/*

     SDL - Simple DirectMedia Layer

     Copyright (C) 1997-2011 Sam Lantinga

     This library is free software; you can redistribute it and/or

     modify it under the terms of the GNU Lesser General Public

     License as published by the Free Software Foundation; either

     version 2.1 of the License, or (at your option) any later version.

     This library 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

     Lesser General Public License for more details.

     You should have received a copy of the GNU Lesser General Public

     License along with this library; if not, write to the Free Software

     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

     Sam Lantinga

     slouken@libsdl.org

 */

 #include "SDL_config.h"

 #include "SDL_video.h"

 #include "SDL_compat.h"

 #include "SDL_sysvideo.h"

 #include "SDL_blit.h"

 #include "SDL_RLEaccel_c.h"

 #include "SDL_pixels_c.h"

 /* Public routines */

 /*

  * Create an empty RGB surface of the appropriate depth

  */

 SDL_Surface *

 SDL_CreateRGBSurface(Uint32 flags,

                      int width, int height, int depth,

                      Uint32 Rmask, Uint32 Gmask, Uint32 Bmask, Uint32 Amask)

 {

     SDL_Surface *surface;

     Uint32 format;

     /* The flags are no longer used, make the compiler happy */

     (void)flags;

     /* Get the pixel format */

     format = SDL_MasksToPixelFormatEnum(depth, Rmask, Gmask, Bmask, Amask);

     if (format == SDL_PIXELFORMAT_UNKNOWN) {

         SDL_SetError("Unknown pixel format");

         return NULL;

     }

     /* Allocate the surface */

     surface = (SDL_Surface *) SDL_calloc(1, sizeof(*surface));

     if (surface == NULL) {

         SDL_OutOfMemory();

         return NULL;

     }

     surface->format = SDL_AllocFormat(format);

     if (!surface->format) {

         SDL_FreeSurface(surface);

         return NULL;

     }

     surface->w = width;

     surface->h = height;

     surface->pitch = SDL_CalculatePitch(surface);

     SDL_SetClipRect(surface, NULL);

     if (SDL_ISPIXELFORMAT_INDEXED(surface->format->format)) {

         SDL_Palette *palette =

             SDL_AllocPalette((1 << surface->format->BitsPerPixel));

         if (!palette) {

             SDL_FreeSurface(surface);

             return NULL;

         }

         if (Rmask || Bmask || Gmask) {

             const SDL_PixelFormat *format = surface->format;

             /* create palette according to masks */

             int i;

             int Rm = 0, Gm = 0, Bm = 0;

             int Rw = 0, Gw = 0, Bw = 0;

             if (Rmask) {

                 Rw = 8 - format->Rloss;

                 for (i = format->Rloss; i > 0; i -= Rw)

                     Rm |= 1 << i;

             }

             if (Gmask) {

                 Gw = 8 - format->Gloss;

                 for (i = format->Gloss; i > 0; i -= Gw)

                     Gm |= 1 << i;

             }

             if (Bmask) {

                 Bw = 8 - format->Bloss;

                 for (i = format->Bloss; i > 0; i -= Bw)

                     Bm |= 1 << i;

             }

             for (i = 0; i < palette->ncolors; ++i) {

                 int r, g, b;

                 r = (i & Rmask) >> format->Rshift;

                 r = (r << format->Rloss) | ((r * Rm) >> Rw);

                 palette->colors[i].r = r;

                 g = (i & Gmask) >> format->Gshift;

                 g = (g << format->Gloss) | ((g * Gm) >> Gw);

                 palette->colors[i].g = g;

                 b = (i & Bmask) >> format->Bshift;

                 b = (b << format->Bloss) | ((b * Bm) >> Bw);

                 palette->colors[i].b = b;

             }

         } else if (palette->ncolors == 2) {

             /* Create a black and white bitmap palette */

             palette->colors[0].r = 0xFF;

             palette->colors[0].g = 0xFF;

             palette->colors[0].b = 0xFF;

             palette->colors[1].r = 0x00;

             palette->colors[1].g = 0x00;

             palette->colors[1].b = 0x00;

         }

         SDL_SetSurfacePalette(surface, palette);

         SDL_FreePalette(palette);

