gfx/graphite2/src/inc/Endian.h@b8a032363ba2 (annotated)
gfx/graphite2/src/inc/Endian.h
Thu, 22 Jan 2015 13:21:57 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Thu, 22 Jan 2015 13:21:57 +0100
- branch
- TOR_BUG_9701
- changeset 15
- b8a032363ba2
- permissions
- -rw-r--r--
Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6
| michael@0 | 1 | /* GRAPHITE2 LICENSING |
| michael@0 | 2 | |
| michael@0 | 3 | Copyright 2011, SIL International |
| michael@0 | 4 | All rights reserved. |
| michael@0 | 5 | |
| michael@0 | 6 | This library is free software; you can redistribute it and/or modify |
| michael@0 | 7 | it under the terms of the GNU Lesser General Public License as published |
| michael@0 | 8 | by the Free Software Foundation; either version 2.1 of License, or |
| michael@0 | 9 | (at your option) any later version. |
| michael@0 | 10 | |
| michael@0 | 11 | This program is distributed in the hope that it will be useful, |
| michael@0 | 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| michael@0 | 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| michael@0 | 14 | Lesser General Public License for more details. |
| michael@0 | 15 | |
| michael@0 | 16 | You should also have received a copy of the GNU Lesser General Public |
| michael@0 | 17 | License along with this library in the file named "LICENSE". |
| michael@0 | 18 | If not, write to the Free Software Foundation, 51 Franklin Street, |
| michael@0 | 19 | Suite 500, Boston, MA 02110-1335, USA or visit their web page on the |
| michael@0 | 20 | internet at http://www.fsf.org/licenses/lgpl.html. |
| michael@0 | 21 | |
| michael@0 | 22 | Alternatively, the contents of this file may be used under the terms of the |
| michael@0 | 23 | Mozilla Public License (http://mozilla.org/MPL) or the GNU General Public |
| michael@0 | 24 | License, as published by the Free Software Foundation, either version 2 |
| michael@0 | 25 | of the License or (at your option) any later version. |
| michael@0 | 26 | */ |
| michael@0 | 27 | |
| michael@0 | 28 | /* |
| michael@0 | 29 | Description: |
| michael@0 | 30 | A set of fast template based decoders for decoding values of any C integer |
| michael@0 | 31 | type up to long int size laid out with most significant byte first or least |
| michael@0 | 32 | significant byte first (aka big endian or little endian). These are CPU |
| michael@0 | 33 | byte order agnostic and will function the same regardless of the CPUs native |
| michael@0 | 34 | byte order. |
| michael@0 | 35 | |
| michael@0 | 36 | Being template based means if the either le or be class is not used then |
| michael@0 | 37 | template code of unused functions will not be instantiated by the compiler |
| michael@0 | 38 | and thus shouldn't cause any overhead. |
| michael@0 | 39 | */ |
| michael@0 | 40 | |
| michael@0 | 41 | #include <cstddef> |
| michael@0 | 42 | |
| michael@0 | 43 | #pragma once |
| michael@0 | 44 | |
| michael@0 | 45 | |
| michael@0 | 46 | class be |
| michael@0 | 47 | { |
| michael@0 | 48 | template<int S> |
| michael@0 | 49 | inline static unsigned long int _peek(const unsigned char * p) { |
| michael@0 | 50 | return _peek<S/2>(p) << (S/2)*8 | _peek<S/2>(p+S/2); |
| michael@0 | 51 | } |
| michael@0 | 52 | public: |
| michael@0 | 53 | template<typename T> |
| michael@0 | 54 | inline static T peek(const void * p) { |
| michael@0 | 55 | return T(_peek<sizeof(T)>(static_cast<const unsigned char *>(p))); |
| michael@0 | 56 | } |
| michael@0 | 57 | |
| michael@0 | 58 | template<typename T> |
| michael@0 | 59 | inline static T read(const unsigned char * &p) { |
| michael@0 | 60 | const T r = T(_peek<sizeof(T)>(p)); |
| michael@0 | 61 | p += sizeof r; |
| michael@0 | 62 | return r; |
| michael@0 | 63 | } |
| michael@0 | 64 | |
| michael@0 | 65 | template<typename T> |
| michael@0 | 66 | inline static T swap(const T x) { |
| michael@0 | 67 | return T(_peek<sizeof(T)>(reinterpret_cast<const unsigned char *>(&x))); |
| michael@0 | 68 | } |
| michael@0 | 69 | |
| michael@0 | 70 | template<typename T> |
| michael@0 | 71 | inline static void skip(const unsigned char * &p, size_t n=1) { |
| michael@0 | 72 | p += sizeof(T)*n; |
| michael@0 | 73 | } |
| michael@0 | 74 | }; |
| michael@0 | 75 | |
| michael@0 | 76 | template<> |
| michael@0 | 77 | inline unsigned long int be::_peek<1>(const unsigned char * p) { return *p; } |
| michael@0 | 78 | |
| michael@0 | 79 | |
| michael@0 | 80 | class le |
| michael@0 | 81 | { |
| michael@0 | 82 | template<int S> |
| michael@0 | 83 | inline static unsigned long int _peek(const unsigned char * p) { |
| michael@0 | 84 | return _peek<S/2>(p) | _peek<S/2>(p+S/2) << (S/2)*8; |
| michael@0 | 85 | } |
| michael@0 | 86 | public: |
| michael@0 | 87 | template<typename T> |
| michael@0 | 88 | inline static T peek(const void * p) { |
| michael@0 | 89 | return T(_peek<sizeof(T)>(static_cast<const unsigned char *>(p))); |
| michael@0 | 90 | } |
| michael@0 | 91 | |
| michael@0 | 92 | template<typename T> |
| michael@0 | 93 | inline static T read(const unsigned char * &p) { |
| michael@0 | 94 | const T r = T(_peek<sizeof(T)>(p)); |
| michael@0 | 95 | p += sizeof r; |
| michael@0 | 96 | return r; |
| michael@0 | 97 | } |
| michael@0 | 98 | |
| michael@0 | 99 | template<typename T> |
| michael@0 | 100 | inline static T swap(const T x) { |
| michael@0 | 101 | return T(_peek<sizeof(T)>(reinterpret_cast<const unsigned char *>(&x))); |
| michael@0 | 102 | } |
| michael@0 | 103 | |
| michael@0 | 104 | template<typename T> |
| michael@0 | 105 | inline static void skip(const unsigned char * &p, size_t n=1) { |
| michael@0 | 106 | p += sizeof(T)*n; |
| michael@0 | 107 | } |
| michael@0 | 108 | }; |
| michael@0 | 109 | |
| michael@0 | 110 | template<> |
| michael@0 | 111 | inline unsigned long int le::_peek<1>(const unsigned char * p) { return *p; } |
| michael@0 | 112 |
