C:/knet/include/kNet/VLEPacker.h
Go to the documentation of this file.
00001 /* Copyright 2010 Jukka Jylänki 00002 00003 Licensed under the Apache License, Version 2.0 (the "License"); 00004 you may not use this file except in compliance with the License. 00005 You may obtain a copy of the License at 00006 00007 http://www.apache.org/licenses/LICENSE-2.0 00008 00009 Unless required by applicable law or agreed to in writing, software 00010 distributed under the License is distributed on an "AS IS" BASIS, 00011 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 00012 See the License for the specific language governing permissions and 00013 limitations under the License. */ 00014 #pragma once 00015 00019 #include "BitOps.h" 00020 #include "NetException.h" 00021 00022 namespace kNet 00023 { 00024 00027 template<int bits1, int bits2> 00028 class VLEType2 00029 { 00030 public: 00031 static const int numBits1 = bits1; 00032 static const int numBits2 = bits2; 00033 00034 // For compatibility when inter-using with VLEType3 00035 static const int numBits3 = 0; 00036 00037 static const u32 maxValue1 = LSBT<numBits1>::val; 00038 static const u32 maxValue2 = LSBT<numBits1+numBits2>::val; 00039 00040 static const u32 maxValue = maxValue2; 00041 00042 static const u32 bitsValue1 = numBits1 + 1; 00043 static const u32 bitsValue2 = numBits1 + 1 + numBits2; 00044 00045 static const u32 maxBits = bitsValue2; 00046 00047 static const u32 bitMask1 = BitMaskT<0, numBits1>::val; 00048 static const u32 bitMask2 = BitMaskT<bitsValue1, numBits2>::val;// == ((1 << numBits2) - 1) << bitsValue1; 00049 00050 static int GetEncodedBitLength(u32 value) 00051 { 00052 if (value <= maxValue1) 00053 return bitsValue1; 00054 else 00055 return bitsValue2; 00056 } 00057 00058 static u32 Encode(u32 value) 00059 { 00060 if (value > maxValue) 00061 throw NetException("VLEType2::Encode: Trying to encode too large value!"); 00062 if (value <= maxValue1) 00063 return value; 00064 else 00065 { 00066 if (value > maxValue) 00067 value = maxValue; 00068 00069 u32 lowPart = value & BitMaskT<0, numBits1>::val; 00070 u32 medPart = value & BitMaskT<numBits1, numBits2>::val; 00071 assert(medPart != 0); 00072 return lowPart | (1 << numBits1) | (medPart << 1); 00073 } 00074 } 00075 00076 static u32 Decode(u32 value) 00077 { 00078 if ((value & (1 << numBits1)) == 0) 00079 return value; 00080 else 00081 { 00082 u32 lowPart = value & BitMaskT<0, numBits1>::val; 00083 u32 medPart = value & BitMaskT<numBits1+1, numBits2>::val; 00084 return lowPart | (medPart >> 1); 00085 } 00086 } 00087 }; 00088 00091 template<int bits1, int bits2, int bits3> 00092 class VLEType3 00093 { 00094 public: 00095 static const int numBits1 = bits1; 00096 static const int numBits2 = bits2; 00097 static const int numBits3 = bits3; 00098 00099 static const u32 maxValue1 = LSBT<numBits1>::val; 00100 static const u32 maxValue2 = LSBT<numBits1+numBits2>::val; 00101 static const u32 maxValue3 = LSBT<numBits1+numBits2+numBits3>::val; 00102 00103 static const u32 maxValue = maxValue3; 00104 00105 static const u32 bitsValue1 = numBits1 + 1; 00106 static const u32 bitsValue2 = numBits1 + 1 + numBits2 + 1; 00107 static const u32 bitsValue3 = numBits1 + 1 + numBits2 + 1 + numBits3; 00108 00109 static const u32 maxBits = bitsValue3; 00110 00111 static const u32 bitMask1 = BitMaskT<0, numBits1>::val; 00112 static const u32 bitMask2 = BitMaskT<bitsValue1, numBits2>::val; // == ((1 << numBits2) - 1) << bitsValue1; 00113 static const u32 bitMask3 = BitMaskT<bitsValue2, numBits3>::val; // == ((1 << numBits3) - 1) << bitsValue2; 00114 00115 static int GetEncodedBitLength(u32 value) 00116 { 00117 if (value <= maxValue1) 00118 return bitsValue1; 00119 else if (value <= maxValue2) 00120 return bitsValue2; 00121 else 00122 return bitsValue3; 00123 } 00124 00125 static u32 Encode(u32 value) 00126 { 00127 if (value > maxValue) 00128 throw NetException("VLEType2::Encode: Trying to encode too large value!"); 00129 00130 if (value > maxValue) 00131 value = maxValue; 00132 00133 if (value <= maxValue1) 00134 return value; 00135 else if (value <= maxValue2) 00136 { 00137 u32 lowPart = value & BitMaskT<0, numBits1>::val; 00138 u32 medPart = value & BitMaskT<numBits1, numBits2>::val; 00139 assert(medPart != 0); 00140 return lowPart | (1 << numBits1) | (medPart << 1); 00141 } 00142 else 00143 { 00144 u32 lowPart = value & BitMaskT<0, numBits1>::val; 00145 u32 medPart = value & BitMaskT<numBits1, numBits2>::val; 00146 u32 highPart = value & BitMaskT<numBits1+numBits2, numBits3>::val; 00147 assert(highPart != 0); 00148 return lowPart | (1 << numBits1) | (medPart << 1) | (1 << (bitsValue1 + numBits2)) | (highPart << 2); 00149 } 00150 } 00151 00152 static u32 Decode(u32 value) 00153 { 00154 if ((value & (1 << numBits1)) == 0) 00155 return value; 00156 else if ((value & (1 << (bitsValue1 + numBits2))) == 0) 00157 { 00158 u32 lowPart = value & BitMaskT<0, numBits1>::val; 00159 u32 medPart = value & BitMaskT<numBits1+1, numBits2>::val; 00160 return lowPart | (medPart >> 1); 00161 } 00162 else 00163 { 00164 u32 lowPart = value & BitMaskT<0, numBits1>::val; 00165 u32 medPart = (value & BitMaskT<numBits1+1, numBits2>::val); 00166 u32 highPart = (value & BitMaskT<numBits1+1+numBits2+1, numBits3>::val); 00167 return lowPart | (medPart >> 1) | (highPart >> 2); 00168 } 00169 } 00170 }; 00171 00172 typedef VLEType3<7, 7, 16> VLE8_16_32; 00173 typedef VLEType2<7, 8> VLE8_16; 00174 typedef VLEType2<7, 24> VLE8_32; 00175 typedef VLEType2<15, 16> VLE16_32; 00176 00177 } // ~kNet
