text: // Copyright (c) 2014 The Liberta Core developers
  // Distributed under the MIT software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  #include "crypto/sha1.h"
  
  #include "crypto/common.h"
  
  #include <string.h>
  
  // Internal implementation code.
  namespace
  {
  /// Internal SHA-1 implementation.
  namespace sha1
  {
  /** One round of SHA-1. */
  void inline Round(uint32_t a, uint32_t& b, uint32_t c, uint32_t d, uint32_t& e, uint32_t f, uint32_t k, uint32_t w)
  {
      e += ((a << 5) | (a >> 27)) + f + k + w;
      b = (b << 30) | (b >> 2);
  }
  
  uint32_t inline f1(uint32_t b, uint32_t c, uint32_t d) { return d ^ (b & (c ^ d)); }
  uint32_t inline f2(uint32_t b, uint32_t c, uint32_t d) { return b ^ c ^ d; }
  uint32_t inline f3(uint32_t b, uint32_t c, uint32_t d) { return (b & c) | (d & (b | c)); }
  
  uint32_t inline left(uint32_t x) { return (x << 1) | (x >> 31); }
  
  /** Initialize SHA-1 state. */
  void inline Initialize(uint32_t* s)
  {
      s[0] = 0x67452301ul;
      s[1] = 0xEFCDAB89ul;
      s[2] = 0x98BADCFEul;
      s[3] = 0x10325476ul;
      s[4] = 0xC3D2E1F0ul;
  }
  
  const uint32_t k1 = 0x5A827999ul;
  const uint32_t k2 = 0x6ED9EBA1ul;
  const uint32_t k3 = 0x8F1BBCDCul;
  const uint32_t k4 = 0xCA62C1D6ul;
  
  /** Perform a SHA-1 transformation, processing a 64-byte chunk. */
  void Transform(uint32_t* s, const unsigned char* chunk)
  {
      uint32_t a = s[0], b = s[1], c = s[2], d = s[3], e = s[4];
      uint32_t w0, w1, w2, w3, w4, w5, w6, w7, w8, w9, w10, w11, w12, w13, w14, w15;
  
      Round(a, b, c, d, e, f1(b, c, d), k1, w0 = ReadBE32(chunk + 0));
      Round(e, a, b, c, d, f1(a, b, c), k1, w1 = ReadBE32(chunk + 4));
      Round(d, e, a, b, c, f1(e, a, b), k1, w2 = ReadBE32(chunk + 8));
      Round(c, d, e, a, b, f1(d, e, a), k1, w3 = ReadBE32(chunk + 12));
      Round(b, c, d, e, a, f1(c, d, e), k1, w4 = ReadBE32(chunk + 16));
      Round(a, b, c, d, e, f1(b, c, d), k1, w5 = ReadBE32(chunk + 20));
      Round(e, a, b, c, d, f1(a, b, c), k1, w6 = ReadBE32(chunk + 24));
      Round(d, e, a, b, c, f1(e, a, b), k1, w7 = ReadBE32(chunk + 28));
      Round(c, d, e, a, b, f1(d, e, a), k1, w8 = ReadBE32(chunk + 32));
      Round(b, c, d, e, a, f1(c, d, e), k1, w9 = ReadBE32(chunk + 36));
      Round(a, b, c, d, e, f1(b, c, d), k1, w10 = ReadBE32(chunk + 40));
      Round(e, a, b, c, d, f1(a, b, c), k1, w11 = ReadBE32(chunk + 44));
      Round(d, e, a, b, c, f1(e, a, b), k1, w12 = ReadBE32(chunk + 48));
      Round(c, d, e, a, b, f1(d, e, a), k1, w13 = ReadBE32(chunk + 52));
      Round(b, c, d, e, a, f1(c, d, e), k1, w14 = ReadBE32(chunk + 56));
      Round(a, b, c, d, e, f1(b, c, d), k1, w15 = ReadBE32(chunk + 60));
  
