/*
    100% free public domain implementation of the SHA-1 algorithm
    by Dominik Reichl <dominik.reichl@t-online.de>
    Web: http://www.dominik-reichl.de/

    Version 1.6 - 2005-02-07 (thanks to Howard Kapustein for patches)
    - You can set the endianness in your files, no need to modify the
      header file of the CSHA1 class any more
    - Aligned data support
    - Made support/compilation of the utility functions (ReportHash
      and HashFile) optional (useful, if bytes count, for example in
      embedded environments)

    Version 1.5 - 2005-01-01
    - 64-bit compiler compatibility added
    - Made variable wiping optional (define SHA1_WIPE_VARIABLES)
    - Removed unnecessary variable initializations
    - ROL32 improvement for the Microsoft compiler (using _rotl)

    ======== Test Vectors (from FIPS PUB 180-1) ========

    SHA1("abc") =
        A9993E36 4706816A BA3E2571 7850C26C 9CD0D89D

    SHA1("abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq") =
        84983E44 1C3BD26E BAAE4AA1 F95129E5 E54670F1

    SHA1(A million repetitions of "a") =
        34AA973C D4C4DAA4 F61EEB2B DBAD2731 6534016F
*/

#include "SHA1.h"
#include <cassert>

#ifdef SHA1_UTILITY_FUNCTIONS
#define SHA1_MAX_FILE_BUFFER 8000
#endif

// Rotate x bits to the left
#ifndef ROL32
#ifdef _MSC_VER
#define ROL32(_val32, _nBits) _rotl(_val32, _nBits)
#else
#define ROL32(_val32, _nBits) (((_val32)<<(_nBits))|((_val32)>>(32-(_nBits))))
#endif
#endif

#ifdef SHA1_LITTLE_ENDIAN
#define SHABLK0(i) (m_block->l[i] = \
    (ROL32(m_block->l[i],24) & 0xFF00FF00) | (ROL32(m_block->l[i],8) & 0x00FF00FF))
#else
#define SHABLK0(i) (m_block->l[i])
#endif

#define SHABLK(i) (m_block->l[i&15] = ROL32(m_block->l[(i+13)&15] ^ m_block->l[(i+8)&15] \
    ^ m_block->l[(i+2)&15] ^ m_block->l[i&15],1))

// SHA-1 rounds
#define _R0(v,w,x,y,z,i) { z+=((w&(x^y))^y)+SHABLK0(i)+0x5A827999+ROL32(v,5); w=ROL32(w,30); }
#define _R1(v,w,x,y,z,i) { z+=((w&(x^y))^y)+SHABLK(i)+0x5A827999+ROL32(v,5); w=ROL32(w,30); }
#define _R2(v,w,x,y,z,i) { z+=(w^x^y)+SHABLK(i)+0x6ED9EBA1+ROL32(v,5); w=ROL32(w,30); }
#define _R3(v,w,x,y,z,i) { z+=(((w|x)&y)|(w&x))+SHABLK(i)+0x8F1BBCDC+ROL32(v,5); w=ROL32(w,30); }
#define _R4(v,w,x,y,z,i) { z+=(w^x^y)+SHABLK(i)+0xCA62C1D6+ROL32(v,5); w=ROL32(w,30); }

CSHA1::CSHA1()
{
    m_block = (SHA1_WORKSPACE_BLOCK *)m_workspace;

    Reset();
}

CSHA1::~CSHA1()
{
    Reset();
}

void CSHA1::Reset()
{
    // SHA1 initialization constants
    m_state[0] = 0x67452301;
    m_state[1] = 0xEFCDAB89;
    m_state[2] = 0x98BADCFE;
    m_state[3] = 0x10325476;
    m_state[4] = 0xC3D2E1F0;

    m_count[0] = 0;
    m_count[1] = 0;
}

void CSHA1::Transform(UINT_32 *state, UINT_8 *buffer)
{
    // Copy state[] to working vars
    UINT_32 a = state[0], b = state[1], c = state[2], d = state[3], e = state[4];

    memcpy(m_block, buffer, 64);

    // 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 state
    state[0] += a;
    state[1] += b;
    state[2] += c;
    state[3] += d;
    state[4] += e;

