/** LoadPict.c **************************************************************
 *
 * Load an ILBM raster image file into an existing bitmap.
 * This is a slightly modified version of ReadPict.c dated 23-Jan-86.
 * 
 * Modified by Gary Bonham, Sparta, Inc.  25 Apr 1986
 * Further mods on 26-Jul-86 to permit it to read only the initial
 * bitmap for ANIM files.  Use LoadAnim.c to read entire anim files.
 *
 * By Jerry Morrison, Steve Shaw, and Steve Hayes, Electronic Arts.
 * This software is in the public domain.
 *
 * USE THIS AS AN EXAMPLE PROGRAM FOR AN IFF READER.
 *
 * The IFF reader portion is essentially a recursive-descent parser.
 ****************************************************************************/

#define LOCAL   static

#include "functions.h"
#include "intuall.h"
#include "libraries/dos.h"
#include "libraries/dosextens.h"
#include "ilbm.h"
#include "readpict.h"
#include "putanim.h"

/* This example's max number of planes in a bitmap. Could use MaxAmDepth. */
#define EXDepth 5
#define maxColorReg (1<<EXDepth)
#define MIN(a,b) ((a)<(b)?(a):(b))

#define SafeFreeMem(p,q) {if(p)FreeMem(p,q);}
#define GetANHD(context,anHdr) \
   IFFReadBytes(context,(BYTE *)anHdr,(long)sizeof(AnimationHeader))

/* Define the size of a temporary buffer used in unscrambling the ILBM rows.*/
#define bufSz 512

extern int Pop;

/*------------ ILBM reader -----------------------------------------------*/
/* ILBMFrame is our "client frame" for reading FORMs ILBM in an IFF file.
 * We allocate one of these on the stack for every LIST or FORM encountered
 * in the file and use it to hold BMHD & CMAP properties. We also allocate
 * an initial one for the whole file.
 * We allocate a new GroupContext (and initialize it by OpenRIFF or
 * OpenRGroup) for every group (FORM, CAT, LIST, or PROP) encountered. It's
 * just a context for reading (nested) chunks.
 *
 * If we were to scan the entire example file outlined below:
 *    reading          proc(s)                new               new
 *
 * --whole file--   ReadPicture+ReadIFF   GroupContext        ILBMFrame
 * CAT              ReadICat                GroupContext
 *   LIST           GetLiILBM+ReadIList       GroupContext        ILBMFrame
 *     PROP ILBM    GetPrILBM                   GroupContext
 *       CMAP       GetCMAP
 *       BMHD       GetBMHD
 *     FORM ILBM    GetFoILBM                   GroupContext        ILBMFrame
 *       BODY       GetBODY
 *     FORM ILBM    GetFoILBM                   GroupContext        ILBMFrame
 *       BODY       GetBODY
 *   FORM ILBM      GetFoILBM                 GroupContext        ILBMFrame
 */

/* NOTE: For a small version of this program, set Fancy to 0.
 * That'll compile a program that reads a single FORM ILBM in a file, which
 * is what DeluxePaint produces. It'll skip all LISTs and PROPs in the input
 * file. It will, however, look inside a CAT for a FORM ILBM.
 * That's suitable for 90% of the uses.
 *
 * For a fancier version that handles LISTs and PROPs, set Fancy to 1.
 * That'll compile a program that dives into a LIST, if present, to read
 * the first FORM ILBM. E.g. a DeluxePrint library of images is a LIST of
 * FORMs ILBM.
 *
 * For an even fancier version, set Fancy to 2. That'll compile a program
 * that dives into non-ILBM FORMs, if present, looking for a nested FORM ILBM.
 * E.g. a DeluxeVideo C.S. animated object file is a FORM ANBM containing a
 * FORM ILBM for each image frame. */
#define Fancy  2

/* Global access to client-provided pointers.*/
LOCAL Allocator *gAllocator = NULL;
LOCAL struct BitMap *gBM = NULL;   /* client's bitmap.*/
LOCAL ILBMFrame *giFrame = NULL;   /* "client frame".*/

