/* base160 code used by ldb_sqlite3 Copyright (C) 2004 Derrell Lipman This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, see <http://www.gnu.org/licenses/>. */ /* * ldb_sqlite3_base160() * * Convert an integer value to a string containing the base 160 representation * of the integer. We always convert to a string representation that is 4 * bytes in length, and we always null terminate. * * Parameters: * val -- * The value to be converted * * result -- * Buffer in which the result is to be placed * * Returns: * nothing */ static unsigned char base160tab[161] = { 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , /* 0-9 */ 58 , 59 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , /* : ; A-H */ 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , /* I-R */ 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 97 , 98 , /* S-Z , a-b */ 99 , 100, 101, 102, 103, 104, 105, 106, 107, 108, /* c-l */ 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, /* m-v */ 119, 120, 121, 122, 160, 161, 162, 163, 164, 165, /* w-z, latin1 */ 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, /* latin1 */ 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, /* latin1 */ 186, 187, 188, 189, 190, 191, 192, 193, 194, 195, /* latin1 */ 196, 197, 198, 199, 200, 201, 202, 203, 204, 205, /* latin1 */ 206, 207, 208, 209, 210, 211, 212, 213, 214, 215, /* latin1 */ 216, 217, 218, 219, 220, 221, 222, 223, 224, 225, /* latin1 */ 226, 227, 228, 229, 230, 231, 232, 233, 234, 235, /* latin1 */ 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, /* latin1 */ 246, 247, 248, 249, 250, 251, 252, 253, 254, 255, /* latin1 */ '\0' }; /* * lsqlite3_base160() * * Convert an unsigned long integer into a base160 representation of the * number. * * Parameters: * val -- * value to be converted * * result -- * character array, 5 bytes long, into which the base160 representation * will be placed. The result will be a four-digit representation of the * number (with leading zeros prepended as necessary), and null * terminated. * * Returns: * Nothing */ void lsqlite3_base160(unsigned long val, unsigned char result[5]) { int i; for (i = 3; i >= 0; i--) { result[i] = base160tab[val % 160]; val /= 160; } result[4] = '\0'; } /* * lsqlite3_base160Next() * * Retrieve the next-greater number in the base160 sequence for the terminal * tree node (the last four digits). Only one tree level (four digits) are * operated on. * * Parameters: * base160 -- a character array containing either an empty string (in which * case no operation is performed), or a string of base160 digits * with a length of a multiple of four digits. * * Upon return, the trailing four digits (one tree level) will * have been incremented by 1. * * Returns: * base160 -- the modified array */ char * lsqlite3_base160Next(char base160[]) { int i; int len; unsigned char * pTab; char * pBase160 = base160; /* * We need a minimum of four digits, and we will always get a multiple of * four digits. */ if (len = strlen(pBase160)) >= 4) { pBase160 += strlen(pBase160) - 1; /* We only carry through four digits: one level in the tree */ for (i = 0; i < 4; i++) { /* What base160 value does this digit have? */ pTab = strchr(base160tab, *pBase160); /* Is there a carry? */ if (pTab < base160tab + sizeof(base160tab) - 1) { /* Nope. Just increment this value and we're done. */ *pBase160 = *++pTab; break; } else { /* * There's a carry. This value gets base160tab[0], we * decrement the buffer pointer to get the next higher-order * digit, and continue in the loop. */ *pBase160-- = base160tab[0]; } } } return base160; }