     }

     /* Get the pixels */

     if (surface->w && surface->h) {

         surface->pixels = SDL_malloc(surface->h * surface->pitch);

         if (!surface->pixels) {

             SDL_FreeSurface(surface);

             SDL_OutOfMemory();

             return NULL;

         }

         /* This is important for bitmaps */

         SDL_memset(surface->pixels, 0, surface->h * surface->pitch);

     }

     /* Allocate an empty mapping */

     surface->map = SDL_AllocBlitMap();

     if (!surface->map) {

         SDL_FreeSurface(surface);

         return NULL;

     }

     /* By default surface with an alpha mask are set up for blending */

     if (Amask) {

         SDL_SetSurfaceBlendMode(surface, SDL_BLENDMODE_BLEND);

     }

     /* The surface is ready to go */

     surface->refcount = 1;

     return surface;

 }

 /*

  * Create an RGB surface from an existing memory buffer

  */

 SDL_Surface *

 SDL_CreateRGBSurfaceFrom(void *pixels,

                          int width, int height, int depth, int pitch,

                          Uint32 Rmask, Uint32 Gmask, Uint32 Bmask,

                          Uint32 Amask)

 {

     SDL_Surface *surface;

     surface =

         SDL_CreateRGBSurface(0, 0, 0, depth, Rmask, Gmask, Bmask, Amask);

     if (surface != NULL) {

         surface->flags |= SDL_PREALLOC;

         surface->pixels = pixels;

         surface->w = width;

         surface->h = height;

         surface->pitch = pitch;

         SDL_SetClipRect(surface, NULL);

     }

     return surface;

 }

 int

 SDL_SetSurfacePalette(SDL_Surface * surface, SDL_Palette * palette)

 {

     if (!surface) {

         SDL_SetError("SDL_SetSurfacePalette() passed a NULL surface");

         return -1;

     }

     return SDL_SetPixelFormatPalette(surface->format, palette);

 }

 int

 SDL_SetSurfaceRLE(SDL_Surface * surface, int flag)

 {

     int flags;

     if (!surface) {

         return -1;

     }

     flags = surface->map->info.flags;

     if (flag) {

         surface->map->info.flags |= SDL_COPY_RLE_DESIRED;

     } else {

         surface->map->info.flags &= ~SDL_COPY_RLE_DESIRED;

     }

     if (surface->map->info.flags != flags) {

         SDL_InvalidateMap(surface->map);

     }

     return 0;

 }

 int

 SDL_SetColorKey(SDL_Surface * surface, int flag, Uint32 key)

 {

     int flags;

     if (!surface) {

         return -1;

     }

     if (flag & SDL_RLEACCEL) {

         SDL_SetSurfaceRLE(surface, 1);

     }

     flags = surface->map->info.flags;

     if (flag) {

         surface->map->info.flags |= SDL_COPY_COLORKEY;

         surface->map->info.colorkey = key;

     } else {

         surface->map->info.flags &= ~SDL_COPY_COLORKEY;

     }

     if (surface->map->info.flags != flags) {

         SDL_InvalidateMap(surface->map);

     }

     /* Compatibility mode */

     if (surface->map->info.flags & SDL_COPY_COLORKEY) {

         surface->flags |= SDL_SRCCOLORKEY;

     } else {

         surface->flags &= ~SDL_SRCCOLORKEY;

     }

     return 0;

 }

 int

 SDL_GetColorKey(SDL_Surface * surface, Uint32 * key)

 {

     if (!surface) {

         return -1;

     }

     if (!(surface->map->info.flags & SDL_COPY_COLORKEY)) {

         return -1;

     }

     if (key) {

         *key = surface->map->info.colorkey;

     }

     return 0;

 }

 /* This is a fairly slow function to switch from colorkey to alpha */

 static void

 SDL_ConvertColorkeyToAlpha(SDL_Surface * surface)

 {

     int x, y;

     if (!surface) {

         return;

     }

     if (!(surface->map->info.flags & SDL_COPY_COLORKEY) ||

         !surface->format->Amask) {

         return;

     }

     SDL_LockSurface(surface);

     switch (surface->format->BytesPerPixel) {

     case 2:

         {

             Uint16 *row, *spot;

