text: /*
   * Copyright 2013 Facebook, Inc.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  
  #ifndef FOLLY_EXPERIMENTAL_SYMBOLIZER_ELF_H_
  # error This file must be included from Elf.h
  #endif
  
  namespace folly {
  namespace symbolizer {
  
  template <class Fn>
  const ElfW(Shdr)* ElfFile::iterateSections(Fn fn) const {
    const ElfW(Shdr)* ptr = &at<ElfW(Shdr)>(elfHeader().e_shoff);
    for (size_t i = 0; i < elfHeader().e_shnum; i++, ptr++) {
      if (fn(*ptr)) {
        return ptr;
      }
    }
  
    return nullptr;
  }
  
  template <class Fn>
  const ElfW(Shdr)* ElfFile::iterateSectionsWithType(uint32_t type, Fn fn)
    const {
    return iterateSections(
        [&](const ElfW(Shdr)& sh) {
          return sh.sh_type == type && fn(sh);
        });
  }
  
  template <class Fn>
  const char* ElfFile::iterateStrings(const ElfW(Shdr)& stringTable, Fn fn)
    const {
    validateStringTable(stringTable);
  
    const char* start = file_ + stringTable.sh_offset;
    const char* end = start + stringTable.sh_size;
  
    const char* ptr = start;
    while (ptr != end && !fn(ptr)) {
      ptr += strlen(ptr) + 1;
    }
  
    return ptr != end ? ptr : nullptr;
  }
  
  template <class Fn>
  const ElfW(Sym)* ElfFile::iterateSymbols(const ElfW(Shdr)& section, Fn fn)
    const {
    FOLLY_SAFE_CHECK(section.sh_entsize == sizeof(ElfW(Sym)),
                     "invalid entry size in symbol table");
  
    const ElfW(Sym)* sym = &at<ElfW(Sym)>(section.sh_offset);
    const ElfW(Sym)* end = sym + (section.sh_size / section.sh_entsize);
  
    while (sym < end) {
      if (fn(*sym)) {
        return sym;
      }
  
      ++sym;
    }
  
    return nullptr;
  }
  
  template <class Fn>
  const ElfW(Sym)* ElfFile::iterateSymbolsWithType(const ElfW(Shdr)& section,
                                                   uint32_t type, Fn fn) const {
    // N.B. st_info has the same representation on 32- and 64-bit platforms
    return iterateSymbols(section, [&](const ElfW(Sym)& sym) -> bool {
      return ELF32_ST_TYPE(sym.st_info) == type && fn(sym);
    });
  }
  
  }  // namespace symbolizer
  }  // namespace folly
  
  