1 /* 2 * Copyright (C) 2008 The Android Open Source Project 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 SkPackBits_DEFINED 18 #define SkPackBits_DEFINED 19 20 #include "SkTypes.h" 21 22 class SkPackBits { 23 public: 24 /** Given the number of 16bit values that will be passed to Pack16, 25 returns the worst-case size needed for the dst[] buffer. 26 */ 27 static size_t ComputeMaxSize16(int count); 28 29 /** Given the number of 8bit values that will be passed to Pack8, 30 returns the worst-case size needed for the dst[] buffer. 31 */ 32 static size_t ComputeMaxSize8(int count); 33 34 /** Write the src array into a packed format. The packing process may end 35 up writing more bytes than it read, so dst[] must be large enough. 36 @param src Input array of 16bit values 37 @param count Number of entries in src[] 38 @param dst Buffer (allocated by caller) to write the packed data 39 into 40 @return the number of bytes written to dst[] 41 */ 42 static size_t Pack16(const uint16_t src[], int count, uint8_t dst[]); 43 44 /** Write the src array into a packed format. The packing process may end 45 up writing more bytes than it read, so dst[] must be large enough. 46 @param src Input array of 8bit values 47 @param count Number of entries in src[] 48 @param dst Buffer (allocated by caller) to write the packed data 49 into 50 @return the number of bytes written to dst[] 51 */ 52 static size_t Pack8(const uint8_t src[], int count, uint8_t dst[]); 53 54 /** Unpack the data in src[], and expand it into dst[]. The src[] data was 55 written by a previous call to Pack16. 56 @param src Input data to unpack, previously created by Pack16. 57 @param srcSize Number of bytes of src to unpack 58 @param dst Buffer (allocated by caller) to expand the src[] into. 59 @return the number of dst elements (not bytes) written into dst. 60 */ 61 static int Unpack16(const uint8_t src[], size_t srcSize, uint16_t dst[]); 62 63 /** Unpack the data in src[], and expand it into dst[]. The src[] data was 64 written by a previous call to Pack8. 65 @param src Input data to unpack, previously created by Pack8. 66 @param srcSize Number of bytes of src to unpack 67 @param dst Buffer (allocated by caller) to expand the src[] into. 68 @return the number of bytes written into dst. 69 */ 70 static int Unpack8(const uint8_t src[], size_t srcSize, uint8_t dst[]); 71 72 /** Unpack the data from src[], skip the first dstSkip bytes, then write 73 dstWrite bytes into dst[]. The src[] data was written by a previous 74 call to Pack8. Return the number of bytes actually writtten into dst[] 75 @param src Input data to unpack, previously created by Pack8. 76 @param dst Buffer (allocated by caller) to expand the src[] into. 77 @param dstSkip Number of bytes of unpacked src to skip before writing 78 into dst 79 @param dstWrite Number of bytes of unpacked src to write into dst (after 80 skipping dstSkip bytes) 81 */ 82 static void Unpack8(uint8_t dst[], size_t dstSkip, size_t dstWrite, 83 const uint8_t src[]); 84 }; 85 86 #endif 87