/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "nsTArray.h"
#include "nsASCIIMask.h"
#include "mozilla/CheckedInt.h"

/**
 * nsTString::Find
 *
 * aOffset specifies starting index
 * aCount specifies number of string compares (iterations)
 */
template <typename T>
int32_t
nsTString<T>::Find(const nsTString<char>& aString, bool aIgnoreCase, int32_t aOffset, int32_t aCount) const
{
  // this method changes the meaning of aOffset and aCount:
  Find_ComputeSearchRange(this->mLength, aString.Length(), aOffset, aCount);

  int32_t result = FindSubstring(this->mData + aOffset, aCount, aString.get(), aString.Length(), aIgnoreCase);
  if (result != kNotFound)
    result += aOffset;
  return result;
}

template <typename T>
int32_t
nsTString<T>::Find(const char* aString, bool aIgnoreCase, int32_t aOffset, int32_t aCount) const
{
  return Find(nsTDependentString<char>(aString), aIgnoreCase, aOffset, aCount);
}


/**
 * nsTString::RFind
 *
 * aOffset specifies starting index
 * aCount specifies number of string compares (iterations)
 */
template <typename T>
int32_t
nsTString<T>::RFind(const nsTString<char>& aString, bool aIgnoreCase, int32_t aOffset, int32_t aCount) const
{
  // this method changes the meaning of aOffset and aCount:
  RFind_ComputeSearchRange(this->mLength, aString.Length(), aOffset, aCount);

  int32_t result = RFindSubstring(this->mData + aOffset, aCount, aString.get(), aString.Length(), aIgnoreCase);
  if (result != kNotFound)
    result += aOffset;
  return result;
}

template <typename T>
int32_t
nsTString<T>::RFind(const char* aString, bool aIgnoreCase, int32_t aOffset, int32_t aCount) const
{
  return RFind(nsTDependentString<char>(aString), aIgnoreCase, aOffset, aCount);
}


/**
 * nsTString::RFindChar
 */
template <typename T>
int32_t
nsTString<T>::RFindChar(char16_t aChar, int32_t aOffset, int32_t aCount) const
{
  return nsBufferRoutines<T>::rfind_char(this->mData, this->mLength, aOffset, aChar, aCount);
}


/**
 * nsTString::FindCharInSet
 */

template <typename T>
int32_t
nsTString<T>::FindCharInSet(const char_type* aSet, int32_t aOffset) const
{
  if (aOffset < 0)
    aOffset = 0;
  else if (aOffset >= int32_t(this->mLength))
    return kNotFound;

  int32_t result = ::FindCharInSet(this->mData + aOffset, this->mLength - aOffset, aSet);
  if (result != kNotFound)
    result += aOffset;
  return result;
}


/**
 * nsTString::RFindCharInSet
 */

template <typename T>
int32_t
nsTString<T>::RFindCharInSet(const char_type* aSet, int32_t aOffset) const
{
  // We want to pass a "data length" to ::RFindCharInSet
  if (aOffset < 0 || aOffset > int32_t(this->mLength))
    aOffset = this->mLength;
  else
    ++aOffset;

  return ::RFindCharInSet(this->mData, aOffset, aSet);
}


/**
   * nsTString::Mid
   */

template <typename T>
typename nsTString<T>::size_type
nsTString<T>::Mid(self_type& aResult, index_type aStartPos, size_type aLengthToCopy) const
{
  if (aStartPos == 0 && aLengthToCopy >= this->mLength)
    aResult = *this;
  else
    aResult = Substring(*this, aStartPos, aLengthToCopy);

  return aResult.mLength;
}


/**
 * nsTString::SetCharAt
 */

template <typename T>
bool
nsTString<T>::SetCharAt(char16_t aChar, uint32_t aIndex)
{
  if (aIndex >= this->mLength)
    return false;

  if (!this->EnsureMutable())
    this->AllocFailed(this->mLength);

  this->mData[aIndex] = char_type(aChar);
  return true;
}


/**
 * nsTString::StripChars,StripChar,StripWhitespace
 */

template<typename T>
template<typename Q, typename EnableIfChar16>
void
nsTString<T>::StripChars(const incompatible_char_type* aSet)
{
  if (!StripChars(aSet, mozilla::fallible)) {
    this->AllocFailed(this->mLength);
  }
}

template<typename T>
template<typename Q, typename EnableIfChar16>
bool
nsTString<T>::StripChars(const incompatible_char_type* aSet, const fallible_t&)
{
  if (!this->EnsureMutable()) {
    return false;
  }

  this->mLength = nsBufferRoutines<T>::strip_chars(this->mData, this->mLength, aSet);
  return true;
}

template<typename T>
void
nsTString<T>::StripChars(const char_type* aSet)
{
  nsTSubstring<T>::StripChars(aSet);
}

template <typename T>
void
nsTString<T>::StripWhitespace()
{
  if (!StripWhitespace(mozilla::fallible)) {
    this->AllocFailed(this->mLength);
  }
}

template <typename T>
bool
nsTString<T>::StripWhitespace(const fallible_t&)
{
  if (!this->EnsureMutable()) {
    return false;
  }

  this->StripTaggedASCII(mozilla::ASCIIMask::MaskWhitespace());
  return true;
}

/**
 * nsTString::ReplaceChar,ReplaceSubstring
 */

template <typename T>
void
nsTString<T>::ReplaceChar(char_type aOldChar, char_type aNewChar)
{
  if (!this->EnsureMutable()) // XXX do this lazily?
    this->AllocFailed(this->mLength);

  for (uint32_t i=0; i<this->mLength; ++i)
  {
    if (this->mData[i] == aOldChar)
      this->mData[i] = aNewChar;
  }
}

