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base160 code used by ldb_sqlite3
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Copyright (C) 2004 Derrell Lipman
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 3 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, see <http://www.gnu.org/licenses/>.
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* ldb_sqlite3_base160()
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* Convert an integer value to a string containing the base 160 representation
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* of the integer. We always convert to a string representation that is 4
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* bytes in length, and we always null terminate.
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* The value to be converted
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* Buffer in which the result is to be placed
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static unsigned char base160tab[161] =
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48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , /* 0-9 */
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58 , 59 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , /* : ; A-H */
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73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , /* I-R */
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83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 97 , 98 , /* S-Z , a-b */
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99 , 100, 101, 102, 103, 104, 105, 106, 107, 108, /* c-l */
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109, 110, 111, 112, 113, 114, 115, 116, 117, 118, /* m-v */
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119, 120, 121, 122, 160, 161, 162, 163, 164, 165, /* w-z, latin1 */
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166, 167, 168, 169, 170, 171, 172, 173, 174, 175, /* latin1 */
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176, 177, 178, 179, 180, 181, 182, 183, 184, 185, /* latin1 */
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186, 187, 188, 189, 190, 191, 192, 193, 194, 195, /* latin1 */
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196, 197, 198, 199, 200, 201, 202, 203, 204, 205, /* latin1 */
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206, 207, 208, 209, 210, 211, 212, 213, 214, 215, /* latin1 */
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216, 217, 218, 219, 220, 221, 222, 223, 224, 225, /* latin1 */
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226, 227, 228, 229, 230, 231, 232, 233, 234, 235, /* latin1 */
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236, 237, 238, 239, 240, 241, 242, 243, 244, 245, /* latin1 */
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246, 247, 248, 249, 250, 251, 252, 253, 254, 255, /* latin1 */
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* Convert an unsigned long integer into a base160 representation of the
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* value to be converted
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* character array, 5 bytes long, into which the base160 representation
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* will be placed. The result will be a four-digit representation of the
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* number (with leading zeros prepended as necessary), and null
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lsqlite3_base160(unsigned long val,
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unsigned char result[5])
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for (i = 3; i >= 0; i--) {
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result[i] = base160tab[val % 160];
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* lsqlite3_base160Next()
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* Retrieve the next-greater number in the base160 sequence for the terminal
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* tree node (the last four digits). Only one tree level (four digits) are
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* base160 -- a character array containing either an empty string (in which
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* case no operation is performed), or a string of base160 digits
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* with a length of a multiple of four digits.
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* Upon return, the trailing four digits (one tree level) will
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* have been incremented by 1.
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* base160 -- the modified array
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lsqlite3_base160Next(char base160[])
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unsigned char * pTab;
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char * pBase160 = base160;
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* We need a minimum of four digits, and we will always get a multiple of
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if ((len = strlen(pBase160)) >= 4)
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pBase160 += strlen(pBase160) - 1;
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/* We only carry through four digits: one level in the tree */
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for (i = 0; i < 4; i++) {
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/* What base160 value does this digit have? */
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pTab = strchr(base160tab, *pBase160);
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/* Is there a carry? */
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if (pTab < base160tab + sizeof(base160tab) - 1) {
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/* Nope. Just increment this value and we're done. */
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* There's a carry. This value gets base160tab[0], we
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* decrement the buffer pointer to get the next higher-order
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* digit, and continue in the loop.
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*pBase160-- = base160tab[0];