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/*

  Based on the public domain implementation of the SHA-1 algorithm

  Copyright (C) Dominik Reichl <dominik.reichl@t-online.de>

*/

#include <QtCore/qendian.h>

#ifdef Q_CC_MSVC

#  include <stdlib.h>

#endif

QT_BEGIN_NAMESPACE

// 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

//

// #define or #undef this, if you want the to wipe all

// temporary variables after processing

#define SHA1_WIPE_VARIABLES

struct Sha1State

{

    quint32 h0;

    quint32 h1;

    quint32 h2;

    quint32 h3;

    quint32 h4;

    quint64 messageSize;

    unsigned char buffer[64];

};

typedef union

{

    quint8  bytes[64];

    quint32 words[16];

} Sha1Chunk;

static inline quint32 rol32(quint32 value, unsigned int shift)

{

#ifdef Q_CC_MSVC

    return _rotl(value, shift);

#else

    return ((value << shift) | (value >> (32 - shift)));

#endif

}

static inline quint32 sha1Word(Sha1Chunk *chunk, const uint position)

{

    return (chunk->words[position & 0xf] = rol32(  chunk->words[(position+13) & 0xf]

                                                 ^ chunk->words[(position+ 8) & 0xf]

                                                 ^ chunk->words[(position+ 2) & 0xf]

                                                 ^ chunk->words[(position)    & 0xf], 1));

}

static inline void sha1Round0(Sha1Chunk *chunk, const uint position,

                              quint32 &v, quint32 &w, quint32 &x, quint32 &y, quint32 &z)

{

    z += ((( w & (x ^ y)) ^ y) + chunk->words[position] + 0x5A827999 + rol32(v, 5));

    w = rol32(w, 30);

}

static inline void sha1Round1(Sha1Chunk *chunk, const uint position,

                              quint32 &v, quint32 &w, quint32 &x, quint32 &y, quint32 &z)

{

    z += ((( w & (x ^ y)) ^ y) + sha1Word(chunk,position) + 0x5A827999 + rol32(v, 5));

    w = rol32(w, 30);

}

static inline void sha1Round2(Sha1Chunk *chunk, const uint position,

                              quint32 &v, quint32 &w, quint32 &x, quint32 &y, quint32 &z)

{

    z += (( w ^ x ^ y) + sha1Word(chunk, position) + 0x6ED9EBA1 + rol32(v, 5));

    w = rol32(w, 30);

}

static inline void sha1Round3(Sha1Chunk *chunk, const uint position,

                              quint32 &v, quint32 &w, quint32 &x, quint32 &y, quint32 &z)

{

    z += (((( w | x) & y) | (w & x)) + sha1Word(chunk, position) + 0x8F1BBCDC + rol32(v, 5));

    w = rol32(w, 30);

}

static inline void sha1Round4(Sha1Chunk *chunk, const uint position,

                              quint32 &v, quint32 &w, quint32 &x, quint32 &y, quint32 &z)

{

    z += ((w ^ x ^ y) + sha1Word(chunk, position) + 0xCA62C1D6 + rol32(v, 5));

    w = rol32(w, 30);

}

static inline void sha1ProcessChunk(Sha1State *state, const unsigned char *buffer)

{

    // Copy state[] to working vars

    quint32 a = state->h0;

    quint32 b = state->h1;

    quint32 c = state->h2;

    quint32 d = state->h3;

    quint32 e = state->h4;

    quint8 chunkBuffer[64];

    memcpy(chunkBuffer, buffer, 64);

    Sha1Chunk *chunk = reinterpret_cast<Sha1Chunk*>(&chunkBuffer);

    for (int i = 0; i < 16; ++i)

        chunk->words[i] = qFromBigEndian(chunk->words[i]);

    sha1Round0(chunk,  0, a,b,c,d,e); sha1Round0(chunk,  1, e,a,b,c,d); sha1Round0(chunk,  2, d,e,a,b,c); sha1Round0(chunk,  3, c,d,e,a,b);

    sha1Round0(chunk,  4, b,c,d,e,a); sha1Round0(chunk,  5, a,b,c,d,e); sha1Round0(chunk,  6, e,a,b,c,d); sha1Round0(chunk,  7, d,e,a,b,c);

    sha1Round0(chunk,  8, c,d,e,a,b); sha1Round0(chunk,  9, b,c,d,e,a); sha1Round0(chunk, 10, a,b,c,d,e); sha1Round0(chunk, 11, e,a,b,c,d);

    sha1Round0(chunk, 12, d,e,a,b,c); sha1Round0(chunk, 13, c,d,e,a,b); sha1Round0(chunk, 14, b,c,d,e,a); sha1Round0(chunk, 15, a,b,c,d,e);

    sha1Round1(chunk, 16, e,a,b,c,d); sha1Round1(chunk, 17, d,e,a,b,c); sha1Round1(chunk, 18, c,d,e,a,b); sha1Round1(chunk, 19, b,c,d,e,a);

    sha1Round2(chunk, 20, a,b,c,d,e); sha1Round2(chunk, 21, e,a,b,c,d); sha1Round2(chunk, 22, d,e,a,b,c); sha1Round2(chunk, 23, c,d,e,a,b);

    sha1Round2(chunk, 24, b,c,d,e,a); sha1Round2(chunk, 25, a,b,c,d,e); sha1Round2(chunk, 26, e,a,b,c,d); sha1Round2(chunk, 27, d,e,a,b,c);

    sha1Round2(chunk, 28, c,d,e,a,b); sha1Round2(chunk, 29, b,c,d,e,a); sha1Round2(chunk, 30, a,b,c,d,e); sha1Round2(chunk, 31, e,a,b,c,d);

