/// \file
/// Base functions to initialize and manipulate any input stream
///

// [The "BSD licence"]
// Copyright (c) 2005-2009 Jim Idle, Temporal Wave LLC
// http://www.temporal-wave.com
// http://www.linkedin.com/in/jimidle
//
// All rights reserved.
//
// 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.
// 3. The name of the author may not be used to endorse or promote products
//    derived from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 THE AUTHOR 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.

#include    <antlr3input.h>


// INT Stream API
//
static	    void			antlr3AsciiConsume			(pANTLR3_INT_STREAM is);
static	    ANTLR3_UCHAR    antlr3AsciiLA				(pANTLR3_INT_STREAM is, ANTLR3_INT32 la);
static	    ANTLR3_UCHAR    antlr3AsciiLA_ucase			(pANTLR3_INT_STREAM is, ANTLR3_INT32 la);
static	    ANTLR3_MARKER   antlr3AsciiIndex			(pANTLR3_INT_STREAM is);
static	    ANTLR3_MARKER   antlr3AsciiMark				(pANTLR3_INT_STREAM is);
static	    void			antlr3AsciiRewind			(pANTLR3_INT_STREAM is, ANTLR3_MARKER mark);
static	    void			antlr3AsciiRewindLast		(pANTLR3_INT_STREAM is);
static	    void			antlr3AsciiRelease			(pANTLR3_INT_STREAM is, ANTLR3_MARKER mark);
static	    void			antlr3AsciiSeek				(pANTLR3_INT_STREAM is, ANTLR3_MARKER seekPoint);
static		pANTLR3_STRING	antlr3AsciiGetSourceName	(pANTLR3_INT_STREAM is);

// ASCII Charstream API functions
//
static	    void			antlr3InputClose			(pANTLR3_INPUT_STREAM input);
static	    void			antlr3InputReset			(pANTLR3_INPUT_STREAM input);
static	    void *			antlr3AsciiLT				(pANTLR3_INPUT_STREAM input, ANTLR3_INT32 lt);
static	    ANTLR3_UINT32   antlr3AsciiSize				(pANTLR3_INPUT_STREAM input);
static	    pANTLR3_STRING  antlr3AsciiSubstr			(pANTLR3_INPUT_STREAM input, ANTLR3_MARKER start, ANTLR3_MARKER stop);
static	    ANTLR3_UINT32   antlr3AsciiGetLine			(pANTLR3_INPUT_STREAM input);
static	    void	  *		antlr3AsciiGetLineBuf		(pANTLR3_INPUT_STREAM input);
static	    ANTLR3_UINT32   antlr3AsciiGetCharPosition	(pANTLR3_INPUT_STREAM input);
static	    void			antlr3AsciiSetLine			(pANTLR3_INPUT_STREAM input, ANTLR3_UINT32 line);
static	    void			antlr3AsciiSetCharPosition	(pANTLR3_INPUT_STREAM input, ANTLR3_UINT32 position);
static	    void			antlr3AsciiSetNewLineChar	(pANTLR3_INPUT_STREAM input, ANTLR3_UINT32 newlineChar);
static		void			antlr3AsciiSetUcaseLA		(pANTLR3_INPUT_STREAM input, ANTLR3_BOOLEAN flag);

/// \brief Common function to setup function interface for an 8 bit ASCII input stream.
///
/// \param input Input stream context pointer
///
/// \remark
///   - Many of the 8 bit ASCII oriented file stream handling functions will be usable
///     by any or at least some other input streams. Therefore it is perfectly acceptable
///     to call this function to install the ASCII handler then override just those functions
///     that would not work for the particular input encoding, such as consume for instance.
/// 
void 
antlr3AsciiSetupStream	(pANTLR3_INPUT_STREAM input, ANTLR3_UINT32 type)
{
    // Build a string factory for this stream
     //
    input->strFactory	= antlr3StringFactoryNew();

    // Default stream set up is for ASCII, therefore there is nothing else
    // to do but set it up as such
    //
    antlr3GenericSetupStream(input, type);
}


void
antlr3GenericSetupStream  (pANTLR3_INPUT_STREAM input, ANTLR3_UINT32 type)
{

    /* Install function pointers for an 8 bit ASCII input
     */

    /* Allocate stream interface
     */
    input->istream			=  antlr3IntStreamNew();
    input->istream->type    = ANTLR3_CHARSTREAM;
    input->istream->super   =  input;

    input->istream->type	= type;

