swibufferedinputstream.cpp

OSB-PIK-OpenVXI-3.0.0源代码 “中国XML论坛 - 专业的XML技术讨论区--XML在语音技术中的应用”

 /****************License************************************************
  *
  * Copyright 2000-2003.  ScanSoft, Inc.    
  *
  * Use of this software is subject to notices and obligations set forth 
  * in the SpeechWorks Public License - Software Version 1.2 which is 
  * included with this software. 
  *
  * ScanSoft is a registered trademark of ScanSoft, Inc., and OpenSpeech, 
  * SpeechWorks and the SpeechWorks logo are registered trademarks or 
  * trademarks of SpeechWorks International, Inc. in the United States 
  * and other countries.
  *
  ***********************************************************************/
 

 #include "SWIbufferedInputStream.hpp"
 #include "SWIoutputStream.hpp"
 #include <string.h>
 
 SWIbufferedInputStream::SWIbufferedInputStream(SWIinputStream *stream,
                                      int bufSize, int lookAhead,
                                      bool ownStream):
   SWIfilterInputStream(stream, ownStream),
   _eofSeen(false), _buffer(NULL)
 {
   _lookAhead = (lookAhead < 1) ? 1 : lookAhead;
   if (bufSize < 1) bufSize = 1;
   _readSize = bufSize > _lookAhead ? bufSize : _lookAhead;
   _pos = _end = _buffer =
     new unsigned char[bufSize + _lookAhead - 1];
 }
 
 SWIbufferedInputStream::~SWIbufferedInputStream()
 {
   close();
 }
 
 int SWIbufferedInputStream::read()
 {
   if (_buffer == NULL) return ILLEGAL_STATE;
   if (_pos < _end) return *_pos++;
 
   int rc = fillBuffer();
   if (rc < 0) return rc;
   rc = *_pos++;
   return rc;
 }
 
 int SWIbufferedInputStream::readBytes(void *data, int dataSize)
 {
   if (_buffer == NULL) return ILLEGAL_STATE;
   if (dataSize  < 0 ) return INVALID_ARGUMENT;
   if (data == NULL && dataSize > 0) return INVALID_ARGUMENT;
 
   unsigned char *p0 = static_cast<unsigned char *>(data);
   unsigned char *p = p0;
   unsigned char *q = p0 + dataSize;
   int rc = SWIstream::SUCCESS;
 
   for (;;)
   {
     while (_pos < _end && p < q) *p++ = *_pos++;
 
     // Have we read the required number of bytes?
     if (p == q) break;
 
     // Ran out of bytes in our buffer.  Only fill the buffer if that would
     // not block and we haven't read a byte yet.
     if (p > p0 && SWIfilterInputStream::waitReady(0) != SUCCESS) break;
 
     // Bail out if an error occurs while filling the buffer.
     if ((rc = fillBuffer()) < 0) break;
   }
 
   int nbRead = p - p0;
   return nbRead > 0 ? nbRead : rc;
 }
 
 int SWIbufferedInputStream::peek(int offset) const
 {
   if (offset < 0 || offset >= _lookAhead)
     return INVALID_ARGUMENT;
 
   if (_buffer == NULL) return ILLEGAL_STATE;
   if (_end - _pos > offset) return _pos[offset];
 
   int remaining =
     const_cast<SWIbufferedInputStream *>(this)->fillBuffer(offset);
 
   if (remaining < 0) return remaining;
   if (remaining > offset) return _pos[offset];
   return END_OF_FILE;
 }
 
 int SWIbufferedInputStream::getLookAhead() const
 {
   return _lookAhead;
 }
 
 int SWIbufferedInputStream::readLine(SWIoutputStream& outstream)
 {
   if (_buffer == NULL) return ILLEGAL_STATE;
   int rc = 0;
   int nbWritten = 0;
 
   for (;;)
   {
     unsigned char *p = _pos;
 
     while (p < _end && *p != '\r' && *p != '\n') p++;
 
     int len = p - _pos;
 
     if (len > 0)
     {
       if ((rc = outstream.writeBytes(_pos, len)) != len)
         break;
 
       nbWritten += len;
       _pos = p;
     }
 
     if (_pos < _end)
     {
       if (*_pos == '\r')
       {
         _pos++;
         if ((rc = fillBuffer()) < 0)
           break;
       }
       if (*_pos == '\n')
         _pos++;
       break;
     }
     else if ((rc = fillBuffer()) < 0)
       break;
   }
 
   if (nbWritten == 0)
     return rc > 0 ? 0 : rc;
 
   return nbWritten;
 }
 
 int SWIbufferedInputStream::readLine(char *buffer, int bufSize)
 {
   if (_buffer == NULL) return ILLEGAL_STATE;
   int rc = 0;
   char *p = buffer;
   char *q = buffer + bufSize - 1; // keep one byte for '\0'
 
   while (p < q)
   {
     while (_pos < _end && p < q)
     {
       switch (*_pos)
       {
        case '\r':
          _pos++;
          rc = fillBuffer();
          if (rc <= 0) goto terminateString;
          if (*_pos != '\n') goto terminateString;
          // no break: intentional
        case '\n':
          _pos++;
          goto terminateString;
        default:
          *p++ = *_pos++;
          break;
       }
     }
     rc = fillBuffer();
     if (rc <= 0) break;
   }
 
  terminateString:
   *p = '\0';
 
   if (p == q)
     return BUFFER_OVERFLOW;
 
   int len = p - buffer;
   if (len == 0)
     return rc > 0 ? 0 : rc;
 
   return len;
 }
 
 bool SWIbufferedInputStream::isBuffered() const
 {
   return true;
 }
 
 SWIstream::Result SWIbufferedInputStream::waitReady(long timeoutMs)
 {
   if (_buffer == NULL) return ILLEGAL_STATE;
   if (_pos < _end) return SUCCESS;
   return SWIfilterInputStream::waitReady(timeoutMs);
 }
 
 SWIstream::Result SWIbufferedInputStream::close()
 {
   delete [] _buffer;
   _end = _pos = _buffer = NULL;
   return SWIfilterInputStream::close();
 }
 
 /**
  * Returns the number of bytes available in the buffer.
  **/
 int SWIbufferedInputStream::fillBuffer(int lowBound)
 {
   int remaining = _end - _pos;
 
   // If there are enough remaining characters, return them so that we won't
   // block trying to fill the look-ahead buffer.
   if (remaining > lowBound) return remaining;
 
   if (remaining == 0 && _eofSeen) return END_OF_FILE;
 
   // shift data at the beginning of the buffer.
   memmove(_buffer, _pos, remaining);
 
   _pos = _buffer;
   _end = _pos + remaining;
 
   // Now read from the stream.
   int rc = SWIfilterInputStream::readBytes(_end, _readSize - remaining);
 
   switch (rc)
   {
    case END_OF_FILE:
      _eofSeen = true;
      return remaining;
    case 0:
      // This should not really happen, it should either return TIMED_OUT or
      // WOULD_BLOCK.
      return TIMED_OUT;
    default:
      if (rc > 0)
      {
        _end += rc;
        return remaining + rc;
      }
      return rc;
   }
 }