/** ReadPict.c *******************************************************
 *
 * Read an ILBM raster image file.               23-Jan-86.
 *
 * 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.
 *
 *********************************************************************
 *
 * Modified to accept a BEAM chunk in an ILBM FORM. Search for lines
 *
 * containing 'dp' to find the difference from the original EA files
 *
 * Date: 20-Feb-89       Registered Developer: ECI004 - Diego Perini
 *
 ********************************************************************/
 
#define LOCAL   static

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

UWORD BeamPalette[592][32]; /* dp */

#define MIN(a,b) ((a)<(b)?(a):(b))

/* Define the size of a temporary buffer used in unscrambling the ILBM rows.*/
#define bufSz 32768L /* dp */

/*------------ 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
 *       BMHD       GetBMHD
 *       CMAP       GetCMAP
 *       BEAM       GetBEAM
 *     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 /* dp */

/* Global access to client-provided pointers.*/
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;
   GroupContext formContext;
   ILBMFrame ilbmFrame;      /* only used for non-clientFrame fields.*/
   struct BitMap *destBitMap; /* dp */

    /* 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);
            } while (iffp >= IFF_OKAY);
        if (iffp == END_MARK)
            iffp = IFF_OKAY;   /* 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_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);
         break; }
      case ID_BEAM: { /* dp */
         ilbmFrame.foundBEAM = TRUE;
         iffp = GetBEAM(&formContext,
                (UWORD *)&BeamPalette[0], ilbmFrame.bmHdr.h);
         break; }
      case ID_CAMG: { /* dp */
         ilbmFrame.foundCAMG = TRUE;
         iffp = GetCAMG(&formContext, &ilbmFrame.camgChunk);
         break; }
      case ID_CRNG: { /* dp */
         iffp = GetCRNG(&formContext,
             &ilbmFrame.crngChunk[ilbmFrame.crngCount++]);
         break; }
      case ID_CCRT: { /* dp */
         iffp = GetCCRT(&formContext,
             &ilbmFrame.ccrtChunk[ilbmFrame.ccrtCount++]);
         break; }
      case ID_BODY: { /* dp */
         if (!ilbmFrame.foundBMHD)
            iffp = BAD_FORM;   /* No BMHD chunk! */
         else
            if (destBitMap = (struct BitMap *)getBitMap(&ilbmFrame))
               {
               iffp = GetBODY( &formContext,
                               destBitMap,
                               (BYTE *)NULL,
                               &ilbmFrame.bmHdr,
                               (BYTE *)bodyBuffer,
                               (LONG)bufSz);
               if (iffp == IFF_OKAY) iffp = IFF_DONE;   /* Eureka */
               *giFrame = ilbmFrame;  /* Copy fields to client's frame.*/
               }
            else
               iffp = CLIENT_ERROR;   /* not enough RAM for the bitmap */
         break; }
      case END_MARK: {
         iffp = BAD_FORM;   /* No BODY chunk! */
         break; }
      } 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[0], &ilbmFrame->nColorRegs);
         break; }
      case ID_BEAM: { /* dp */
         ilbmFrame->foundBEAM = TRUE;
         iffp = GetBEAM(&propContext,
                (UWORD *)&BeamPalette[0], ilbmFrame->bmHdr.h);
         break; }
      case ID_CAMG: { /* dp */
         ilbmFrame->foundCAMG = TRUE;
         iffp = GetCAMG(&propContext, &ilbmFrame->camgChunk);
         break; }
      case ID_CRNG: { /* dp */
         iffp = GetCRNG(&propContext,
             &ilbmFrame->crngChunk[ilbmFrame->crngCount++]);
         break; }
      case ID_CCRT: { /* dp */
         iffp = GetCCRT(&propContext,
             &ilbmFrame->ccrtChunk[ilbmFrame->ccrtCount++]);
         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, iFrame)
   LONG file;
   ILBMFrame *iFrame;   /* Top level "client frame".*/
   {
   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;
   iFrame->foundBEAM  = FALSE;
   iFrame->foundCAMG  = FALSE;
   iFrame->crngCount  = 0;
   iFrame->ccrtCount  = 0;

   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 essential 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);
   }