276 lines
6.6 KiB
C
276 lines
6.6 KiB
C
/*
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SDL_image: An example image loading library for use with SDL
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Copyright (C) 1997-2012 Sam Lantinga <slouken@libsdl.org>
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This software is provided 'as-is', without any express or implied
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warranty. In no event will the authors be held liable for any damages
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arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely, subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must not
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claim that you wrote the original software. If you use this software
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in a product, an acknowledgment in the product documentation would be
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appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and must not be
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misrepresented as being the original software.
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3. This notice may not be removed or altered from any source distribution.
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*/
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/*
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* PCX file reader:
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* Supports:
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* 1..4 bits/pixel in multiplanar format (1 bit/plane/pixel)
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* 8 bits/pixel in single-planar format (8 bits/plane/pixel)
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* 24 bits/pixel in 3-plane format (8 bits/plane/pixel)
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*
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* (The <8bpp formats are expanded to 8bpp surfaces)
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*
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* Doesn't support:
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* single-planar packed-pixel formats other than 8bpp
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* 4-plane 32bpp format with a fourth "intensity" plane
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*/
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#include <gint/gint.h>
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#include "SDL/SDL_endian.h"
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#include "SDL/SDL_image.h"
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#ifdef LOAD_PCX
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struct PCXheader {
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Uint8 Manufacturer;
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Uint8 Version;
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Uint8 Encoding;
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Uint8 BitsPerPixel;
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Sint16 Xmin, Ymin, Xmax, Ymax;
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Sint16 HDpi, VDpi;
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Uint8 Colormap[48];
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Uint8 Reserved;
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Uint8 NPlanes;
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Sint16 BytesPerLine;
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Sint16 PaletteInfo;
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Sint16 HscreenSize;
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Sint16 VscreenSize;
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Uint8 Filler[54];
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};
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/* See if an image is contained in a data source */
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int IMG_isPCX(SDL_RWops *src)
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{
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int start;
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int is_PCX;
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const int ZSoft_Manufacturer = 10;
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const int PC_Paintbrush_Version = 5;
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const int PCX_Uncompressed_Encoding = 0;
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const int PCX_RunLength_Encoding = 1;
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struct PCXheader pcxh;
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if ( !src )
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return 0;
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start = SDL_RWtell(src);
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is_PCX = 0;
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if ( SDL_RWread(src, &pcxh, sizeof(pcxh), 1) == 1 ) {
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if ( (pcxh.Manufacturer == ZSoft_Manufacturer) &&
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(pcxh.Version == PC_Paintbrush_Version) &&
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(pcxh.Encoding == PCX_RunLength_Encoding ||
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pcxh.Encoding == PCX_Uncompressed_Encoding) ) {
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is_PCX = 1;
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}
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}
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SDL_RWseek(src, start, RW_SEEK_SET);
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return(is_PCX);
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}
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/* Load a PCX type image from an SDL datasource */
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SDL_Surface *IMG_LoadPCX_RW(SDL_RWops *src)
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{
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int start;
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struct PCXheader pcxh;
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Uint32 Rmask;
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Uint32 Gmask;
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Uint32 Bmask;
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Uint32 Amask;
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SDL_Surface *surface = NULL;
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int width, height;
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int y, bpl;
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Uint8 *row, *buf = NULL;
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char *error = NULL;
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int bits, src_bits;
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if ( !src ) {
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/* The error message has been set in SDL_RWFromFile */
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return NULL;
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}
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start = SDL_RWtell(src);
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if ( ! SDL_RWread(src, &pcxh, sizeof(pcxh), 1) ) {
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error = "file truncated";
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goto done;
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}
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pcxh.Xmin = SDL_SwapLE16(pcxh.Xmin);
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pcxh.Ymin = SDL_SwapLE16(pcxh.Ymin);
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pcxh.Xmax = SDL_SwapLE16(pcxh.Xmax);
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pcxh.Ymax = SDL_SwapLE16(pcxh.Ymax);
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pcxh.BytesPerLine = SDL_SwapLE16(pcxh.BytesPerLine);
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/* Create the surface of the appropriate type */
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width = (pcxh.Xmax - pcxh.Xmin) + 1;
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height = (pcxh.Ymax - pcxh.Ymin) + 1;
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Rmask = Gmask = Bmask = Amask = 0;
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src_bits = pcxh.BitsPerPixel * pcxh.NPlanes;
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if((pcxh.BitsPerPixel == 1 && pcxh.NPlanes >= 1 && pcxh.NPlanes <= 4)
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|| (pcxh.BitsPerPixel == 8 && pcxh.NPlanes == 1)) {
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bits = 8;
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} else if(pcxh.BitsPerPixel == 8 && pcxh.NPlanes == 3) {
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bits = 24;
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if ( SDL_BYTEORDER == SDL_LIL_ENDIAN ) {
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Rmask = 0x000000FF;
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Gmask = 0x0000FF00;
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Bmask = 0x00FF0000;
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} else {
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Rmask = 0xFF0000;
