326 lines
11 KiB
C++
326 lines
11 KiB
C++
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/*++
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Copyright (c) 1995 Microsoft Corporation
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Module Name:
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lexer.cxx
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Abstract:
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This file exports the class the class CLexer and other declarations
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that recognize the tokens in the string repressentation of the search
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filter. The format of the search filter according to the specification of
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Minimal SQL Grammar which is a subset of ANSI SQL 92.
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Author:
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Shankara Shastry [ShankSh] 13-Dec-1996
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*/
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/*
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#include <stdlib.h>
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#include <nt.h>
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#include <ntrtl.h>
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#include <nturtl.h>
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#include <windows.h>
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#include <wtypes.h>
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*/
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#include "dswarn.h"
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#include "..\..\..\include\procs.hxx"
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//
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// chunk of memory allocated for lexeme each time memory is needed.
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//
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#define LEXEME_UNIT_LENGTH 256
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//
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// Allowable tokens in the search string
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//
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#define TOKEN_ERROR 0
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#define TOKEN_EQ 1
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#define TOKEN_STAR 2
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#define TOKEN_LPARAN 3
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#define TOKEN_RPARAN 4
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#define TOKEN_INTEGER_LITERAL 5
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#define TOKEN_REAL_LITERAL 6
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#define TOKEN_STRING_LITERAL 7
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#define TOKEN_USER_DEFINED_NAME 8
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#define TOKEN_COMMA 9
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#define TOKEN_LT 10
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#define TOKEN_GT 11
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#define TOKEN_LE 12
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#define TOKEN_GE 13
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#define TOKEN_NE 14
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#define TOKEN_SELECT 15
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#define TOKEN_ALL 16
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#define TOKEN_FROM 17
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#define TOKEN_WHERE 18
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#define TOKEN_BOOLEAN_LITERAL 19
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#define TOKEN_AND 20
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#define TOKEN_OR 21
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#define TOKEN_NOT 22
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#define TOKEN_ORDER 23
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#define TOKEN_BY 24
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#define TOKEN_ASC 25
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#define TOKEN_DESC 26
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#define TOKEN_END 27
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#define TOKEN_START 0
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#define MAX_KEYWORD_LEN 20
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#define gKWTable { \
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L"SELECT", \
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L"ALL", \
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L"FROM", \
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L"WHERE", \
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L"AND", \
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L"OR", \
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L"NOT", \
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L"TRUE", \
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L"FALSE", \
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L"ON", \
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L"OFF", \
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L"YES", \
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L"NO", \
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L"ORDER", \
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L"BY", \
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L"ASC", \
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L"DESC", \
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L"" }
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#define gKW2Token {\
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TOKEN_SELECT, \
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TOKEN_ALL, \
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TOKEN_FROM, \
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TOKEN_WHERE, \
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TOKEN_AND, \
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TOKEN_OR, \
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TOKEN_NOT, \
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TOKEN_BOOLEAN_LITERAL, \
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TOKEN_BOOLEAN_LITERAL, \
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TOKEN_BOOLEAN_LITERAL, \
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TOKEN_BOOLEAN_LITERAL, \
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TOKEN_BOOLEAN_LITERAL, \
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TOKEN_BOOLEAN_LITERAL, \
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TOKEN_ORDER, \
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TOKEN_BY, \
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TOKEN_ASC, \
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TOKEN_DESC, \
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TOKEN_ERROR }
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//
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// Final states;
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//
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#define STATE_ERROR 100
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#define STATE_EQ 101
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#define STATE_STAR 102
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#define STATE_LPARAN 103
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#define STATE_RPARAN 104
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#define STATE_INTEGER_LITERAL 105
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#define STATE_REAL_LITERAL 106
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#define STATE_STRING_LITERAL 107
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#define STATE_USER_DEFINED_NAME 108
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#define STATE_COMMA 109
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#define STATE_LT 110
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#define STATE_GT 111
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#define STATE_LE 112
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#define STATE_GE 113
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#define STATE_NE 114
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#define STATE_SELECT 115
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#define STATE_ALL 116
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#define STATE_FROM 117
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#define STATE_WHERE 118
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#define STATE_BOOLEAN_LITERAL 119
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#define STATE_AND 120
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#define STATE_OR 121
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#define STATE_NOT 122
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#define STATE_ORDER 123
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#define STATE_BY 124
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#define STATE_ASC 125
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#define STATE_DESC 126
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#define STATE_END 127
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#define START_STATE 0
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#define FINAL_STATES_BEGIN 100
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#define MAX_DFA_STATES 12 // No. of states in the DFA
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// No. of different groups of characters for which the DFA behaves differently
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// For eg., all alphabetical characters generate the same behaviour and can be
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// considered the same as for DFA is concerned. This is mainly to reduce the
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// size of the table.
