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      1 /* Conversion functions for versioning information.
      2    Copyright (C) 2006, 2007 Red Hat, Inc.
      3    This file is part of elfutils.
      4    Written by Ulrich Drepper <drepper (at) redhat.com>, 2006.
      5 
      6    This file is free software; you can redistribute it and/or modify
      7    it under the terms of either
      8 
      9      * the GNU Lesser General Public License as published by the Free
     10        Software Foundation; either version 3 of the License, or (at
     11        your option) any later version
     12 
     13    or
     14 
     15      * the GNU General Public License as published by the Free
     16        Software Foundation; either version 2 of the License, or (at
     17        your option) any later version
     18 
     19    or both in parallel, as here.
     20 
     21    elfutils is distributed in the hope that it will be useful, but
     22    WITHOUT ANY WARRANTY; without even the implied warranty of
     23    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     24    General Public License for more details.
     25 
     26    You should have received copies of the GNU General Public License and
     27    the GNU Lesser General Public License along with this program.  If
     28    not, see <http://www.gnu.org/licenses/>.  */
     29 
     30 #include <assert.h>
     31 #include <gelf.h>
     32 
     33 #include "libelfP.h"
     34 
     35 
     36 static void
     37 elf_cvt_gnuhash (void *dest, const void *src, size_t len, int encode)
     38 {
     39   /* The GNU hash table format on 64 bit machines mixes 32 bit and 64 bit
     40      words.  We must detangle them here.   */
     41   Elf32_Word *dest32 = dest;
     42   const Elf32_Word *src32 = src;
     43 
     44   /* First four control words, 32 bits.  */
     45   for (unsigned int cnt = 0; cnt < 4; ++cnt)
     46     {
     47       if (len < 4)
     48 	return;
     49       dest32[cnt] = bswap_32 (src32[cnt]);
     50       len -= 4;
     51     }
     52 
     53   Elf32_Word bitmask_words = encode ? src32[2] : dest32[2];
     54 
     55   /* Now the 64 bit words.  */
     56   Elf64_Xword *dest64 = (Elf64_Xword *) &dest32[4];
     57   const Elf64_Xword *src64 = (const Elf64_Xword *) &src32[4];
     58   for (unsigned int cnt = 0; cnt < bitmask_words; ++cnt)
     59     {
     60       if (len < 8)
     61 	return;
     62       dest64[cnt] = bswap_64 (src64[cnt]);
     63       len -= 8;
     64     }
     65 
     66   /* The rest are 32 bit words again.  */
     67   src32 = (const Elf32_Word *) &src64[bitmask_words];
     68   dest32 = (Elf32_Word *) &dest64[bitmask_words];
     69   while (len >= 4)
     70     {
     71       *dest32++ = bswap_32 (*src32++);
     72       len -= 4;
     73     }
     74 }
     75