diff options
Diffstat (limited to 'src/unstable/bitstring.h')
| -rw-r--r-- | src/unstable/bitstring.h | 224 |
1 files changed, 224 insertions, 0 deletions
diff --git a/src/unstable/bitstring.h b/src/unstable/bitstring.h new file mode 100644 index 0000000..7a8fc48 --- /dev/null +++ b/src/unstable/bitstring.h | |||
| @@ -0,0 +1,224 @@ | |||
| 1 | /* | ||
| 2 | * Copyright (C) 2007-2011 Xagasoft, All rights reserved. | ||
| 3 | * | ||
| 4 | * This file is part of the libbu++ library and is released under the | ||
| 5 | * terms of the license contained in the file LICENSE. | ||
| 6 | */ | ||
| 7 | |||
| 8 | #ifndef BU_BITSTRING_H | ||
| 9 | #define BU_BITSTRING_H | ||
| 10 | |||
| 11 | #include "bu/util.h" | ||
| 12 | #include "bu/string.h" | ||
| 13 | |||
| 14 | namespace Bu | ||
| 15 | { | ||
| 16 | /** | ||
| 17 | * Manages an arbitrarily sized string of bits, and allows basic interaction | ||
| 18 | * with them. This includes basic non-mathematical bitwise operations such | ||
| 19 | * as setting and testing bits, shifting the string, inversion and a few | ||
| 20 | * extras like randomization. On linux systems this takes advantage of long | ||
| 21 | * longs giving you a maximum size of about 2tb per string. | ||
| 22 | * | ||
| 23 | * For more general and mathematical type interaction see BitStringInt. | ||
| 24 | * | ||
| 25 | */ | ||
| 26 | class BitString | ||
| 27 | { | ||
| 28 | public: | ||
| 29 | /** | ||
| 30 | * Constructs a blank and basic BitString. This is actually useful | ||
| 31 | * since you can resize BitStrings at will, and even retain the data | ||
| 32 | * that was in them. | ||
| 33 | */ | ||
| 34 | BitString(); | ||
| 35 | |||
| 36 | /** | ||
| 37 | * Constructs a BitString object as a copy of another BitString. This | ||
| 38 | * is a standard copy constructor and produces an exact duplicate of | ||
| 39 | * the original BitString object. | ||
| 40 | *@param xSrc Source BitString to copy data from. | ||
| 41 | */ | ||
| 42 | BitString( const BitString &xSrc ); | ||
| 43 | |||
| 44 | /** | ||
| 45 | * Constructs a BitString with length iBits and optionally fills it with | ||
| 46 | * random data. The default setting, to not fill randomly, will produce | ||
| 47 | * a blank (all zeros) string of the specified size. | ||
| 48 | *@param iBits The length of the new BitString in bits. | ||
| 49 | *@param bFillRandomly Wether or not to randomize this BitString. | ||
| 50 | */ | ||
| 51 | BitString( long iBits, bool bFillRandomly=false ); | ||
| 52 | |||
| 53 | /** | ||
| 54 | * Virtual deconstructor for the BitString. Takes care of cleanup for | ||
| 55 | * you. What more do you really want to know? | ||
| 56 | */ | ||
| 57 | virtual ~BitString(); | ||
| 58 | |||
| 59 | // basic interaction | ||
| 60 | /** | ||
| 61 | * Sets a bit in the BitString. In it's normal mode it will always turn | ||
| 62 | * the given bit on, to clear a bit set bBitState to false instead of | ||
| 63 | * true. This operation runs in O(1). | ||
| 64 | *@param iBit The zero-based index of the bit to modify. | ||
| 65 | *@param bBitState Set to true to set the bit to 1, set to false to set | ||
| 66 | * the bit to 0. | ||
| 67 | */ | ||
| 68 | void setBit( long iBit, bool bBitState=true ); | ||
| 69 | |||
| 70 | /** | ||
| 71 | * Reverses the state of the given bit. This will set the given bit | ||
| 72 | * to a 1 if it was 0, and to 0 if it was 1. This operation runs in | ||
| 73 | * O(1), and it should be noted that using this is marginally faster | ||
| 74 | * than doing the test and flip yourself with getBit and setBit since | ||
| 75 | * it uses a bitwise not operation and doesn't actually test the bit | ||
