2 * Mesa 3-D graphics library
5 * Copyright (C) 1999-2008 Brian Paul All Rights Reserved.
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27 * \file glapi_getproc.c
29 * Code for implementing glXGetProcAddress(), etc.
30 * This was originally in glapi.c but refactored out.
34 #include "glapi/glapi_priv.h"
35 #include "glapi/glapitable.h"
38 #define FIRST_DYNAMIC_OFFSET (sizeof(struct _glapi_table) / sizeof(void *))
41 /**********************************************************************
42 * Static function management.
46 #if !defined(DISPATCH_FUNCTION_SIZE)
47 # define NEED_FUNCTION_POINTER
49 #include "glapi/glprocs.h"
53 * Search the table of static entrypoint functions for the named function
54 * and return the corresponding glprocs_table_t entry.
56 static const glprocs_table_t *
57 get_static_proc( const char * n )
60 for (i = 0; static_functions[i].Name_offset >= 0; i++) {
61 const char *testName = gl_string_table + static_functions[i].Name_offset;
63 /* skip the prefix on the name */
64 if (strcmp(testName, n + 1) == 0)
66 if (strcmp(testName, n) == 0)
69 return &static_functions[i];
77 * Return dispatch table offset of the named static (built-in) function.
78 * Return -1 if function not found.
81 get_static_proc_offset(const char *funcName)
83 const glprocs_table_t * const f = get_static_proc( funcName );
94 * Return dispatch function address for the named static (built-in) function.
95 * Return NULL if function not found.
98 get_static_proc_address(const char *funcName)
100 const glprocs_table_t * const f = get_static_proc( funcName );
105 #if defined(DISPATCH_FUNCTION_SIZE) && defined(GLX_INDIRECT_RENDERING)
106 return (f->Address == NULL)
107 ? get_entrypoint_address(f->Offset)
109 #elif defined(DISPATCH_FUNCTION_SIZE)
110 return get_entrypoint_address(f->Offset);
119 * Return the name of the function at the given offset in the dispatch
120 * table. For debugging only.
123 get_static_proc_name( GLuint offset )
126 for (i = 0; static_functions[i].Name_offset >= 0; i++) {
127 if (static_functions[i].Offset == offset) {
128 return gl_string_table + static_functions[i].Name_offset;
136 /**********************************************************************
137 * Extension function management.
142 * Track information about a function added to the GL API.
144 struct _glapi_function {
146 * Name of the function.
152 * Text string that describes the types of the parameters passed to the
153 * named function. Parameter types are converted to characters using the
155 * - 'i' for \c GLint, \c GLuint, and \c GLenum
156 * - 'p' for any pointer type
157 * - 'f' for \c GLfloat and \c GLclampf
158 * - 'd' for \c GLdouble and \c GLclampd
160 const char * parameter_signature;
164 * Offset in the dispatch table where the pointer to the real function is
165 * located. If the driver has not requested that the named function be
166 * added to the dispatch table, this will have the value ~0.
168 unsigned dispatch_offset;
172 * Pointer to the dispatch stub for the named function.
175 * The semantic of this field should be changed slightly. Currently, it
176 * is always expected to be non-\c NULL. However, it would be better to
177 * only allocate the entry-point stub when the application requests the
178 * function via \c glXGetProcAddress. This would save memory for all the
179 * functions that the driver exports but that the application never wants
182 _glapi_proc dispatch_stub;
186 static struct _glapi_function ExtEntryTable[MAX_EXTENSION_FUNCS];
187 static GLuint NumExtEntryPoints = 0;
190 static struct _glapi_function *
191 get_extension_proc(const char *funcName)
194 for (i = 0; i < NumExtEntryPoints; i++) {
195 if (strcmp(ExtEntryTable[i].name, funcName) == 0) {
196 return & ExtEntryTable[i];
204 get_extension_proc_offset(const char *funcName)
206 const struct _glapi_function * const f = get_extension_proc( funcName );
211 return f->dispatch_offset;
216 get_extension_proc_address(const char *funcName)
218 const struct _glapi_function * const f = get_extension_proc( funcName );
223 return f->dispatch_stub;
228 get_extension_proc_name(GLuint offset)
231 for (i = 0; i < NumExtEntryPoints; i++) {
232 if (ExtEntryTable[i].dispatch_offset == offset) {
233 return ExtEntryTable[i].name;
241 * strdup() is actually not a standard ANSI C or POSIX routine.
242 * Irix will not define it if ANSI mode is in effect.
245 str_dup(const char *str)
248 copy = malloc(strlen(str) + 1);
257 * Generate new entrypoint
259 * Use a temporary dispatch offset of ~0 (i.e. -1). Later, when the driver
260 * calls \c _glapi_add_dispatch we'll put in the proper offset. If that
261 * never happens, and the user calls this function, he'll segfault. That's
262 * what you get when you try calling a GL function that doesn't really exist.
264 * \param funcName Name of the function to create an entry-point for.
