/*
  +----------------------------------------------------------------------+
  | Swoole                                                               |
  +----------------------------------------------------------------------+
  | This source file is subject to version 2.0 of the Apache license,    |
  | that is bundled with this package in the file LICENSE, and is        |
  | available through the world-wide-web at the following url:           |
  | http://www.apache.org/licenses/LICENSE-2.0.html                      |
  | If you did not receive a copy of the Apache2.0 license and are unable|
  | to obtain it through the world-wide-web, please send a note to       |
  | license@swoole.com so we can mail you a copy immediately.            |
  +----------------------------------------------------------------------+
  | Author: Tianfeng Han  <mikan.tenny@gmail.com>                        |
  +----------------------------------------------------------------------+
*/
#include <string.h>

#include "sha1.h"

#define rol(value, bits) (((value) << (bits)) | ((value) >> (32 - (bits))))

/* blk0() and blk() perform the initial expand. */
/* I got the idea of expanding during the round function from SSLeay */

#ifdef LITTLE_ENDIAN
#define blk0(i) (block->l[i] = (rol(block->l[i],24)&(sha1_quadbyte)0xFF00FF00) \
    |(rol(block->l[i],8)&(sha1_quadbyte)0x00FF00FF))
#else
#define blk0(i) block->l[i]
#endif

#define blk(i) (block->l[i&15] = rol(block->l[(i+13)&15]^block->l[(i+8)&15] \
    ^block->l[(i+2)&15]^block->l[i&15],1))

/* (R0+R1), R2, R3, R4 are the different operations used in SHA1 */
#define R0(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk0(i)+0x5A827999+rol(v,5);w=rol(w,30);
#define R1(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk(i)+0x5A827999+rol(v,5);w=rol(w,30);
#define R2(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0x6ED9EBA1+rol(v,5);w=rol(w,30);
#define R3(v,w,x,y,z,i) z+=(((w|x)&y)|(w&x))+blk(i)+0x8F1BBCDC+rol(v,5);w=rol(w,30);
#define R4(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0xCA62C1D6+rol(v,5);w=rol(w,30);

typedef union _BYTE64QUAD16 {
    sha1_byte c[64];
    sha1_quadbyte l[16];
} BYTE64QUAD16;
static void swSha1_transform(sha1_quadbyte state[5], sha1_byte buffer[64]);
/* Hash a single 512-bit block. This is the core of the algorithm. */
static void swSha1_transform(sha1_quadbyte state[5], sha1_byte buffer[64]) {
    sha1_quadbyte a, b, c, d, e;
    BYTE64QUAD16 src;
    BYTE64QUAD16 *block;

    /* slow but cast-align */
    memcpy(src.c, buffer, sizeof(sha1_byte) * 64);
    block = &src;
    /* 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;
}


/* swSha1_init - Initialize new context */
void swSha1_init(SHA_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 swSha1_update(SHA_CTX *context, sha1_byte *data, unsigned int len) {
    unsigned int 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));
        swSha1_transform(context->state, context->buffer);
        for ( ; i + 63 < len; i += 64) {
            swSha1_transform(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 swSha1_final(sha1_byte digest[SHA1_DIGEST_LENGTH], SHA_CTX *context) {
    sha1_quadbyte i, j;
    sha1_byte finalcount[8];

    for (i = 0; i < 8; i++) {
        finalcount[i] = (sha1_byte)((context->count[(i >= 4 ? 0 : 1)]
                >> ((3-(i & 3)) * 8) ) & 255);  /* Endian independent */
    }
    swSha1_update(context, (sha1_byte *)"\200", 1);
    while ((context->count[0] & 504) != 448) {
        swSha1_update(context, (sha1_byte *)"\0", 1);
    }
    /* Should cause a swSha1_Transform() */
    swSha1_update(context, finalcount, 8);
    for (i = 0; i < SHA1_DIGEST_LENGTH; i++) {
        digest[i] = (sha1_byte)
                ((context->state[i>>2] >> ((3-(i & 3)) * 8) ) & 255);
    }
    /* Wipe variables */
    i = j = 0;
    memset(context->buffer, 0, SHA1_BLOCK_LENGTH);
    memset(context->state, 0, SHA1_DIGEST_LENGTH);
    memset(context->count, 0, 8);
    memset(&finalcount, 0, 8);
}
