1 /*
2 * Copyright 2013 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8 #include "gl/GrGLExtensions.h"
9 #include "gl/GrGLDefines.h"
10 #include "gl/GrGLUtil.h"
11
12 #include "SkTSearch.h"
13 #include "SkTSort.h"
14
15 namespace { // This cannot be static because it is used as a template parameter.
extension_compare(const SkString & a,const SkString & b)16 inline bool extension_compare(const SkString& a, const SkString& b) {
17 return strcmp(a.c_str(), b.c_str()) < 0;
18 }
19 }
20
21 // finds the index of ext in strings or a negative result if ext is not found.
find_string(const SkTArray<SkString> & strings,const char ext[])22 static int find_string(const SkTArray<SkString>& strings, const char ext[]) {
23 if (strings.empty()) {
24 return -1;
25 }
26 SkString extensionStr(ext);
27 int idx = SkTSearch<SkString, extension_compare>(&strings.front(),
28 strings.count(),
29 extensionStr,
30 sizeof(SkString));
31 return idx;
32 }
33
GrGLExtensions(const GrGLExtensions & that)34 GrGLExtensions::GrGLExtensions(const GrGLExtensions& that) : fStrings(SkNEW(SkTArray<SkString>)) {
35 *this = that;
36 }
37
operator =(const GrGLExtensions & that)38 GrGLExtensions& GrGLExtensions::operator=(const GrGLExtensions& that) {
39 *fStrings = *that.fStrings;
40 fInitialized = that.fInitialized;
41 return *this;
42 }
43
init(GrGLStandard standard,GrGLGetStringProc getString,GrGLGetStringiProc getStringi,GrGLGetIntegervProc getIntegerv)44 bool GrGLExtensions::init(GrGLStandard standard,
45 GrGLGetStringProc getString,
46 GrGLGetStringiProc getStringi,
47 GrGLGetIntegervProc getIntegerv) {
48 fInitialized = false;
49 fStrings->reset();
50
51 if (NULL == getString) {
52 return false;
53 }
54
55 // glGetStringi and indexed extensions were added in version 3.0 of desktop GL and ES.
56 const GrGLubyte* verString = getString(GR_GL_VERSION);
57 GrGLVersion version = GrGLGetVersionFromString((const char*) verString);
58 if (GR_GL_INVALID_VER == version) {
59 return false;
60 }
61
62 bool indexed = version >= GR_GL_VER(3, 0);
63
64 if (indexed) {
65 if (NULL == getStringi || NULL == getIntegerv) {
66 return false;
67 }
68 GrGLint extensionCnt = 0;
69 getIntegerv(GR_GL_NUM_EXTENSIONS, &extensionCnt);
70 fStrings->push_back_n(extensionCnt);
71 for (int i = 0; i < extensionCnt; ++i) {
72 const char* ext = (const char*) getStringi(GR_GL_EXTENSIONS, i);
73 (*fStrings)[i] = ext;
74 }
75 } else {
76 const char* extensions = (const char*) getString(GR_GL_EXTENSIONS);
77 if (NULL == extensions) {
78 return false;
79 }
80 while (true) {
81 // skip over multiple spaces between extensions
82 while (' ' == *extensions) {
83 ++extensions;
84 }
85 // quit once we reach the end of the string.
86 if ('\0' == *extensions) {
87 break;
88 }
89 // we found an extension
90 size_t length = strcspn(extensions, " ");
91 fStrings->push_back().set(extensions, length);
92 extensions += length;
93 }
94 }
95 if (!fStrings->empty()) {
96 SkTLessFunctionToFunctorAdaptor<SkString, extension_compare> cmp;
97 SkTQSort(&fStrings->front(), &fStrings->back(), cmp);
98 }
99 fInitialized = true;
100 return true;
101 }
102
has(const char ext[]) const103 bool GrGLExtensions::has(const char ext[]) const {
104 SkASSERT(fInitialized);
105 return find_string(*fStrings, ext) >= 0;
106 }
107
remove(const char ext[])108 bool GrGLExtensions::remove(const char ext[]) {
109 SkASSERT(fInitialized);
110 int idx = find_string(*fStrings, ext);
111 if (idx >= 0) {
112 // This is not terribly effecient but we really only expect this function to be called at
113 // most a handful of times when our test programs start.
114 SkAutoTDelete< SkTArray<SkString> > oldStrings(fStrings.detach());
115 fStrings.reset(SkNEW(SkTArray<SkString>(oldStrings->count() - 1)));
116 fStrings->push_back_n(idx, &oldStrings->front());
117 fStrings->push_back_n(oldStrings->count() - idx - 1, &(*oldStrings)[idx] + 1);
118 return true;
119 } else {
120 return false;
121 }
122 }
123
add(const char ext[])124 void GrGLExtensions::add(const char ext[]) {
125 int idx = find_string(*fStrings, ext);
126 if (idx < 0) {
127 // This is not the most effecient approach since we end up doing a full sort of the
128 // extensions after the add
129 fStrings->push_back().set(ext);
130 SkTLessFunctionToFunctorAdaptor<SkString, extension_compare> cmp;
131 SkTQSort(&fStrings->front(), &fStrings->back(), cmp);
132 }
133 }
134
print(const char * sep) const135 void GrGLExtensions::print(const char* sep) const {
136 if (NULL == sep) {
137 sep = " ";
138 }
139 int cnt = fStrings->count();
140 for (int i = 0; i < cnt; ++i) {
141 GrPrintf("%s%s", (*fStrings)[i].c_str(), (i < cnt - 1) ? sep : "");
142 }
143 }
144