view test/testwin.c @ 4158:96ce26f24b01 SDL-1.2

Date: Sun, 7 Sep 2008 15:17:00 +0200 From: c2woody@gmx.net Subject: [SDL] SDL 1.2 doube free/pointer zeroing missing Hello, this is about a crash/debug breakage for the current SDL 1.2 source tree (today's svn checkout, same problem in 1.2.13 and before as far as relevant). In some places memory is free()d but the associated pointer is not zeroed, leading to for example double free()s. For me this happened because SDL_StopEventThread() was executed twice (during restart of the subsystems), once for the close down in SDL_VideoQuit() and once at the startup, right at the beginning of SDL_StartEventLoop(). Thus the code SDL_DestroyMutex(SDL_EventQ.lock); (see SDL_events.c) was called twice and executed the SDL_free(mutex); twice as well, leading to a crash (msvc 64bit for which it was noticed). I've tried to check all other occurrences of SDL_free and similar code in msvc, see the attached patch (udiff against revision 4082). Non-windows only codepaths have neither been checked nor touched. Comments/ideas welcome. Attached patch: NULLifies some pointers after they have been free()d.
author Sam Lantinga <slouken@libsdl.org>
date Wed, 12 Nov 2008 17:23:40 +0000
parents 9776ab9063de
children
line wrap: on
line source


/* Bring up a window and play with it */

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

#define BENCHMARK_SDL

#define NOTICE(X)	printf("%s", X);

#include "SDL.h"

/* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */
static void quit(int rc)
{
	SDL_Quit();
	exit(rc);
}

void DrawPict(SDL_Surface *screen, char *bmpfile,
					int speedy, int flip, int nofade)
{
	SDL_Surface *picture;
	SDL_Rect dest, update;
	int i, centered;
	int ncolors;
	SDL_Color *colors, *cmap;

	/* Load the image into a surface */
	if ( bmpfile == NULL ) {
		bmpfile = "sample.bmp";		/* Sample image */
	}
fprintf(stderr, "Loading picture: %s\n", bmpfile);
	picture = SDL_LoadBMP(bmpfile);
	if ( picture == NULL ) {
		fprintf(stderr, "Couldn't load %s: %s\n", bmpfile,
							SDL_GetError());
		return;
	}

	/* Set the display colors -- on a hicolor display this is a no-op */
	if ( picture->format->palette ) {
		ncolors = picture->format->palette->ncolors;
		colors  = (SDL_Color *)malloc(ncolors*sizeof(SDL_Color));
		cmap    = (SDL_Color *)malloc(ncolors*sizeof(SDL_Color));
		memcpy(colors, picture->format->palette->colors,
						ncolors*sizeof(SDL_Color));
	} else {
		int       r, g, b;

		/* Allocate 256 color palette */
		ncolors = 256;
		colors  = (SDL_Color *)malloc(ncolors*sizeof(SDL_Color));
		cmap    = (SDL_Color *)malloc(ncolors*sizeof(SDL_Color));

		/* Set a 3,3,2 color cube */
		for ( r=0; r<8; ++r ) {
			for ( g=0; g<8; ++g ) {
				for ( b=0; b<4; ++b ) {
					i = ((r<<5)|(g<<2)|b);
					colors[i].r = r<<5;
					colors[i].g = g<<5;
					colors[i].b = b<<6;
				}
			}
		}
	}
NOTICE("testwin: setting colors\n");
	if ( ! SDL_SetColors(screen, colors, 0, ncolors) &&
				(screen->format->palette != NULL) ) {
		fprintf(stderr,
"Warning: Couldn't set all of the colors, but SDL will map the image\n"
"         (colormap fading will suffer - try the -warp option)\n"
		);
	}

	/* Set the screen to black (not really necessary) */
	if ( SDL_LockSurface(screen) == 0 ) {
		Uint32 black;
		Uint8 *pixels;

		black = SDL_MapRGB(screen->format, 0, 0, 0);
		pixels = (Uint8 *)screen->pixels;
		for ( i=0; i<screen->h; ++i ) {
			memset(pixels, black,
				screen->w*screen->format->BytesPerPixel);
			pixels += screen->pitch;
		}
		SDL_UnlockSurface(screen);
		SDL_UpdateRect(screen, 0, 0, 0, 0);
	}
	
