reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame^] | 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 |