michael@0: /*
michael@0:  * Copyright 2013 Google Inc.
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: #include "gl/GrGLExtensions.h"
michael@0: #include "gl/GrGLDefines.h"
michael@0: #include "gl/GrGLUtil.h"
michael@0: 
michael@0: #include "SkTSearch.h"
michael@0: #include "SkTSort.h"
michael@0: 
michael@0: namespace { // This cannot be static because it is used as a template parameter.
michael@0: inline bool extension_compare(const SkString& a, const SkString& b) {
michael@0:     return strcmp(a.c_str(), b.c_str()) < 0;
michael@0: }
michael@0: }
michael@0: 
michael@0: // finds the index of ext in strings or a negative result if ext is not found.
michael@0: static int find_string(const SkTArray<SkString>& strings, const char ext[]) {
michael@0:     if (strings.empty()) {
michael@0:         return -1;
michael@0:     }
michael@0:     SkString extensionStr(ext);
michael@0:     int idx = SkTSearch<SkString, extension_compare>(&strings.front(),
michael@0:                                                      strings.count(),
michael@0:                                                      extensionStr,
michael@0:                                                      sizeof(SkString));
michael@0:     return idx;
michael@0: }
michael@0: 
michael@0: GrGLExtensions::GrGLExtensions(const GrGLExtensions& that) : fStrings(SkNEW(SkTArray<SkString>)) {
michael@0:     *this = that;
michael@0: }
michael@0: 
michael@0: GrGLExtensions& GrGLExtensions::operator=(const GrGLExtensions& that) {
michael@0:     *fStrings = *that.fStrings;
michael@0:     fInitialized = that.fInitialized;
michael@0:     return *this;
michael@0: }
michael@0: 
michael@0: bool GrGLExtensions::init(GrGLStandard standard,
michael@0:                           GrGLGetStringProc getString,
michael@0:                           GrGLGetStringiProc getStringi,
michael@0:                           GrGLGetIntegervProc getIntegerv) {
michael@0:     fInitialized = false;
michael@0:     fStrings->reset();
michael@0: 
michael@0:     if (NULL == getString) {
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     // glGetStringi and indexed extensions were added in version 3.0 of desktop GL and ES.
michael@0:     const GrGLubyte* verString = getString(GR_GL_VERSION);
michael@0:     if (NULL == verString) {
michael@0:         return false;
michael@0:     }
michael@0:     GrGLVersion version = GrGLGetVersionFromString((const char*) verString);
michael@0:     bool indexed = version >= GR_GL_VER(3, 0);
michael@0: 
michael@0:     if (indexed) {
michael@0:         if (NULL == getStringi || NULL == getIntegerv) {
michael@0:             return false;
michael@0:         }
michael@0:         GrGLint extensionCnt = 0;
michael@0:         getIntegerv(GR_GL_NUM_EXTENSIONS, &extensionCnt);
michael@0:         fStrings->push_back_n(extensionCnt);
michael@0:         for (int i = 0; i < extensionCnt; ++i) {
michael@0:             const char* ext = (const char*) getStringi(GR_GL_EXTENSIONS, i);
michael@0:             (*fStrings)[i] = ext;
michael@0:         }
michael@0:     } else {
michael@0:         const char* extensions = (const char*) getString(GR_GL_EXTENSIONS);
michael@0:         if (NULL == extensions) {
michael@0:             return false;
michael@0:         }
michael@0:         while (true) {
michael@0:             // skip over multiple spaces between extensions
michael@0:             while (' ' == *extensions) {
michael@0:                 ++extensions;
michael@0:             }
michael@0:             // quit once we reach the end of the string.
michael@0:             if ('\0' == *extensions) {
michael@0:                 break;
michael@0:             }
michael@0:             // we found an extension
michael@0:             size_t length = strcspn(extensions, " ");
michael@0:             fStrings->push_back().set(extensions, length);
michael@0:             extensions += length;
michael@0:         }
michael@0:     }
michael@0:     if (!fStrings->empty()) {
michael@0:         SkTLessFunctionToFunctorAdaptor<SkString, extension_compare> cmp;
michael@0:         SkTQSort(&fStrings->front(), &fStrings->back(), cmp);
michael@0:     }
michael@0:     fInitialized = true;
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: bool GrGLExtensions::has(const char ext[]) const {
michael@0:     SkASSERT(fInitialized);
michael@0:     return find_string(*fStrings, ext) >= 0;
michael@0: }
michael@0: 
michael@0: bool GrGLExtensions::remove(const char ext[]) {
michael@0:     SkASSERT(fInitialized);
michael@0:     int idx = find_string(*fStrings, ext);
michael@0:     if (idx >= 0) {
michael@0:         // This is not terribly effecient but we really only expect this function to be called at
michael@0:         // most a handful of times when our test programs start.
michael@0:         SkAutoTDelete< SkTArray<SkString> > oldStrings(fStrings.detach());
michael@0:         fStrings.reset(SkNEW(SkTArray<SkString>(oldStrings->count() - 1)));
michael@0:         fStrings->push_back_n(idx, &oldStrings->front());
michael@0:         fStrings->push_back_n(oldStrings->count() - idx - 1, &(*oldStrings)[idx] + 1);
michael@0:         return true;
michael@0:     } else {
michael@0:         return false;
michael@0:     }
michael@0: }
michael@0: 
michael@0: void GrGLExtensions::add(const char ext[]) {
michael@0:     int idx = find_string(*fStrings, ext);
michael@0:     if (idx < 0) {
michael@0:         // This is not the most effecient approach since we end up doing a full sort of the
michael@0:         // extensions after the add
michael@0:         fStrings->push_back().set(ext);
michael@0:         SkTLessFunctionToFunctorAdaptor<SkString, extension_compare> cmp;
michael@0:         SkTQSort(&fStrings->front(), &fStrings->back(), cmp);
michael@0:     }
michael@0: }
michael@0: 
michael@0: void GrGLExtensions::print(const char* sep) const {
michael@0:     if (NULL == sep) {
michael@0:         sep = " ";
michael@0:     }
michael@0:     int cnt = fStrings->count();
michael@0:     for (int i = 0; i < cnt; ++i) {
michael@0:         GrPrintf("%s%s", (*fStrings)[i].c_str(), (i < cnt - 1) ? sep : "");
michael@0:     }
michael@0: }