270 lines
11 KiB
C++
270 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 CQryLexer 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 RFC 1960.
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Author:
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Shankara Shastry [ShankSh] 08-Jul-1996
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*/
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#ifndef _QRYLEXER_HXX
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#define _QRYLEXER_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_LPARAN 1
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#define TOKEN_RPARAN 2
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#define TOKEN_OR 3
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#define TOKEN_AND 4
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#define TOKEN_NOT 5
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#define TOKEN_APPROX_EQ 6
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#define TOKEN_EQ 7
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#define TOKEN_LE 8
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#define TOKEN_GE 9
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#define TOKEN_PRESENT 10
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#define TOKEN_ATTRTYPE 11
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#define TOKEN_ATTRVAL 12
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#define TOKEN_ENDINPUT 13
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#define TOKEN_START 0
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//
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// Final states;
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//
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#define ERROR_STATE 100
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#define STATE_LPARAN 101
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#define STATE_RPARAN 102
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#define STATE_OR 103
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#define STATE_AND 104
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#define STATE_NOT 105
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#define STATE_APPORX_EQ 106
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#define STATE_EQ 107
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#define STATE_LE 108
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#define STATE_GE 109
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#define STATE_PRESENT 110
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#define STATE_ATTRTYPE 111
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#define STATE_ATTRVAL 112
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#define STATE_END 113
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#define FINAL_STATES_BEGIN 100
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// Since the lexical specification forces the lexer to have some knowledge
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// of the grammar, there are two start states where recognizing an ATTRTYPE
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// or ATTRVAL is valid. DFA starts with ATTRTYPE_START_STATE and switches to
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// ATTRVAL_START_STATE when an AttrType is recognized and vice-versa
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#define ATTRTYPE_START_STATE 0
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#define ATTRVAL_START_STATE 1
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#define MAX_STATES 11 // 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 18
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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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#define ACTION_PUSHBACK_2CHAR 3
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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' 'num' '.' 'other' '\0' 'space' ';'
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0 {101,0}, {102,0}, {103,0}, {104,0}, {105,0}, {100,0}, { 3, 0}, { 4, 0}, { 5, 0}, {100,0}, { 6, 1}, { 7, 0}, { 8, 0}, {100,0}, {100,0}, {113,0}, { 0 , 0}, {100,0}, \
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1 {101,0}, {102,0}, {103,0}, {104,0}, {105,0}, { 2, 0}, { 3, 0}, { 4, 0}, { 5, 0}, { 9,0}, {100,0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, {113,0}, { 1, 0}, { 9, 0}, \
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2 {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {106,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100, 0}, {100,0}, \
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3 {107,2}, {107,2}, {107,2}, {107,2}, {107,2}, {107,2}, {107,2}, {107,2}, {107,2}, {010,0}, {107,2}, {107,2}, {107,2}, {107,2}, {107,2}, {107,2}, {107, 2}, {107,2}, \
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4 {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {108,0}, {100,0}, {100,0}, {100,0}, {100,0}, {108,2}, {108,2}, {100,0}, {100,0}, {100,0}, {100, 0}, {100,0}, \
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5 {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {109,0}, {100,0}, {100,0}, {100,0}, {100,0}, {109,2}, {109,2}, {100,0}, {100,0}, {100,0}, {100, 0}, {100,0}, \
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6 { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, {100,0}, { 9 , 0}, { 9, 0}, \
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7 {111,2}, {111,2}, {111,2}, {111,2}, {111,2}, {111,2}, {111,2}, {111,2}, {111,0}, {100,0}, {111,2}, { 7, 0}, { 7, 0}, {111,2}, {111,2}, {111,2}, { 7, 0}, { 7, 0}, \
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8 {111,2}, {111,2}, {111,2}, {111,2}, {111,2}, {111,2}, {111,2}, {111,2}, {111,2}, {100,0}, {111,2}, {111,2}, { 8, 0}, { 8, 0}, {111,2}, {111,2}, {111, 2}, {111,2}, \
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9 {112,2}, {112,2}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9,0}, { 6, 1}, { 9, 0}, { 9 0}, { 9, 0}, { 9, 0}, {112,2}, { 9 , 0}, { 9, 0}, \
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10 {100,0}, {110,2}, {100,0}, {100,0}, {100,0}, {100,0}, {108,0}, {100,0}, {100,0}, {100,0}, {100,0}, {107,3}, {100,0}, {100,0}, {100,0}, {100,0}, {100, 0}, {100,0}, \
