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Overview
Comment: | Add missing bt_varint.c file. |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA1: |
e5d33eb4729a9a800215133f69e740e0 |
User & Date: | dan 2013-10-19 05:50:29.213 |
Context
2013-10-19
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20:24 | Begin to add logging to btree database. check-in: ca59333dcd user: dan tags: trunk | |
05:50 | Add missing bt_varint.c file. check-in: e5d33eb472 user: dan tags: trunk | |
2013-10-18
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17:07 | Add new file bt_lock.c. Currently contains stubs only. check-in: a4c634a7d6 user: dan tags: trunk | |
Changes
Added src/bt_varint.c.
> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 | /* ** 2012-02-08 ** ** The author disclaims copyright to this source code. In place of ** a legal notice, here is a blessing: ** ** May you do good and not evil. ** May you find forgiveness for yourself and forgive others. ** May you share freely, never taking more than you give. ** ************************************************************************* ** ** SQLite4-compatible varint implementation. */ #include "btInt.h" /************************************************************************* ** The following is a copy of the varint.c module from SQLite 4. */ /* ** Decode the varint in z[]. Write the integer value into *pResult and ** return the number of bytes in the varint. */ static int btSqlite4GetVarint64(const unsigned char *z, u64 *pResult){ unsigned int x; if( z[0]<=240 ){ *pResult = z[0]; return 1; } if( z[0]<=248 ){ *pResult = (z[0]-241)*256 + z[1] + 240; return 2; } if( z[0]==249 ){ *pResult = 2288 + 256*z[1] + z[2]; return 3; } if( z[0]==250 ){ *pResult = (z[1]<<16) + (z[2]<<8) + z[3]; return 4; } x = (z[1]<<24) + (z[2]<<16) + (z[3]<<8) + z[4]; if( z[0]==251 ){ *pResult = x; return 5; } if( z[0]==252 ){ *pResult = (((u64)x)<<8) + z[5]; return 6; } if( z[0]==253 ){ *pResult = (((u64)x)<<16) + (z[5]<<8) + z[6]; return 7; } if( z[0]==254 ){ *pResult = (((u64)x)<<24) + (z[5]<<16) + (z[6]<<8) + z[7]; return 8; } *pResult = (((u64)x)<<32) + (0xffffffff & ((z[5]<<24) + (z[6]<<16) + (z[7]<<8) + z[8])); return 9; } /* ** Write a 32-bit unsigned integer as 4 big-endian bytes. */ static void btVarintWrite32(unsigned char *z, unsigned int y){ z[0] = (unsigned char)(y>>24); z[1] = (unsigned char)(y>>16); z[2] = (unsigned char)(y>>8); z[3] = (unsigned char)(y); } /* ** Write a varint into z[]. The buffer z[] must be at least 9 characters ** long to accommodate the largest possible varint. Return the number of ** bytes of z[] used. */ static int btSqlite4PutVarint64(unsigned char *z, u64 x){ unsigned int w, y; if( x<=240 ){ z[0] = (unsigned char)x; return 1; } if( x<=2287 ){ y = (unsigned int)(x - 240); z[0] = (unsigned char)(y/256 + 241); z[1] = (unsigned char)(y%256); return 2; } if( x<=67823 ){ y = (unsigned int)(x - 2288); z[0] = 249; z[1] = (unsigned char)(y/256); z[2] = (unsigned char)(y%256); return 3; } y = (unsigned int)x; w = (unsigned int)(x>>32); if( w==0 ){ if( y<=16777215 ){ z[0] = 250; z[1] = (unsigned char)(y>>16); z[2] = (unsigned char)(y>>8); z[3] = (unsigned char)(y); return 4; } z[0] = 251; btVarintWrite32(z+1, y); return 5; } if( w<=255 ){ z[0] = 252; z[1] = (unsigned char)w; btVarintWrite32(z+2, y); return 6; } if( w<=32767 ){ z[0] = 253; z[1] = (unsigned char)(w>>8); z[2] = (unsigned char)w; btVarintWrite32(z+3, y); return 7; } if( w<=16777215 ){ z[0] = 254; z[1] = (unsigned char)(w>>16); z[2] = (unsigned char)(w>>8); z[3] = (unsigned char)w; btVarintWrite32(z+4, y); return 8; } z[0] = 255; btVarintWrite32(z+1, w); btVarintWrite32(z+5, y); return 9; } /* ** End of SQLite 4 code. *************************************************************************/ int sqlite4BtVarintPut64(u8 *aData, i64 iVal){ return btSqlite4PutVarint64(aData, (u64)iVal); } int sqlite4BtVarintGet64(const u8 *aData, i64 *piVal){ return btSqlite4GetVarint64(aData, (u64 *)piVal); } int sqlite4BtVarintPut32(u8 *aData, int iVal){ return btSqlite4PutVarint64(aData, (u64)iVal); } int sqlite4BtVarintGet32(u8 *z, int *piVal){ u64 i; int ret; if( z[0]<=240 ){ *piVal = z[0]; return 1; } if( z[0]<=248 ){ *piVal = (z[0]-241)*256 + z[1] + 240; return 2; } if( z[0]==249 ){ *piVal = 2288 + 256*z[1] + z[2]; return 3; } if( z[0]==250 ){ *piVal = (z[1]<<16) + (z[2]<<8) + z[3]; return 4; } ret = btSqlite4GetVarint64(z, &i); *piVal = i; return ret; } int sqlite4BtVarintLen32(int n){ u8 aData[9]; return sqlite4BtVarintPut32(aData, n); } /* ** The argument is the first byte of a varint. This function returns the ** total number of bytes in the entire varint (including the first byte). */ int sqlite4BtVarintSize(u8 c){ if( c<241 ) return 1; if( c<249 ) return 2; return (int)(c - 246); } |