1 /* 2 * Copyright 2011 Google Inc. All Rights Reserved. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef SFNTLY_CPP_SRC_SFNTLY_MATH_FONT_MATH_H_ 18 #define SFNTLY_CPP_SRC_SFNTLY_MATH_FONT_MATH_H_ 19 20 #include "sfntly/port/type.h" 21 22 namespace sfntly { 23 24 class FontMath { 25 public: 26 static int32_t Log2(int32_t a) { 27 int r = 0; // r will be lg(a) 28 while (a != 0) { 29 a >>= 1; 30 r++; 31 } 32 return r - 1; 33 } 34 35 // Calculates the amount of padding needed. The values provided need to be in 36 // the same units. So, if the size is given as the number of bytes then the 37 // alignment size must also be specified as byte size to align to. 38 // @param size the size of the data that may need padding 39 // @param alignmentSize the number of units to align to 40 // @return the number of units needing to be added for alignment 41 static int32_t PaddingRequired(int32_t size, int32_t alignment_size) { 42 int32_t padding = alignment_size - (size % alignment_size); 43 return padding == alignment_size ? 0 : padding; 44 } 45 }; 46 47 } // namespace sfntly 48 49 #endif // SFNTLY_CPP_SRC_SFNTLY_MATH_FONT_MATH_H_ 50