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#define MAX_CHAR_CLASSES 17
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// which specifies all other characters not mentioned explicitly.
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#define OTHER_CHAR_CLASS 14
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//Various actions associated with a particular entry in the DFA table.
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#define ACTION_DEFAULT 0
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#define ACTION_IGNORE_ESCAPECHAR 1
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#define ACTION_PUSHBACK_CHAR 2
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/* The state transition table is a table Table[i,j] with i being the current
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state and j being the input sets and the value Table[i,j] being the structure
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containing the next state and the action id to be performed. State 0 and 1 are
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the starting states when recognizing AttrType and AttrVal respectively.*/
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/* '<' '>' '=' '*' '(' ')' '+' '-' alpha-{e,E} digit '.' ''' {E,e} 'space' 'other' '\0' ',' */
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#define gStateTable {\
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/* 0 */ {{ 1, 0}, { 2, 0}, {101,0}, {102,0}, {103,0}, {104,0}, { 4, 0}, { 4, 0}, { 3, 0}, { 5, 0}, { 6, 0}, {10, 1}, { 3, 0}, { 0 ,1}, {100,0}, {127,0}, {109,0}}, \
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/* 1 */ {{110,2}, {114,0}, {112,0}, {110,2}, {110,2}, {110,2}, {110,2}, {110,2}, {110,2}, {110,2}, {110,2}, {110,2}, {110,2}, {110,2}, {110,2}, {110,2}, {110,2}}, \
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/* 2 */ {{111,2}, {111,2}, {113,0}, {111,2}, {111,2}, {111,2}, {111,2}, {111,2}, {111,2}, {111,2}, {111,2}, {111,2}, {111,2}, {111,2}, {111,2}, {111,2}, {111,2}}, \
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/* 3 */ {{108,2}, {108,2}, {108,2}, { 3,0}, {108,2}, {108,2}, { 3,0}, { 3,0}, { 3, 0}, { 3, 0}, { 3,0}, { 3,0}, { 3, 0}, {108,2}, {108,2}, {108,2}, {108,2}}, \
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/* 4 */ {{100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, { 5, 0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,2}, {100,0}}, \
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/* 5 */ {{105,2}, {105,2}, {105,2}, {105,2}, {105,2}, {105,2}, {105,2}, {105,2}, {105,2}, { 5, 0}, { 6, 0}, {105,2}, { 8, 0}, {105,2}, {105,2}, {105,2}, {105,2}}, \
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/* 6 */ {{100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, { 7, 0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,2}, {100,0}}, \
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/* 7 */ {{106,2}, {106,2}, {106,2}, {106,2}, {106,2}, {106,2}, {106,2}, {106,2}, {106,2}, { 7, 0}, {106,2}, {106,2}, { 8, 0}, {106,2}, {106,2}, {106,2}, {106,2}}, \
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/* 8 */ {{100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, { 9, 0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,2}, {100,0}}, \
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/* 9 */ {{106,2}, {106,2}, {106,2}, {106,2}, {106,2}, {106,2}, {106,2}, {106,2}, {106,2}, { 9, 0}, {106,2}, {106,2}, {106,2}, {106,2}, {106,2}, {106,2}, {106,2}}, \
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/* 10*/ {{ 10,0}, { 10,0}, { 10,0}, { 10,0}, { 10,0}, { 10,0}, { 10,0}, { 10,0}, { 10,0}, { 10,0}, { 10,0}, { 11,1}, { 10,0}, { 10,0}, { 10,0}, {100,2}, { 10,0}}, \
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/* 11*/ {{107,2}, {107,2}, {107,2}, {107,2}, {107,2}, {107,2}, {107,2}, {107,2}, {107,2}, {107,2}, {107,2}, { 10,0}, {107,2}, {107,2}, {107,2}, {107,2}, {107,2}}}
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// This is the table containing the character class to which a particular
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// character belongs. This is used to index the state transition table.