             Uint16 ckey = (Uint16) surface->map->info.colorkey;

             Uint16 mask = (Uint16) (~surface->format->Amask);

             row = (Uint16 *) surface->pixels;

             for (y = surface->h; y--;) {

                 spot = row;

                 for (x = surface->w; x--;) {

                     if (*spot == ckey) {

                         *spot &= mask;

                     }

                     ++spot;

                 }

                 row += surface->pitch / 2;

             }

         }

         break;

     case 3:

         /* FIXME */

         break;

     case 4:

         {

             Uint32 *row, *spot;

             Uint32 ckey = surface->map->info.colorkey;

             Uint32 mask = ~surface->format->Amask;

             row = (Uint32 *) surface->pixels;

             for (y = surface->h; y--;) {

                 spot = row;

                 for (x = surface->w; x--;) {

                     if (*spot == ckey) {

                         *spot &= mask;

                     }

                     ++spot;

                 }

                 row += surface->pitch / 4;

             }

         }

         break;

     }

     SDL_UnlockSurface(surface);

     SDL_SetColorKey(surface, 0, 0);

     SDL_SetSurfaceBlendMode(surface, SDL_BLENDMODE_BLEND);

 }

 int

 SDL_SetSurfaceColorMod(SDL_Surface * surface, Uint8 r, Uint8 g, Uint8 b)

 {

     int flags;

     if (!surface) {

         return -1;

     }

     surface->map->info.r = r;

     surface->map->info.g = g;

     surface->map->info.b = b;

     flags = surface->map->info.flags;

     if (r != 0xFF || g != 0xFF || b != 0xFF) {

         surface->map->info.flags |= SDL_COPY_MODULATE_COLOR;

     } else {

         surface->map->info.flags &= ~SDL_COPY_MODULATE_COLOR;

     }

     if (surface->map->info.flags != flags) {

         SDL_InvalidateMap(surface->map);

     }

     return 0;

 }

 int

 SDL_GetSurfaceColorMod(SDL_Surface * surface, Uint8 * r, Uint8 * g, Uint8 * b)

 {

     if (!surface) {

         return -1;

     }

     if (r) {

         *r = surface->map->info.r;

     }

     if (g) {

         *g = surface->map->info.g;

     }

     if (b) {

         *b = surface->map->info.b;

     }

     return 0;

 }

 int

 SDL_SetSurfaceAlphaMod(SDL_Surface * surface, Uint8 alpha)

 {

     int flags;

     if (!surface) {

         return -1;

     }

     surface->map->info.a = alpha;

     flags = surface->map->info.flags;

     if (alpha != 0xFF) {

         surface->map->info.flags |= SDL_COPY_MODULATE_ALPHA;

     } else {

         surface->map->info.flags &= ~SDL_COPY_MODULATE_ALPHA;

     }

     if (surface->map->info.flags != flags) {

         SDL_InvalidateMap(surface->map);

     }

     return 0;

 }

 int

 SDL_GetSurfaceAlphaMod(SDL_Surface * surface, Uint8 * alpha)

 {

     if (!surface) {

         return -1;

     }

     if (alpha) {

         *alpha = surface->map->info.a;

     }

     return 0;

 }

 int

 SDL_SetSurfaceBlendMode(SDL_Surface * surface, SDL_BlendMode blendMode)

 {

     int flags, status;

     if (!surface) {

         return -1;

     }

     status = 0;

     flags = surface->map->info.flags;

     surface->map->info.flags &=

         ~(SDL_COPY_BLEND | SDL_COPY_ADD | SDL_COPY_MOD);

     switch (blendMode) {

     case SDL_BLENDMODE_NONE:

         break;

     case SDL_BLENDMODE_BLEND:

         surface->map->info.flags |= SDL_COPY_BLEND;

         break;

     case SDL_BLENDMODE_ADD:

         surface->map->info.flags |= SDL_COPY_ADD;

         break;

     case SDL_BLENDMODE_MOD:

         surface->map->info.flags |= SDL_COPY_MOD;

         break;

     default:

         SDL_Unsupported();

         status = -1;

         break;

     }

     if (surface->map->info.flags != flags) {

         SDL_InvalidateMap(surface->map);

