imports.c

Mesa is an open-source implementation of the OpenGL specification - a system for rendering interacti

/**
 * Find the first bit set in a word.
 */
int
_mesa_ffs(int i)
{
#if (defined(_WIN32) ) || defined(__IBMC__) || defined(__IBMCPP__)
   register int bit = 0;
   if (i != 0) {
      if ((i & 0xffff) == 0) {
         bit += 16;
         i >>= 16;
      }
      if ((i & 0xff) == 0) {
         bit += 8;
         i >>= 8;
      }
      if ((i & 0xf) == 0) {
         bit += 4;
         i >>= 4;
      }
      while ((i & 1) == 0) {
         bit++;
         i >>= 1;
      }
      bit++;
   }
   return bit;
#else
   return ffs(i);
#endif
}


/**
 * Find position of first bit set in given value.
 * XXX Warning: this function can only be used on 64-bit systems!
 * \return  position of least-significant bit set, starting at 1, return zero
 *          if no bits set.
 */
int
#ifdef __MINGW32__
_mesa_ffsll(long val)
#else
_mesa_ffsll(long long val)
#endif
{
#ifdef ffsll
   return ffsll(val);
#else
   int bit;

   assert(sizeof(val) == 8);

   bit = _mesa_ffs(val);
   if (bit != 0)
      return bit;

   bit = _mesa_ffs(val >> 32);
   if (bit != 0)
      return 32 + bit;

   return 0;
#endif
}


/**
 * Return number of bits set in given GLuint.
 */
unsigned int
_mesa_bitcount(unsigned int n)
{
   unsigned int bits;
   for (bits = 0; n > 0; n = n >> 1) {
      bits += (n & 1);
   }
   return bits;
}


/**
 * Convert a 4-byte float to a 2-byte half float.
 * Based on code from:
 * http://www.opengl.org/discussion_boards/ubb/Forum3/HTML/008786.html
 */
GLhalfARB
_mesa_float_to_half(float val)
{
   const int flt = *((int *) (void *) &val);
   const int flt_m = flt & 0x7fffff;
   const int flt_e = (flt >> 23) & 0xff;
   const int flt_s = (flt >> 31) & 0x1;
   int s, e, m = 0;
   GLhalfARB result;
   
   /* sign bit */
   s = flt_s;

   /* handle special cases */
   if ((flt_e == 0) && (flt_m == 0)) {
      /* zero */
      /* m = 0; - already set */
      e = 0;
   }
   else if ((flt_e == 0) && (flt_m != 0)) {
      /* denorm -- denorm float maps to 0 half */
      /* m = 0; - already set */
      e = 0;
   }
   else if ((flt_e == 0xff) && (flt_m == 0)) {
      /* infinity */
      /* m = 0; - already set */
      e = 31;
   }
   else if ((flt_e == 0xff) && (flt_m != 0)) {
      /* NaN */
      m = 1;
      e = 31;
   }
   else {
      /* regular number */
      const int new_exp = flt_e - 127;
      if (new_exp < -24) {
         /* this maps to 0 */
         /* m = 0; - already set */
         e = 0;
      }
      else if (new_exp < -14) {
         /* this maps to a denorm */
         unsigned int exp_val = (unsigned int) (-14 - new_exp); /* 2^-exp_val*/
         e = 0;
         switch (exp_val) {
            case 0:
               _mesa_warning(NULL,
                   "float_to_half: logical error in denorm creation!\n");
               /* m = 0; - already set */
               break;
            case 1: m = 512 + (flt_m >> 14); break;
            case 2: m = 256 + (flt_m >> 15); break;
            case 3: m = 128 + (flt_m >> 16); break;
            case 4: m = 64 + (flt_m >> 17); break;
            case 5: m = 32 + (flt_m >> 18); break;
            case 6: m = 16 + (flt_m >> 19); break;
            case 7: m = 8 + (flt_m >> 20); break;
            case 8: m = 4 + (flt_m >> 21); break;
            case 9: m = 2 + (flt_m >> 22); break;
            case 10: m = 1; break;
         }
      }
      else if (new_exp > 15) {
         /* map this value to infinity */
         /* m = 0; - already set */
         e = 31;
      }
      else {
         /* regular */
         e = new_exp + 15;
         m = flt_m >> 13;
      }
   }

   result = (s << 15) | (e << 10) | m;
   return result;
}


/**
 * Convert a 2-byte half float to a 4-byte float.
 * Based on code from:
 * http://www.opengl.org/discussion_boards/ubb/Forum3/HTML/008786.html
 */
float
_mesa_half_to_float(GLhalfARB val)
{
   /* XXX could also use a 64K-entry lookup table */
   const int m = val & 0x3ff;
   const int e = (val >> 10) & 0x1f;
   const int s = (val >> 15) & 0x1;
   int flt_m, flt_e, flt_s, flt;
   float result;

