deps/boost_1_63_0/boost/uuid/sha1.hpp

   1 // boost/uuid/sha1.hpp header file  ----------------------------------------------//
   2
   3 // Copyright 2007 Andy Tompkins.
   4 // Distributed under the Boost Software License, Version 1.0. (See
   5 // accompanying file LICENSE_1_0.txt or copy at
   6 // http://www.boost.org/LICENSE_1_0.txt)
   7
   8 // Revision History
   9 //  29 May 2007 - Initial Revision
  10 //  25 Feb 2008 - moved to namespace boost::uuids::detail
  11 //  10 Jan 2012 - can now handle the full size of messages (2^64 - 1 bits)
  12
  13 // This is a byte oriented implementation
  14
  15 #ifndef BOOST_UUID_SHA1_H
  16 #define BOOST_UUID_SHA1_H
  17
  18 #include <boost/static_assert.hpp>
  19 #include <stdexcept>
  20 #include <boost/throw_exception.hpp>
  21 #include <cstddef>
  22 #include <string>
  23
  24 #ifdef BOOST_NO_STDC_NAMESPACE
  25 namespace std {
  26     using ::size_t;
  27 } // namespace std
  28 #endif
  29
  30 namespace boost {
  31 namespace uuids {
  32 namespace detail {
  33
  34 BOOST_STATIC_ASSERT(sizeof(unsigned char)*8 == 8);
  35 BOOST_STATIC_ASSERT(sizeof(unsigned int)*8 == 32);
  36
  37 inline unsigned int left_rotate(unsigned int x, std::size_t n)
  38 {
  39     return (x<<n) ^ (x>> (32-n));
  40 }
  41
  42 class sha1
  43 {
  44 public:
  45     typedef unsigned int(&digest_type)[5];
  46 public:
  47     sha1();
  48
  49     void reset();
  50
  51     void process_byte(unsigned char byte);
  52     void process_block(void const* bytes_begin, void const* bytes_end);
  53     void process_bytes(void const* buffer, std::size_t byte_count);
  54
  55     void get_digest(digest_type digest);
  56
  57 private:
  58     void process_block();
  59     void process_byte_impl(unsigned char byte);
  60
  61 private:
  62     unsigned int h_[5];
  63
  64     unsigned char block_[64];
  65
  66     std::size_t block_byte_index_;
  67     std::size_t bit_count_low;
  68     std::size_t bit_count_high;
  69 };
  70
  71 inline sha1::sha1()
  72 {
  73     reset();
  74 }
  75
  76 inline void sha1::reset()
  77 {
  78     h_[0] = 0x67452301;
  79     h_[1] = 0xEFCDAB89;
  80     h_[2] = 0x98BADCFE;
  81     h_[3] = 0x10325476;
  82     h_[4] = 0xC3D2E1F0;
  83
  84     block_byte_index_ = 0;
  85     bit_count_low = 0;
  86     bit_count_high = 0;
  87 }
  88
  89 inline void sha1::process_byte(unsigned char byte)
  90 {
  91     process_byte_impl(byte);
  92
  93     // size_t max value = 0xFFFFFFFF
  94     //if (bit_count_low + 8 >= 0x100000000) { // would overflow
  95     //if (bit_count_low >= 0x100000000-8) {
  96     if (bit_count_low < 0xFFFFFFF8) {
  97         bit_count_low += 8;
  98     } else {
  99         bit_count_low = 0;
 100
 101         if (bit_count_high <= 0xFFFFFFFE) {
 102             ++bit_count_high;
 103         } else {
 104             BOOST_THROW_EXCEPTION(std::runtime_error("sha1 too many bytes"));
 105         }
 106     }
 107 }
 108
 109 inline void sha1::process_byte_impl(unsigned char byte)
 110 {
 111     block_[block_byte_index_++] = byte;
 112
 113     if (block_byte_index_ == 64) {
 114         block_byte_index_ = 0;
 115         process_block();
 116     }
 117 }
 118
 119 inline void sha1::process_block(void const* bytes_begin, void const* bytes_end)
 120 {
 121     unsigned char const* begin = static_cast<unsigned char const*>(bytes_begin);
 122     unsigned char const* end = static_cast<unsigned char const*>(bytes_end);
 123     for(; begin != end; ++begin) {
 124         process_byte(*begin);
