include/SDL_assert.h
changeset 3647 c5925cd41955
child 3649 1e74d7984d0b
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/include/SDL_assert.h	Wed Jan 13 06:47:17 2010 +0000
@@ -0,0 +1,151 @@
+/*
+    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"
+
+/* This is an assert macro for SDL's internal use. Not for the public API! */
+
+#ifndef _SDL_assert_h
+#define _SDL_assert_h
+
+#ifndef SDL_ASSERT_LEVEL
+#error SDL_ASSERT_LEVEL is not defined. Please fix your SDL_config.h.
+#endif
+
+/*
+sizeof (x) makes the compiler still parse the expression even without
+assertions enabled, so the code is always checked at compile time, but
+doesn't actually generate code for it, so there are no side effects or
+expensive checks at run time, just the constant size of what x WOULD be,
+which presumably gets optimized out as unused.
+This also solves the problem of...
+
+    int somevalue = blah();
+    SDL_assert(somevalue == 1);
+
+...which would cause compiles to complain that somevalue is unused if we
+disable assertions.
+*/
+
+#define SDL_disabled_assert(condition) \
+    do { (void) sizeof ((condition)); } while (0)
+
+#if (SDL_ASSERT_LEVEL > 0)
+
+/*
+These are macros and not first class functions so that the debugger breaks
+on the assertion line and not in some random guts of SDL, and so each
+macro can have unique static variables associated with it.
+*/
+
+#if (defined(_MSC_VER) && ((_M_IX86) || (_M_X64)))
+    #define SDL_TriggerBreakpoint() __asm { int 3 }
+#elif (defined(__GNUC__) && ((__i386__) || (__x86_64__)))
+    #define SDL_TriggerBreakpoint() __asm__ __volatile__ ( "int $3\n\t" )
+#elif defined(unix)
+    #include <signal.h>
+    #define SDL_TriggerBreakpoint() raise(SIGTRAP)
+#else
+    #error Please define your platform or set SDL_ASSERT_LEVEL to 0.
+#endif
+
+#if (__STDC_VERSION__ >= 199901L) /* C99 supports __func__ as a standard. */
+#   define SDL_FUNCTION __func__
+#elif ((__GNUC__ >= 2) || defined(_MSC_VER))
+#   define SDL_FUNCTION __FUNCTION__
+#else
+#   define SDL_FUNCTION "???"
+#endif
+
+typedef enum
+{
+    SDL_ASSERTION_RETRY,  /**< Retry the assert immediately. */
+    SDL_ASSERTION_BREAK,  /**< Make the debugger trigger a breakpoint. */
+    SDL_ASSERTION_ABORT,  /**< Terminate the program. */
+    SDL_ASSERTION_IGNORE,  /**< Ignore the assert. */
+    SDL_ASSERTION_ALWAYS_IGNORE,  /**< Ignore the assert from now on. */
+} SDL_assert_state;
+
+typedef struct SDL_assert_data
+{
+    int always_ignore;
+    unsigned int trigger_count;
+    const char *condition;
+    const char *filename;
+    int linenum;
+    const char *function;
+    struct SDL_assert_data *next;
+} SDL_assert_data;
+
+SDL_assert_state SDL_ReportAssertion(SDL_assert_data *, const char *, int);
+
+/* the do {} while(0) avoids dangling else problems:
+    if (x) SDL_assert(y); else blah();
+       ... without the do/while, the "else" could attach to this macro's "if".
+   We try to handle just the minimum we need here in a macro...the loop,
+   the static vars, and break points. The heavy lifting is handled in
+   SDL_ReportAssertion(), in SDL_assert.c.
+*/
+#define SDL_enabled_assert(condition) \
+    do { \
+        while ( !(condition) ) { \
+			static struct SDL_assert_data assert_data = { \
+                0, 0, #condition, __FILE__, 0, 0, 0 \
+            }; \
+			const SDL_assert_state state = SDL_ReportAssertion(&assert_data, \
+                                                               SDL_FUNCTION, \
+															   __LINE__); \
+            if (state == SDL_ASSERTION_RETRY) { \
+                continue; /* go again. */ \
+            } else if (state == SDL_ASSERTION_BREAK) { \
+                SDL_TriggerBreakpoint(); \
+            } \
+            break; /* not retrying. */ \
+        } \
+    } while (0)
+
+#endif  /* enabled assertions support code */
+
+/* Enable various levels of assertions. */
+#if SDL_ASSERT_LEVEL == 0   /* assertions disabled */
+#   define SDL_assert(condition) SDL_disabled_assert(condition)
+#   define SDL_assert_release(condition) SDL_disabled_assert(condition)
+#   define SDL_assert_paranoid(condition) SDL_disabled_assert(condition)
+#elif SDL_ASSERT_LEVEL == 1  /* release settings. */
+#   define SDL_assert(condition) SDL_enabled_assert(condition)
+#   define SDL_assert_release(condition) SDL_enabled_assert(condition)
+#   define SDL_assert_paranoid(condition) SDL_enabled_assert(condition)
+#elif SDL_ASSERT_LEVEL == 2  /* normal settings. */
+#   define SDL_assert(condition) SDL_enabled_assert(condition)
+#   define SDL_assert_release(condition) SDL_enabled_assert(condition)
+#   define SDL_assert_paranoid(condition) SDL_disabled_assert(condition)
+#elif SDL_ASSERT_LEVEL == 3  /* paranoid settings. */
+#   define SDL_assert(condition) SDL_enabled_assert(condition)
+#   define SDL_assert_release(condition) SDL_enabled_assert(condition)
+#   define SDL_assert_paranoid(condition) SDL_enabled_assert(condition)
+#else
+#   error Unknown assertion level. Please fix your SDL_config.h.
+#endif
+
+#endif /* _SDL_assert_h */
+
+/* vi: set ts=4 sw=4 expandtab: */
+