/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/*****************************************************************************
 *   "Gif-Lib" - Yet another gif library.
 *
 * Written by:  Gershon Elber                Ver 0.1, Jun. 1989
 * Extensively hacked by: Eric S. Raymond        Ver 1.?, Sep 1992
 *****************************************************************************
 * GIF construction tools
 *****************************************************************************
 * History:
 * 15 Sep 92 - Version 1.0 by Eric Raymond.
 ****************************************************************************/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "gif_lib.h"

#define MAX(x, y)    (((x) > (y)) ? (x) : (y))

/******************************************************************************
 * Miscellaneous utility functions
 *****************************************************************************/

/* return smallest bitfield size n will fit in */
int
BitSize(int n) {

    register int i;

    for (i = 1; i <= 8; i++)
        if ((1 << i) >= n)
            break;
    return (i);
}

/******************************************************************************
 * Color map object functions
 *****************************************************************************/

/*
 * Allocate a color map of given size; initialize with contents of
 * ColorMap if that pointer is non-NULL.
 */
ColorMapObject *
MakeMapObject(int ColorCount,
              const GifColorType * ColorMap) {

    ColorMapObject *Object;

    /*** FIXME: Our ColorCount has to be a power of two.  Is it necessary to
     * make the user know that or should we automatically round up instead? */
    if (ColorCount != (1 << BitSize(ColorCount))) {
        return ((ColorMapObject *) NULL);
    }

    Object = (ColorMapObject *)malloc(sizeof(ColorMapObject));
    if (Object == (ColorMapObject *) NULL) {
        return ((ColorMapObject *) NULL);
    }

    Object->Colors = (GifColorType *)calloc(ColorCount, sizeof(GifColorType));
    if (Object->Colors == (GifColorType *) NULL) {
        free(Object);
        return ((ColorMapObject *) NULL);
    }

    Object->ColorCount = ColorCount;
    Object->BitsPerPixel = BitSize(ColorCount);

    if (ColorMap) {
        memcpy((char *)Object->Colors,
               (char *)ColorMap, ColorCount * sizeof(GifColorType));
    }

    return (Object);
}

/*
 * Free a color map object
 */
void
FreeMapObject(ColorMapObject * Object) {

    if (Object != NULL) {
        free(Object->Colors);
        free(Object);
        Object = NULL;
    }
}

#ifdef DEBUG
void
DumpColorMap(ColorMapObject * Object,
             FILE * fp) {

    if (Object) {
        int i, j, Len = Object->ColorCount;

        for (i = 0; i < Len; i += 4) {
            for (j = 0; j < 4 && j < Len; j++) {
                fprintf(fp, "%3d: %02x %02x %02x   ", i + j,
                        Object->Colors[i + j].Red,
                        Object->Colors[i + j].Green,
                        Object->Colors[i + j].Blue);
            }
            fprintf(fp, "\n");
        }
    }
}
#endif /* DEBUG */

/******************************************************************************
 * Extension record functions
 *****************************************************************************/

void
MakeExtension(SavedImage * New,
              int Function) {

    New->Function = Function;
    /*** FIXME:
     * Someday we might have to deal with multiple extensions.
     * ??? Was this a note from Gershon or from me?  Does the multiple
     * extension blocks solve this or do we need multiple Functions?  Or is
     * this an obsolete function?  (People should use AddExtensionBlock
     * instead?)
     * Looks like AddExtensionBlock needs to take the int Function argument
     * then it can take the place of this function.  Right now people have to
     * use both.  Fix AddExtensionBlock and add this to the deprecation list.
     */
}

int
AddExtensionBlock(SavedImage * New,
                  int Len,
                  unsigned char ExtData[]) {

    ExtensionBlock *ep;

    if (New->ExtensionBlocks == NULL)
        New->ExtensionBlocks=(ExtensionBlock *)malloc(sizeof(ExtensionBlock));
    else
        New->ExtensionBlocks = (ExtensionBlock *)realloc(New->ExtensionBlocks,
                                      sizeof(ExtensionBlock) *
                                      (New->ExtensionBlockCount + 1));

    if (New->ExtensionBlocks == NULL)
        return (GIF_ERROR);

    ep = &New->ExtensionBlocks[New->ExtensionBlockCount++];

    ep->ByteCount=Len;
    ep->Bytes = (char *)malloc(ep->ByteCount);
    if (ep->Bytes == NULL)
        return (GIF_ERROR);

    if (ExtData) {
        memcpy(ep->Bytes, ExtData, Len);
        ep->Function = New->Function;
    }

    return (GIF_OK);
}

void
FreeExtension(SavedImage * Image)
{
    ExtensionBlock *ep;

    if ((Image == NULL) || (Image->ExtensionBlocks == NULL)) {
        return;
    }
    for (ep = Image->ExtensionBlocks;
         ep < (Image->ExtensionBlocks + Image->ExtensionBlockCount); ep++)
        (void)free((char *)ep->Bytes);
    free((char *)Image->ExtensionBlocks);
    Image->ExtensionBlocks = NULL;
}