    /* Intstream API
     */
    input->istream->consume			=  antlr3AsciiConsume;			/* Consume the next 8 bit character in the buffer			*/
    input->istream->_LA				=  antlr3AsciiLA;				/* Return the UTF32 character at offset n (1 based)			*/
    input->istream->index			=  antlr3AsciiIndex;			/* Current index (offset from first character			    */
    input->istream->mark			=  antlr3AsciiMark;				/* Record the current lex state for later restore			*/
    input->istream->rewind			=  antlr3AsciiRewind;			/* How to rewind the input									*/
    input->istream->rewindLast		=  antlr3AsciiRewindLast;		/* How to rewind the input									*/
    input->istream->seek			=  antlr3AsciiSeek;				/* How to seek to a specific point in the stream		    */
    input->istream->release			=  antlr3AsciiRelease;			/* Reset marks after mark n									*/
	input->istream->getSourceName	=  antlr3AsciiGetSourceName;	// Return a string that names the input source

	/* Charstream API
     */
    input->close					=  antlr3InputClose;			/* Close down the stream completely										*/
    input->free						=  antlr3InputClose;			/* Synonym for free														*/
    input->reset					=  antlr3InputReset;			/* Reset input to start													*/
    input->_LT						=  antlr3AsciiLT;				/* Same as _LA for 8 bit Ascii file										*/
    input->size						=  antlr3AsciiSize;				/* Return the size of the input buffer									*/
    input->substr					=  antlr3AsciiSubstr;			/* Return a string from the input stream								*/
    input->getLine					=  antlr3AsciiGetLine;			/* Return the current line number in the input stream					*/
    input->getLineBuf				=  antlr3AsciiGetLineBuf;	    /* Return a pointer to the start of the current line being consumed	    */
    input->getCharPositionInLine    =  antlr3AsciiGetCharPosition;  /* Return the offset into the current line of input						*/
    input->setLine					=  antlr3AsciiSetLine;			/* Set the input stream line number (does not set buffer pointers)	    */
    input->setCharPositionInLine    =  antlr3AsciiSetCharPosition;  /* Set the offset in to the current line (does not set any pointers	)   */
    input->SetNewLineChar			=  antlr3AsciiSetNewLineChar;   /* Set the value of the newline trigger character						*/
	input->setUcaseLA				= antlr3AsciiSetUcaseLA;

	input->charByteSize				= 1;		// Size in bytes of characters in this stream.

    /* Initialize entries for tables etc
     */
    input->markers  = NULL;

    /* Set up the input stream brand new
     */
    input->reset(input);
    
    /* Install default line separator character (it can be replaced
     * by the grammar programmer later)
     */
    input->SetNewLineChar(input, (ANTLR3_UCHAR)'\n');
}

static pANTLR3_STRING
antlr3AsciiGetSourceName(pANTLR3_INT_STREAM is)
{
	return	is->streamName;
}

/** \brief Close down an input stream and free any memory allocated by it.
 *
 * \param input Input stream context pointer
 */
static void
antlr3InputClose(pANTLR3_INPUT_STREAM input)
{
    // Close any markers in the input stream
    //
    if	(input->markers != NULL)
    {
		input->markers->free(input->markers);
		input->markers = NULL;
    }

    // Close the string factory
    //
    if	(input->strFactory != NULL)
    {
		input->strFactory->close(input->strFactory);
    }

    // Free the input stream buffer if we allocated it
    //
    if	(input->isAllocated && input->data != NULL)
    {
		ANTLR3_FREE(input->data);
		input->data = NULL;
    }
    
    input->istream->free(input->istream);

    // Finally, free the space for the structure itself
    //
    ANTLR3_FREE(input);

    // Done
    //
}

static void		
antlr3AsciiSetUcaseLA		(pANTLR3_INPUT_STREAM input, ANTLR3_BOOLEAN flag)
{
	if	(flag)
	{
		// Return the upper case version of the characters
		//
		input->istream->_LA		    =  antlr3AsciiLA_ucase;
	}
	else
	{
		// Return the raw characters as they are in the buffer
		//
		input->istream->_LA		    =  antlr3AsciiLA;
	}
}


/** \brief Reset a re-startable input stream to the start
 *
 * \param input Input stream context pointer
 */
static void
antlr3InputReset(pANTLR3_INPUT_STREAM input)
{

    input->nextChar		= input->data;	/* Input at first character */
    input->line			= 1;		/* starts at line 1	    */
    input->charPositionInLine	= -1;
    input->currentLine		= input->data;
    input->markDepth		= 0;		/* Reset markers	    */
    
