+}
+
+
+/**
+ * When we're about to read pixel data out of a PBO (via glDrawPixels,
+ * glTexImage, etc) or write data into a PBO (via glReadPixels,
+ * glGetTexImage, etc) we call this function to check that we're not
+ * going to read out of bounds.
+ *
+ * XXX This would also be a convenient time to check that the PBO isn't
+ * currently mapped. Whoever calls this function should check for that.
+ * Remember, we can't use a PBO when it's mapped!
+ *
+ * \param width width of image to read/write
+ * \param height height of image to read/write
+ * \param depth depth of image to read/write
+ * \param format format of image to read/write
+ * \param type datatype of image to read/write
+ * \param ptr the user-provided pointer/offset
+ * \return GL_TRUE if the PBO access is OK, GL_FALSE if the access would
+ * go out of bounds.
+ */
+GLboolean
+_mesa_validate_pbo_access(GLuint dimensions,
+ const struct gl_pixelstore_attrib *pack,
+ GLsizei width, GLsizei height, GLsizei depth,
+ GLenum format, GLenum type, const GLvoid *ptr)
+{
+ GLvoid *start, *end;
+ const GLubyte *sizeAddr; /* buffer size, cast to a pointer */
+
+ ASSERT(pack->BufferObj->Name != 0);
+
+ if (pack->BufferObj->Size == 0)
+ /* no buffer! */
+ return GL_FALSE;
+
+ /* get address of first pixel we'll read */
+ start = _mesa_image_address(dimensions, pack, ptr, width, height,
+ format, type, 0, 0, 0);
+
+ /* get address just past the last pixel we'll read */
+ end = _mesa_image_address(dimensions, pack, ptr, width, height,
+ format, type, depth-1, height-1, width);
+