/******************************************************************************
 * Image block allocation functions
******************************************************************************/

/* Private Function:
 * Frees the last image in the GifFile->SavedImages array
 */
void
FreeLastSavedImage(GifFileType *GifFile) {

    SavedImage *sp;

    if ((GifFile == NULL) || (GifFile->SavedImages == NULL))
        return;

    /* Remove one SavedImage from the GifFile */
    GifFile->ImageCount--;
    sp = &GifFile->SavedImages[GifFile->ImageCount];

    /* Deallocate its Colormap */
    if (sp->ImageDesc.ColorMap)
        FreeMapObject(sp->ImageDesc.ColorMap);

    /* Deallocate the image data */
    if (sp->RasterBits)
        free((char *)sp->RasterBits);

    /* Deallocate any extensions */
    if (sp->ExtensionBlocks)
        FreeExtension(sp);

    /*** FIXME: We could realloc the GifFile->SavedImages structure but is
     * there a point to it? Saves some memory but we'd have to do it every
     * time.  If this is used in FreeSavedImages then it would be inefficient
     * (The whole array is going to be deallocated.)  If we just use it when
     * we want to free the last Image it's convenient to do it here.
     */
}

/*
 * Append an image block to the SavedImages array
 */
SavedImage *
MakeSavedImage(GifFileType * GifFile,
               const SavedImage * CopyFrom) {

    SavedImage *sp;

    if (GifFile->SavedImages == NULL)
        GifFile->SavedImages = (SavedImage *)malloc(sizeof(SavedImage));
    else
        GifFile->SavedImages = (SavedImage *)realloc(GifFile->SavedImages,
                               sizeof(SavedImage) * (GifFile->ImageCount + 1));

    if (GifFile->SavedImages == NULL)
        return ((SavedImage *)NULL);
    else {
        sp = &GifFile->SavedImages[GifFile->ImageCount++];
        memset((char *)sp, '\0', sizeof(SavedImage));

        if (CopyFrom) {
            memcpy((char *)sp, CopyFrom, sizeof(SavedImage));

            /*
             * Make our own allocated copies of the heap fields in the
             * copied record.  This guards against potential aliasing
             * problems.
             */

            /* first, the local color map */
            if (sp->ImageDesc.ColorMap) {
                sp->ImageDesc.ColorMap = MakeMapObject(
                                         CopyFrom->ImageDesc.ColorMap->ColorCount,
                                         CopyFrom->ImageDesc.ColorMap->Colors);
                if (sp->ImageDesc.ColorMap == NULL) {
                    FreeLastSavedImage(GifFile);
                    return (SavedImage *)(NULL);
                }
            }

            /* next, the raster */
            sp->RasterBits = (unsigned char *)malloc(sizeof(GifPixelType) *
                                                   CopyFrom->ImageDesc.Height *
                                                   CopyFrom->ImageDesc.Width);
            if (sp->RasterBits == NULL) {
                FreeLastSavedImage(GifFile);
                return (SavedImage *)(NULL);
            }
            memcpy(sp->RasterBits, CopyFrom->RasterBits,
                   sizeof(GifPixelType) * CopyFrom->ImageDesc.Height *
                   CopyFrom->ImageDesc.Width);

            /* finally, the extension blocks */
            if (sp->ExtensionBlocks) {
                sp->ExtensionBlocks = (ExtensionBlock *)malloc(
                                      sizeof(ExtensionBlock) *
                                      CopyFrom->ExtensionBlockCount);
                if (sp->ExtensionBlocks == NULL) {
                    FreeLastSavedImage(GifFile);
                    return (SavedImage *)(NULL);
                }
                memcpy(sp->ExtensionBlocks, CopyFrom->ExtensionBlocks,
                       sizeof(ExtensionBlock) * CopyFrom->ExtensionBlockCount);

                /*
                 * For the moment, the actual blocks can take their
                 * chances with free().  We'll fix this later.
                 *** FIXME: [Better check this out... Toshio]
                 * 2004 May 27: Looks like this was an ESR note.
                 * It means the blocks are shallow copied from InFile to
                 * OutFile.  However, I don't see that in this code....
                 * Did ESR fix it but never remove this note (And other notes
                 * in gifspnge?)
                 */
            }
        }

        return (sp);
    }
}

void
FreeSavedImages(GifFileType * GifFile) {

    SavedImage *sp;

    if ((GifFile == NULL) || (GifFile->SavedImages == NULL)) {
        return;
    }
    for (sp = GifFile->SavedImages;
         sp < GifFile->SavedImages + GifFile->ImageCount; sp++) {
        if (sp->ImageDesc.ColorMap)
            FreeMapObject(sp->ImageDesc.ColorMap);

        if (sp->RasterBits)
            free((char *)sp->RasterBits);

        if (sp->ExtensionBlocks)
            FreeExtension(sp);
    }
    free((char *)GifFile->SavedImages);
    GifFile->SavedImages=NULL;
}