    // Wipe variables
#ifdef SHA1_WIPE_VARIABLES
    a = b = c = d = e = 0;
#endif
}

// Use this function to hash in binary data and strings
void CSHA1::Update(UINT_8 *data, UINT_32 len)
{
    UINT_32 i, j;

    j = (m_count[0] >> 3) & 63;

    if((m_count[0] += len << 3) < (len << 3)) m_count[1]++;

    m_count[1] += (len >> 29);

    if((j + len) > 63)
    {
        i = 64 - j;
        memcpy(&m_buffer[j], data, i);
        Transform(m_state, m_buffer);

        for(; i + 63 < len; i += 64) Transform(m_state, &data[i]);

        j = 0;
    }
    else i = 0;

    memcpy(&m_buffer[j], &data[i], len - i);
}

#ifdef SHA1_UTILITY_FUNCTIONS
// Hash in file contents
bool CSHA1::HashFile(char *szFileName)
{
    unsigned long ulFileSize, ulRest, ulBlocks;
    unsigned long i;
    UINT_8 uData[SHA1_MAX_FILE_BUFFER];
    FILE *fIn;

    if(szFileName == NULL) return false;

    fIn = fopen(szFileName, "rb");
    if(fIn == NULL) return false;

    fseek(fIn, 0, SEEK_END);
    ulFileSize = (unsigned long)ftell(fIn);
    fseek(fIn, 0, SEEK_SET);

    if(ulFileSize != 0)
    {
        ulBlocks = ulFileSize / SHA1_MAX_FILE_BUFFER;
        ulRest = ulFileSize % SHA1_MAX_FILE_BUFFER;
    }
    else
    {
        ulBlocks = 0;
        ulRest = 0;
    }

    for(i = 0; i < ulBlocks; i++)
    {
        size_t nread = fread(uData, 1, SHA1_MAX_FILE_BUFFER, fIn);
                assert(nread == SHA1_MAX_FILE_BUFFER);
        Update((UINT_8 *)uData, SHA1_MAX_FILE_BUFFER);
    }

    if(ulRest != 0)
    {
        size_t nread = fread(uData, 1, ulRest, fIn);
                assert(nread == ulRest);
        Update((UINT_8 *)uData, (unsigned int) ulRest);
    }

    fclose(fIn); fIn = NULL;
    return true;
}
#endif

void CSHA1::Final()
{
    UINT_32 i;
    UINT_8 finalcount[8];

    for(i = 0; i < 8; i++)
        finalcount[i] = (UINT_8)((m_count[((i >= 4) ? 0 : 1)]
            >> ((3 - (i & 3)) * 8) ) & 255); // Endian independent

    Update((UINT_8 *)"\200", 1);

    while ((m_count[0] & 504) != 448)
        Update((UINT_8 *)"\0", 1);

    Update(finalcount, 8); // Cause a SHA1Transform()

    for(i = 0; i < 20; i++)
    {
        m_digest[i] = (UINT_8)((m_state[i >> 2] >> ((3 - (i & 3)) * 8) ) & 255);
    }

    // Wipe variables for security reasons
#ifdef SHA1_WIPE_VARIABLES
    i = 0;
    memset(m_buffer, 0, 64);
    memset(m_state, 0, 20);
    memset(m_count, 0, 8);
    memset(finalcount, 0, 8);
    Transform(m_state, m_buffer);
#endif
}

#ifdef SHA1_UTILITY_FUNCTIONS
// Get the final hash as a pre-formatted string
void CSHA1::ReportHash(char *szReport, unsigned char uReportType)
{
    unsigned char i;
    char szTemp[16];

    if(szReport == NULL) return;

    if(uReportType == REPORT_HEX)
    {
        sprintf(szTemp, "%02X", m_digest[0]);
        strcat(szReport, szTemp);

        for(i = 1; i < 20; i++)
        {
            sprintf(szTemp, " %02X", m_digest[i]);
            strcat(szReport, szTemp);
        }
    }
    else if(uReportType == REPORT_DIGIT)
    {
        sprintf(szTemp, "%u", m_digest[0]);
        strcat(szReport, szTemp);

        for(i = 1; i < 20; i++)
        {
            sprintf(szTemp, " %u", m_digest[i]);
            strcat(szReport, szTemp);
        }
    }
    else strcpy(szReport, "Error: Unknown report type!");
}
#endif

// Get the raw message digest
void CSHA1::GetHash(UINT_8 *puDest)
{
    memcpy(puDest, m_digest, 20);
}