      Round(e, a, b, c, d, f1(a, b, c), k1, w0 = left(w0 ^ w13 ^ w8 ^ w2));
      Round(d, e, a, b, c, f1(e, a, b), k1, w1 = left(w1 ^ w14 ^ w9 ^ w3));
      Round(c, d, e, a, b, f1(d, e, a), k1, w2 = left(w2 ^ w15 ^ w10 ^ w4));
      Round(b, c, d, e, a, f1(c, d, e), k1, w3 = left(w3 ^ w0 ^ w11 ^ w5));
      Round(a, b, c, d, e, f2(b, c, d), k2, w4 = left(w4 ^ w1 ^ w12 ^ w6));
      Round(e, a, b, c, d, f2(a, b, c), k2, w5 = left(w5 ^ w2 ^ w13 ^ w7));
      Round(d, e, a, b, c, f2(e, a, b), k2, w6 = left(w6 ^ w3 ^ w14 ^ w8));
      Round(c, d, e, a, b, f2(d, e, a), k2, w7 = left(w7 ^ w4 ^ w15 ^ w9));
      Round(b, c, d, e, a, f2(c, d, e), k2, w8 = left(w8 ^ w5 ^ w0 ^ w10));
      Round(a, b, c, d, e, f2(b, c, d), k2, w9 = left(w9 ^ w6 ^ w1 ^ w11));
      Round(e, a, b, c, d, f2(a, b, c), k2, w10 = left(w10 ^ w7 ^ w2 ^ w12));
      Round(d, e, a, b, c, f2(e, a, b), k2, w11 = left(w11 ^ w8 ^ w3 ^ w13));
      Round(c, d, e, a, b, f2(d, e, a), k2, w12 = left(w12 ^ w9 ^ w4 ^ w14));
      Round(b, c, d, e, a, f2(c, d, e), k2, w13 = left(w13 ^ w10 ^ w5 ^ w15));
      Round(a, b, c, d, e, f2(b, c, d), k2, w14 = left(w14 ^ w11 ^ w6 ^ w0));
      Round(e, a, b, c, d, f2(a, b, c), k2, w15 = left(w15 ^ w12 ^ w7 ^ w1));
  
      Round(d, e, a, b, c, f2(e, a, b), k2, w0 = left(w0 ^ w13 ^ w8 ^ w2));
      Round(c, d, e, a, b, f2(d, e, a), k2, w1 = left(w1 ^ w14 ^ w9 ^ w3));
      Round(b, c, d, e, a, f2(c, d, e), k2, w2 = left(w2 ^ w15 ^ w10 ^ w4));
      Round(a, b, c, d, e, f2(b, c, d), k2, w3 = left(w3 ^ w0 ^ w11 ^ w5));
      Round(e, a, b, c, d, f2(a, b, c), k2, w4 = left(w4 ^ w1 ^ w12 ^ w6));
      Round(d, e, a, b, c, f2(e, a, b), k2, w5 = left(w5 ^ w2 ^ w13 ^ w7));
      Round(c, d, e, a, b, f2(d, e, a), k2, w6 = left(w6 ^ w3 ^ w14 ^ w8));
      Round(b, c, d, e, a, f2(c, d, e), k2, w7 = left(w7 ^ w4 ^ w15 ^ w9));
      Round(a, b, c, d, e, f3(b, c, d), k3, w8 = left(w8 ^ w5 ^ w0 ^ w10));
      Round(e, a, b, c, d, f3(a, b, c), k3, w9 = left(w9 ^ w6 ^ w1 ^ w11));
      Round(d, e, a, b, c, f3(e, a, b), k3, w10 = left(w10 ^ w7 ^ w2 ^ w12));
      Round(c, d, e, a, b, f3(d, e, a), k3, w11 = left(w11 ^ w8 ^ w3 ^ w13));
      Round(b, c, d, e, a, f3(c, d, e), k3, w12 = left(w12 ^ w9 ^ w4 ^ w14));
      Round(a, b, c, d, e, f3(b, c, d), k3, w13 = left(w13 ^ w10 ^ w5 ^ w15));
      Round(e, a, b, c, d, f3(a, b, c), k3, w14 = left(w14 ^ w11 ^ w6 ^ w0));
      Round(d, e, a, b, c, f3(e, a, b), k3, w15 = left(w15 ^ w12 ^ w7 ^ w1));
  
      Round(c, d, e, a, b, f3(d, e, a), k3, w0 = left(w0 ^ w13 ^ w8 ^ w2));
      Round(b, c, d, e, a, f3(c, d, e), k3, w1 = left(w1 ^ w14 ^ w9 ^ w3));
      Round(a, b, c, d, e, f3(b, c, d), k3, w2 = left(w2 ^ w15 ^ w10 ^ w4));
      Round(e, a, b, c, d, f3(a, b, c), k3, w3 = left(w3 ^ w0 ^ w11 ^ w5));
      Round(d, e, a, b, c, f3(e, a, b), k3, w4 = left(w4 ^ w1 ^ w12 ^ w6));
      Round(c, d, e, a, b, f3(d, e, a), k3, w5 = left(w5 ^ w2 ^ w13 ^ w7));
      Round(b, c, d, e, a, f3(c, d, e), k3, w6 = left(w6 ^ w3 ^ w14 ^ w8));
      Round(a, b, c, d, e, f3(b, c, d), k3, w7 = left(w7 ^ w4 ^ w15 ^ w9));
      Round(e, a, b, c, d, f3(a, b, c), k3, w8 = left(w8 ^ w5 ^ w0 ^ w10));
      Round(d, e, a, b, c, f3(e, a, b), k3, w9 = left(w9 ^ w6 ^ w1 ^ w11));
      Round(c, d, e, a, b, f3(d, e, a), k3, w10 = left(w10 ^ w7 ^ w2 ^ w12));
      Round(b, c, d, e, a, f3(c, d, e), k3, w11 = left(w11 ^ w8 ^ w3 ^ w13));
      Round(a, b, c, d, e, f2(b, c, d), k4, w12 = left(w12 ^ w9 ^ w4 ^ w14));
      Round(e, a, b, c, d, f2(a, b, c), k4, w13 = left(w13 ^ w10 ^ w5 ^ w15));
      Round(d, e, a, b, c, f2(e, a, b), k4, w14 = left(w14 ^ w11 ^ w6 ^ w0));
      Round(c, d, e, a, b, f2(d, e, a), k4, w15 = left(w15 ^ w12 ^ w7 ^ w1));
  