 125     }
 126 }
 127
 128 inline void sha1::process_bytes(void const* buffer, std::size_t byte_count)
 129 {
 130     unsigned char const* b = static_cast<unsigned char const*>(buffer);
 131     process_block(b, b+byte_count);
 132 }
 133
 134 inline void sha1::process_block()
 135 {
 136     unsigned int w[80];
 137     for (std::size_t i=0; i<16; ++i) {
 138         w[i]  = (block_[i*4 + 0] << 24);
 139         w[i] |= (block_[i*4 + 1] << 16);
 140         w[i] |= (block_[i*4 + 2] << 8);
 141         w[i] |= (block_[i*4 + 3]);
 142     }
 143     for (std::size_t i=16; i<80; ++i) {
 144         w[i] = left_rotate((w[i-3] ^ w[i-8] ^ w[i-14] ^ w[i-16]), 1);
 145     }
 146
 147     unsigned int a = h_[0];
 148     unsigned int b = h_[1];
 149     unsigned int c = h_[2];
 150     unsigned int d = h_[3];
 151     unsigned int e = h_[4];
 152
 153     for (std::size_t i=0; i<80; ++i) {
 154         unsigned int f;
 155         unsigned int k;
 156
 157         if (i<20) {
 158             f = (b & c) | (~b & d);
 159             k = 0x5A827999;
 160         } else if (i<40) {
 161             f = b ^ c ^ d;
 162             k = 0x6ED9EBA1;
 163         } else if (i<60) {
 164             f = (b & c) | (b & d) | (c & d);
 165             k = 0x8F1BBCDC;
 166         } else {
 167             f = b ^ c ^ d;
 168             k = 0xCA62C1D6;
 169         }
 170
 171         unsigned temp = left_rotate(a, 5) + f + e + k + w[i];
 172         e = d;
 173         d = c;
 174         c = left_rotate(b, 30);
 175         b = a;
 176         a = temp;
 177     }
 178
 179     h_[0] += a;
 180     h_[1] += b;
 181     h_[2] += c;
 182     h_[3] += d;
 183     h_[4] += e;
 184 }
 185
 186 inline void sha1::get_digest(digest_type digest)
 187 {
 188     // append the bit '1' to the message
 189     process_byte_impl(0x80);
 190
 191     // append k bits '0', where k is the minimum number >= 0
 192     // such that the resulting message length is congruent to 56 (mod 64)
 193     // check if there is enough space for padding and bit_count
 194     if (block_byte_index_ > 56) {
 195         // finish this block
 196         while (block_byte_index_ != 0) {
 197             process_byte_impl(0);
 198         }
 199
 200         // one more block
 201         while (block_byte_index_ < 56) {
 202             process_byte_impl(0);
 203         }
 204     } else {
 205         while (block_byte_index_ < 56) {
 206             process_byte_impl(0);
 207         }
 208     }
 209
 210     // append length of message (before pre-processing)
 211     // as a 64-bit big-endian integer
 212     process_byte_impl( static_cast<unsigned char>((bit_count_high>>24) & 0xFF) );
 213     process_byte_impl( static_cast<unsigned char>((bit_count_high>>16) & 0xFF) );
 214     process_byte_impl( static_cast<unsigned char>((bit_count_high>>8 ) & 0xFF) );
 215     process_byte_impl( static_cast<unsigned char>((bit_count_high)     & 0xFF) );
 216     process_byte_impl( static_cast<unsigned char>((bit_count_low>>24) & 0xFF) );
 217     process_byte_impl( static_cast<unsigned char>((bit_count_low>>16) & 0xFF) );
 218     process_byte_impl( static_cast<unsigned char>((bit_count_low>>8 ) & 0xFF) );
 219     process_byte_impl( static_cast<unsigned char>((bit_count_low)     & 0xFF) );
 220
 221     // get final digest
 222     digest[0] = h_[0];
 223     digest[1] = h_[1];
 224     digest[2] = h_[2];
 225     digest[3] = h_[3];
 226     digest[4] = h_[4];
 227 }
 228
 229 }}} // namespace boost::uuids::detail
 230
 231 #endif