1 2 /* 3 * Copyright 2008 The Android Open Source Project 4 * 5 * Use of this source code is governed by a BSD-style license that can be 6 * found in the LICENSE file. 7 */ 8 9 10 #ifndef SkPackBits_DEFINED 11 #define SkPackBits_DEFINED 12 13 #include "SkTypes.h" 14 15 class SkPackBits { 16 public: 17 /** Given the number of 16bit values that will be passed to Pack16, 18 returns the worst-case size needed for the dst[] buffer. 19 */ 20 static size_t ComputeMaxSize16(int count); 21 22 /** Given the number of 8bit values that will be passed to Pack8, 23 returns the worst-case size needed for the dst[] buffer. 24 */ 25 static size_t ComputeMaxSize8(int count); 26 27 /** Write the src array into a packed format. The packing process may end 28 up writing more bytes than it read, so dst[] must be large enough. 29 @param src Input array of 16bit values 30 @param count Number of entries in src[] 31 @param dst Buffer (allocated by caller) to write the packed data 32 into 33 @return the number of bytes written to dst[] 34 */ 35 static size_t Pack16(const uint16_t src[], int count, uint8_t dst[]); 36 37 /** Write the src array into a packed format. The packing process may end 38 up writing more bytes than it read, so dst[] must be large enough. 39 @param src Input array of 8bit values 40 @param count Number of entries in src[] 41 @param dst Buffer (allocated by caller) to write the packed data 42 into 43 @return the number of bytes written to dst[] 44 */ 45 static size_t Pack8(const uint8_t src[], int count, uint8_t dst[]); 46 47 /** Unpack the data in src[], and expand it into dst[]. The src[] data was 48 written by a previous call to Pack16. 49 @param src Input data to unpack, previously created by Pack16. 50 @param srcSize Number of bytes of src to unpack 51 @param dst Buffer (allocated by caller) to expand the src[] into. 52 @return the number of dst elements (not bytes) written into dst. 53 */ 54 static int Unpack16(const uint8_t src[], size_t srcSize, uint16_t dst[]); 55 56 /** Unpack the data in src[], and expand it into dst[]. The src[] data was 57 written by a previous call to Pack8. 58 @param src Input data to unpack, previously created by Pack8. 59 @param srcSize Number of bytes of src to unpack 60 @param dst Buffer (allocated by caller) to expand the src[] into. 61 @return the number of bytes written into dst. 62 */ 63 static int Unpack8(const uint8_t src[], size_t srcSize, uint8_t dst[]); 64 65 /** Unpack the data from src[], skip the first dstSkip bytes, then write 66 dstWrite bytes into dst[]. The src[] data was written by a previous 67 call to Pack8. Return the number of bytes actually writtten into dst[] 68 @param src Input data to unpack, previously created by Pack8. 69 @param dst Buffer (allocated by caller) to expand the src[] into. 70 @param dstSkip Number of bytes of unpacked src to skip before writing 71 into dst 72 @param dstWrite Number of bytes of unpacked src to write into dst (after 73 skipping dstSkip bytes) 74 */ 75 static void Unpack8(uint8_t dst[], size_t dstSkip, size_t dstWrite, 76 const uint8_t src[]); 77 }; 78 79 #endif 80