     }

     /* Compatibility mode */

     if (surface->map->info.flags & SDL_COPY_BLEND) {

         surface->flags |= SDL_SRCALPHA;

     } else {

         surface->flags &= ~SDL_SRCALPHA;

     }

     return status;

 }

 int

 SDL_GetSurfaceBlendMode(SDL_Surface * surface, SDL_BlendMode *blendMode)

 {

     if (!surface) {

         return -1;

     }

     if (!blendMode) {

         return 0;

     }

     switch (surface->map->

             info.flags & (SDL_COPY_BLEND | SDL_COPY_ADD | SDL_COPY_MOD)) {

     case SDL_COPY_BLEND:

         *blendMode = SDL_BLENDMODE_BLEND;

         break;

     case SDL_COPY_ADD:

         *blendMode = SDL_BLENDMODE_ADD;

         break;

     case SDL_COPY_MOD:

         *blendMode = SDL_BLENDMODE_MOD;

         break;

     default:

         *blendMode = SDL_BLENDMODE_NONE;

         break;

     }

     return 0;

 }

 SDL_bool

 SDL_SetClipRect(SDL_Surface * surface, const SDL_Rect * rect)

 {

     SDL_Rect full_rect;

     /* Don't do anything if there's no surface to act on */

     if (!surface) {

         return SDL_FALSE;

     }

     /* Set up the full surface rectangle */

     full_rect.x = 0;

     full_rect.y = 0;

     full_rect.w = surface->w;

     full_rect.h = surface->h;

     /* Set the clipping rectangle */

     if (!rect) {

         surface->clip_rect = full_rect;

         return SDL_TRUE;

     }

     return SDL_IntersectRect(rect, &full_rect, &surface->clip_rect);

 }

 void

 SDL_GetClipRect(SDL_Surface * surface, SDL_Rect * rect)

 {

     if (surface && rect) {

         *rect = surface->clip_rect;

     }

 }

 /* 

  * Set up a blit between two surfaces -- split into three parts:

  * The upper part, SDL_UpperBlit(), performs clipping and rectangle 

  * verification.  The lower part is a pointer to a low level

  * accelerated blitting function.

  *

  * These parts are separated out and each used internally by this 

  * library in the optimimum places.  They are exported so that if

  * you know exactly what you are doing, you can optimize your code

  * by calling the one(s) you need.

  */

 int

 SDL_LowerBlit(SDL_Surface * src, SDL_Rect * srcrect,

               SDL_Surface * dst, SDL_Rect * dstrect)

 {

     /* Check to make sure the blit mapping is valid */

     if ((src->map->dst != dst) ||

         (dst->format->palette &&

          src->map->palette_version != dst->format->palette->version)) {

         if (SDL_MapSurface(src, dst) < 0) {

             return (-1);

         }

         /* just here for debugging */

 /*         printf */

 /*             ("src = 0x%08X src->flags = %08X src->map->info.flags = %08x\ndst = 0x%08X dst->flags = %08X dst->map->info.flags = %08X\nsrc->map->blit = 0x%08x\n", */

 /*              src, dst->flags, src->map->info.flags, dst, dst->flags, */

 /*              dst->map->info.flags, src->map->blit); */

     }

     return (src->map->blit(src, srcrect, dst, dstrect));

 }

 int

 SDL_UpperBlit(SDL_Surface * src, const SDL_Rect * srcrect,

               SDL_Surface * dst, SDL_Rect * dstrect)

 {

     SDL_Rect fulldst;

     int srcx, srcy, w, h;

     /* Make sure the surfaces aren't locked */

     if (!src || !dst) {

         SDL_SetError("SDL_UpperBlit: passed a NULL surface");

         return (-1);

     }

     if (src->locked || dst->locked) {

         SDL_SetError("Surfaces must not be locked during blit");

         return (-1);

     }

     /* If the destination rectangle is NULL, use the entire dest surface */

     if (dstrect == NULL) {

         fulldst.x = fulldst.y = 0;

         dstrect = &fulldst;

     }

     /* clip the source rectangle to the source surface */

     if (srcrect) {

         int maxw, maxh;

         srcx = srcrect->x;

         w = srcrect->w;

         if (srcx < 0) {

             w += srcx;

             dstrect->x -= srcx;

             srcx = 0;

