/*
 * parse.c - iffparse file IO support module
 *   based on some of looki.c by Leo Schwab
 *
 * The filename for clipboard is -c or -cUnit as in -c0 -c1 etc. (default 0)
 */

#include <exec/types.h>

#include "iffp/iff.h"

/* local function prototypes */

LONG stdio_stream(struct Hook *, struct IFFHandle *, struct IFFStreamCmd *);

UBYTE *omodes[2] = {"r","w"};


/* openifile
 *
 * Passed a ParseInfo structure with a not-in-use IFFHandle, filename
 *   ("-c" or -cUnit like "-c1" for clipboard), and IFF open mode
 *   (IFFF_READ or IFFF_WRITE) opens file or clipboard for use with
 *   iffparse.library support modules.
 *
 * Returns 0 for success or an IFFERR (libraries/iffparse.h)
 */

LONG openifile(struct ParseInfo *pi, UBYTE *filename, ULONG iffopenmode)
{
	struct IFFHandle	*iff;
	BOOL	cboard;
	ULONG 	unit = PRIMARY_CLIP;
	LONG 	error;

	if(!pi)			return(CLIENT_ERROR);
        if(!(iff=pi->iff))	return(CLIENT_ERROR);

	cboard = (*filename == '-'  &&  filename[1] == 'c');
 	if(cboard && filename[2])	unit = atoi(&filename[2]);

	if (cboard)
		{
		/*
		 * Set up IFFHandle for Clipboard I/O.
		 */
		pi->clipboard = TRUE;
		if (!(iff->iff_Stream =
				(ULONG)OpenClipboard(unit)))
			{
			message("Clipboard open of unit %ld failed.\n",unit);
			return(NOFILE);
			}
		InitIFFasClip(iff);
		}
	else
		{
		pi->clipboard = FALSE;
		/*
		 * Set up IFFHandle for buffered stdio I/O.
		 */
		if (!(iff->iff_Stream = (ULONG)
		   fopen(filename, omodes[iffopenmode & 1])))
			{
			message("%s: File open failed.\n",filename);
			return(NOFILE);
			}
		else initiffasstdio(iff);
		}

	D(bug("%s file opened: \n", cboard ? "[Clipboard]" : filename));

	pi->filename = filename;

	error=OpenIFF(iff, iffopenmode);

	pi->opened = error ? FALSE : TRUE;	/* currently open handle */

	D(bug("OpenIFF error = %ld\n",error));
	return(error);
}


/* closeifile
 *
 * closes file or clipboard opened with openifile, and frees all
 *   iffparse context parsed by parseifile.
 *
 * Note - You should closeifile as soon as possible if using clipboard
 *   ("-c[n]").  You also need to closeifile if, for example, you wish to
 *   reopen the file to write changes back out.  See the copychunks.c
 *   module for routines which allow you clone the chunks iffparse has
 *   gathered so that you can closeifile and still be able to modify and
 *   write back out gathered chunks.
 *
 */

void closeifile(struct ParseInfo *pi)
{
struct IFFHandle *iff;

	D(bug("closeifile:\n"));

	if(!pi)			return;
    	if(!(iff=pi->iff))	return;

	DD(bug("closeifile: About to CloseIFF if open, iff=$%lx, opened=%ld\n",
			iff, pi->opened));

	if(pi->opened)	CloseIFF(iff);

	DD(bug("closeifile: About to close %s, stream=$%lx\n",
			pi->clipboard ? "clipboard" : "file", iff->iff_Stream));
	if(iff->iff_Stream)
		{
		if (pi->clipboard)
		   CloseClipboard((struct ClipHandle *)(iff->iff_Stream));
		else
		   fclose ((FILE *)(iff->iff_Stream));
		}

	iff->iff_Stream = NULL;
	pi->clipboard = NULL;
	pi->opened = NULL;
}


/* parseifile
 *
 * Passed a ParseInfo with an initialized and open IFFHandle,
 *  grouptype (like ID_FORM), groupid (like ID_ILBM),
 *  and TAG_DONE terminated longword arrays of type,id
 *  for chunks to be grabbed, gathered, and stopped on
 *  (like { ID_ILBM, ID_BMHD, ID_ILBM, ID_CAMG, TAG_DONE })
 *  will parse an IFF file, grabbing/gathering and stopping
 *  on specified chunk.
 *
 * Note - you can call getcontext() (to continue after a stop chunk) or
 *  nextcontext() (after IFFERR_EOC, to parse next form in the same file)
 *  if you wish to continue parsing the same IFF file.  If parseifile()
 *  has to delve into a complex format to find your desired FORM, the
 *  pi->hunt flag will be set.  This should be a signal to you that
 *  you may not have the capability to simply modify and rewrite
 *  the data you have gathered.
 *
 * Returns 0 for success else and IFFERR (libraries/iffparse.h)
 */

