/*
**	termBuffer.c
**
**	Auxilary routines for text buffer/capture management.
**
**	Copyright © 1990-1993 by Olaf `Olsen' Barthel & MXM
**		All Rights Reserved
*/

#include "termGlobal.h"

	/* Maximum size of an allocated line string. */

#define STRING_SIZE	(1 + 255 + 1)

	/* How many strings to include in a single puddle. */

#define STRING_COUNT	10

	/* The number of lines the buffer will grow. */

#define BUFFER_GROW	100

	/* Memory allocation routines. */

STATIC STRPTR		(* __regargs AllocString)(STRPTR,LONG);
STATIC VOID		(* __regargs FreeString)(STRPTR);

	/* Memory pool header (Kickstart 3.0 required). */

STATIC APTR		BufferPoolHeader;

	/* OldAllocString(STRPTR String,WORD Len):
	 *
	 +	Allocate space for a string, old flavour.
	 */

STATIC STRPTR __regargs
OldAllocString(STRPTR String,LONG Len)
{
	STRPTR Mem;

	if(Len > 255)
		Len = 255;

	if(Mem = (STRPTR)AllocMem(1 + Len + 1,MEMF_ANY | MEMF_PUBLIC))
	{
		*Mem++ = Len;

		memcpy(Mem,String,Len);

		Mem[Len] = 0;

		return((STRPTR)Mem);
	}
	else
		return(NULL);
}

	/* OldFreeString(STRPTR String):
	 *
	 *	Free the space occupied by a string, old flavour.
	 */

STATIC VOID __regargs
OldFreeString(STRPTR String)
{
	FreeMem(&String[-1],1 + String[-1] + 1);
}

	/* NewAllocString(STRPTR String,WORD Len):
	 *
	 +	Allocate space for a string, new pooled version.
	 */

STATIC STRPTR __regargs
NewAllocString(STRPTR String,LONG Len)
{
	STRPTR Mem;

	if(Len > 255)
		Len = 255;

	if(Mem = (STRPTR)AllocPooled(BufferPoolHeader,1 + Len + 1))
	{
		*Mem++ = Len;

		memcpy(Mem,String,Len);

		Mem[Len] = 0;

		return((STRPTR)Mem);
	}
	else
		return(NULL);
}

	/* NewFreeString(STRPTR String):
	 *
	 *	Free the space occupied by a string, new pooled version.
	 */

STATIC VOID __regargs
NewFreeString(STRPTR String)
{
	FreePooled(BufferPoolHeader,&String[-1],1 + String[-1] + 1);
}

	/* AddLine(STRPTR Line,LONG Size):
	 *
	 *	Add a line to the display buffer.
	 */

STATIC VOID __regargs
AddLine(register STRPTR Line,register LONG Size)
{
		/* Are we still to update the buffer contents? */

	if(!BufferClosed)
	{
			/* Remove trailing spaces. */

		while(Size > 0 && Line[Size - 1] == ' ')
			Size--;

			/* Is the buffer array initialized? */

		if(BufferLines)
		{
			ULONG Signals = 0;

				/* Pick up the global access semaphore
				 * (two tasks are sharing the data).
				 */

			ObtainSemaphore(BufferSemaphore);

				/* Check for limit. */

			if(Config -> CaptureConfig -> MaxBufferSize && BufferSpace >= Config -> CaptureConfig -> MaxBufferSize)
			{
				register LONG i;

				BufferSpace -= BufferLines[0][-1];

				(*FreeString)(BufferLines[0]);

				for(i = 1 ; i < MaxLines ; i++)
					BufferLines[i - 1] = BufferLines[i];

				Lines--;

					/* Tell the buffer task to
					 * refresh the display.
					 */

				Signals = SIG_MOVEUP;
			}
			else
			{
					/* We've reached the last line in the buffer. */

				if(Lines == MaxLines)
				{
					STRPTR *MoreBuffer;

						/* Allocate space for some more lines. */

					if(MoreBuffer = (STRPTR *)AllocVec((MaxLines + BUFFER_GROW) * sizeof(STRPTR),MEMF_ANY | MEMF_CLEAR))
					{
						register LONG i;

						BufferChanged = TRUE;

							/* Copy the old lines to the new
							 * buffer.
							 */

						for(i = 0 ; i < Lines ; i++)
							MoreBuffer[i] = BufferLines[i];

							/* Free the old lines. */

						FreeVec(BufferLines);

							/* Set the new buffer. */

						MaxLines += BUFFER_GROW;

						BufferLines = MoreBuffer;
					}
					else
					{
						BufferChanged = TRUE;

							/* We couldn't get enough memory
							 * to extend the number of lines
							 * in the buffer, so we'll have
							 * to wrap the contents of the
							 * buffer around.
							 */

						if(Lines)
						{
							register LONG i;