         }

         maxw = src->w - srcx;

         if (maxw < w)

             w = maxw;

         srcy = srcrect->y;

         h = srcrect->h;

         if (srcy < 0) {

             h += srcy;

             dstrect->y -= srcy;

             srcy = 0;

         }

         maxh = src->h - srcy;

         if (maxh < h)

             h = maxh;

     } else {

         srcx = srcy = 0;

         w = src->w;

         h = src->h;

     }

     /* clip the destination rectangle against the clip rectangle */

     {

         SDL_Rect *clip = &dst->clip_rect;

         int dx, dy;

         dx = clip->x - dstrect->x;

         if (dx > 0) {

             w -= dx;

             dstrect->x += dx;

             srcx += dx;

         }

         dx = dstrect->x + w - clip->x - clip->w;

         if (dx > 0)

             w -= dx;

         dy = clip->y - dstrect->y;

         if (dy > 0) {

             h -= dy;

             dstrect->y += dy;

             srcy += dy;

         }

         dy = dstrect->y + h - clip->y - clip->h;

         if (dy > 0)

             h -= dy;

     }

     if (w > 0 && h > 0) {

         SDL_Rect sr;

         sr.x = srcx;

         sr.y = srcy;

         sr.w = dstrect->w = w;

         sr.h = dstrect->h = h;

         return SDL_LowerBlit(src, &sr, dst, dstrect);

     }

     dstrect->w = dstrect->h = 0;

     return 0;

 }

 /*

  * Scale and blit a surface 

 */

 int

 SDL_BlitScaled(SDL_Surface * src, const SDL_Rect * srcrect,

                SDL_Surface * dst, const SDL_Rect * dstrect)

 {

     /* Save off the original dst width, height */

     int dstW = dstrect->w;

     int dstH = dstrect->h;

     SDL_Rect final_dst = *dstrect;

     SDL_Rect final_src = *srcrect;

     /* Clip the dst surface to the dstrect */

     SDL_SetClipRect( dst, &final_dst );

     /* If the dest was clipped to a zero sized rect then exit */

     if ( dst->clip_rect.w <= 0 || dst->clip_rect.h <= 0 ) {

         return -1;

     }

     /* Did the dst width change? */

     if ( dstW != dst->clip_rect.w ) {

         /* scale the src width appropriately */

         final_src.w = final_src.w * dst->clip_rect.w / dstW;

     }

     /* Did the dst height change? */

     if ( dstH != dst->clip_rect.h ) {

         /* scale the src width appropriately */

         final_src.h = final_src.h * dst->clip_rect.h / dstH;

     }

     /* Clip the src surface to the srcrect */

     SDL_SetClipRect( src, &final_src );

     src->map->info.flags |= SDL_COPY_NEAREST;

     if ( src->format->format == dst->format->format && !SDL_ISPIXELFORMAT_INDEXED(src->format->format) ) {

         return SDL_SoftStretch( src, &final_src, dst, &final_dst );

     } else {

         return SDL_LowerBlit( src, &final_src, dst, &final_dst );

     }

 }

 /*

  * Lock a surface to directly access the pixels

  */

 int

 SDL_LockSurface(SDL_Surface * surface)

 {

     if (!surface->locked) {

         /* Perform the lock */

         if (surface->flags & SDL_RLEACCEL) {

             SDL_UnRLESurface(surface, 1);

             surface->flags |= SDL_RLEACCEL;     /* save accel'd state */

         }

     }

     /* Increment the surface lock count, for recursive locks */

     ++surface->locked;

     /* Ready to go.. */

     return (0);

 }

 /*

  * Unlock a previously locked surface

  */

 void

 SDL_UnlockSurface(SDL_Surface * surface)

 {

     /* Only perform an unlock if we are locked */

     if (!surface->locked || (--surface->locked > 0)) {

         return;

     }

     /* Update RLE encoded surface with new data */

     if ((surface->flags & SDL_RLEACCEL) == SDL_RLEACCEL) {

         surface->flags &= ~SDL_RLEACCEL;        /* stop lying */

         SDL_RLESurface(surface);

     }

 }

 /* 

  * Convert a surface into the specified pixel format.

