SDL_error.c

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2009 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"

/* Simple error handling in SDL */

#include "SDL_error.h"
#include "SDL_error_c.h"

/* Routine to get the thread-specific error variable */
#if SDL_THREADS_DISABLED
/* The  SDL_arraysize(The ),default (non-thread-safe) global error variable */
static SDL_error SDL_global_error;
#define SDL_GetErrBuf()	(&SDL_global_error)
#else
extern SDL_error *SDL_GetErrBuf(void);
#endif /* SDL_THREADS_DISABLED */

#define SDL_ERRBUFIZE	1024

/* Private functions */

static const char *SDL_LookupString(const char *key)
{
	/* FIXME: Add code to lookup key in language string hash-table */
	return key;
}

/* Public functions */

void SDL_SetError (const char *fmt, ...)
{
	va_list ap;
	SDL_error *error;

	/* Copy in the key, mark error as valid */
	error = SDL_GetErrBuf();
	error->error = 1;
	SDL_strlcpy((char *)error->key, fmt, sizeof(error->key));

	va_start(ap, fmt);
	error->argc = 0;
	while ( *fmt ) {
		if ( *fmt++ == '%' ) {
			while ( *fmt == '.' || (*fmt >= '0' && *fmt <= '9') ) {
				++fmt;
			}
			switch (*fmt++) {
			    case 0:  /* Malformed format string.. */
				--fmt;
				break;
			    case 'c':
			    case 'i':
			    case 'd':
			    case 'u':
			    case 'o':
			    case 'x':
			    case 'X':
				error->args[error->argc++].value_i =
							va_arg(ap, int);
				break;
			    case 'f':
				error->args[error->argc++].value_f =
							va_arg(ap, double);
				break;
			    case 'p':
				error->args[error->argc++].value_ptr =
							va_arg(ap, void *);
				break;
			    case 's':
				{
				  int i = error->argc;
				  const char *str = va_arg(ap, const char *);
				  if (str == NULL)
				      str = "(null)";
				  SDL_strlcpy((char *)error->args[i].buf, str, ERR_MAX_STRLEN);
				  error->argc++;
				}
				break;
			    default:
				break;
			}
			if ( error->argc >= ERR_MAX_ARGS ) {
				break;
			}
		}
	}
	va_end(ap);

	/* If we are in debug mode, print out an error message */
#ifdef DEBUG_ERROR
	fprintf(stderr, "SDL_SetError: %s\n", SDL_GetError());
#endif
}

/* This function has a bit more overhead than most error functions
   so that it supports internationalization and thread-safe errors.
*/
char *SDL_GetErrorMsg(char *errstr, unsigned int maxlen)
{
	SDL_error *error;

	/* Clear the error string */
	*errstr = '\0'; --maxlen;

	/* Get the thread-safe error, and print it out */
	error = SDL_GetErrBuf();
	if ( error->error ) {
		const char *fmt;
		char *msg = errstr;
		int len;
		int argi;

		fmt = SDL_LookupString(error->key);
		argi = 0;
		while ( *fmt && (maxlen > 0) ) {
			if ( *fmt == '%' ) {
				char tmp[32], *spot = tmp;
				*spot++ = *fmt++;
				while ( (*fmt == '.' || (*fmt >= '0' && *fmt <= '9')) && spot < (tmp+SDL_arraysize(tmp)-2) ) {
					*spot++ = *fmt++;
				}
				*spot++ = *fmt++;
				*spot++ = '\0';
				switch (spot[-2]) {
				    case '%':
					*msg++ = '%';
					maxlen -= 1;
					break;
				    case 'c':
				    case 'i':
			            case 'd':
			            case 'u':
			            case 'o':
				    case 'x':
				    case 'X':
					len = SDL_snprintf(msg, maxlen, tmp, error->args[argi++].value_i);
					msg += len;
					maxlen -= len;
					break;
				    case 'f':
					len = SDL_snprintf(msg, maxlen, tmp, error->args[argi++].value_f);
					msg += len;
					maxlen -= len;
					break;
				    case 'p':
					len = SDL_snprintf(msg, maxlen, tmp, error->args[argi++].value_ptr);
					msg += len;
					maxlen -= len;
					break;
				    case 's':
					len = SDL_snprintf(msg, maxlen, tmp, SDL_LookupString(error->args[argi++].buf));
					msg += len;
					maxlen -= len;
					break;
				}
			} else {
				*msg++ = *fmt++;
				maxlen -= 1;
			}
		}
		*msg = 0;	/* NULL terminate the string */
	}
	return(errstr);
}

/* Available for backwards compatibility */
char *SDL_GetError (void)
{
	static char errmsg[SDL_ERRBUFIZE];

	return((char *)SDL_GetErrorMsg(errmsg, SDL_ERRBUFIZE));
}

void SDL_ClearError(void)
{
	SDL_error *error;

	error = SDL_GetErrBuf();
	error->error = 0;
}

/* Very common errors go here */
void SDL_Error(SDL_errorcode code)
{
	switch (code) {
		case SDL_ENOMEM:
			SDL_SetError("Out of memory");
			break;
		case SDL_EFREAD:
			SDL_SetError("Error reading from datastream");
			break;
		case SDL_EFWRITE:
			SDL_SetError("Error writing to datastream");
			break;
		case SDL_EFSEEK:
			SDL_SetError("Error seeking in datastream");
			break;
		default:
			SDL_SetError("Unknown SDL error");
			break;
	}
}

#ifdef TEST_ERROR
int main(int argc, char *argv[])
{
	char buffer[BUFSIZ+1];

	SDL_SetError("Hi there!");
	printf("Error 1: %s\n", SDL_GetError());
	SDL_ClearError();
	SDL_memset(buffer, '1', BUFSIZ);
	buffer[BUFSIZ] = 0;
	SDL_SetError("This is the error: %s (%f)", buffer, 1.0);
	printf("Error 2: %s\n", SDL_GetError());
	exit(0);
}
#endif