/*

 * Copyright (c) 1997, 2017, 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 "memory/allocation.inline.hpp"

#include "prims/jvm.h"

#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* file, Elf_Shdr shdr, int index) {

  assert(file, "null file handle");

  m_table = NULL;

  m_index = index;

  m_next = NULL;

  m_file = file;

  m_status = NullDecoder::no_error;

  // try to load the string table

  long cur_offset = ftell(file);

  m_table = (char*)os::malloc(sizeof(char) * shdr.sh_size, mtInternal);

  if (m_table != NULL) {

    // if there is an error, mark the error

    if (fseek(file, shdr.sh_offset, SEEK_SET) ||

      fread((void*)m_table, shdr.sh_size, 1, file) != 1 ||

      fseek(file, cur_offset, SEEK_SET)) {

      m_status = NullDecoder::file_invalid;

      os::free((void*)m_table);

      m_table = NULL;

    }

  } else {

    memcpy(&m_shdr, &shdr, sizeof(Elf_Shdr));

  }

}

ElfStringTable::~ElfStringTable() {

  if (m_table != NULL) {

    os::free((void*)m_table);

  }

  if (m_next != NULL) {

    delete m_next;

  }

}

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

  if (NullDecoder::is_error(m_status)) {

    return false;

  }

  if (m_table != NULL) {

    jio_snprintf(buf, buflen, "%s", (const char*)(m_table + pos));

    return true;

  } else {

    long cur_pos = ftell(m_file);

    if (cur_pos == -1 ||

      fseek(m_file, m_shdr.sh_offset + pos, SEEK_SET) ||

      fread(buf, 1, buflen, m_file) <= 0 ||

      fseek(m_file, cur_pos, SEEK_SET)) {

      m_status = NullDecoder::file_invalid;

      return false;

    }

    return true;

  }

}

#endif // !_WINDOWS && !__APPLE__