266 * \sa _glapi_add_entrypoint
269 static struct _glapi_function *
270 add_function_name( const char * funcName )
272 struct _glapi_function * entry = NULL;
273 _glapi_proc entrypoint = NULL;
274 char * name_dup = NULL;
276 if (NumExtEntryPoints >= MAX_EXTENSION_FUNCS)
279 if (funcName == NULL)
282 name_dup = str_dup(funcName);
283 if (name_dup == NULL)
286 entrypoint = generate_entrypoint(~0);
288 if (entrypoint == NULL) {
293 entry = & ExtEntryTable[NumExtEntryPoints];
296 entry->name = name_dup;
297 entry->parameter_signature = NULL;
298 entry->dispatch_offset = ~0;
299 entry->dispatch_stub = entrypoint;
305 static struct _glapi_function *
306 set_entry_info( struct _glapi_function * entry, const char * signature, unsigned offset )
308 char * sig_dup = NULL;
310 if (signature == NULL)
313 sig_dup = str_dup(signature);
317 fill_in_entrypoint_offset(entry->dispatch_stub, offset);
319 entry->parameter_signature = sig_dup;
320 entry->dispatch_offset = offset;
327 * Fill-in the dispatch stub for the named function.
329 * This function is intended to be called by a hardware driver. When called,
330 * a dispatch stub may be created created for the function. A pointer to this
331 * dispatch function will be returned by glXGetProcAddress.
333 * \param function_names Array of pointers to function names that should
334 * share a common dispatch offset.
335 * \param parameter_signature String representing the types of the parameters
336 * passed to the named function. Parameter types
337 * are converted to characters using the following
339 * - 'i' for \c GLint, \c GLuint, and \c GLenum
340 * - 'p' for any pointer type
341 * - 'f' for \c GLfloat and \c GLclampf
342 * - 'd' for \c GLdouble and \c GLclampd
345 * The offset in the dispatch table of the named function. A pointer to the
346 * driver's implementation of the named function should be stored at
347 * \c dispatch_table[\c offset]. Return -1 if error/problem.
349 * \sa glXGetProcAddress
352 * This function can only handle up to 8 names at a time. As far as I know,
353 * the maximum number of names ever associated with an existing GL function is
354 * 4 (\c glPointParameterfSGIS, \c glPointParameterfEXT,
355 * \c glPointParameterfARB, and \c glPointParameterf), so this should not be
356 * too painful of a limitation.
359 * Determine whether or not \c parameter_signature should be allowed to be
360 * \c NULL. It doesn't seem like much of a hardship for drivers to have to
361 * pass in an empty string.
364 * Determine if code should be added to reject function names that start with
368 * Add code to compare \c parameter_signature with the parameter signature of
369 * a static function. In order to do that, we need to find a way to \b get
370 * the parameter signature of a static function.
374 _glapi_add_dispatch( const char * const * function_names,
375 const char * parameter_signature )
377 static int next_dynamic_offset = FIRST_DYNAMIC_OFFSET;
378 const char * const real_sig = (parameter_signature != NULL)
379 ? parameter_signature : "";
380 struct _glapi_function * entry[8];
381 GLboolean is_static[8];
385 init_glapi_relocs_once();
387 (void) memset( is_static, 0, sizeof( is_static ) );
388 (void) memset( entry, 0, sizeof( entry ) );
390 /* Find the _single_ dispatch offset for all function names that already
391 * exist (and have a dispatch offset).
394 for ( i = 0 ; function_names[i] != NULL ; i++ ) {
395 const char * funcName = function_names[i];
397 int extension_offset;
399 if (funcName[0] != 'g' || funcName[1] != 'l')
402 /* search built-in functions */
403 static_offset = get_static_proc_offset(funcName);
405 if (static_offset >= 0) {
407 is_static[i] = GL_TRUE;
409 /* FIXME: Make sure the parameter signatures match! How do we get
410 * FIXME: the parameter signature for static functions?
413 if ( (offset != ~0) && (static_offset != offset) ) {
417 offset = static_offset;
422 /* search added extension functions */
423 entry[i] = get_extension_proc(funcName);
425 if (entry[i] != NULL) {
426 extension_offset = entry[i]->dispatch_offset;
428 /* The offset may be ~0 if the function name was added by
429 * glXGetProcAddress but never filled in by the driver.
432 if (extension_offset == ~0) {
436 if (strcmp(real_sig, entry[i]->parameter_signature) != 0) {
440 if ( (offset != ~0) && (extension_offset != offset) ) {
444 offset = extension_offset;
448 /* If all function names are either new (or with no dispatch offset),
449 * allocate a new dispatch offset.
453 offset = next_dynamic_offset;
454 next_dynamic_offset++;
457 /* Fill in the dispatch offset for the new function names (and those with
458 * no dispatch offset).
461 for ( i = 0 ; function_names[i] != NULL ; i++ ) {
466 /* generate entrypoints for new function names */
467 if (entry[i] == NULL) {
468 entry[i] = add_function_name( function_names[i] );
469 if (entry[i] == NULL) {
470 /* FIXME: Possible memory leak here. */
475 if (entry[i]->dispatch_offset == ~0) {
476 set_entry_info( entry[i], real_sig, offset );
485 * Return offset of entrypoint for named function within dispatch table.
