/*
 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"

#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(uint32_t *state, const uint8_t *buffer)
{
    // Copy state[] to working vars
    uint32_t 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(const uint8_t *data, uint32_t len)
{
    uint32_t 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;
    uint8_t 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++)
    {
        fread(uData, 1, SHA1_MAX_FILE_BUFFER, fIn);
        Update((uint8_t *)uData, SHA1_MAX_FILE_BUFFER);
    }

    if (ulRest != 0)
    {
        fread(uData, 1, ulRest, fIn);
        Update((uint8_t *)uData, ulRest);
    }

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

void CSHA1::Final()
{
    uint32_t i;
    uint8_t finalcount[8];

    for (i = 0; i < 8; i++)
        finalcount[i] = (uint8_t)((m_count[((i >= 4) ? 0 : 1)] >> ((3 - (i & 3)) * 8)) & 255); // Endian independent

    Update((uint8_t *)"\200", 1);

    while ((m_count[0] & 504) != 448)
        Update((uint8_t *)"\0", 1);

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

    for (i = 0; i < 20; i++)
    {
        m_digest[i] = (uint8_t)((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(uint8_t *puDest)
{
    memcpy(puDest, m_digest, 20);
}