    sha1Round2(chunk, 32, d,e,a,b,c); sha1Round2(chunk, 33, c,d,e,a,b); sha1Round2(chunk, 34, b,c,d,e,a); sha1Round2(chunk, 35, a,b,c,d,e);

    sha1Round2(chunk, 36, e,a,b,c,d); sha1Round2(chunk, 37, d,e,a,b,c); sha1Round2(chunk, 38, c,d,e,a,b); sha1Round2(chunk, 39, b,c,d,e,a);

    sha1Round3(chunk, 40, a,b,c,d,e); sha1Round3(chunk, 41, e,a,b,c,d); sha1Round3(chunk, 42, d,e,a,b,c); sha1Round3(chunk, 43, c,d,e,a,b);

    sha1Round3(chunk, 44, b,c,d,e,a); sha1Round3(chunk, 45, a,b,c,d,e); sha1Round3(chunk, 46, e,a,b,c,d); sha1Round3(chunk, 47, d,e,a,b,c);

    sha1Round3(chunk, 48, c,d,e,a,b); sha1Round3(chunk, 49, b,c,d,e,a); sha1Round3(chunk, 50, a,b,c,d,e); sha1Round3(chunk, 51, e,a,b,c,d);

    sha1Round3(chunk, 52, d,e,a,b,c); sha1Round3(chunk, 53, c,d,e,a,b); sha1Round3(chunk, 54, b,c,d,e,a); sha1Round3(chunk, 55, a,b,c,d,e);

    sha1Round3(chunk, 56, e,a,b,c,d); sha1Round3(chunk, 57, d,e,a,b,c); sha1Round3(chunk, 58, c,d,e,a,b); sha1Round3(chunk, 59, b,c,d,e,a);

    sha1Round4(chunk, 60, a,b,c,d,e); sha1Round4(chunk, 61, e,a,b,c,d); sha1Round4(chunk, 62, d,e,a,b,c); sha1Round4(chunk, 63, c,d,e,a,b);

    sha1Round4(chunk, 64, b,c,d,e,a); sha1Round4(chunk, 65, a,b,c,d,e); sha1Round4(chunk, 66, e,a,b,c,d); sha1Round4(chunk, 67, d,e,a,b,c);

    sha1Round4(chunk, 68, c,d,e,a,b); sha1Round4(chunk, 69, b,c,d,e,a); sha1Round4(chunk, 70, a,b,c,d,e); sha1Round4(chunk, 71, e,a,b,c,d);

    sha1Round4(chunk, 72, d,e,a,b,c); sha1Round4(chunk, 73, c,d,e,a,b); sha1Round4(chunk, 74, b,c,d,e,a); sha1Round4(chunk, 75, a,b,c,d,e);

    sha1Round4(chunk, 76, e,a,b,c,d); sha1Round4(chunk, 77, d,e,a,b,c); sha1Round4(chunk, 78, c,d,e,a,b); sha1Round4(chunk, 79, b,c,d,e,a);

    // Add the working vars back into state

    state->h0 += a;

    state->h1 += b;

    state->h2 += c;

    state->h3 += d;

    state->h4 += e;

    // Wipe variables

#ifdef SHA1_WIPE_VARIABLES

    a = b = c = d = e = 0;

    memset(chunkBuffer, 0, 64);

#endif

}

static inline void sha1InitState(Sha1State *state)

{

    state->h0 = 0x67452301;

    state->h1 = 0xEFCDAB89;

    state->h2 = 0x98BADCFE;

    state->h3 = 0x10325476;

    state->h4 = 0xC3D2E1F0;

    state->messageSize = 0;

}

static inline void sha1Update(Sha1State *state, const unsigned char *data, qint64 len)

{

    quint32 rest = static_cast<quint32>(state->messageSize & Q_UINT64_C(63));

    quint64 availableData = static_cast<quint64>(len) + static_cast<quint64>(rest);

    state->messageSize += len;

    if (availableData < Q_UINT64_C(64)) {

        memcpy(&state->buffer[rest], &data[0], len);

    } else {

        qint64 i = static_cast<qint64>(64 - rest);

        memcpy(&state->buffer[rest], &data[0], static_cast<qint32>(i));

        sha1ProcessChunk(state, state->buffer);

        qint64 lastI = len - ((len + rest) & Q_INT64_C(63));

        for( ; i < lastI; i += 64)

            sha1ProcessChunk(state, &data[i]);

        memcpy(&state->buffer[0], &data[i], len - i);

    }

}

static inline void sha1FinalizeState(Sha1State *state)

{

    quint64 messageSize = state->messageSize;

    unsigned char sizeInBits[8];

    qToBigEndian(messageSize << 3, sizeInBits);

    sha1Update(state, (const unsigned char *)"\200", 1);

    unsigned char zero[64];

    memset(zero, 0, 64);

    if (static_cast<int>(messageSize & 63) > 56 - 1) {

        sha1Update(state, zero, 64 - 1 - static_cast<int>(messageSize & 63));

        sha1Update(state, zero, 64 - 8);

    } else {

        sha1Update(state, zero, 64 - 1 - 8 - static_cast<int>(messageSize & 63));

    }

    sha1Update(state, sizeInBits, 8);

#ifdef SHA1_WIPE_VARIABLES

    memset(state->buffer, 0, 64);

    memset(zero, 0, 64);

    state->messageSize = 0;

#endif

}

static inline void sha1ToHash(Sha1State *state, unsigned char* buffer)

{

    qToBigEndian(state->h0, buffer);

    qToBigEndian(state->h1, buffer + 4);

    qToBigEndian(state->h2, buffer + 8);

    qToBigEndian(state->h3, buffer + 12);

    qToBigEndian(state->h4, buffer + 16);

}

QT_END_NAMESPACE