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      1 /*
      2  * Mesa 3-D graphics library
      3  *
      4  * Copyright (C) 1999-2008  Brian Paul   All Rights Reserved.
      5  * Copyright (C) 2010  VMware, Inc.  All Rights Reserved.
      6  *
      7  * Permission is hereby granted, free of charge, to any person obtaining a
      8  * copy of this software and associated documentation files (the "Software"),
      9  * to deal in the Software without restriction, including without limitation
     10  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
     11  * and/or sell copies of the Software, and to permit persons to whom the
     12  * Software is furnished to do so, subject to the following conditions:
     13  *
     14  * The above copyright notice and this permission notice shall be included
     15  * in all copies or substantial portions of the Software.
     16  *
     17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
     18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
     20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
     21  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
     22  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
     23  * OTHER DEALINGS IN THE SOFTWARE.
     24  */
     25 
     26 
     27 /**
     28  * No-op dispatch table.
     29  *
     30  * This file defines a special dispatch table which is loaded with no-op
     31  * functions.
     32  *
     33  * Mesa can register a "no-op handler function" which will be called in
     34  * the event that a no-op function is called.
     35  *
     36  * In the past, the dispatch table was loaded with pointers to a single
     37  * no-op function.  But that broke on Windows because the GL entrypoints
     38  * use __stdcall convention.  __stdcall means the callee cleans up the
     39  * stack.  So one no-op function can't properly clean up the stack.  This
     40  * would lead to crashes.
     41  *
     42  * Another benefit of unique no-op functions is we can accurately report
     43  * the function's name in an error message.
     44  */
     45 
     46 
     47 #include <stdlib.h>
     48 #include <string.h>
     49 #include "glapi/glapi_priv.h"
     50 
     51 
     52 void
     53 _glapi_noop_enable_warnings(unsigned char enable)
     54 {
     55 }
     56 
     57 void
     58 _glapi_set_warning_func(_glapi_proc func)
     59 {
     60 }
     61 
     62 
     63 /**
     64  * We'll jump though this function pointer whenever a no-op function
     65  * is called.
     66  */
     67 static _glapi_nop_handler_proc nop_handler = NULL;
     68 
     69 
     70 /**
     71  * Register the no-op handler call-back function.
     72  */
     73 void
     74 _glapi_set_nop_handler(_glapi_nop_handler_proc func)
     75 {
     76    nop_handler = func;
     77 }
     78 
     79 
     80 /**
     81  * Called by each of the no-op GL entrypoints.
     82  */
     83 static void
     84 nop(const char *func)
     85 {
     86    if (nop_handler)
     87       nop_handler(func);
     88 }
     89 
     90 
     91 /**
     92  * This is called if the user somehow calls an unassigned GL dispatch function.
     93  */
     94 static GLint
     95 NoOpUnused(void)
     96 {
     97    nop("unused GL entry point");
     98    return 0;
     99 }
    100 
    101 /*
    102  * Defines for the glapitemp.h functions.
    103  */
    104 #define KEYWORD1 static
    105 #define KEYWORD1_ALT static
    106 #define KEYWORD2 GLAPIENTRY
    107 #define NAME(func)  NoOp##func
    108 #define DISPATCH(func, args, msg)  nop(#func);
    109 #define RETURN_DISPATCH(func, args, msg)  nop(#func); return 0
    110 
    111 
    112 /*
    113  * Defines for the table of no-op entry points.
    114  */
    115 #define TABLE_ENTRY(name) (_glapi_proc) NoOp##name
    116 #define DISPATCH_TABLE_NAME __glapi_noop_table
    117 #define UNUSED_TABLE_NAME __unused_noop_functions
    118 
    119 #include "glapi/glapitemp.h"
    120 
    121 
    122 /** Return pointer to new dispatch table filled with no-op functions */
    123 struct _glapi_table *
    124 _glapi_new_nop_table(unsigned num_entries)
    125 {
    126    struct _glapi_table *table = malloc(num_entries * sizeof(_glapi_proc));
    127    if (table) {
    128       memcpy(table, __glapi_noop_table,
    129              num_entries * sizeof(_glapi_proc));
    130    }
    131    return table;
    132 }
    133