/*

 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code 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 General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#include "precompiled.hpp"

#if !defined(_WINDOWS) && !defined(__APPLE__)

#include "jvm.h"

#include "memory/allocation.inline.hpp"

#include "runtime/os.hpp"

#include "utilities/elfStringTable.hpp"

// We will try to load whole string table into memory if we can.

// Otherwise, fallback to more expensive file operation.

ElfStringTable::ElfStringTable(FILE* const file, Elf_Shdr& shdr, int index) :

  _next(NULL), _index(index), _section(file, shdr), _fd(file) {

  _status = _section.status();

}

ElfStringTable::~ElfStringTable() {

  if (_next != NULL) {

    delete _next;

  }

}

bool ElfStringTable::string_at(size_t pos, char* buf, int buflen) {

  if (NullDecoder::is_error(get_status())) {

    return false;

  }

  assert(buflen > 0, "no buffer");

  if (pos >= _section.section_header()->sh_size) {

    return false;

  }

  const char* data = (const char*)_section.section_data();

  if (data != NULL) {

    jio_snprintf(buf, buflen, "%s", data + pos);

    return true;

  } else {  // no cache data, read from file instead

    const Elf_Shdr* const shdr = _section.section_header();

    MarkedFileReader mfd(_fd);

    if (mfd.has_mark() &&

      mfd.set_position(shdr->sh_offset + pos) &&

      mfd.read((void*)buf, size_t(buflen))) {

      buf[buflen - 1] = '\0';

      return true;

    } else {

      // put it in error state to avoid retry

      _status = NullDecoder::file_invalid;

      return false;

    }

  }

}

#endif // !_WINDOWS && !__APPLE__