C++ self_type::Data方法代码示例

void
nsTString_CharT::ReplaceSubstring( const self_type& aTarget, const self_type& aNewValue )
  {
    if (aTarget.Length() == 0)
      return;

    uint32_t i = 0;
    while (i < mLength)
      {
        int32_t r = FindSubstring(mData + i, mLength - i, aTarget.Data(), aTarget.Length(), false);
        if (r == kNotFound)
          break;

        Replace(i + r, aTarget.Length(), aNewValue);
        i += r + aNewValue.Length();
      }
  }

bool
nsTSubstring_CharT::Assign( const self_type& str, const fallible_t& )
  {
    // |str| could be sharable.  we need to check its flags to know how to
    // deal with it.

    if (&str == this)
      return true;

    if (!str.mLength)
      {
        Truncate();
        mFlags |= str.mFlags & F_VOIDED;
        return true;
      }

    if (str.mFlags & F_SHARED)
      {
        // nice! we can avoid a string copy :-)

        // |str| should be null-terminated
        NS_ASSERTION(str.mFlags & F_TERMINATED, "shared, but not terminated");

        ::ReleaseData(mData, mFlags);

        mData = str.mData;
        mLength = str.mLength;
        SetDataFlags(F_TERMINATED | F_SHARED);

        // get an owning reference to the mData
        nsStringBuffer::FromData(mData)->AddRef();
        return true;
      }
    else if (str.mFlags & F_LITERAL)
      {
        NS_ABORT_IF_FALSE(str.mFlags & F_TERMINATED, "Unterminated literal");

        AssignLiteral(str.mData, str.mLength);
        return true;
      }

    // else, treat this like an ordinary assignment.
    return Assign(str.Data(), str.Length(), fallible_t());
  }

bool
nsTString_CharT::ReplaceSubstring(const self_type& aTarget,
                                  const self_type& aNewValue,
                                  const fallible_t&)
{
  if (aTarget.Length() == 0)
    return true;

  // Remember all of the non-matching parts.
  AutoTArray<Segment, 16> nonMatching;
  uint32_t i = 0;
  uint32_t newLength = 0;
  while (true)
  {
    int32_t r = FindSubstring(mData + i, mLength - i, static_cast<const char_type*>(aTarget.Data()), aTarget.Length(), false);
    int32_t until = (r == kNotFound) ? mLength - i : r;
    nonMatching.AppendElement(Segment(i, until));
    newLength += until;
    if (r == kNotFound) {
      break;
    }

    newLength += aNewValue.Length();
    i += r + aTarget.Length();
    if (i >= mLength) {
      // Add an auxiliary entry at the end of the list to help as an edge case
      // for the algorithms below.
      nonMatching.AppendElement(Segment(mLength, 0));
      break;
    }
  }

  // If there's only one non-matching segment, then the target string was not
  // found, and there's nothing to do.
  if (nonMatching.Length() == 1) {
    MOZ_ASSERT(nonMatching[0].mBegin == 0 && nonMatching[0].mLength == mLength,
               "We should have the correct non-matching segment.");
    return true;
  }

  // Make sure that we can mutate our buffer.
  // Note that we always allocate at least an mLength sized buffer, because the
  // rest of the algorithm relies on having access to all of the original
  // string.  In other words, we over-allocate in the shrinking case.
  char_type* oldData;
  uint32_t oldFlags;
  if (!MutatePrep(XPCOM_MAX(mLength, newLength), &oldData, &oldFlags))
    return false;
  if (oldData) {
    // Copy all of the old data to the new buffer.
    char_traits::copy(mData, oldData, mLength);
    ::ReleaseData(oldData, oldFlags);
  }

  if (aTarget.Length() >= aNewValue.Length()) {
    // In the shrinking case, start filling the buffer from the beginning.
    const uint32_t delta = (aTarget.Length() - aNewValue.Length());
    for (i = 1; i < nonMatching.Length(); ++i) {
      // When we move the i'th non-matching segment into position, we need to
      // account for the characters deleted by the previous |i| replacements by
      // subtracting |i * delta|.
      const char_type* sourceSegmentPtr = mData + nonMatching[i].mBegin;
      char_type* destinationSegmentPtr = mData + nonMatching[i].mBegin - i * delta;
      // Write the i'th replacement immediately before the new i'th non-matching
      // segment.
      char_traits::copy(destinationSegmentPtr - aNewValue.Length(),
                        aNewValue.Data(), aNewValue.Length());
      char_traits::move(destinationSegmentPtr, sourceSegmentPtr,
                        nonMatching[i].mLength);
    }
  } else {
    // In the growing case, start filling the buffer from the end.
    const uint32_t delta = (aNewValue.Length() - aTarget.Length());
    for (i = nonMatching.Length() - 1; i > 0; --i) {
      // When we move the i'th non-matching segment into position, we need to
      // account for the characters added by the previous |i| replacements by
      // adding |i * delta|.
      const char_type* sourceSegmentPtr = mData + nonMatching[i].mBegin;
      char_type* destinationSegmentPtr = mData + nonMatching[i].mBegin + i * delta;
      char_traits::move(destinationSegmentPtr, sourceSegmentPtr,
                        nonMatching[i].mLength);
      // Write the i'th replacement immediately before the new i'th non-matching
      // segment.
      char_traits::copy(destinationSegmentPtr - aNewValue.Length(),
                        aNewValue.Data(), aNewValue.Length());
    }
  }

  // Adjust the length and make sure the string is null terminated.
  mLength = newLength;
  mData[mLength] = char_type(0);

  return true;
}