File indexing completed on 2024-05-12 05:43:30

 /*
     Copyright (C) 2015 Volker Krause <vkrause@kde.org>
 
     This program is free software; you can redistribute it and/or modify it
     under the terms of the GNU Library General Public License as published by
     the Free Software Foundation; either version 2 of the License, or (at your
     option) any later version.
 
     This program is distributed in the hope that it will be useful, but WITHOUT
     ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
     FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
     License for more details.
 
     You should have received a copy of the GNU General Public License
     along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
 
 #include "elfsysvhashsection.h"
 #include "elfsymboltablesection.h"
 
 #include <elf.h>
 #include <cassert>
 
 ElfSysvHashSection::ElfSysvHashSection(ElfFile* file, ElfSectionHeader* shdr):
     ElfHashSection(file, shdr)
 {
 }
 
 ElfSysvHashSection::~ElfSysvHashSection() = default;
 
 uint32_t ElfSysvHashSection::bucketCount() const
 {
     return *reinterpret_cast<const uint32_t*>(rawData());
 }
 
 uint32_t ElfSysvHashSection::bucket(uint32_t index) const
 {
     return *(reinterpret_cast<const uint32_t*>(rawData()) + 2 + index);
 }
 
 uint32_t ElfSysvHashSection::chainCount() const
 {
     return *(reinterpret_cast<const uint32_t*>(rawData()) + 1);
 }
 
 uint32_t ElfSysvHashSection::chain(uint32_t index) const
 {
     return *(reinterpret_cast<const uint32_t*>(rawData()) + 2 + bucketCount() + index);
 }
 
 uint32_t ElfSysvHashSection::hash(const char* name)
 {
     unsigned long h = 0, g;
     while (*name)
     {
         h = (h << 4) + *name++;
         if ((g = h & 0xf0000000))
             h ^= g >> 24;
         h &= ~g;
     }
     return h;
 }
 
 ElfSymbolTableEntry* ElfSysvHashSection::lookup(const char* name) const
 {
     const auto x = hash(name);
 
     const auto symTab = linkedSection<ElfSymbolTableSection>();
     assert(symTab);
     auto y = bucket(x % bucketCount());
     while (y != STN_UNDEF) {
         const auto entry = symTab->entry(y);
         if (strcmp(entry->name(), name) == 0)
             return entry;
         y = chain(y);
     }
 
     return nullptr;
 }
 
 QVector<uint32_t> ElfSysvHashSection::histogram() const
 {
     QVector<uint32_t> hist;
     for (uint i = 0; i < bucketCount(); ++i) {
         int count = 0;
 
         auto y = bucket(i);
         while (y != STN_UNDEF) {
             ++count;
             y = chain(y);
         }
 
         hist.resize(std::max(hist.size(), count + 1));
         hist[count]++;
     }
     return hist;
 }
 
 double ElfSysvHashSection::averagePrefixLength() const
 {
     int sum = 0;
     int count = 0;
 
     const auto symTab = linkedSection<ElfSymbolTableSection>();
     assert(symTab);
 
     for (uint i = 0; i < bucketCount(); ++i) {
         auto y1 = bucket(i);
         while (y1 != STN_UNDEF) {
             const auto entry1 = symTab->entry(y1);
             auto y2 = chain(y1);
             while (y2 != STN_UNDEF) {
                 const auto entry2 = symTab->entry(y2);
                 sum += commonPrefixLength(entry1->name(), entry2->name());
                 ++count;
                 y2 = chain(y2);
             }
 
             y1 = chain(y1);
         }
     }
 
     return count > 0 ? (double)sum / (double)count : 0.0;
 }