// Copyright 2010 Google Inc. All Rights Reserved.
//
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// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
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// in the documentation and/or other materials provided with the
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// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
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#include <assert.h>

#include "common/dwarf/bytereader-inl.h"
#include "common/dwarf/bytereader.h"

namespace dwarf2reader {

ByteReader::ByteReader(enum Endianness endian)
    :offset_reader_(NULL), address_reader_(NULL), endian_(endian),
     address_size_(0), offset_size_(0)
{ }

ByteReader::~ByteReader() { }

void ByteReader::SetOffsetSize(uint8 size) {
  offset_size_ = size;
  assert(size == 4 || size == 8);
  if (size == 4) {
    this->offset_reader_ = &ByteReader::ReadFourBytes;
  } else {
    this->offset_reader_ = &ByteReader::ReadEightBytes;
  }
}

void ByteReader::SetAddressSize(uint8 size) {
  address_size_ = size;
  assert(size == 4 || size == 8);
  if (size == 4) {
    this->address_reader_ = &ByteReader::ReadFourBytes;
  } else {
    this->address_reader_ = &ByteReader::ReadEightBytes;
  }
}

uint64 ByteReader::ReadInitialLength(const char* start, size_t* len) {
  const uint64 initial_length = ReadFourBytes(start);
  start += 4;

  // In DWARF2/3, if the initial length is all 1 bits, then the offset
  // size is 8 and we need to read the next 8 bytes for the real length.
  if (initial_length == 0xffffffff) {
    SetOffsetSize(8);
    *len = 12;
    return ReadOffset(start);
  } else {
    SetOffsetSize(4);
    *len = 4;
  }
  return initial_length;
}

}  // namespace dwarf2reader