/** GetFoILBM() *************************************************************
 *
 * Called via ReadPicture to handle every FORM encountered in an IFF file.
 * Reads FORMs ILBM and skips all others.
 * Inside a FORM ILBM, it stops once it reads a BODY. It complains if it
 * finds no BODY or if it has no BMHD to decode the BODY.
 *
 * Once we find a BODY chunk, we'll allocate the BitMap and read the image.
 *
 ****************************************************************************/
LOCAL BYTE bodyBuffer[bufSz];
IFFP GetFoILBM(parent)
GroupContext *parent;
{
   /*compilerBug register*/ IFFP iffp;
   PLANEPTR plane0; /* GB - 25 apr 86 */
   GroupContext formContext;
   AnimationHeader animHdr;
   ILBMFrame ilbmFrame;      /* only used for non-clientFrame fields.*/
   register int i;
   LONG plsize;   /* Plane size in bytes. */
   long nPlanes; /* number of planes in our display image */

   /* Handle a non-ILBM FORM. */
   if (parent->subtype != ID_ILBM) {
#if Fancy >= 2
      /* Open a non-ILBM FORM and recursively scan it for ILBMs.*/
      iffp = OpenRGroup(parent, &formContext);
      CheckIFFP();
      do {
          iffp = GetF1ChunkHdr(&formContext);
/*          if (iffp == IFF_DONE) iffp = IFF_OKAY;*/
      } while (iffp >= IFF_OKAY);
      if (iffp == END_MARK)  iffp = IFF_DONE;   /* then continue scanning the file */
      CloseRGroup(&formContext);
      return(iffp);
#else
      return(IFF_OKAY); /* Just skip this FORM and keep scanning the file.*/
#endif
   }

   ilbmFrame = *(ILBMFrame *)parent->clientFrame;
   iffp = OpenRGroup(parent, &formContext);
   CheckIFFP();

   do {
      switch (iffp = GetFChunkHdr(&formContext)) {
         case ID_ANHD: {
	    iffp = GetANHD(&formContext, &animHdr);
            Pop = animHdr.operation;
	    break;
         }
         case ID_BMHD: {
            ilbmFrame.foundBMHD = TRUE;
            iffp = GetBMHD(&formContext, &ilbmFrame.bmHdr);
            break;
         }
         case ID_CMAP: {
            ilbmFrame.nColorRegs = maxColorReg;  /* we have room for this many */
            iffp = GetCMAP(&formContext, (WORD *)&ilbmFrame.colorMap[0]
                   , &ilbmFrame.nColorRegs);
                                          /* was &ilbmFrame.colorMap, (fixed) robp. */
            break;
         }
         case ID_BODY: {
            if (!ilbmFrame.foundBMHD)  return(BAD_FORM);   /* No BMHD chunk! */
            nPlanes = MIN(ilbmFrame.bmHdr.nPlanes, EXDepth);
            plane0 = gBM->Planes[0]; /* save ptr to existing bitmap  - GB 25 apr 86*/
            InitBitMap(gBM,(long)nPlanes,(long)ilbmFrame.bmHdr.pageWidth
                      ,(long)ilbmFrame.bmHdr.pageHeight);
            plsize = RowBytes((long)ilbmFrame.bmHdr.pageWidth)
                            * (long)ilbmFrame.bmHdr.pageHeight;
              /* Assume all planes were allocated contiguously.
               * Here we partition up the memory for the required bitmaps
               * on the assumption that there was enough allocated.
               */
            if (plane0) {  /* GB - 25 apr 86 */
               for (i = 0; i < nPlanes; i++) gBM->Planes[i] = plane0 + plsize*i;
               iffp = GetBODY(&formContext,gBM,0L,&ilbmFrame.bmHdr
                      ,bodyBuffer,bufSz);
               *giFrame = ilbmFrame;  /* Copy fields to client's frame.*/
               if (iffp == IFF_OKAY) iffp = IFF_DONE;   /* Eureka */
            }
            else iffp = CLIENT_ERROR;   /* RAM not allocated for the bitmap */
            break;
         }
         case END_MARK: {
            Pop = 0;
            iffp = IFF_DONE; 
            break;
         } /* No BODY chunk! */
      }
   } while (iffp >= IFF_OKAY);  /* loop if valid ID of ignored chunk or a
                               * subroutine returned IFF_OKAY (no errors).*/

   if (iffp != IFF_DONE)  return(iffp);

   /* If we get this far, there were no errors. */
   CloseRGroup(&formContext);
   return(iffp);
}

