//==============================================================================
// incharstream.cpp
//	Generic input character stream.
//
// Notice
//	Copyright ©2010 by David R. Tribble, all rights reserved.
//	Permission is granted to any person or entity except those designated
//	by the United States Department of State as a terrorist, or terrorist
//	government or agency, to use and distribute this source code provided
//	that the original copyright notice remains present and unaltered.
//==============================================================================

// Identification

static char	REV[] =
    "@(#)drt/src/lib/incharstream.cpp $Revision: 1.1 $$Date: 2011/05/08 02:40:13 $";


// Includes

#include <ctype.h>
#define sys_ctype_h
#include <errno.h>
#define sys_errno_h
#include <iso646.h>
#define sys_iso646_h
#include <stdio.h>
#define sys_stdio_h
#include <string.h>
#define sys_string_h

#if _WIN32
 #define WINDOWS_LEAN_AND_MEAN
 #include <fcntl.h>
 #include <io.h>
#endif

#include "incharstream.hpp"


// Manifest constants

#define BUF_SIZE	(16 * 1024)		// I/O vbuffer size


//------------------------------------------------------------------------------
// InCharStream::~InCharStream()
//	Destructor.
//------------------------------------------------------------------------------
/*virtual*/
InCharStream::~InCharStream()
{
#if InCharStream_VS != 100
 #error class InCharStream has changed
#endif

    // De-initialize
    close();
}


//------------------------------------------------------------------------------
// InCharStream::InCharStream()
//	Constructor.
//------------------------------------------------------------------------------
InCharStream::InCharStream():
    CharStream()
{
#if InCharStream_VS != 100
 #error class InCharStream has changed
#endif

    // Initialize
}


//------------------------------------------------------------------------------
// InCharStream::close()
//	Close the input stream.
//------------------------------------------------------------------------------
/*virtual*/
bool InCharStream::close()
{
#if InCharStream_VS/100 != 1
 #error class InCharStream has changed
#endif

    // Do nothing
    return true;
}


//------------------------------------------------------------------------------
// InCharStream::read()
//	Read a character from the input stream.
//
// Notes
//	This function assumes that InCharStream::read(int[],int) has been
//	implemented in an overridding subclass.
//
// Returns
//	A Unicode character code in the range [0x0000,0xFFFF], or
//	CH_EOLN if a newline sequence was read, or
//	CH_EOF if the end of the stream (end of file) was reached.
//------------------------------------------------------------------------------
/*virtual*/
int InCharStream::read()
{
#if InCharStream_VS/100 != 1
 #error class InCharStream has changed
#endif

    int		buf[1];
    int		len;

    // Read a single char from the input
    if (read(buf, 1) > 0)
        return buf[0];
    return CH_EOF;
}


//------------------------------------------------------------------------------
// InCharStream::read()
//	Read characters from the input stream.
//
// Notes
//	This function assumes that InCharStream::read() has been implemented in
//	an overridding subclass.
//
// Returns
//	Number of characters written into 'buf', or -1 if the end of the stream
//	(end of file) was reached.
//	Note that newline sequences are written into 'buf' as CH_EOLN codes.
//------------------------------------------------------------------------------
/*virtual*/
int InCharStream::read(int buf[], int len)
{
#if InCharStream_VS/100 != 1
 #error class InCharStream has changed
#endif

    int		cnt;

    // Sanity checks
    if (len <= 0)
        return 0;
    if (buf == NULL)
        return -1;

    // Read characters from the input stream
    cnt = 0;
    while (cnt < len)
    {
        int	ch;

        // Read the next input char
        ch = read();
        if (ch == CH_EOF)
        {
            // End of file
            return (cnt == 0 ? -1 : cnt);
        }

        buf[cnt++] = ch;
    }

    return cnt;
}

// End incharstream.cpp