| 76 | * itself. | ||
| 77 | *@param iBit The index of the bit to flip. | ||
| 78 | */ | ||
| 79 | void flipBit( long iBit ); | ||
| 80 | |||
| 81 | /** | ||
| 82 | * Gets the state of the given bit. This follows the standard | ||
| 83 | * convention used so far, a returned value of true means the bit in | ||
| 84 | * question is 1, and a value of flase means the bit is 0. All bits | ||
| 85 | * out of range of the BitString are treated as off, but are | ||
| 86 | * "accessable" in that this does not produce any kind of error | ||
| 87 | * message. This is intentional. This operation runs in O(1). | ||
| 88 | *@param iBit The index of the bit to test. | ||
| 89 | *@returns True for a 1, false for a 0. | ||
| 90 | */ | ||
| 91 | bool getBit( long iBit ); | ||
| 92 | |||
| 93 | /** | ||
| 94 | * Inverts the entire BitString, in effect this calls flipBit on every | ||
| 95 | * bit in the string but is faster since it can operate on whole bytes | ||
| 96 | * at a time instead of individual bits. This operation runs in O(N). | ||
| 97 | */ | ||
| 98 | void invert(); | ||
| 99 | |||
| 100 | /** | ||
| 101 | * Returns the number of bits allocated in this BitString. This | ||
| 102 | * operation runs in O(1) time since this value is cached and not | ||
| 103 | * computed. | ||
| 104 | *@returns The number of bits allocated in this BitString. | ||
| 105 | */ | ||
| 106 | DEPRECATED | ||
| 107 | long getBitLength(); | ||
| 108 | |||
| 109 | long getSize(); | ||
| 110 | |||
| 111 | /** | ||
| 112 | * Sets the entire BitString to zeros, but it does it very quickly. | ||
| 113 | * This operation runs in O(N). | ||
| 114 | */ | ||
| 115 | void clear(); | ||
| 116 | |||
| 117 | /** | ||
| 118 | * Gets another BitString that is autonomous of the current one | ||
| 119 | * (contains a copy of the memory, not a pointer) and contains a subset | ||
| 120 | * of the data in the current BitString. This is an inclusive | ||
| 121 | * operation, so grabbing bits 0-5 will give you 6 bits. This is based | ||
| 122 | * on a very tricky bit-shifting algorithm and runs very quickly, in | ||
| 123 | * O(N) time. Passing in a value of zero for iUpper, or any value for | ||
| 124 | * iUpper that is less than iLower will set iUpper equal to the number | ||
| 125 | * of bits in the BitString. | ||
| 126 | *@param iLower The first bit in the current string, will be the first | ||
| 127 | * bit (0 index) in the new sub string. | ||
| 128 | *@param iUpper The last bit in the current string, will be the last | ||
| 129 | * bit in the new sub string. iUpper is included in the sub string. | ||
| 130 | *@returns A new BitString object ready to be used. Please note that | ||
| 131 | * managing this new object is up to whomever calls this function. | ||
| 132 | */ | ||
| 133 | class BitString getSubString( long iLower, long iUpper ); | ||
| 134 | |||
| 135 | /** | ||
| 136 | * Sets the number of bits in the BitString, allocating more memory if | ||
| 137 | * necesarry, or freeing extra if able. The default operation of this | ||
| 138 | * function clears all data in the BitString while resizing it. If you | ||
| 139 | * would like to keep as much of the data that you had in your BitString | ||
| 140 | * as possible, then set bClear to false, and any data that will fit | ||
| 141 | * into the new BitString length will be retained. If increasing the | ||
| 142 | * number of bits, the new bits will come into existance cleared (set | ||
| 143 | * to 0). | ||
| 144 | *@param iLength The number of bits to set the BitString to. | ||
| 145 | *@param bClear When true, all data is eradicated and zeroed, when set | ||