   /* sign bit */
   flt_s = s;

   /* handle special cases */
   if ((e == 0) && (m == 0)) {
      /* zero */
      flt_m = 0;
      flt_e = 0;
   }
   else if ((e == 0) && (m != 0)) {
      /* denorm -- denorm half will fit in non-denorm single */
      const float half_denorm = 1.0f / 16384.0f; /* 2^-14 */
      float mantissa = ((float) (m)) / 1024.0f;
      float sign = s ? -1.0f : 1.0f;
      return sign * mantissa * half_denorm;
   }
   else if ((e == 31) && (m == 0)) {
      /* infinity */
      flt_e = 0xff;
      flt_m = 0;
   }
   else if ((e == 31) && (m != 0)) {
      /* NaN */
      flt_e = 0xff;
      flt_m = 1;
   }
   else {
      /* regular */
      flt_e = e + 112;
      flt_m = m << 13;
   }

   flt = (flt_s << 31) | (flt_e << 23) | flt_m;
   result = *((float *) (void *) &flt);
   return result;
}

/*@}*/


/**********************************************************************/
/** \name Sort & Search */
/*@{*/

/**
 * Wrapper for bsearch().
 */
void *
_mesa_bsearch( const void *key, const void *base, size_t nmemb, size_t size, 
               int (*compar)(const void *, const void *) )
{
   return bsearch(key, base, nmemb, size, compar);
}

/*@}*/


/**********************************************************************/
/** \name Environment vars */
/*@{*/

/**
 * Wrapper for getenv().
 */
char *
_mesa_getenv( const char *var )
{
#if defined(_XBOX)
   return NULL;
#else
   return getenv(var);
#endif
}

/*@}*/


/**********************************************************************/
/** \name String */
/*@{*/

/** Wrapper around strstr() */
char *
_mesa_strstr( const char *haystack, const char *needle )
{
   return strstr(haystack, needle);
}

/** Wrapper around strncat() */
char *
_mesa_strncat( char *dest, const char *src, size_t n )
{
   return strncat(dest, src, n);
}

/** Wrapper around strcpy() */
char *
_mesa_strcpy( char *dest, const char *src )
{
   return strcpy(dest, src);
}

/** Wrapper around strncpy() */
char *
_mesa_strncpy( char *dest, const char *src, size_t n )
{
   return strncpy(dest, src, n);
}

/** Wrapper around strlen() */
size_t
_mesa_strlen( const char *s )
{
   return strlen(s);
}

/** Wrapper around strcmp() */
int
_mesa_strcmp( const char *s1, const char *s2 )
{
   return strcmp(s1, s2);
}

/** Wrapper around strncmp() */
int
_mesa_strncmp( const char *s1, const char *s2, size_t n )
{
   return strncmp(s1, s2, n);
}

/**
 * Implemented using _mesa_malloc() and _mesa_strcpy.
 * Note that NULL is handled accordingly.
 */
char *
_mesa_strdup( const char *s )
{
   if (s) {
      size_t l = _mesa_strlen(s);
      char *s2 = (char *) _mesa_malloc(l + 1);
      if (s2)
         _mesa_strcpy(s2, s);
      return s2;
   }
   else {
      return NULL;
   }
}

/** Wrapper around atoi() */
int
_mesa_atoi(const char *s)
{
   return atoi(s);
}

/** Wrapper around strtod() */
double
_mesa_strtod( const char *s, char **end )
{
   return strtod(s, end);
}

/*@}*/


/**********************************************************************/
/** \name I/O */
/*@{*/

/** Wrapper around vsprintf() */
int
_mesa_sprintf( char *str, const char *fmt, ... )
{
   int r;
   va_list args;
   va_start( args, fmt );  
   r = vsprintf( str, fmt, args );
   va_end( args );
   return r;
}

/** Wrapper around printf(), using vsprintf() for the formatting. */
void
_mesa_printf( const char *fmtString, ... )
{
   char s[MAXSTRING];
   va_list args;
   va_start( args, fmtString );  
   vsnprintf(s, MAXSTRING, fmtString, args);
   va_end( args );
   fprintf(stderr,"%s", s);
}

/** Wrapper around vsprintf() */
int
_mesa_vsprintf( char *str, const char *fmt, va_list args )
{
   return vsprintf( str, fmt, args );
}

/*@}*/


/**********************************************************************/
/** \name Diagnostics */
/*@{*/

