102 lines
2.1 KiB
C++
102 lines
2.1 KiB
C++
/*++
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Copyright (C) 1999 Microsoft Corporation
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Module Name:
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GENLEX.H
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Abstract:
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Generic lexer framework classes.
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History:
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--*/
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#ifndef _GENLEX_H_
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#define _GENLEX_H_
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#include <Polarity.h>
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class CGenLexSource
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{
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public:
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virtual wchar_t NextChar() = 0;
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// Return 0 on end-of-input
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virtual void Pushback(wchar_t) = 0;
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virtual void Reset() = 0;
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};
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class CTextLexSource : public CGenLexSource
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{
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const wchar_t *m_pSrcBuf;
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const wchar_t *m_pStart;
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public:
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CTextLexSource(const wchar_t *pSrc) { SetString(pSrc); }
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// Binds directly to <pSrc> buffer, but doesn't delete it.
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wchar_t NextChar()
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{
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if (!m_pSrcBuf)
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return 0;
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else
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return *m_pSrcBuf++ ? m_pSrcBuf[-1] : 0;
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}
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void Pushback(wchar_t)
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{
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if (m_pSrcBuf)
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--m_pSrcBuf;
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}
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void Reset() { m_pSrcBuf = m_pStart; }
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void SetString (const wchar_t *pSrc) { m_pSrcBuf = m_pStart = pSrc; }
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};
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#pragma pack(2)
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struct LexEl
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{
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wchar_t cFirst, cLast;
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WORD wGotoState;
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WORD wReturnTok;
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WORD wInstructions;
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};
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#pragma pack()
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// Lexer driver instructions
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#define GLEX_ACCEPT 0x1 // Add the char to the token
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#define GLEX_CONSUME 0x2 // Consume the char without adding to token
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#define GLEX_PUSHBACK 0x4 // Place the char back in the source buffer for next token
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#define GLEX_NOT 0x8 // A match occurs if the char is NOT the one specified
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#define GLEX_LINEFEED 0x10 // Increase the source linecount
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#define GLEX_RETURN 0x20 // Return the indicated token to caller
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#define GLEX_ANY wchar_t(0xFFFF) // Any character
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#define GLEX_EMPTY wchar_t(0xFFFE) // When subrange is not specified
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class POLARITY CGenLexer
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{
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wchar_t *m_pTokenBuf;
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int m_nCurrentLine;
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int m_nCurBufSize;
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CGenLexSource *m_pSrc;
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LexEl *m_pTable;
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public:
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CGenLexer(LexEl *pTbl, CGenLexSource *pSrc);
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~CGenLexer();
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int NextToken();
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// Returns 0 on end of input.
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wchar_t* GetTokenText() { return m_pTokenBuf; }
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int GetLineNum() { return m_nCurrentLine; }
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void Reset();
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};
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#endif
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