LONG parseifile(pi,groupid,grouptype,propchks,collectchks,stopchks)
struct	ParseInfo *pi;
LONG groupid, grouptype;
LONG *propchks, *collectchks, *stopchks;
{
struct IFFHandle *iff;
register struct ContextNode	*cn;
LONG			error = 0L;


    	if(!(iff=pi->iff))	return(CLIENT_ERROR);

	if(!iff->iff_Stream)	return(IFFERR_READ);

	pi->hunt = FALSE;

	/*
	 * Declare property, collection and stop chunks.
	 */
	if (propchks)
	  if (error = PropChunks (iff, propchks, chkcnt(propchks)))
		return (error);
	if (collectchks)
	  if (error =
	      CollectionChunks(iff, collectchks, chkcnt(collectchks)))
		return (error);
	if (stopchks)
	  if (error = StopChunks (iff, stopchks, chkcnt(stopchks)))
		return (error);

	/*
	 * We want to stop at the end of an ILBM context.
	 */
	if (grouptype)
	  if (error = StopOnExit (iff, grouptype, groupid))
		return(error);

	/*
	 * Take first parse step to enter main chunk.
	 */
	if (error = ParseIFF (iff, IFFPARSE_STEP))
		return(error);

	/*
	 * Test the chunk info to see if simple form of type we want (ILBM).
	 */
	if (!(cn = CurrentChunk (iff)))
		{
		/*
		 * This really should never happen.  If it does, it means
		 * our parser is broken.
		 */
		message("Parsing error; no top chunk!\n");
		return(NOFILE);
		}

	if (cn->cn_ID != groupid  ||  cn->cn_Type != grouptype)
		{

		D(bug("This is a(n) %.4s.%.4s.  Looking for embedded %.4s's...\n",
		  &cn->cn_Type, &cn->cn_ID, &grouptype));

		pi->hunt = TRUE;	/* Warning - this is a complex file */
		}

	if(!error)	error = getcontext(iff);
	return(error);
}

/* chkcnt
 *
 * simply counts the number of chunk pairs (type,id) in array
 */
LONG chkcnt(LONG *taggedarray)
{
LONG k = 0;

	while(taggedarray[k] != TAG_DONE) k++;
	return(k>>1);
}


/* currentchunkis
 *
 * returns the ID of the current chunk (like ID_CAMG)
 */
LONG currentchunkis(struct IFFHandle *iff, LONG type, LONG id)
{
register struct ContextNode	*cn;
LONG result = 0;

	if (cn = CurrentChunk (iff))
		{
		if((cn->cn_Type == type)&&(cn->cn_ID == id)) result = 1;
		}
	return(result);
}


/* contextis
 *
 * returns the enclosing context of the current chunk (like ID_ILBM)
 */
LONG contextis(struct IFFHandle *iff, LONG type, LONG id)
{
register struct ContextNode	*cn;
LONG result = 0;

       if (cn = (CurrentChunk (iff)))
           {
           if (cn = (ParentChunk(cn)))
               {
               if((cn->cn_Type == type)&&(cn->cn_ID == id)) result = 1;
               }
	   }

	D(bug("This is a %.4s %.4s\n",&cn->cn_Type,&cn->cn_ID));

	return(result);
}


/* getcontext()
 *
 * Continues to gather the context which was specified to parseifile(),
 *  stopping at specified stop chunk, or end of context, or EOF
 *
 * Returns 0 (stopped on a stop chunk)
 *      or IFFERR_EOC (end of context, not an error)
 *      or IFFER_EOF (end of file)
 */
LONG getcontext(iff)
struct	IFFHandle *iff;
{
	LONG error = 0L;

	/* Based on our parse initialization,
	 * ParseIFF() will return on a stop chunk (error = 0)
	 * or end of context for an ILBM FORM (error = IFFERR_EOC)
	 * or end of file (error = IFFERR_EOF)
	 */
	return(error = ParseIFF(iff, IFFPARSE_SCAN));
}


/* nextcontext
 *
 * If you have finished parsing and reading your context (IFFERR_EOC),
 *   nextcontext will enter the next context contained in the file
 *   and parse it.
 *
 * Returns 0 or an IFFERR such as IFFERR_EOF (end of file)
 */

LONG nextcontext(iff)
struct	IFFHandle *iff;
{
	LONG error = 0L;

	error = ParseIFF(iff, IFFPARSE_STEP);

