Optimize our GL extension checks to avoid mallocs.

We want to avoid any unnecessary mallocs when checking GL/GLX
extensions. The GL extension string can be quite long and contain
several hundred extensions. The old code forced one malloc for each
extension + 1 extra malloc for the extension string itself when
it was copied into the QByteArray.

Reviewed-by: Kim

1 files changed, 24 insertions, 23 deletions

diff --git a/src/opengl/qgl.cpp b/src/opengl/qgl.cpp
index dcf8c00..b6f8919 100644
--- a/src/opengl/qgl.cpp
+++ b/src/opengl/qgl.cpp
@@ -4822,38 +4822,39 @@ QGLWidget::QGLWidget(QGLContext *context, QWidget *parent,
 
 void QGLExtensions::init_extensions()
 {
-    QList<QByteArray> extensions = QByteArray(reinterpret_cast<const char *>(glGetString(GL_EXTENSIONS))).split(' ');
-    if (extensions.contains("GL_ARB_texture_rectangle"))
+    QGLExtensionMatcher extensions(reinterpret_cast<const char *>(glGetString(GL_EXTENSIONS)));
+
+    if (extensions.match("GL_ARB_texture_rectangle"))
         glExtensions |= TextureRectangle;
-    if (extensions.contains("GL_ARB_multisample"))
+    if (extensions.match("GL_ARB_multisample"))
         glExtensions |= SampleBuffers;
-    if (extensions.contains("GL_SGIS_generate_mipmap"))
+    if (extensions.match("GL_SGIS_generate_mipmap"))
         glExtensions |= GenerateMipmap;
-    if (extensions.contains("GL_ARB_texture_compression"))
+    if (extensions.match("GL_ARB_texture_compression"))
         glExtensions |= TextureCompression;
-    if (extensions.contains("GL_EXT_texture_compression_s3tc"))
+    if (extensions.match("GL_EXT_texture_compression_s3tc"))
         glExtensions |= DDSTextureCompression;
-    if (extensions.contains("GL_OES_compressed_ETC1_RGB8_texture"))
+    if (extensions.match("GL_OES_compressed_ETC1_RGB8_texture"))
         glExtensions |= ETC1TextureCompression;
-    if (extensions.contains("GL_IMG_texture_compression_pvrtc"))
+    if (extensions.match("GL_IMG_texture_compression_pvrtc"))
         glExtensions |= PVRTCTextureCompression;
-    if (extensions.contains("GL_ARB_fragment_program"))
+    if (extensions.match("GL_ARB_fragment_program"))
         glExtensions |= FragmentProgram;
-    if (extensions.contains("GL_ARB_fragment_shader"))
+    if (extensions.match("GL_ARB_fragment_shader"))
         glExtensions |= FragmentShader;
-    if (extensions.contains("GL_ARB_texture_mirrored_repeat"))
+    if (extensions.match("GL_ARB_texture_mirrored_repeat"))
         glExtensions |= MirroredRepeat;
-    if (extensions.contains("GL_EXT_framebuffer_object"))
+    if (extensions.match("GL_EXT_framebuffer_object"))
         glExtensions |= FramebufferObject;
-    if (extensions.contains("GL_EXT_stencil_two_side"))
+    if (extensions.match("GL_EXT_stencil_two_side"))
         glExtensions |= StencilTwoSide;
-    if (extensions.contains("GL_EXT_stencil_wrap"))
+    if (extensions.match("GL_EXT_stencil_wrap"))
         glExtensions |= StencilWrap;
-    if (extensions.contains("GL_EXT_packed_depth_stencil"))
+    if (extensions.match("GL_EXT_packed_depth_stencil"))
         glExtensions |= PackedDepthStencil;
-    if (extensions.contains("GL_NV_float_buffer"))
+    if (extensions.match("GL_NV_float_buffer"))
         glExtensions |= NVFloatBuffer;
-    if (extensions.contains("GL_ARB_pixel_buffer_object"))
+    if (extensions.match("GL_ARB_pixel_buffer_object"))
         glExtensions |= PixelBufferObject;
 #if defined(QT_OPENGL_ES_2)
     glExtensions |= FramebufferObject;
@@ -4861,26 +4862,26 @@ void QGLExtensions::init_extensions()
     glExtensions |= FragmentShader;
 #endif
 #if defined(QT_OPENGL_ES_1) || defined(QT_OPENGL_ES_1_CL)
-    if (extensions.contains("GL_OES_framebuffer_object"))
+    if (extensions.match("GL_OES_framebuffer_object"))
         glExtensions |= FramebufferObject;
 #endif
 #if defined(QT_OPENGL_ES)
-    if (extensions.contains("GL_OES_packed_depth_stencil"))
+    if (extensions.match("GL_OES_packed_depth_stencil"))
         glExtensions |= PackedDepthStencil;
 #endif
-    if (extensions.contains("GL_ARB_framebuffer_object")) {
+    if (extensions.match("GL_ARB_framebuffer_object")) {
         // ARB_framebuffer_object also includes EXT_framebuffer_blit.
         glExtensions |= FramebufferObject;
         glExtensions |= FramebufferBlit;
     }
 
-    if (extensions.contains("GL_EXT_framebuffer_blit"))
+    if (extensions.match("GL_EXT_framebuffer_blit"))
         glExtensions |= FramebufferBlit;
 
-    if (extensions.contains("GL_ARB_texture_non_power_of_two"))
+    if (extensions.match("GL_ARB_texture_non_power_of_two"))
         glExtensions |= NPOTTextures;
 
-    if (extensions.contains("GL_EXT_bgra"))
+    if (extensions.match("GL_EXT_bgra"))
         glExtensions |= BGRATextureFormat;
 }