template <typename T>
void
nsTString<T>::ReplaceChar(const char_type* aSet, char_type aNewChar)
{
  if (!this->EnsureMutable()) // XXX do this lazily?
    this->AllocFailed(this->mLength);

  char_type* data = this->mData;
  uint32_t lenRemaining = this->mLength;

  while (lenRemaining)
  {
    int32_t i = ::FindCharInSet(data, lenRemaining, aSet);
    if (i == kNotFound)
      break;

    data[i++] = aNewChar;
    data += i;
    lenRemaining -= i;
  }
}

void ReleaseData(void* aData, nsAString::DataFlags aFlags);

template <typename T>
void
nsTString<T>::ReplaceSubstring(const char_type* aTarget,
                               const char_type* aNewValue)
{
  ReplaceSubstring(nsTDependentString<T>(aTarget),
                   nsTDependentString<T>(aNewValue));
}

template <typename T>
bool
nsTString<T>::ReplaceSubstring(const char_type* aTarget,
                               const char_type* aNewValue,
                               const fallible_t& aFallible)
{
  return ReplaceSubstring(nsTDependentString<T>(aTarget),
                          nsTDependentString<T>(aNewValue),
                          aFallible);
}

template <typename T>
void
nsTString<T>::ReplaceSubstring(const self_type& aTarget,
                               const self_type& aNewValue)
{
  if (!ReplaceSubstring(aTarget, aNewValue, mozilla::fallible)) {
    // Note that this may wildly underestimate the allocation that failed, as
    // we could have been replacing multiple copies of aTarget.
    this->AllocFailed(this->mLength + (aNewValue.Length() - aTarget.Length()));
  }
}

template <typename T>
bool
nsTString<T>::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;
  mozilla::CheckedUint32 newLength;
  while (true)
  {
    int32_t r = FindSubstring(this->mData + i, this->mLength - i, static_cast<const char_type*>(aTarget.Data()), aTarget.Length(), false);
    int32_t until = (r == kNotFound) ? this->mLength - i : r;
    nonMatching.AppendElement(Segment(i, until));
    newLength += until;
    if (r == kNotFound) {
      break;
    }

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

  if (!newLength.isValid()) {
    return false;
  }

  // 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 == this->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 this->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;
  DataFlags oldFlags;
  if (!this->MutatePrep(XPCOM_MAX(this->mLength, newLength.value()), &oldData, &oldFlags))
    return false;
  if (oldData) {
    // Copy all of the old data to the new buffer.
    char_traits::copy(this->mData, oldData, this->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 = this->mData + nonMatching[i].mBegin;
      char_type* destinationSegmentPtr = this->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 = this->mData + nonMatching[i].mBegin;
      char_type* destinationSegmentPtr = this->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.
  this->mLength = newLength.value();
  this->mData[this->mLength] = char_type(0);

  return true;
}

/**
 * nsTString::Trim
 */

template <typename T>
void
nsTString<T>::Trim(const char* aSet, bool aTrimLeading, bool aTrimTrailing, bool aIgnoreQuotes)
{
  // the old implementation worried about aSet being null :-/
  if (!aSet)
    return;

  char_type* start = this->mData;
  char_type* end   = this->mData + this->mLength;

  // skip over quotes if requested
  if (aIgnoreQuotes && this->mLength > 2 && this->mData[0] == this->mData[this->mLength - 1] &&
      (this->mData[0] == '\'' || this->mData[0] == '"'))
  {
    ++start;
    --end;
  }

  uint32_t setLen = nsCharTraits<char>::length(aSet);

  if (aTrimLeading)
  {
    uint32_t cutStart = start - this->mData;
    uint32_t cutLength = 0;

    // walk forward from start to end
    for (; start != end; ++start, ++cutLength)
    {
      int32_t pos = FindChar1(aSet, setLen, 0, *start, setLen);
      if (pos == kNotFound)
        break;
    }

    if (cutLength)
    {
      this->Cut(cutStart, cutLength);

      // reset iterators
      start = this->mData + cutStart;
      end   = this->mData + this->mLength - cutStart;
    }
  }

  if (aTrimTrailing)
  {
    uint32_t cutEnd = end - this->mData;
    uint32_t cutLength = 0;

    // walk backward from end to start
    --end;
    for (; end >= start; --end, ++cutLength)
    {
      int32_t pos = FindChar1(aSet, setLen, 0, *end, setLen);
      if (pos == kNotFound)
        break;
    }

    if (cutLength)
      this->Cut(cutEnd - cutLength, cutLength);
  }
}


/**
 * nsTString::CompressWhitespace.
 */

template <typename T>
void
nsTString<T>::CompressWhitespace(bool aTrimLeading, bool aTrimTrailing)
{
  // Quick exit
  if (this->mLength == 0) {
    return;
  }

  if (!this->EnsureMutable())
    this->AllocFailed(this->mLength);

  const ASCIIMaskArray& mask = mozilla::ASCIIMask::MaskWhitespace();

  char_type* to   = this->mData;
  char_type* from = this->mData;
  char_type* end  = this->mData + this->mLength;

  // Compresses runs of whitespace down to a normal space ' ' and convert
  // any whitespace to a normal space.  This assumes that whitespace is
  // all standard 7-bit ASCII.
  bool skipWS = aTrimLeading;
  while (from < end) {
    uint32_t theChar = *from++;
    if (mozilla::ASCIIMask::IsMasked(mask, theChar)) {
      if (!skipWS) {
        *to++ = ' ';
        skipWS = true;
      }
    } else {
      *to++ = theChar;
      skipWS = false;
    }
  }

  // If we need to trim the trailing whitespace, back up one character.
  if (aTrimTrailing && skipWS && to > this->mData) {
    to--;
  }

  *to = char_type(0); // add the null
  this->mLength = to - this->mData;
}