      Round(b, c, d, e, a, f2(c, d, e), k4, w0 = left(w0 ^ w13 ^ w8 ^ w2));
      Round(a, b, c, d, e, f2(b, c, d), k4, w1 = left(w1 ^ w14 ^ w9 ^ w3));
      Round(e, a, b, c, d, f2(a, b, c), k4, w2 = left(w2 ^ w15 ^ w10 ^ w4));
      Round(d, e, a, b, c, f2(e, a, b), k4, w3 = left(w3 ^ w0 ^ w11 ^ w5));
      Round(c, d, e, a, b, f2(d, e, a), k4, w4 = left(w4 ^ w1 ^ w12 ^ w6));
      Round(b, c, d, e, a, f2(c, d, e), k4, w5 = left(w5 ^ w2 ^ w13 ^ w7));
      Round(a, b, c, d, e, f2(b, c, d), k4, w6 = left(w6 ^ w3 ^ w14 ^ w8));
      Round(e, a, b, c, d, f2(a, b, c), k4, w7 = left(w7 ^ w4 ^ w15 ^ w9));
      Round(d, e, a, b, c, f2(e, a, b), k4, w8 = left(w8 ^ w5 ^ w0 ^ w10));
      Round(c, d, e, a, b, f2(d, e, a), k4, w9 = left(w9 ^ w6 ^ w1 ^ w11));
      Round(b, c, d, e, a, f2(c, d, e), k4, w10 = left(w10 ^ w7 ^ w2 ^ w12));
      Round(a, b, c, d, e, f2(b, c, d), k4, w11 = left(w11 ^ w8 ^ w3 ^ w13));
      Round(e, a, b, c, d, f2(a, b, c), k4, w12 = left(w12 ^ w9 ^ w4 ^ w14));
      Round(d, e, a, b, c, f2(e, a, b), k4, left(w13 ^ w10 ^ w5 ^ w15));
      Round(c, d, e, a, b, f2(d, e, a), k4, left(w14 ^ w11 ^ w6 ^ w0));
      Round(b, c, d, e, a, f2(c, d, e), k4, left(w15 ^ w12 ^ w7 ^ w1));
  
      s[0] += a;
      s[1] += b;
      s[2] += c;
      s[3] += d;
      s[4] += e;
  }
  
  } // namespace sha1
  
  } // namespace
  
  ////// SHA1
  
  CSHA1::CSHA1() : bytes(0)
  {
      sha1::Initialize(s);
  }
  
  CSHA1& CSHA1::Write(const unsigned char* data, size_t len)
  {
      const unsigned char* end = data + len;
      size_t bufsize = bytes % 64;
      if (bufsize && bufsize + len >= 64) {
          // Fill the buffer, and process it.
          memcpy(buf + bufsize, data, 64 - bufsize);
          bytes += 64 - bufsize;
          data += 64 - bufsize;
          sha1::Transform(s, buf);
          bufsize = 0;
      }
      while (end >= data + 64) {
          // Process full chunks directly from the source.
          sha1::Transform(s, data);
          bytes += 64;
          data += 64;
      }
      if (end > data) {
          // Fill the buffer with what remains.
          memcpy(buf + bufsize, data, end - data);
          bytes += end - data;
      }
      return *this;
  }
  
  void CSHA1::Finalize(unsigned char hash[OUTPUT_SIZE])
  {
      static const unsigned char pad[64] = {0x80};
      unsigned char sizedesc[8];
      WriteBE64(sizedesc, bytes << 3);
      Write(pad, 1 + ((119 - (bytes % 64)) % 64));
      Write(sizedesc, 8);
      WriteBE32(hash, s[0]);
      WriteBE32(hash + 4, s[1]);
      WriteBE32(hash + 8, s[2]);
      WriteBE32(hash + 12, s[3]);
      WriteBE32(hash + 16, s[4]);
  }
  
  CSHA1& CSHA1::Reset()
  {
      bytes = 0;
      sha1::Initialize(s);
      return *this;
  }
  