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Gmask = 0x00FF00;
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Bmask = 0x0000FF;
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}
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} else {
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error = "unsupported PCX format";
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goto done;
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}
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surface = SDL_AllocSurface(SDL_SWSURFACE, width, height,
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bits, Rmask, Gmask, Bmask, Amask);
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if ( surface == NULL )
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goto done;
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bpl = pcxh.NPlanes * pcxh.BytesPerLine;
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if (bpl > surface->pitch) {
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error = "bytes per line is too large (corrupt?)";
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}
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buf = malloc(bpl);
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row = surface->pixels;
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for ( y=0; y<surface->h; ++y ) {
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/* decode a scan line to a temporary buffer first */
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int i, count = 0;
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Uint8 ch;
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Uint8 *dst = (src_bits == 8) ? row : buf;
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if ( pcxh.Encoding == 0 ) {
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if(!SDL_RWread(src, dst, bpl, 1)) {
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error = "file truncated";
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goto done;
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}
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} else {
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for(i = 0; i < bpl; i++) {
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if(!count) {
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if(!SDL_RWread(src, &ch, 1, 1)) {
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error = "file truncated";
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goto done;
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}
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if( (ch & 0xc0) == 0xc0) {
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count = ch & 0x3f;
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if(!SDL_RWread(src, &ch, 1, 1)) {
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error = "file truncated";
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goto done;
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}
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} else
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count = 1;
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}
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dst[i] = ch;
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count--;
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}
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}
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if(src_bits <= 4) {
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/* expand planes to 1 byte/pixel */
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Uint8 *src = buf;
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int plane;
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for(plane = 0; plane < pcxh.NPlanes; plane++) {
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int i, j, x = 0;
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for(i = 0; i < pcxh.BytesPerLine; i++) {
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Uint8 byte = *src++;
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for(j = 7; j >= 0; j--) {
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unsigned bit = (byte >> j) & 1;
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/* skip padding bits */
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if (i * 8 + j >= width)
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continue;
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row[x++] |= bit << plane;
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}
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}
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}
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} else if(src_bits == 24) {
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/* de-interlace planes */
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Uint8 *src = buf;
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int plane;
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for(plane = 0; plane < pcxh.NPlanes; plane++) {
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int x;
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dst = row + plane;
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for(x = 0; x < width; x++) {
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*dst = *src++;
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dst += pcxh.NPlanes;
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}
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}
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}
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row += surface->pitch;
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}
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if(bits == 8) {
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SDL_Color *colors = surface->format->palette->colors;
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int nc = 1 << src_bits;
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int i;
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surface->format->palette->ncolors = nc;
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if(src_bits == 8) {
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Uint8 ch;
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/* look for a 256-colour palette */
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do {
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if ( !SDL_RWread(src, &ch, 1, 1)) {
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error = "file truncated";
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goto done;
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}
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} while ( ch != 12 );
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for(i = 0; i < 256; i++) {
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SDL_RWread(src, &colors[i].r, 1, 1);
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SDL_RWread(src, &colors[i].g, 1, 1);
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SDL_RWread(src, &colors[i].b, 1, 1);
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}
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} else {
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for(i = 0; i < nc; i++) {
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colors[i].r = pcxh.Colormap[i * 3];
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colors[i].g = pcxh.Colormap[i * 3 + 1];
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colors[i].b = pcxh.Colormap[i * 3 + 2];
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}
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}
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}
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done:
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free(buf);
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if ( error ) {
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SDL_RWseek(src, start, RW_SEEK_SET);
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if ( surface ) {
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SDL_FreeSurface(surface);
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surface = NULL;
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}
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IMG_SetError(error);
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}
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return(surface);
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}
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#else
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/* See if an image is contained in a data source */
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int IMG_isPCX(SDL_RWops *src)
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{
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return(0);
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}
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/* Load a PCX type image from an SDL datasource */
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SDL_Surface *IMG_LoadPCX_RW(SDL_RWops *src)
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{
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return(NULL);
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}
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#endif /* LOAD_PCX */
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