/**
 * Report a warning (a recoverable error condition) to stderr if
 * either DEBUG is defined or the MESA_DEBUG env var is set.
 *
 * \param ctx GL context.
 * \param fmtString printf() alike format string.
 */
void
_mesa_warning( GLcontext *ctx, const char *fmtString, ... )
{
   GLboolean debug;
   char str[MAXSTRING];
   va_list args;
   (void) ctx;
   va_start( args, fmtString );  
   (void) vsnprintf( str, MAXSTRING, fmtString, args );
   va_end( args );
#ifdef DEBUG
   debug = GL_TRUE; /* always print warning */
#else
   debug = _mesa_getenv("MESA_DEBUG") ? GL_TRUE : GL_FALSE;
#endif
   if (debug) {
      fprintf(stderr, "Mesa warning: %s\n", str);
   }
}

/**
 * Report an internla implementation problem.
 * Prints the message to stderr via fprintf().
 *
 * \param ctx GL context.
 * \param s problem description string.
 */
void
_mesa_problem( const GLcontext *ctx, const char *fmtString, ... )
{
   va_list args;
   char str[MAXSTRING];
   (void) ctx;

   va_start( args, fmtString );  
   vsnprintf( str, MAXSTRING, fmtString, args );
   va_end( args );

   fprintf(stderr, "Mesa %s implementation error: %s\n", MESA_VERSION_STRING, str);
   fprintf(stderr, "Please report at bugzilla.freedesktop.org\n");
}

/**
 * Record an OpenGL state error.  These usually occur when the users
 * passes invalid parameters to a GL function.
 *
 * If debugging is enabled (either at compile-time via the DEBUG macro, or
 * run-time via the MESA_DEBUG environment variable), report the error with
 * _mesa_debug().
 * 
 * \param ctx the GL context.
 * \param error the error value.
 * \param fmtString printf() style format string, followed by optional args
 */
void
_mesa_error( GLcontext *ctx, GLenum error, const char *fmtString, ... )
{
   const char *debugEnv;
   GLboolean debug;

   debugEnv = _mesa_getenv("MESA_DEBUG");

#ifdef DEBUG
   if (debugEnv && _mesa_strstr(debugEnv, "silent"))
      debug = GL_FALSE;
   else
      debug = GL_TRUE;
#else
   if (debugEnv)
      debug = GL_TRUE;
   else
      debug = GL_FALSE;
#endif

   if (debug) {
      va_list args;
      char where[MAXSTRING];
      const char *errstr;

      va_start( args, fmtString );  
      vsnprintf( where, MAXSTRING, fmtString, args );
      va_end( args );

      switch (error) {
	 case GL_NO_ERROR:
	    errstr = "GL_NO_ERROR";
	    break;
	 case GL_INVALID_VALUE:
	    errstr = "GL_INVALID_VALUE";
	    break;
	 case GL_INVALID_ENUM:
	    errstr = "GL_INVALID_ENUM";
	    break;
	 case GL_INVALID_OPERATION:
	    errstr = "GL_INVALID_OPERATION";
	    break;
	 case GL_STACK_OVERFLOW:
	    errstr = "GL_STACK_OVERFLOW";
	    break;
	 case GL_STACK_UNDERFLOW:
	    errstr = "GL_STACK_UNDERFLOW";
	    break;
	 case GL_OUT_OF_MEMORY:
	    errstr = "GL_OUT_OF_MEMORY";
	    break;
         case GL_TABLE_TOO_LARGE:
            errstr = "GL_TABLE_TOO_LARGE";
            break;
         case GL_INVALID_FRAMEBUFFER_OPERATION_EXT:
            errstr = "GL_INVALID_FRAMEBUFFER_OPERATION";
            break;
	 default:
	    errstr = "unknown";
	    break;
      }
      _mesa_debug(ctx, "User error: %s in %s\n", errstr, where);
   }

   _mesa_record_error(ctx, error);
}  

/**
 * Report debug information.  Print error message to stderr via fprintf().
 * No-op if DEBUG mode not enabled.
 * 
 * \param ctx GL context.
 * \param fmtString printf()-style format string, followed by optional args.
 */
void
_mesa_debug( const GLcontext *ctx, const char *fmtString, ... )
{
#ifdef DEBUG
   char s[MAXSTRING];
   va_list args;
   va_start(args, fmtString);
   vsnprintf(s, MAXSTRING, fmtString, args);
   va_end(args);
   fprintf(stderr, "Mesa: %s", s);
#endif /* DEBUG */
   (void) ctx;
   (void) fmtString;
}

/*@}*/


/**
 * Wrapper for exit().
 */
void
_mesa_exit( int status )
{
   exit(status);
}