    /* Free up the markers table if it is there
     */
    if	(input->markers != NULL)
    {
	input->markers->free(input->markers);
    }

    /* Install a new markers table
     */
    input->markers  = antlr3VectorNew(0);
}

/** \brief Consume the next character in an 8 bit ASCII input stream
 *
 * \param input Input stream context pointer
 */
static void
antlr3AsciiConsume(pANTLR3_INT_STREAM is)
{
    pANTLR3_INPUT_STREAM input;

    input   = ((pANTLR3_INPUT_STREAM) (is->super));

    if	((pANTLR3_UINT8)(input->nextChar) < (((pANTLR3_UINT8)input->data) + input->sizeBuf))
    {	
	/* Indicate one more character in this line
	 */
	input->charPositionInLine++;
	
	if  ((ANTLR3_UCHAR)(*((pANTLR3_UINT8)input->nextChar)) == input->newlineChar)
	{
	    /* Reset for start of a new line of input
	     */
	    input->line++;
	    input->charPositionInLine	= 0;
	    input->currentLine		= (void *)(((pANTLR3_UINT8)input->nextChar) + 1);
	}

	/* Increment to next character position
	 */
	input->nextChar = (void *)(((pANTLR3_UINT8)input->nextChar) + 1);
    }
}

/** \brief Return the input element assuming an 8 bit ascii input
 *
 * \param[in] input Input stream context pointer
 * \param[in] la 1 based offset of next input stream element
 *
 * \return Next input character in internal ANTLR3 encoding (UTF32)
 */
static ANTLR3_UCHAR 
antlr3AsciiLA(pANTLR3_INT_STREAM is, ANTLR3_INT32 la)
{
    pANTLR3_INPUT_STREAM input;
	
    input   = ((pANTLR3_INPUT_STREAM) (is->super));

    if	(( ((pANTLR3_UINT8)input->nextChar) + la - 1) >= (((pANTLR3_UINT8)input->data) + input->sizeBuf))
    {
		return	ANTLR3_CHARSTREAM_EOF;
    }
    else
    {
		return	(ANTLR3_UCHAR)(*((pANTLR3_UINT8)input->nextChar + la - 1));
    }
}

/** \brief Return the input element assuming an 8 bit ASCII input and
 *         always return the UPPER CASE character.
 *		   Note that this is 8 bit and so we assume that the toupper
 *		   function will use the correct locale for 8 bits.
 *
 * \param[in] input Input stream context pointer
 * \param[in] la 1 based offset of next input stream element
 *
 * \return Next input character in internal ANTLR3 encoding (UTF32)
 */
static ANTLR3_UCHAR
antlr3AsciiLA_ucase	(pANTLR3_INT_STREAM is, ANTLR3_INT32 la)
{
    pANTLR3_INPUT_STREAM input;
	
    input   = ((pANTLR3_INPUT_STREAM) (is->super));

    if	(( ((pANTLR3_UINT8)input->nextChar) + la - 1) >= (((pANTLR3_UINT8)input->data) + input->sizeBuf))
    {
		return	ANTLR3_CHARSTREAM_EOF;
    }
    else
    {
		return	(ANTLR3_UCHAR)toupper((*((pANTLR3_UINT8)input->nextChar + la - 1)));
    }
}


/** \brief Return the input element assuming an 8 bit ascii input
 *
 * \param[in] input Input stream context pointer
 * \param[in] lt 1 based offset of next input stream element
 *
 * \return Next input character in internal ANTLR3 encoding (UTF32)
 */
static void * 
antlr3AsciiLT(pANTLR3_INPUT_STREAM input, ANTLR3_INT32 lt)
{
    /* Casting is horrible but it means no warnings and LT should never be called
     * on a character stream anyway I think. If it is then, the void * will need to be 
     * cast back in a similar manner. Yuck! But this means that LT for Token streams and
     * tree streams is correct.
     */
    return (ANTLR3_FUNC_PTR(input->istream->_LA(input->istream, lt)));
}