| 146 | * to false an effort is made to retain the existing data. | ||
| 147 | *@returns true on success, false on failure. | ||
| 148 | */ | ||
| 149 | DEPRECATED | ||
| 150 | bool setBitLength( long iLength, bool bClear=true ); | ||
| 151 | bool setSize( long iLength, bool bClear=true ); | ||
| 152 | |||
| 153 | /** | ||
| 154 | * Randomize the entire BitString, one bit at a time. This is actually | ||
| 155 | * the function called by the constructor when the user selects initial | ||
| 156 | * randomization. This function uses the system random() function, so | ||
| 157 | * srandom may be used to effect this process at will. | ||
| 158 | */ | ||
| 159 | void randomize(); | ||
| 160 | |||
| 161 | /** | ||
| 162 | * Operates exactly like <<. All data in the BitString is shifted to | ||
| 163 | * the left by some number of bits, any data pushed off the edge of the | ||
| 164 | * BitString is lost, and all new data coming in will be zeroed. | ||
| 165 | * Using a negative value in the shiftLeft function will turn it into | ||
| 166 | * the shiftRight function. | ||
| 167 | *@param iAmt The number of bit positions to shift all data. | ||
| 168 | */ | ||
| 169 | void shiftLeft( long iAmt ); // just like << | ||
| 170 | |||
| 171 | /** | ||
| 172 | * Operates exactly like >>. All data in the BitString is shifted to | ||
| 173 | * the right by some number of bits, any data pushed off the edge of the | ||
| 174 | * BitString is lost, and all new data coming in will be zeroed. | ||
| 175 | * Using a negative value in the shiftRight function will turn it into | ||
| 176 | * the shiftLeft function. | ||
| 177 | *@param iAmt The number of bit positions to shift all data. | ||
| 178 | */ | ||
| 179 | void shiftRight( long iAmt ); // just like >> | ||
| 180 | |||
| 181 | /** | ||
| 182 | * Searches through the BitString and returns the index of the highest | ||
| 183 | * order bit position (the highest index) with an on bit (a bit set to | ||
| 184 | * 1). This is a handy helper function and rather faster than calling | ||
| 185 | * getBit() over and over again. | ||
| 186 | *@returns The index of the highest indexed on bit. | ||
| 187 | */ | ||
| 188 | long getHighestOrderBitPos(); | ||
| 189 | |||
| 190 | // Conversion | ||
| 191 | /** | ||
| 192 | * Convert a block of data (no more than 32 bits) to a primitive long | ||
| 193 | * type. | ||
| 194 | * This is done in a little bit interesting way, so it may not always be | ||
| 195 | * the fastest way to access the data that you want, although it will | ||
| 196 | * always ensure that the long that is written makes numerical sense, as | ||
| 197 | * we write numbers, regaurdless of platform. | ||
| 198 | *@param iStart The first bit in the BitString to include in the long | ||
| 199 | *@param iSize THe number of bits to include, if this value is set over | ||
| 200 | * 32 it will be automatically truncated to, or however many bits there | ||
| 201 | * are in a long in your system. | ||
| 202 | *@returns A long converted from your raw BitString data. | ||
| 203 | */ | ||
| 204 | long toLong( long iStart = 0, long iSize = 32 ); | ||
| 205 | |||
| 206 | Bu::String toString(); | ||
| 207 | |||
| 208 | //operators | ||
| 209 | BitString &operator=( const BitString &xSrc ); | ||
| 210 | BitString operator~(); | ||
| 211 | BitString operator<<( const long iAmt ); | ||
| 212 | BitString operator>>( const long iAmt ); | ||
| 213 | |||
| 214 | private: | ||
| 215 | void fixup(); | ||
| 216 | void setMask(); | ||
| 217 | unsigned char *caData; | ||
| 218 | long iBits; | ||
| 219 | long iBytes; | ||
| 220 | unsigned char cTopByteMask; | ||
| 221 | }; | ||
| 222 | }; | ||
| 223 | |||
| 224 | #endif | ||
