[855] | 1 | /**************************************************************************
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| 2 | *
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| 3 | * QueryLex.cpp -- Lexical analyser for a simple query language
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| 4 | * Copyright (C) 2000 Rodger McNab
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| 5 | *
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| 6 | * This program is free software; you can redistribute it and/or modify
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| 7 | * it under the terms of the GNU General Public License as published by
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| 8 | * the Free Software Foundation; either version 2 of the License, or
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| 9 | * (at your option) any later version.
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| 10 | *
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| 11 | * This program is distributed in the hope that it will be useful,
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| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 14 | * GNU General Public License for more details.
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| 15 | *
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| 16 | * You should have received a copy of the GNU General Public License
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| 17 | * along with this program; if not, write to the Free Software
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| 18 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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| 19 | *
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| 20 | * $Id: QueryLex.cpp 855 2000-01-14 02:17:52Z sjboddie $
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| 21 | *
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| 22 | **************************************************************************/
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| 23 |
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| 24 | #include "QueryLex.h"
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| 25 | #include "unitool.h"
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| 26 | #include "words.h"
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| 27 |
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| 28 | inline void AddNChar (UCArray::const_iterator &here,
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| 29 | UCArray &text,
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| 30 | int len) {
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| 31 | while (len > 0) {
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| 32 | text.push_back (*here++);
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| 33 | len--;
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| 34 | }
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| 35 | }
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| 36 |
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| 37 | static bool ParseInteger (UCArray::const_iterator &here,
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| 38 | UCArray::const_iterator end,
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| 39 | LexEl &el) {
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| 40 | el.Clear();
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| 41 |
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| 42 | // this version of end is used in unitool
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| 43 | UCArray::const_iterator endMinus1 = end-1;
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| 44 |
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| 45 | int charLen;
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| 46 | unsigned short c; // one character lookahead
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| 47 | charLen = parse_utf8_char (here, endMinus1, &c);
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| 48 |
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| 49 | // check for positive or negative
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| 50 | bool neg = false;
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| 51 | if (c == '+') {
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| 52 | AddNChar (here, el.text, charLen);
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| 53 | charLen = parse_utf8_char (here, endMinus1, &c);
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| 54 | } else if (c == '-') {
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| 55 | neg = true;
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| 56 | AddNChar (here, el.text, charLen);
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| 57 | charLen = parse_utf8_char (here, endMinus1, &c);
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| 58 | }
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| 59 |
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| 60 | // read in number part
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| 61 | el.num = 0;
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| 62 | el.lexType = IntegerE;
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| 63 | while (c >= '0' && c <= '9') {
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| 64 | el.num = el.num*10 + c - '0';
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| 65 | AddNChar (here, el.text, charLen);
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| 66 | charLen = parse_utf8_char (here, endMinus1, &c);
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| 67 | }
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| 68 |
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| 69 | if (neg) el.num *= -1;
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| 70 |
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| 71 | return (!el.text.empty());
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| 72 | }
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| 73 |
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| 74 | static bool ParseTerm (UCArray::const_iterator &here,
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| 75 | UCArray::const_iterator end,
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| 76 | UCArray &text) {
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| 77 | UCArray::const_iterator endMinus1 = end-1;
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| 78 | here = ParseIndexWord (here, endMinus1, text);
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| 79 | return !text.empty();
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| 80 | }
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| 81 |
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| 82 |
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| 83 | bool ParseLexEl (UCArray::const_iterator &here,
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| 84 | UCArray::const_iterator end,
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| 85 | LexEl &el) {
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| 86 | el.Clear();
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| 87 |
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| 88 | // strange things can happen if here == end == 0
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| 89 | if (here == end) return false;
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| 90 |
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| 91 | // this version of end is used in unitool
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| 92 | UCArray::const_iterator endMinus1 = end-1;
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| 93 |
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| 94 | // ignore all white space
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| 95 | int charLen;
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| 96 | unsigned short c; // one character lookahead
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| 97 | charLen = parse_utf8_char (here, endMinus1, &c);
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| 98 | while (here != end && is_unicode_space (c)) {
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| 99 | here += charLen;
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| 100 | charLen = parse_utf8_char (here, endMinus1, &c);
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| 101 | }
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| 102 | if (here == end) return false;
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| 103 |
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| 104 | if (c == '(') {
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| 105 | el.lexType = OpenBracketE;
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| 106 | AddNChar (here, el.text, charLen);
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| 107 | return true;
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| 108 |
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| 109 | } else if (c == ')') {
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| 110 | el.lexType = CloseBracketE;
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| 111 | AddNChar (here, el.text, charLen);
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| 112 | return true;
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| 113 |
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| 114 | } else if (c == '\"') {
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| 115 | el.lexType = QuoteE;
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| 116 | AddNChar (here, el.text, charLen);
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| 117 | return true;
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| 118 |
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| 119 | } else if (c == '#') {
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| 120 | el.lexType = TermWeightE;
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| 121 | AddNChar (here, el.text, charLen);
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| 122 | return true;
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| 123 |
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| 124 | } else if (c == '$') {
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| 125 | el.lexType = StemMethodE;
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| 126 | AddNChar (here, el.text, charLen);
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| 127 | return true;
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| 128 |
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| 129 | } else if (c == '^') {
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| 130 | el.lexType = RangeE;
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| 131 | AddNChar (here, el.text, charLen);
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| 132 | return true;
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| 133 |
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| 134 | } else if (c == '@') {
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| 135 | el.lexType = AtE;
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| 136 | AddNChar (here, el.text, charLen);
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| 137 | return true;
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| 138 |
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| 139 | } else if (c == ':') {
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| 140 | el.lexType = TagE;
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| 141 | AddNChar (here, el.text, charLen);
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| 142 | return true;
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| 143 |
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| 144 | } else if (c == '+' || c == '-' ||
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| 145 | (c >= '0' && c <= '9')) {
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| 146 | return ParseInteger (here, end, el);
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| 147 | }
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| 148 |
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| 149 | // assume it is a term of some sort
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| 150 | if (!ParseTerm (here, end, el.text)) return false;
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| 151 |
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| 152 | UCArray AND; SetCStr (AND, "AND");
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| 153 | if (el.text == AND) {
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| 154 | el.lexType = AndOpE;
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| 155 | return true;
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| 156 | }
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| 157 | UCArray OR; SetCStr (OR, "OR");
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| 158 | if (el.text == OR) {
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| 159 | el.lexType = OrOpE;
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| 160 | return true;
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| 161 | }
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| 162 | UCArray NOT; SetCStr (NOT, "NOT");
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| 163 | if (el.text == NOT) {
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| 164 | el.lexType = NotOpE;
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| 165 | return true;
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| 166 | }
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| 167 |
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| 168 | el.lexType = TermE;
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| 169 | return true;
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| 170 | }
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| 171 |
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