third_party/WebKit/Source/wtf/text/TextCodec.h

/*
 * Copyright (C) 2004, 2006 Apple Computer, Inc.  All rights reserved.
 * Copyright (C) 2006 Alexey Proskuryakov <ap@nypop.com>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef TextCodec_h
#define TextCodec_h

#include "wtf/Forward.h"
#include "wtf/Noncopyable.h"
#include "wtf/text/Unicode.h"
#include "wtf/text/WTFString.h"
#include <memory>

namespace WTF {

class TextEncoding;

// Specifies what will happen when a character is encountered that is
// not encodable in the character set.
enum UnencodableHandling {
  // Substitutes the replacement character "?".
  QuestionMarksForUnencodables,

  // Encodes the character as an XML entity. For example, U+06DE
  // would be "&#1758;" (0x6DE = 1758 in octal).
  EntitiesForUnencodables,

  // Encodes the character as en entity as above, but escaped
  // non-alphanumeric characters. This is used in URLs.
  // For example, U+6DE would be "%26%231758%3B".
  URLEncodedEntitiesForUnencodables,

  // Encodes the character as a CSS entity.  For example U+06DE
  // would be \06de.  See: https://www.w3.org/TR/css-syntax-3/#escaping
  CSSEncodedEntitiesForUnencodables,
};

typedef char UnencodableReplacementArray[32];

enum FlushBehavior {
  // More bytes are coming, don't flush the codec.
  DoNotFlush = 0,

  // A fetch has hit EOF. Some codecs handle fetches differently, for compat
  // reasons.
  FetchEOF,

  // Do a full flush of the codec.
  DataEOF
};

static_assert(!DoNotFlush, "DoNotFlush should be falsy");
static_assert(FetchEOF, "FetchEOF should be truthy");
static_assert(DataEOF, "DataEOF should be truthy");

class WTF_EXPORT TextCodec {
  WTF_MAKE_NONCOPYABLE(TextCodec);
  USING_FAST_MALLOC(TextCodec);

 public:
  TextCodec() {}
  virtual ~TextCodec();

  String decode(const char* str,
                size_t length,
                FlushBehavior flush = DoNotFlush) {
    bool ignored;
    return decode(str, length, flush, false, ignored);
  }

  virtual String decode(const char*,
                        size_t length,
                        FlushBehavior,
                        bool stopOnError,
                        bool& sawError) = 0;
  virtual CString encode(const UChar*, size_t length, UnencodableHandling) = 0;
  virtual CString encode(const LChar*, size_t length, UnencodableHandling) = 0;

  // Fills a null-terminated string representation of the given
  // unencodable character into the given replacement buffer.
  // The length of the string (not including the null) will be returned.
  static int getUnencodableReplacement(unsigned codePoint,
                                       UnencodableHandling,
                                       UnencodableReplacementArray);
};

typedef void (*EncodingNameRegistrar)(const char* alias, const char* name);

typedef std::unique_ptr<TextCodec> (
    *NewTextCodecFunction)(const TextEncoding&, const void* additionalData);
typedef void (*TextCodecRegistrar)(const char* name,
                                   NewTextCodecFunction,
                                   const void* additionalData);

}  // namespace WTF

using WTF::TextCodec;

#endif  // TextCodec_h