	/* Display the picture */
	if ( speedy ) {
		SDL_Surface *displayfmt;

fprintf(stderr, "Converting picture\n");
		displayfmt = SDL_DisplayFormat(picture);
		if ( displayfmt == NULL ) {
			fprintf(stderr,
				"Couldn't convert image: %s\n", SDL_GetError());
			goto done;
		}
		SDL_FreeSurface(picture);
		picture = displayfmt;
	}
	printf("(image surface located in %s memory)\n", 
			(picture->flags&SDL_HWSURFACE) ? "video" : "system");
	centered = (screen->w - picture->w)/2;
	if ( centered < 0 ) {
		centered = 0;
	}
	dest.y = (screen->h - picture->h)/2;
	dest.w = picture->w;
	dest.h = picture->h;
NOTICE("testwin: moving image\n");
	for ( i=0; i<=centered; ++i ) {
		dest.x = i;
		update = dest;
		if ( SDL_BlitSurface(picture, NULL, screen, &update) < 0 ) {
			fprintf(stderr, "Blit failed: %s\n", SDL_GetError());
			break;
		}
		if ( flip ) {
			SDL_Flip(screen);
		} else {
			SDL_UpdateRects(screen, 1, &update);
		}
	}

#ifdef SCREENSHOT
	if ( SDL_SaveBMP(screen, "screen.bmp") < 0 )
		printf("Couldn't save screen: %s\n", SDL_GetError());
#endif

#ifndef BENCHMARK_SDL
	/* Let it sit there for a while */
	SDL_Delay(5*1000);
#endif
	/* Fade the colormap */
	if ( ! nofade ) {
		int maxstep;
		SDL_Color final;
		SDL_Color palcolors[256];
		struct {
			Sint16 r, g, b;
		} cdist[256];

NOTICE("testwin: fading out...\n");
		memcpy(cmap, colors, ncolors*sizeof(SDL_Color));
		maxstep = 32-1;
		final.r = 0xFF;
		final.g = 0x00;
		final.b = 0x00;
		memcpy(palcolors, colors, ncolors*sizeof(SDL_Color));
		for ( i=0; i<ncolors; ++i ) {
			cdist[i].r = final.r-palcolors[i].r;
			cdist[i].g = final.g-palcolors[i].g;
			cdist[i].b = final.b-palcolors[i].b;
		}
		for ( i=0; i<=maxstep/2; ++i ) {	/* halfway fade */
			int c;
			for ( c=0; c<ncolors; ++c ) {
				colors[c].r =
					palcolors[c].r+((cdist[c].r*i))/maxstep;
				colors[c].g =
					palcolors[c].g+((cdist[c].g*i))/maxstep;
				colors[c].b =
					palcolors[c].b+((cdist[c].b*i))/maxstep;
			}
			SDL_SetColors(screen, colors, 0, ncolors);
			SDL_Delay(1);
		}
		final.r = 0x00;
		final.g = 0x00;
		final.b = 0x00;
		memcpy(palcolors, colors, ncolors*sizeof(SDL_Color));
		for ( i=0; i<ncolors; ++i ) {
			cdist[i].r = final.r-palcolors[i].r;
			cdist[i].g = final.g-palcolors[i].g;
			cdist[i].b = final.b-palcolors[i].b;
		}
		maxstep /= 2;
		for ( i=0; i<=maxstep; ++i ) {		/* finish fade out */
			int c;
			for ( c=0; c<ncolors; ++c ) {
				colors[c].r =
					palcolors[c].r+((cdist[c].r*i))/maxstep;
				colors[c].g =
					palcolors[c].g+((cdist[c].g*i))/maxstep;
				colors[c].b =
					palcolors[c].b+((cdist[c].b*i))/maxstep;
			}
			SDL_SetColors(screen, colors, 0, ncolors);
			SDL_Delay(1);
		}
		for ( i=0; i<ncolors; ++i ) {
			colors[i].r = final.r;
			colors[i].g = final.g;
			colors[i].b = final.b;
		}
		SDL_SetColors(screen, colors, 0, ncolors);
NOTICE("testwin: fading in...\n");
		memcpy(palcolors, colors, ncolors*sizeof(SDL_Color));
		for ( i=0; i<ncolors; ++i ) {
			cdist[i].r = cmap[i].r-palcolors[i].r;
			cdist[i].g = cmap[i].g-palcolors[i].g;
			cdist[i].b = cmap[i].b-palcolors[i].b;
		}
		for ( i=0; i<=maxstep; ++i ) {	/* 32 step fade in */
			int c;
			for ( c=0; c<ncolors; ++c ) {
				colors[c].r =
					palcolors[c].r+((cdist[c].r*i))/maxstep;
				colors[c].g =
					palcolors[c].g+((cdist[c].g*i))/maxstep;
				colors[c].b =
					palcolors[c].b+((cdist[c].b*i))/maxstep;
			}
			SDL_SetColors(screen, colors, 0, ncolors);
			SDL_Delay(1);
		}
NOTICE("testwin: fading over\n");
	}
	
done:
	/* Free the picture and return */
	SDL_FreeSurface(picture);
	free(colors); free(cmap);
	return;
}

int main(int argc, char *argv[])
{
	SDL_Surface *screen;
	/* Options */
	int speedy, flip, nofade;
	int delay;
	int w, h;
	int desired_bpp;
	Uint32 video_flags;
#ifdef BENCHMARK_SDL
	Uint32 then, now;
#endif
	/* Set default options and check command-line */
	speedy = 0;
	flip = 0;
	nofade = 0;
	delay = 1;