  */

 SDL_Surface *

 SDL_ConvertSurface(SDL_Surface * surface, SDL_PixelFormat * format,

                    Uint32 flags)

 {

     SDL_Surface *convert;

     Uint32 copy_flags;

     SDL_Rect bounds;

     /* Check for empty destination palette! (results in empty image) */

     if (format->palette != NULL) {

         int i;

         for (i = 0; i < format->palette->ncolors; ++i) {

             if ((format->palette->colors[i].r != 0xFF) ||

                 (format->palette->colors[i].g != 0xFF) ||

                 (format->palette->colors[i].b != 0xFF))

                 break;

         }

         if (i == format->palette->ncolors) {

             SDL_SetError("Empty destination palette");

             return (NULL);

         }

     }

     /* Create a new surface with the desired format */

     convert = SDL_CreateRGBSurface(flags, surface->w, surface->h,

                                    format->BitsPerPixel, format->Rmask,

                                    format->Gmask, format->Bmask,

                                    format->Amask);

     if (convert == NULL) {

         return (NULL);

     }

     /* Copy the palette if any */

     if (format->palette && convert->format->palette) {

         SDL_memcpy(convert->format->palette->colors,

                    format->palette->colors,

                    format->palette->ncolors * sizeof(SDL_Color));

         convert->format->palette->ncolors = format->palette->ncolors;

     }

     /* Save the original copy flags */

     copy_flags = surface->map->info.flags;

     surface->map->info.flags = 0;

     /* Copy over the image data */

     bounds.x = 0;

     bounds.y = 0;

     bounds.w = surface->w;

     bounds.h = surface->h;

     SDL_LowerBlit(surface, &bounds, convert, &bounds);

     /* Clean up the original surface, and update converted surface */

     convert->map->info.r = surface->map->info.r;

     convert->map->info.g = surface->map->info.g;

     convert->map->info.b = surface->map->info.b;

     convert->map->info.a = surface->map->info.a;

     convert->map->info.flags =

         (copy_flags &

          ~(SDL_COPY_COLORKEY | SDL_COPY_BLEND

            | SDL_COPY_RLE_DESIRED | SDL_COPY_RLE_COLORKEY |

            SDL_COPY_RLE_ALPHAKEY));

     surface->map->info.flags = copy_flags;

     if (copy_flags & SDL_COPY_COLORKEY) {

         Uint8 keyR, keyG, keyB, keyA;

         SDL_GetRGBA(surface->map->info.colorkey, surface->format, &keyR,

                     &keyG, &keyB, &keyA);

         SDL_SetColorKey(convert, 1,

                         SDL_MapRGBA(convert->format, keyR, keyG, keyB, keyA));

         /* This is needed when converting for 3D texture upload */

         SDL_ConvertColorkeyToAlpha(convert);

     }

     SDL_SetClipRect(convert, &surface->clip_rect);

     /* Enable alpha blending by default if the new surface has an

      * alpha channel or alpha modulation */

     if ((surface->format->Amask && format->Amask) ||

         (copy_flags & (SDL_COPY_COLORKEY|SDL_COPY_MODULATE_ALPHA))) {

         SDL_SetSurfaceBlendMode(convert, SDL_BLENDMODE_BLEND);

     }

     if ((copy_flags & SDL_COPY_RLE_DESIRED) || (flags & SDL_RLEACCEL)) {

         SDL_SetSurfaceRLE(convert, SDL_RLEACCEL);

     }

     /* We're ready to go! */

     return (convert);

 }

 SDL_Surface *

 SDL_ConvertSurfaceFormat(SDL_Surface * surface, Uint32 pixel_format,

                          Uint32 flags)

 {

     SDL_PixelFormat *fmt;

     SDL_Surface *convert;

     fmt = SDL_AllocFormat(pixel_format);

     if (fmt) {

         convert = SDL_ConvertSurface(surface, fmt, flags);

         SDL_FreeFormat(fmt);

     }

     return convert;

 }

 /*

  * Create a surface on the stack for quick blit operations

  */

 static __inline__ SDL_bool

 SDL_CreateSurfaceOnStack(int width, int height, Uint32 pixel_format,

                          void * pixels, int pitch, SDL_Surface * surface, 

                          SDL_PixelFormat * format, SDL_BlitMap * blitmap)