/** Notes on extending GetFoILBM ********************************************
 *
 * To read more kinds of chunks, just add clauses to the switch statement.
 * To read more kinds of property chunks (GRAB, CAMG, etc.) add clauses to
 * the switch statement in GetPrILBM, too.
 *
 * To read a FORM type that contains a variable number of data chunks--e.g.
 * a FORM FTXT with any number of CHRS chunks--replace the ID_BODY case with
 * an ID_CHRS case that doesn't set iffp = IFF_DONE, and make the END_MARK
 * case do whatever cleanup you need.
 *
 ****************************************************************************/

/** GetPrILBM() *************************************************************
 *
 * Called via ReadPicture to handle every PROP encountered in an IFF file.
 * Reads PROPs ILBM and skips all others.
 *
 ****************************************************************************/
#if Fancy
IFFP GetPrILBM(parent)
GroupContext *parent;
{
   /*compilerBug register*/ IFFP iffp;
   GroupContext propContext;
   ILBMFrame *ilbmFrame = (ILBMFrame *)parent->clientFrame;

   if (parent->subtype != ID_ILBM) return(IFF_OKAY);   /* just continue scaning the file */

   iffp = OpenRGroup(parent, &propContext);
   CheckIFFP();

   do {
      switch (iffp = GetPChunkHdr(&propContext)) {
         case ID_BMHD: {
            ilbmFrame->foundBMHD = TRUE;
            iffp = GetBMHD(&propContext, &ilbmFrame->bmHdr);
            break;
         }
         case ID_CMAP: {
            ilbmFrame->nColorRegs = maxColorReg; /* we have room for this many */
            iffp = GetCMAP(&propContext,(WORD *)&ilbmFrame->colorMap,&ilbmFrame->nColorRegs);
            break;
         }
      }
   } while (iffp >= IFF_OKAY);  /* loop if valid ID of ignored chunk or a
                                 * subroutine returned IFF_OKAY (no errors).*/

   CloseRGroup(&propContext);
   return(iffp == END_MARK ? IFF_OKAY : iffp);
}
#endif

/** GetLiILBM() *************************************************************
 *
 * Called via ReadPicture to handle every LIST encountered in an IFF file.
 *
 ****************************************************************************/
#if Fancy
IFFP GetLiILBM(parent) 
GroupContext *parent;
{
   ILBMFrame newFrame;   /* allocate a new Frame */
   newFrame = *(ILBMFrame *)parent->clientFrame;  /* copy parent frame */
   return( ReadIList(parent, (ClientFrame *)&newFrame) );
}
#endif

/** ReadPicture() **********************************************************/
IFFP ReadPicture(file, bm, iFrame, allocator)
LONG file;
struct BitMap *bm;
ILBMFrame *iFrame;   /* Top level "client frame".*/

   /* **** ERROR IN SOURCE CODE, WAS jFrame, now iFrame */
   /* fixed */

Allocator *allocator;
{
   IFFP iffp = IFF_OKAY;
#if Fancy
   iFrame->clientFrame.getList = GetLiILBM;
   iFrame->clientFrame.getProp = GetPrILBM;
#else
   iFrame->clientFrame.getList = SkipGroup;
   iFrame->clientFrame.getProp = SkipGroup;
#endif
   iFrame->clientFrame.getForm = GetFoILBM;
   iFrame->clientFrame.getCat  = ReadICat ;

   /* Initialize the top-level client frame's property settings to the
    * program-wide defaults. This example just records that we haven't read
    * any BMHD property or CMAP color registers yet. For the color map, that
    * means the default is to leave the machine's color registers alone.
    * If you want to read a property like GRAB, init it here to (0, 0). */
   iFrame->foundBMHD  = FALSE;
   iFrame->nColorRegs = 0;

   gAllocator = allocator;
   gBM = bm;
   giFrame = iFrame;
  /* Store a pointer to the client's frame in a global variable so that
   * GetFoILBM can update client's frame when done.  Why do we have so
   * many frames & frame pointers floating around causing confusion?
   * Because IFF supports PROPs which apply to all FORMs in a LIST,
   * unless a given FORM overrides some property.  
   * When you write code to read several FORMs,
   * it is ssential to maintain a frame at each level of the syntax
   * so that the properties for the LIST don't get overwritten by any
   * properties specified by individual FORMs.
   * We decided it was best to put that complexity into this one-FORM example,
   * so that those who need it later will have a useful starting place.
   */

   iffp = ReadIFF(file, (ClientFrame *)iFrame);
   return(iffp);
}