							BufferSpace -= BufferLines[0][-1];

							(*FreeString)(BufferLines[0]);

							for(i = 1 ; i < MaxLines ; i++)
								BufferLines[i - 1] = BufferLines[i];

							Lines--;

								/* Tell the buffer task to
								 * refresh the display.
								 */

							Signals = SIG_MOVEUP;
						}
					}
				}
			}

				/* Allocate a new line and copy the buffer contents
				 * into it.
				 */

			if(BufferLines[Lines] = (*AllocString)(Line,Size))
			{
				BufferChanged = TRUE;

				Lines++;

				BufferSpace += Size;
			}

			ReleaseSemaphore(BufferSemaphore);

				/* Tell the buffer task to update the display. */

			if(!Signals)
			{
				Signals = SIG_UPDATE;

				UpdateReview(FALSE);
			}
			else
				UpdateReview(TRUE);

			if(BufferProcess)
				Signal(BufferProcess,Signals);
		}
	}
}

	/* StoreBuffer(APTR Buffer,LONG Size):
	 *
	 *	Store data in the display buffer.
	 */

VOID __regargs
StoreBuffer(register STRPTR Buffer,register LONG Size)
{
	STATIC UBYTE	 LineBuffer[BUFFER_LINE_WIDTH];
	STATIC LONG 	 BufferCount = 0;

	register UBYTE c;

	while(Size--)
	{
			/* Look which char we are to handle. */

		switch(c = *Buffer++)
		{
				/* Move the cursor one step back. */

			case BKS:

				if(BufferCount)
					BufferCount--;

				break;

				/* Move the cursor to the next tab
				 * stop.
				 */

			case TAB:

				if(((BufferCount + 8) & ~7) < LastColumn)
				{
					register LONG Delta = ((BufferCount + 8) & ~7) - BufferCount;

					memset(&LineBuffer[BufferCount],' ',Delta);

					BufferCount += Delta;
				}
				else
				{
					AddLine(LineBuffer,BufferCount);

					BufferCount = 0;
				}

				break;

				/* Terminate the current line. */

			case ENT:

				AddLine(LineBuffer,BufferCount);

				BufferCount = 0;

				break;

				/* Stuff the character into the buffer. */

			default:

				if(Config -> TerminalConfig -> FontMode == FONT_STANDARD)
				{
					if(IsPrintable[c])
						LineBuffer[BufferCount++] = c;
				}
				else
				{
					if(c)
						LineBuffer[BufferCount++] = c;
				}

				break;
		}

			/* The line is full, add it to the display buffer. */

		if(BufferCount >= LastColumn || BufferCount == BUFFER_LINE_WIDTH)
		{
			AddLine(LineBuffer,BufferCount);

			BufferCount = 0;
		}
	}
}

	/* DeleteBuffer():
	 *
	 *	Delete buffer resources.
	 */

VOID
DeleteBuffer()
{
	if(BufferLines)
	{
		if(!BufferPoolHeader)
		{
			LONG i;

			for(i = 0 ; i < Lines ; i++)
			{
				if(BufferLines[i])
					(*FreeString)(BufferLines[i]);
			}
		}

		FreeVec(BufferLines);

		BufferLines = NULL;
	}

	if(BufferPoolHeader)
	{
		DeletePool(BufferPoolHeader);

		BufferPoolHeader = NULL;
	}

	if(BufferSemaphore)
	{
		FreeVec(BufferSemaphore);

		BufferSemaphore = NULL;
	}
}

	/* CreateBuffer():
	 *
	 *	Allocate buffer resources.
	 */

BYTE
CreateBuffer()
{
	if(BufferLines = (STRPTR *)AllocVec(MaxLines * sizeof(STRPTR),MEMF_ANY | MEMF_CLEAR | MEMF_PUBLIC))
	{
		if(BufferSemaphore = (struct SignalSemaphore *)AllocVec(sizeof(struct SignalSemaphore),MEMF_ANY | MEMF_PUBLIC))
		{
			InitSemaphore(BufferSemaphore);

				/* Create a memory pool header if possible. */

			if(Kick30)
			{
				if(BufferPoolHeader = CreatePool(MEMF_ANY | MEMF_PUBLIC,STRING_SIZE * STRING_COUNT,STRING_SIZE * STRING_COUNT))
				{
					AllocString	= NewAllocString;
					FreeString	= NewFreeString;

					return(TRUE);
				}
			}

			AllocString	= OldAllocString;
			FreeString	= OldFreeString;

			return(TRUE);
		}

		FreeVec(BufferLines);

