xapian-applications/omega/values.h

   1 /** @file
   2  * @brief constants and functions for document value handling.
   3  */
   4 /* Copyright (C) 2006,2010,2015,2019,2023 Olly Betts
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  19  */
  20
  21 #ifndef OMEGA_INCLUDED_VALUES_H
  22 #define OMEGA_INCLUDED_VALUES_H
  23
  24 #ifndef PACKAGE
  25 # error config.h must be included first in each C++ source file
  26 #endif
  27
  28 #include <cstring>
  29 #include <string>
  30
  31 #include <cstdint>
  32
  33 enum value_slot {
  34     VALUE_LASTMOD = 0,  // 4 byte big endian value - seconds since 1970.
  35     VALUE_MD5 = 1,      // 16 byte MD5 checksum of original document.
  36     VALUE_SIZE = 2,     // sortable_serialise(<file size in bytes>).
  37     VALUE_CTIME = 3,    // Like VALUE_LASTMOD, but for last metadata change.
  38     VALUE_CREATED = 4   // Like VALUE_LASTMOD, but for created timestamp.
  39 };
  40
  41 #ifndef WORDS_BIGENDIAN
  42 inline std::uint32_t swap_endianness_32(std::uint32_t v) {
  43 # if HAVE_DECL___BUILTIN_BSWAP32
  44     return __builtin_bswap32(v);
  45 # elif HAVE_DECL__BYTESWAP_ULONG
  46     return _byteswap_ulong(v);
  47 # else
  48     return (v << 24) | ((v & 0xff00) << 8) | ((v >> 8) & 0xff00) | (v >> 24);
  49 # endif
  50 }
  51 #endif
  52
  53 inline std::uint32_t binary_string_to_int(const std::string &s)
  54 {
  55     if (s.size() != 4) return static_cast<std::uint32_t>(-1);
  56     std::uint32_t v;
  57     std::memcpy(&v, s.data(), 4);
  58 #ifndef WORDS_BIGENDIAN
  59     v = swap_endianness_32(v);
  60 #endif
  61     return v;
  62 }
  63
  64 inline std::string int_to_binary_string(std::uint32_t v)
  65 {
  66 #ifndef WORDS_BIGENDIAN
  67     v = swap_endianness_32(v);
  68 #endif
  69     return std::string(reinterpret_cast<const char*>(&v), 4);
  70 }
  71
  72 #endif