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/* Copyright (c) Mark J. Kilgard, 1994, 1997. */
/* This program is freely distributable without licensing fees
and is provided without guarantee or warrantee expressed or
implied. This program is -not- in the public domain. */
#include <stdlib.h>
#include <string.h>
#include "glutint.h"
/* CENTRY */
int APIENTRY
glutExtensionSupported(const char *extension)
{
static const GLubyte *extensions = NULL;
const GLubyte *start;
GLubyte *where, *terminator;
/* Extension names should not have spaces. */
where = (GLubyte *) strchr(extension, ' ');
if (where || *extension == '\0')
return 0;
if (!extensions) {
extensions = glGetString(GL_EXTENSIONS);
}
/* It takes a bit of care to be fool-proof about parsing the
OpenGL extensions string. Don't be fooled by sub-strings,
etc. */
start = extensions;
for (;;) {
/* If your application crashes in the strstr routine below,
you are probably calling glutExtensionSupported without
having a current window. Calling glGetString without
a current OpenGL context has unpredictable results.
Please fix your program. */
where = (GLubyte *) strstr((const char *) start, extension);
if (!where)
break;
terminator = where + strlen(extension);
if (where == start || *(where - 1) == ' ') {
if (*terminator == ' ' || *terminator == '\0') {
return 1;
}
}
start = terminator;
}
return 0;
}
/* ENDCENTRY */
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