#ifdef _WIN32_WCE
	w = 240;
	h = 320;
	desired_bpp = 8;
	video_flags = SDL_FULLSCREEN;
#else
	w = 640;
	h = 480;
	desired_bpp = 0;
	video_flags = 0;
#endif
	if ( SDL_Init(SDL_INIT_VIDEO) < 0 ) {
		fprintf(stderr,
			"Couldn't initialize SDL: %s\n", SDL_GetError());
		return(1);
	}

	while ( argc > 1 ) {
		if ( strcmp(argv[1], "-speedy") == 0 ) {
			speedy = 1;
			argv += 1;
			argc -= 1;
		} else
		if ( strcmp(argv[1], "-nofade") == 0 ) {
			nofade = 1;
			argv += 1;
			argc -= 1;
		} else
		if ( strcmp(argv[1], "-delay") == 0 ) {
			if ( argv[2] ) {
				delay = atoi(argv[2]);
				argv += 2;
				argc -= 2;
			} else {
				fprintf(stderr,
				"The -delay option requires an argument\n");
				quit(1);
			}
		} else
		if ( strcmp(argv[1], "-width") == 0 ) {
			if ( argv[2] && ((w = atoi(argv[2])) > 0) ) {
				argv += 2;
				argc -= 2;
			} else {
				fprintf(stderr,
				"The -width option requires an argument\n");
				quit(1);
			}
		} else
		if ( strcmp(argv[1], "-height") == 0 ) {
			if ( argv[2] && ((h = atoi(argv[2])) > 0) ) {
				argv += 2;
				argc -= 2;
			} else {
				fprintf(stderr,
				"The -height option requires an argument\n");
				quit(1);
			}
		} else
		if ( strcmp(argv[1], "-bpp") == 0 ) {
			if ( argv[2] ) {
				desired_bpp = atoi(argv[2]);
				argv += 2;
				argc -= 2;
			} else {
				fprintf(stderr,
				"The -bpp option requires an argument\n");
				quit(1);
			}
		} else
		if ( strcmp(argv[1], "-warp") == 0 ) {
			video_flags |= SDL_HWPALETTE;
			argv += 1;
			argc -= 1;
		} else
		if ( strcmp(argv[1], "-hw") == 0 ) {
			video_flags |= SDL_HWSURFACE;
			argv += 1;
			argc -= 1;
		} else
		if ( strcmp(argv[1], "-flip") == 0 ) {
			video_flags |= SDL_DOUBLEBUF;
			argv += 1;
			argc -= 1;
		} else
		if ( strcmp(argv[1], "-fullscreen") == 0 ) {
			video_flags |= SDL_FULLSCREEN;
			argv += 1;
			argc -= 1;
		} else
			break;
	}

	/* Initialize the display */
	screen = SDL_SetVideoMode(w, h, desired_bpp, video_flags);
	if ( screen == NULL ) {
		fprintf(stderr, "Couldn't set %dx%dx%d video mode: %s\n",
					w, h, desired_bpp, SDL_GetError());
		quit(1);
	}
	printf("Set%s %dx%dx%d mode\n",
			screen->flags & SDL_FULLSCREEN ? " fullscreen" : "",
			screen->w, screen->h, screen->format->BitsPerPixel);
	printf("(video surface located in %s memory)\n",
			(screen->flags&SDL_HWSURFACE) ? "video" : "system");
	if ( screen->flags & SDL_DOUBLEBUF ) {
		printf("Double-buffering enabled\n");
		flip = 1;
	}

	/* Set the window manager title bar */
	SDL_WM_SetCaption("SDL test window", "testwin");

	/* Do all the drawing work */
#ifdef BENCHMARK_SDL
	then = SDL_GetTicks();
	DrawPict(screen, argv[1], speedy, flip, nofade);
	now = SDL_GetTicks();
	printf("Time: %d milliseconds\n", now-then);
#else
	DrawPict(screen, argv[1], speedy, flip, nofade);
#endif
	SDL_Delay(delay*1000);
	SDL_Quit();
	return(0);
}