	D(bug("nextcontext: Got through next step\n"));

	return(error);
}


/* findpropdata
 *
 * finds specified chunk parsed from IFF file, and
 *   returns pointer to its sp_Data (or 0 for not found)
 */
UBYTE *findpropdata(iff, type, id)
struct IFFHandle	*iff;
LONG type, id;
	{
	register struct StoredProperty	*sp;

	if(sp = FindProp (iff, type, id)) return(sp->sp_Data);
	return(0);
	}


/*
 * File I/O hook functions which the IFF library will call.
 * A return of 0 indicates success (no error).
 *
 * Iffparse.library calls this code via struct Hook and Hook.asm
 */
static LONG
stdio_stream (hook, iff, actionpkt)
struct Hook		*hook;
struct IFFHandle	*iff;
struct IFFStreamCmd	*actionpkt;
{
	register FILE	*stream;
	register LONG	nbytes;
	register int	actual;
	register UBYTE	*buf;
	long	len;

	stream	= (FILE *) iff->iff_Stream;
	if(!stream)	return(1);

	nbytes	= actionpkt->sc_NBytes;
	buf	= (UBYTE *) actionpkt->sc_Buf;

	switch (actionpkt->sc_Command) {
	case IFFSCC_READ:
		do {
			actual = nbytes > 32767 ? 32767 : nbytes;
			if ((len=fread (buf, 1, actual, stream)) != actual)
				break;
			nbytes -= actual;
			buf += actual;
		} while (nbytes > 0);
		return (nbytes ? IFFERR_READ : 0 );

	case IFFSCC_WRITE:
		do {
			actual = nbytes > 32767 ? 32767 : nbytes;
			if ((len=fwrite (buf, 1, actual, stream)) != actual)
				break;
			nbytes -= actual;
			buf += actual;
		} while (nbytes > 0);
		return (nbytes ? IFFERR_WRITE : 0);

	case IFFSCC_SEEK:
		return ((fseek (stream, nbytes, 1) == -1) ? IFFERR_SEEK : 0);

	default:
		/*  No _INIT or _CLEANUP required.  */
		return (0);
	}
}

/* initiffasstdio (ie. init iff as stdio)
 *
 * sets up hook callback for the file stream handler above
 */
void initiffasstdio (iff)
struct IFFHandle *iff;
{
	extern LONG		HookEntry();
	static struct Hook	stdiohook = {
		{ NULL },
		(ULONG (*)()) HookEntry,
		(ULONG (*)()) stdio_stream,
		NULL
	};

	/*
	 * Initialize the IFF structure to point to the buffered I/O
	 * routines.  Unbuffered I/O is terribly slow.
	 */
	InitIFF (iff, IFFF_FSEEK | IFFF_RSEEK, &stdiohook);
}


/*
 * IFFerr
 *
 * Returns pointer to IFF Error string or NULL (no error)
 */
UBYTE *IFFerr(error)
LONG	error;
{
	/*
	 * English error messages for possible IFFERR_#? returns from various
	 * IFF routines.  To get the index into this array, take your IFFERR
	 * code, negate it, and subtract one.
	 *  idx = -error - 1;
	 */
	static UBYTE	*errormsgs[] = {
		"End of file (not an error).",
		"End of context (not an error).",
		"No lexical scope.",
		"Insufficient memory.",
		"Stream read error.",
		"Stream write error.",
		"Stream seek error.",
		"File is corrupt.",
		"IFF syntax error.",
		"Not an IFF file.",
		"Required hook vector missing.",
		"Return to client."
	};
	static UBYTE unknown[32];
	static UBYTE client[] = "Client error";
	static UBYTE nofile[] = "File not found or wrong type";

	if (error < 0)
		{
		return(errormsgs[(-error) - 1]);
		}
	else if(error = CLIENT_ERROR)
		{
		return(client);
		}
	else if(error = NOFILE)
		{
		return(nofile);
		}
	else if(error)
		{
		sprintf(unknown,"Unknown error %ld",error);
		return(unknown);
		}
	else return(NULL);
}


/*
 * PutCk
 *
 * Writes one chunk of data to an iffhandle
 *
 */
long PutCk(struct IFFHandle *iff, long id, long size, void *data)
    {
    long error = 0, wlen;

    D(bug("PutCk: asked to push chunk \"%.4s\" ($%lx) length %ld\n",&id,id,size));

    if(error=PushChunk(iff, 0, id, size))
	{
	D(bug("PutCk: PushChunk of %.4s, error = %s, size = %ld\n",
		id, IFFerr(error), id));
	}
    else
	{
	D(bug("PutCk: PushChunk of %.4s, error = %ld\n",&id, error));

	/* Write the actual data */
	if((wlen = WriteChunkBytes(iff,data,size)) != size)
	    {
	    D(bug("WriteChunkBytes error: size = %ld, wrote %ld\n",size,wlen));
	    error = IFFERR_WRITE;
	    }
	else error = PopChunk(iff);
	D(bug("PutCk: After PopChunk - error = %ld\n",error));
	}
    return(error);
    }