/** \brief Calculate the current index in the output stream.
 * \param[in] input Input stream context pointer
 */
static ANTLR3_MARKER
antlr3AsciiIndex(pANTLR3_INT_STREAM is)
{
    pANTLR3_INPUT_STREAM input;

    input   = ((pANTLR3_INPUT_STREAM) (is->super));

    return  (ANTLR3_MARKER)(((pANTLR3_UINT8)input->nextChar));
}

/** \brief Return the size of the current input stream, as an Ascii file
 *   which in this case is the total input. Other implementations may provide
 *   more sophisticated implementations to deal with non-recoverable streams 
 *   and so on.
 *
 * \param[in] input Input stream context pointer
 */
static	ANTLR3_UINT32 
antlr3AsciiSize(pANTLR3_INPUT_STREAM input)
{
    return  input->sizeBuf;
}

/** \brief Mark the current input point in an Ascii 8 bit stream
 *  such as a file stream, where all the input is available in the
 *  buffer.
 *
 * \param[in] is Input stream context pointer
 */
static ANTLR3_MARKER
antlr3AsciiMark	(pANTLR3_INT_STREAM is)
{
    pANTLR3_LEX_STATE	    state;
    pANTLR3_INPUT_STREAM    input;

    input   = ((pANTLR3_INPUT_STREAM) (is->super));

    /* New mark point 
     */
    input->markDepth++;

    /* See if we are revisiting a mark as we can just reuse the vector
     * entry if we are, otherwise, we need a new one
     */
    if	(input->markDepth > input->markers->count)
    {	
	state	= ANTLR3_MALLOC(sizeof(ANTLR3_LEX_STATE));

	/* Add it to the table
	 */
	input->markers->add(input->markers, state, ANTLR3_FREE_FUNC);	/* No special structure, just free() on delete */
    }
    else
    {
	state	= (pANTLR3_LEX_STATE)input->markers->get(input->markers, input->markDepth - 1);

	/* Assume no errors for speed, it will just blow up if the table failed
	 * for some reasons, hence lots of unit tests on the tables ;-)
	 */
    }

    /* We have created or retrieved the state, so update it with the current
     * elements of the lexer state.
     */
    state->charPositionInLine	= input->charPositionInLine;
    state->currentLine		= input->currentLine;
    state->line			= input->line;
    state->nextChar		= input->nextChar;

    is->lastMarker  = input->markDepth;

    /* And that's it
     */
    return  input->markDepth;
}
/** \brief Rewind the lexer input to the state specified by the last produced mark.
 * 
 * \param[in] input Input stream context pointer
 *
 * \remark
 * Assumes ASCII (or at least, 8 Bit) input stream.
 */
static void
antlr3AsciiRewindLast	(pANTLR3_INT_STREAM is)
{
    is->rewind(is, is->lastMarker);
}

/** \brief Rewind the lexer input to the state specified by the supplied mark.
 * 
 * \param[in] input Input stream context pointer
 *
 * \remark
 * Assumes ASCII (or at least, 8 Bit) input stream.
 */
static void
antlr3AsciiRewind	(pANTLR3_INT_STREAM is, ANTLR3_MARKER mark)
{
    pANTLR3_LEX_STATE	state;
    pANTLR3_INPUT_STREAM input;

    input   = ((pANTLR3_INPUT_STREAM) is->super);

    /* Perform any clean up of the marks
     */
    input->istream->release(input->istream, mark);

    /* Find the supplied mark state 
     */
    state   = (pANTLR3_LEX_STATE)input->markers->get(input->markers, (ANTLR3_UINT32)(mark - 1));

    /* Seek input pointer to the requested point (note we supply the void *pointer
     * to whatever is implementing the int stream to seek).
     */
    antlr3AsciiSeek(is, (ANTLR3_MARKER)(state->nextChar));

    /* Reset to the reset of the information in the mark
     */
    input->charPositionInLine	= state->charPositionInLine;
    input->currentLine		= state->currentLine;
    input->line			= state->line;
    input->nextChar		= state->nextChar;

    /* And we are done
     */
}

/** \brief Rewind the lexer input to the state specified by the supplied mark.
 * 
 * \param[in] input Input stream context pointer
 *
 * \remark
 * Assumes ASCII (or at least, 8 Bit) input stream.
 */
static void
antlr3AsciiRelease	(pANTLR3_INT_STREAM is, ANTLR3_MARKER mark)
{
    pANTLR3_INPUT_STREAM input;

    input   = ((pANTLR3_INPUT_STREAM) (is->super));

    /* We don't do much here in fact as we never free any higher marks in
     * the hashtable as we just resuse any memory allocated for them.
     */
    input->markDepth	= (ANTLR3_UINT32)(mark - 1);
}