488 _glapi_get_proc_offset(const char *funcName)
492 /* search extension functions first */
493 offset = get_extension_proc_offset(funcName);
497 /* search static functions */
498 return get_static_proc_offset(funcName);
504 * Return pointer to the named function. If the function name isn't found
505 * in the name of static functions, try generating a new API entrypoint on
506 * the fly with assembly language.
509 _glapi_get_proc_address(const char *funcName)
512 struct _glapi_function * entry;
514 init_glapi_relocs_once();
517 /* skip the prefix on the name */
518 if (funcName[1] != 'g' || funcName[2] != 'l')
521 if (funcName[0] != 'g' || funcName[1] != 'l')
525 /* search extension functions first */
526 func = get_extension_proc_address(funcName);
530 /* search static functions */
531 func = get_static_proc_address(funcName);
535 /* generate entrypoint, dispatch offset must be filled in by the driver */
536 entry = add_function_name(funcName);
540 return entry->dispatch_stub;
546 * Return the name of the function at the given dispatch offset.
547 * This is only intended for debugging.
550 _glapi_get_proc_name(GLuint offset)
554 /* search built-in functions */
555 n = get_static_proc_name(offset);
560 /* search added extension functions */
561 return get_extension_proc_name(offset);
566 /**********************************************************************
567 * GL API table functions.
572 * Return size of dispatch table struct as number of functions (or
576 _glapi_get_dispatch_table_size(void)
579 * The dispatch table size (number of entries) is the size of the
580 * _glapi_table struct plus the number of dynamic entries we can add.
581 * The extra slots can be filled in by DRI drivers that register new
582 * extension functions.
584 return FIRST_DYNAMIC_OFFSET + MAX_EXTENSION_FUNCS;
589 * Make sure there are no NULL pointers in the given dispatch table.
590 * Intended for debugging purposes.
593 _glapi_check_table_not_null(const struct _glapi_table *table)
595 #ifdef EXTRA_DEBUG /* set to DEBUG for extra DEBUG */
596 const GLuint entries = _glapi_get_dispatch_table_size();
597 const void **tab = (const void **) table;
599 for (i = 1; i < entries; i++) {
609 * Do some spot checks to be sure that the dispatch table
610 * slots are assigned correctly. For debugging only.
613 _glapi_check_table(const struct _glapi_table *table)
615 #ifdef EXTRA_DEBUG /* set to DEBUG for extra DEBUG */
617 GLuint BeginOffset = _glapi_get_proc_offset("glBegin");
618 char *BeginFunc = (char*) &table->Begin;
619 GLuint offset = (BeginFunc - (char *) table) / sizeof(void *);
620 assert(BeginOffset == offset);
623 GLuint viewportOffset = _glapi_get_proc_offset("glViewport");
624 char *viewportFunc = (char*) &table->Viewport;
625 GLuint offset = (viewportFunc - (char *) table) / sizeof(void *);
626 assert(viewportOffset == offset);
629 GLuint VertexPointerOffset = _glapi_get_proc_offset("glVertexPointer");
630 char *VertexPointerFunc = (char*) &table->VertexPointer;
631 GLuint offset = (VertexPointerFunc - (char *) table) / sizeof(void *);
632 assert(VertexPointerOffset == offset);
635 GLuint ResetMinMaxOffset = _glapi_get_proc_offset("glResetMinmax");
636 char *ResetMinMaxFunc = (char*) &table->ResetMinmax;
637 GLuint offset = (ResetMinMaxFunc - (char *) table) / sizeof(void *);
638 assert(ResetMinMaxOffset == offset);
641 GLuint blendColorOffset = _glapi_get_proc_offset("glBlendColor");
642 char *blendColorFunc = (char*) &table->BlendColor;
643 GLuint offset = (blendColorFunc - (char *) table) / sizeof(void *);
644 assert(blendColorOffset == offset);
647 GLuint secondaryColor3fOffset = _glapi_get_proc_offset("glSecondaryColor3fEXT");
648 char *secondaryColor3fFunc = (char*) &table->SecondaryColor3fEXT;
649 GLuint offset = (secondaryColor3fFunc - (char *) table) / sizeof(void *);
650 assert(secondaryColor3fOffset == offset);
653 GLuint pointParameterivOffset = _glapi_get_proc_offset("glPointParameterivNV");
654 char *pointParameterivFunc = (char*) &table->PointParameterivNV;
655 GLuint offset = (pointParameterivFunc - (char *) table) / sizeof(void *);
656 assert(pointParameterivOffset == offset);
659 GLuint setFenceOffset = _glapi_get_proc_offset("glSetFenceNV");
660 char *setFenceFunc = (char*) &table->SetFenceNV;
661 GLuint offset = (setFenceFunc - (char *) table) / sizeof(void *);
662 assert(setFenceOffset == offset);