 {

     if (SDL_ISPIXELFORMAT_INDEXED(pixel_format)) {

         SDL_SetError("Indexed pixel formats not supported");

         return SDL_FALSE;

     }

     if (SDL_InitFormat(format, pixel_format) < 0) {

         return SDL_FALSE;

     }

     SDL_zerop(surface);

     surface->flags = SDL_PREALLOC;

     surface->format = format;

     surface->pixels = pixels;

     surface->w = width;

     surface->h = height;

     surface->pitch = pitch;

     /* We don't actually need to set up the clip rect for our purposes */

     /*SDL_SetClipRect(surface, NULL);*/

     /* Allocate an empty mapping */

     SDL_zerop(blitmap);

     blitmap->info.r = 0xFF;

     blitmap->info.g = 0xFF;

     blitmap->info.b = 0xFF;

     blitmap->info.a = 0xFF;

     surface->map = blitmap;

     /* The surface is ready to go */

     surface->refcount = 1;

     return SDL_TRUE;

 }

 /*

  * Copy a block of pixels of one format to another format

  */

 int SDL_ConvertPixels(int width, int height,

                       Uint32 src_format, const void * src, int src_pitch,

                       Uint32 dst_format, void * dst, int dst_pitch)

 {

     SDL_Surface src_surface, dst_surface;

     SDL_PixelFormat src_fmt, dst_fmt;

     SDL_BlitMap src_blitmap, dst_blitmap;

     SDL_Rect rect;

     /* Fast path for same format copy */

     if (src_format == dst_format) {

         int bpp;

         if (SDL_ISPIXELFORMAT_FOURCC(src_format)) {

             switch (src_format) {

             case SDL_PIXELFORMAT_YV12:

             case SDL_PIXELFORMAT_IYUV:

             case SDL_PIXELFORMAT_YUY2:

             case SDL_PIXELFORMAT_UYVY:

             case SDL_PIXELFORMAT_YVYU:

                 bpp = 2;

             default:

                 SDL_SetError("Unknown FOURCC pixel format");

                 return -1;

             }

         } else {

             bpp = SDL_BYTESPERPIXEL(src_format);

         }

         width *= bpp;

         while (height-- > 0) {

             SDL_memcpy(dst, src, width);

             src = (Uint8*)src + src_pitch;

             dst = (Uint8*)dst + dst_pitch;

         }

         return SDL_TRUE;

     }

     if (!SDL_CreateSurfaceOnStack(width, height, src_format, (void*)src,

                                   src_pitch,

                                   &src_surface, &src_fmt, &src_blitmap)) {

         return -1;

     }

     if (!SDL_CreateSurfaceOnStack(width, height, dst_format, dst, dst_pitch,

                                   &dst_surface, &dst_fmt, &dst_blitmap)) {

         return -1;

     }

     /* Set up the rect and go! */

     rect.x = 0;

     rect.y = 0;

     rect.w = width;

     rect.h = height;

     return SDL_LowerBlit(&src_surface, &rect, &dst_surface, &rect);

 }

 /*

  * Free a surface created by the above function.

  */

 void

 SDL_FreeSurface(SDL_Surface * surface)

 {

     if (surface == NULL) {

         return;

     }

     if (surface->flags & SDL_DONTFREE) {

         return;

     }

     if (--surface->refcount > 0) {

         return;

     }

     while (surface->locked > 0) {

         SDL_UnlockSurface(surface);

     }

     if (surface->flags & SDL_RLEACCEL) {

         SDL_UnRLESurface(surface, 0);

     }

     if (surface->format) {

         SDL_SetSurfacePalette(surface, NULL);

         SDL_FreeFormat(surface->format);

         surface->format = NULL;

     }

     if (surface->map != NULL) {

         SDL_FreeBlitMap(surface->map);

         surface->map = NULL;

     }

     if (surface->pixels && ((surface->flags & SDL_PREALLOC) != SDL_PREALLOC)) {

         SDL_free(surface->pixels);

     }

     SDL_free(surface);

 }

 /* vi: set ts=4 sw=4 expandtab: */