0xEFCDAB89;
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    ctx->state[2] = 0x98BADCFE;
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    ctx->state[3] = 0x10325476;
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    ctx->state[4] = 0xC3D2E1F0;
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    ctx->count    = 0;
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}
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void av_sha1_update(AVSHA1* ctx, const uint8_t* data, unsigned int len){
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    unsigned int i, j;
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    j = ctx->count & 63;
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    ctx->count += len;
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#ifdef CONFIG_SMALL
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    for( i = 0; i < len; i++ ){
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        ctx->buffer[ j++ ] = data[i];
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        if( 64 == j ){
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            transform(ctx->state, ctx->buffer);
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            j = 0;
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        }
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    }
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#else
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    if ((j + len) > 63) {
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        memcpy(&ctx->buffer[j], data, (i = 64-j));
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        transform(ctx->state, ctx->buffer);
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        for ( ; i + 63 < len; i += 64) {
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            transform(ctx->state, &data[i]);
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        }
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        j=0;
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    }
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    else i = 0;
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    memcpy(&ctx->buffer[j], &data[i], len - i);
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#endif
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}
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void av_sha1_final(AVSHA1* ctx, uint8_t digest[20]){
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    int i;
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    uint64_t finalcount= be2me_64(ctx->count<<3);
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    av_sha1_update(ctx, "\200", 1);
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    while ((ctx->count & 63) != 56) {
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        av_sha1_update(ctx, "", 1);
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    }
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    av_sha1_update(ctx, (uint8_t *)&finalcount, 8); /* Should cause a transform() */
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    for(i=0; i<5; i++)
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        ((uint32_t*)digest)[i]= be2me_32(ctx->state[i]);
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}
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// use the following to test
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// gcc -DTEST -DHAVE_AV_CONFIG_H -I.. sha1.c -O2 -W -Wall -o sha1 && time ./sha1
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#ifdef TEST
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#include <stdio.h>
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#undef printf
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int main(void){
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    int i, k;
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    AVSHA1 ctx;
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    unsigned char digest[20];
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    for(k=0; k<3; k++){
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        av_sha1_init(&ctx);
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        if(k==0)
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            av_sha1_update(&ctx, "abc", 3);
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        else if(k==1)
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            av_sha1_update(&ctx, "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq", 56);
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        else
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            for(i=0; i<1000*1000; i++)
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                av_sha1_update(&ctx, "a", 1);
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        av_sha1_final(&ctx, digest);
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        for (i = 0; i < 20; i++)
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            printf("%02X", digest[i]);
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        putchar('\n');
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    }
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    //Test Vectors (from FIPS PUB 180-1)
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    printf("A9993E36 4706816A BA3E2571 7850C26C 9CD0D89D\n"
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           "84983E44 1C3BD26E BAAE4AA1 F95129E5 E54670F1\n"
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           "34AA973C D4C4DAA4 F61EEB2B DBAD2731 6534016F\n");
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    return 0;
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}
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#endif