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// Basically, for each of the characters possible, this points to one of the
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// columns in the state transition table defined above.
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// Most of them are 14 indicating that they are 'other'
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#define gCharClassTable { \
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15, 14, 14, 14, 14, 14, 14, 14, 14, 13, 13, 13, 13, 13, 14, 14, \
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14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, \
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13, 14, 14, 14, 14, 14, 14, 11, 4, 5, 3, 6, 16, 7, 10, 14, \
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9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 14, 14, 0, 2, 1, 14, \
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14, 8, 8, 8, 8, 12, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, \
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8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 14, 14, 14, 14, 14, \
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14, 8, 8, 8, 8, 12, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, \
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8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 14, 14, 14, 14, 14, \
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14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, \
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14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, \
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14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, \
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14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, \
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14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, \
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14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, \
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14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, \
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14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, \
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}
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// structure representing an entry in the DFA;
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typedef struct DFA_STATE {
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DWORD dwNextState;
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DWORD dwActionId;
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}DFA_STATE;
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//CLexeme maintains the lexeme corresponding to the current token
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class CLexeme
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{
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public:
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CLexeme();
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HRESULT
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PushNextChar(
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WCHAR wcNextChar);
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~CLexeme();
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void
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ResetLexeme() { _dwIndex = 0; }
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LPWSTR
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CLexeme::GetLexeme() { return (_pszLexeme); }
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private:
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LPWSTR _pszLexeme;
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DWORD _dwMaxLength;
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DWORD _dwIndex;
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};
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//CLexer maintains all the state information and returns the next token
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class CLexer
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{
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public:
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// Initialize the lexer with the string szBuffer.
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CLexer(LPWSTR szBuffer);
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~CLexer();
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// Return the next token and its value.
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HRESULT
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CLexer::GetNextToken(LPWSTR *szToken, LPDWORD pdwToken);
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HRESULT
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CLexer::GetCurrentToken(
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LPWSTR *ppszToken,
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LPDWORD pdwToken
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);
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private:
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WCHAR
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CLexer::NextChar();
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void
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CLexer::PushbackChar();
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DWORD
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CLexer::GetCharClass(WCHAR wc) {
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if(wc < 256)
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return (_pCharClassTable[wc]);
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else
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// some unicode character; put in the other class.
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return (OTHER_CHAR_CLASS);
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}
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// Given the currentState reached and the character just scanned and the
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// action id, perform the action
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HRESULT
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CLexer::PerformAction(
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DWORD dwCurrState,
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WCHAR wcCurrChar,
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DWORD dwActionId
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);
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DWORD
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CLexer::GetTokenFromState(
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DWORD dwCurrState
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);
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// The common DFA state transition table for all the instances of the class
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static DFA_STATE _pStateTable[][MAX_CHAR_CLASSES];
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// The common table mapping the characters to the character classes.
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static DWORD _pCharClassTable[];
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// The table to hold the keywords
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static WCHAR _pKeywordTable[][MAX_KEYWORD_LEN];
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static DWORD _pKW2Token[];
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LPWSTR _Buffer; // String being analysed
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LPWSTR _ptr; // pointer to the next character to be analysed.
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DFA_STATE _currState; // maintains the state information for the DFA
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DWORD _dwState; // maintains the state information for the DFA
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DWORD _dwEndofString; // To indicate end of pattern
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CLexeme _lexeme;
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DWORD _dwStateSave; // maintains the state information for the DFA
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BOOL _bInitialized;
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};
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