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*/
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#define gStateTable {\
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{{101,0}, {102,0}, {103,0}, {104,0}, {105,0}, {100,0}, { 3, 0}, { 4, 0}, { 5, 0}, {100,0}, { 6, 1}, { 7, 0}, { 8, 0}, {100,0}, {100,0}, {113,0}, { 0 , 0}, {100,0}}, \
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{{101,0}, {102,0}, {103,0}, {104,0}, {105,0}, { 2, 0}, { 3, 0}, { 4, 0}, { 5, 0}, { 9,0}, {100,0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, {113,0}, { 1 , 0}, { 9, 0}}, \
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{{100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {106,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100, 0}, {100,0}}, \
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{{107,2}, {107,2}, {107,2}, {107,2}, {107,2}, {107,2}, {107,2}, {107,2}, {107,2}, {012,0}, {107,2}, {107,2}, {107,2}, {107,2}, {107,2}, {107,2}, {107, 2}, {107,2}}, \
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{{100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {108,0}, {100,0}, {100,0}, {100,0}, {100,0}, {108,2}, {108,2}, {100,0}, {100,0}, {100,0}, {100, 0}, {100,0}}, \
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{{100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {109,0}, {100,0}, {100,0}, {100,0}, {100,0}, {109,2}, {109,2}, {100,0}, {100,0}, {100,0}, {100, 0}, {100,0}}, \
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{{ 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, {100,0}, { 9 , 0}, { 9, 0}}, \
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{{111,2}, {111,2}, {111,2}, {111,2}, {111,2}, {111,2}, {111,2}, {111,2}, {111,0}, {100,0}, {111,2}, { 7, 0}, { 7, 0}, {111,2}, {111,2}, {111,2}, { 7, 0}, { 7, 0}}, \
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{{111,2}, {111,2}, {111,2}, {111,2}, {111,2}, {111,2}, {111,2}, {111,2}, {111,2}, {100,0}, {111,2}, {111,2}, { 8, 0}, { 8, 0}, {111,2}, {111,2}, {111, 2}, {111,2}}, \
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{{112,2}, {112,2}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, { 9,0}, { 6, 1}, { 9, 0}, { 9, 0}, { 9, 0}, { 9, 0}, {112,2}, { 9 , 0}, { 9, 0}}, \
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{{100,0}, {110,2}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {100,0}, {107,3}, {100,0}, {100,0}, {100,0}, {100,0}, {100, 0}, {100,0}}}
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// This is the table comtaining the chsracter class to which a particular
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// character belongs. This is used to index the state transition table.
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// Basivally, 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, 16, 16, 16, 16, 16, 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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16, 4, 14, 14, 14, 14, 3, 14, 0, 1, 9, 14, 14, 14, 13, 14, \
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12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 14, 17, 7, 6, 8, 14, \
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14, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, \
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11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 14, 10, 14, 14, 14, \
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14, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, \
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11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 14, 2, 14, 5, 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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LPWSTR
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RemoveWhiteSpaces(
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LPWSTR pszText
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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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HRESULT
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PushBackChar();
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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 (RemoveWhiteSpaces(_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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//CQryLexer maintains all the state information and returns the next token
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class CQryLexer
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{
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public:
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// Initialize the lexer with the string szBuffer.
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CQryLexer(LPWSTR szBuffer);
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~CQryLexer();
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// Return the next token and its value.
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HRESULT
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CQryLexer::GetNextToken(LPWSTR *szToken, LPDWORD pdwToken);
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HRESULT
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CQryLexer::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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CQryLexer::NextChar();
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void
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CQryLexer::PushbackChar();
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DWORD
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CQryLexer::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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CQryLexer::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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CQryLexer::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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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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BOOL _bGetNext;
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};
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#endif
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