		BufferLines = NULL;
	}

	return(FALSE);
}

	/* FreeBuffer():
	 *
	 *	Release the contents of the text buffer.
	 */

VOID
FreeBuffer()
{
		/* Free the contents of the display buffer. */

	if(BufferLines)
	{
		APTR NewPoolHeader;

			/* Simple, create another pool header if possible. */

		if(BufferPoolHeader)
			NewPoolHeader = CreatePool(MEMF_ANY | MEMF_PUBLIC,STRING_SIZE * STRING_COUNT,STRING_SIZE * STRING_COUNT);
		else
			NewPoolHeader = NULL;

			/* If a new pool header is available, free the old
			 * pool and replace it with the new pool, else
			 * do it again by hand.
			 */

		if(NewPoolHeader)
		{
			DeletePool(BufferPoolHeader);

			BufferPoolHeader = NewPoolHeader;
		}
		else
		{
			LONG i;

			for(i = 0 ; i < Lines ; i++)
			{
				if(BufferLines[i])
					(*FreeString)(BufferLines[i]);
			}
		}

		FreeVec(BufferLines);

		Lines = 0;

		MaxLines = BUFFER_GROW;

		BufferLines = (STRPTR *)AllocVec(MaxLines * sizeof(STRPTR),MEMF_ANY | MEMF_CLEAR);

		UpdateReview(TRUE);
	}

	BufferSpace = 0;

	BufferChanged = FALSE;
}

	/* CreateSearchInfo(STRPTR Pattern):
	 *
	 *	Create auxilary data required by SearchTextBuffer().
	 */

struct SearchInfo * __regargs
CreateSearchInfo(STRPTR Pattern)
{
	struct SearchInfo *Info;

		/* Allocate the buffer. */

	if(Info = (struct SearchInfo *)AllocVec(sizeof(struct SearchInfo),MEMF_ANY | MEMF_PUBLIC))
	{
		WORD i;

			/* Determine pattern width. */

		Info -> PatternWidth = strlen(Pattern);

			/* Turn the pattern into upper case characters. */

		for(i = 0 ; i <= Info -> PatternWidth ; i++)
			Info -> Pattern[i] = ToUpper(Pattern[i]);

			/* Fill the entire range with the maximum pattern width. */

		for(i = 0 ; i < 256 ; i++)
			Info -> Distance[i] = Info -> PatternWidth;

			/* Fill in the matching distances. */

		for(i = 0 ; i < Info -> PatternWidth - 1 ; i++)
			Info -> Distance[Info -> Pattern[i]] = Info -> PatternWidth - i - 1;

			/* Restart from scratch. */

		Info -> FoundY = -1;
	}

	return(Info);
}

	/* DeleteSearchInfo(struct SearchInfo *Info):
	 *
	 *	Free buffer allocated by CreateSearchInfo().
	 */

VOID __regargs
DeleteSearchInfo(struct SearchInfo *Info)
{
	if(Info)
		FreeVec(Info);
}

	/* SearchTextBuffer():
	 *
	 *	String search function, based on the Boyer-Moore search
	 *	algorithm.
	 */

LONG __regargs
SearchTextBuffer(struct SearchInfo *Info)
{
	if(BufferLines)
	{
		UBYTE	*Distance,
			*Pattern;
		WORD	LineWidth,
			PatternWidth;
		STRPTR	Line;

		LONG	i;
		WORD	j,k,l,Index;

			/* Extract relevant data. */

		Distance	= Info -> Distance;
		Pattern		= Info -> Pattern;
		PatternWidth	= Info -> PatternWidth;

			/* Update the search positions. */

		if(Info -> FoundY == -1)
		{
			Info -> FoundX	= 0;
			Info -> FoundY	= 0;
			Index		= 0;
		}
		else
		{
			if(!(Index = Info -> Index))
				Info -> FoundY = (Info -> FoundY + 1) % Lines;
		}

			/* Run down the buffer. */

		for(i = Info -> FoundY ; i < Lines ; i++)
		{
			Line = BufferLines[i];

				/* Is there anything to search for? */

			if((LineWidth = Line[-1]) >= PatternWidth)
			{
					/* Cast the magic spell of Boyer-Moore... */

				if(Index)
					j = Index;
				else
					j = PatternWidth;

				do
				{
					k = PatternWidth - 1;
					l = j - 1;

					while(k >= 0 && Pattern[k] == ToUpper(Line[l]))
					{
						l--;
						k--;
					}

					j += Distance[ToUpper(Line[j - 1])];

					if(k < 0)
					{
						Info -> FoundX	= l + 1;
						Info -> FoundY	= i;

						if(j <= LineWidth)
							Info -> Index = j;
						else
							Info -> Index = 0;

						return(i);
					}
				}
				while(j <= LineWidth);

				Index = 0;
			}
		}
	}

	return(-1);
}