/** \brief Rewind the lexer input to the state specified by the supplied mark.
 * 
 * \param[in] input Input stream context pointer
 *
 * \remark
 * Assumes ASCII (or at least, 8 Bit) input stream.
 */
static void
antlr3AsciiSeek	(pANTLR3_INT_STREAM is, ANTLR3_MARKER seekPoint)
{
	ANTLR3_INT32   count;
	pANTLR3_INPUT_STREAM input;

	input   = ANTLR3_FUNC_PTR(((pANTLR3_INPUT_STREAM) is->super));

	/* If the requested seek point is less than the current
	* input point, then we assume that we are resetting from a mark
	* and do not need to scan, but can just set to there.
	*/
	if	(seekPoint <= (ANTLR3_MARKER)(input->nextChar))
	{
		input->nextChar	= ((pANTLR3_UINT8) seekPoint);
	}
	else
	{
		count	= (ANTLR3_UINT32)(seekPoint - (ANTLR3_MARKER)(input->nextChar));

		while (count--)
		{
			is->consume(is);
		}
	}
}
/** Return a substring of the ASCII (8 bit) input stream in
 *  newly allocated memory.
 *
 * \param input Input stream context pointer
 * \param start Offset in input stream where the string starts
 * \param stop  Offset in the input stream where the string ends.
 */
static pANTLR3_STRING
antlr3AsciiSubstr		(pANTLR3_INPUT_STREAM input, ANTLR3_MARKER start, ANTLR3_MARKER stop)
{
	return  input->strFactory->newPtr(input->strFactory, (pANTLR3_UINT8)start, (ANTLR3_UINT32)(stop - start + 1));
}

/** \brief Return the line number as understood by the 8 bit/ASCII input stream.
 *
 * \param input Input stream context pointer
 * \return	Line number in input stream that we believe we are working on.
 */
static ANTLR3_UINT32   
antlr3AsciiGetLine		(pANTLR3_INPUT_STREAM input)
{
    return  input->line;
}

/** Return a pointer into the input stream that points at the start
 *  of the current input line as triggered by the end of line character installed
 *  for the stream ('\n' unless told differently).
 *
 * \param[in] input 
 */
static void	  * 
antlr3AsciiGetLineBuf	(pANTLR3_INPUT_STREAM input)
{
    return  input->currentLine;
}

/** Return the current offset in to the current line in the input stream.
 *
 * \param input Input stream context pointer
 * \return      Current line offset
 */
static ANTLR3_UINT32
antlr3AsciiGetCharPosition	(pANTLR3_INPUT_STREAM input)
{
    return  input->charPositionInLine;
}

/** Set the current line number as understood by the input stream.
 *
 * \param input Input stream context pointer
 * \param line  Line number to tell the input stream we are on
 *
 * \remark
 *  This function does not change any pointers, it just allows the programmer to set the
 *  line number according to some external criterion, such as finding a lexed directive
 *  like: #nnn "file.c" for instance, such that error reporting and so on in is in sync
 *  with some original source format.
 */
static void
antlr3AsciiSetLine		(pANTLR3_INPUT_STREAM input, ANTLR3_UINT32 line)
{
    input->line	= line;
}

/** Set the current offset in the current line to be a particular setting.
 *
 * \param[in] input    Input stream context pointer
 * \param[in] position New setting for current offset.
 *
 * \remark
 * This does not set the actual pointers in the input stream, it is purely for reporting
 * purposes and so on as per antlr3AsciiSetLine();
 */
static void
antlr3AsciiSetCharPosition	(pANTLR3_INPUT_STREAM input, ANTLR3_UINT32 position)
{
    input->charPositionInLine = position;
}

/** Set the newline trigger character in the input stream to the supplied parameter.
 *
 * \param[in] input	    Input stream context pointer
 * \param[in] newlineChar   Character to set to be the newline trigger.
 *
 * \remark
 *  - The supplied newLineChar is in UTF32 encoding (which means ASCII and latin1 etc
 *    are the same encodings), but the input stream catered to by this function is 8 bit
 *    only, so it is up to the programmer to ensure that the character supplied is valid.
 */
static void 
antlr3AsciiSetNewLineChar	(pANTLR3_INPUT_STREAM input, ANTLR3_UINT32 newlineChar)
{
    input->newlineChar	= newlineChar;
}