libeval_compiler.h

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/*
 This file is part of libeval, a simple math expression evaluator
 
 Copyright (C) 2007 Michael Geselbracht, [email protected]
 Copyright (C) 2019-2020 KiCad Developers, see AUTHORS.txt for contributors.
 
 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.
 
 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 GNU General Public License for more details.
 
 You should have received a copy of the GNU General Public License
 along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
 
#ifndef __LIBEVAL_COMPILER_H
#define __LIBEVAL_COMPILER_H
 
#include <cstddef>
#include <functional>
#include <map>
#include <string>
#include <stack>
 
#include <base_units.h>
#include <wx/intl.h>
 
#if defined(WIN32)
// This gets leaked by python headers on MSVC only and will cause chaos
#undef COMPILER
#endif
 
#define TR_OP_BINARY_MASK 0x200
#define TR_OP_UNARY_MASK 0x100
 
#define TR_OP_MUL 0x201
#define TR_OP_DIV 0x202
#define TR_OP_ADD 0x203
#define TR_OP_SUB 0x204
#define TR_OP_LESS 0x205
#define TR_OP_GREATER 0x206
#define TR_OP_LESS_EQUAL 0x207
#define TR_OP_GREATER_EQUAL 0x208
#define TR_OP_EQUAL 0x209
#define TR_OP_NOT_EQUAL 0x20a
#define TR_OP_BOOL_AND 0x20b
#define TR_OP_BOOL_OR 0x20c
#define TR_OP_BOOL_NOT 0x100
#define TR_OP_FUNC_CALL 24
#define TR_OP_METHOD_CALL 25
#define TR_UOP_PUSH_VAR 1
#define TR_UOP_PUSH_VALUE 2
 
// This namespace is used for the lemon parser
namespace LIBEVAL
{
 
class COMPILER;
 
enum COMPILATION_STAGE
{
 CST_PARSE = 0,
 CST_CODEGEN,
 CST_RUNTIME
};
 
struct ERROR_STATUS
{
 bool pendingError = false;
 
 COMPILATION_STAGE stage;
 wxString message;
 int srcPos;
};
 
 
enum VAR_TYPE_T
{
 VT_STRING = 1,
 VT_NUMERIC,
 VT_UNDEFINED,
 VT_PARSE_ERROR
};
 
enum TOKEN_TYPE_T
{
 TR_UNDEFINED = 0,
 TR_NUMBER = 1,
 TR_IDENTIFIER = 2,
 TR_ASSIGN = 3,
 TR_STRUCT_REF = 4,
 TR_STRING = 5,
 TR_UNIT = 6,
 TR_ARG_LIST = 7,
 TR_NULL = 8
};
 
class UOP;
class UCODE;
class CONTEXT;
class VAR_REF;
 
typedef std::function<void( CONTEXT*, void* )> FUNC_CALL_REF;
 
struct T_TOKEN_VALUE
{
 wxString* str;
 double num;
 int idx;
};
 
// Lemon can't handle c'tors and d'tors, so we provide a poor-man's version.
constexpr T_TOKEN_VALUE defaultTokenValue = { nullptr, 0.0, 0 };
 
 
struct T_TOKEN
{
 int token;
 T_TOKEN_VALUE value;
};
 
// Lemon can't handle c'tors and d'tors, so we provide a poor-man's version.
constexpr T_TOKEN defaultToken = { TR_UNDEFINED, defaultTokenValue };
 
 
class TREE_NODE
{
public:
 T_TOKEN_VALUE value;
 
 int op;
 TREE_NODE* leaf[2];
 UOP* uop;
 bool valid;
 bool isTerminal;
 bool isVisited;
 int srcPos;
 
 void SetUop( int aOp, double aValue );
 void SetUop( int aOp, const wxString& aValue, bool aStringIsWildcard );
 void SetUop( int aOp, std::unique_ptr<VAR_REF> aRef = nullptr );
 void SetUop( int aOp, FUNC_CALL_REF aFunc, std::unique_ptr<VAR_REF> aRef = nullptr );
};
 
 
TREE_NODE* newNode( LIBEVAL::COMPILER* compiler, int op,
 const T_TOKEN_VALUE& value = defaultTokenValue );
 
class UNIT_RESOLVER
{
public:
 UNIT_RESOLVER()
 {
 }
 
 virtual ~UNIT_RESOLVER()
 {
 }
 
 virtual const std::vector<wxString>& GetSupportedUnits() const
 {
 static const std::vector<wxString> nullUnits;
 
 return nullUnits;
 }
 
 virtual wxString GetSupportedUnitsMessage() const
 {
 return wxEmptyString;
 }
 
 virtual double Convert( const wxString& aString, int unitType ) const
 {
 return 0.0;
 };
};
 
 
class VALUE
{
public:
 VALUE() :
 m_type( VT_UNDEFINED ),
 m_valueDbl( 0 ),
 m_stringIsWildcard( false ),
 m_isDeferredDbl( false ),
 m_isDeferredStr( false )
 {};
 
 VALUE( const wxString& aStr, bool aIsWildcard = false ) :
 m_type( VT_STRING ),
 m_valueDbl( 0 ),
 m_valueStr( aStr ),
 m_stringIsWildcard( aIsWildcard ),
 m_isDeferredDbl( false ),
 m_isDeferredStr( false )
 {};
 
 VALUE( const double aVal ) :
 m_type( VT_NUMERIC ),
 m_valueDbl( aVal ),
 m_stringIsWildcard( false ),
 m_isDeferredDbl( false ),
 m_isDeferredStr( false )
 {};
 
 virtual ~VALUE()
 {};
 
 virtual double AsDouble() const
 {
 if( m_isDeferredDbl )
 {
 m_valueDbl = m_lambdaDbl();
 m_isDeferredDbl = false;
 }
 
 return m_valueDbl;
 }
 
 virtual const wxString& AsString() const
 {
 if( m_isDeferredStr )
 {
 m_valueStr = m_lambdaStr();
 m_isDeferredStr = false;
 }
 
 return m_valueStr;
 }
 
 virtual bool EqualTo( CONTEXT* aCtx, const VALUE* b ) const;
 
 // NB: this is not an inverse of EqualTo as they both return false for undefined values.
 virtual bool NotEqualTo( CONTEXT* aCtx, const VALUE* b ) const;
 
 VAR_TYPE_T GetType() const { return m_type; };
 
 void Set( double aValue )
 {
 m_type = VT_NUMERIC;
 m_valueDbl = aValue;
 }
 
 void SetDeferredEval( std::function<double()> aLambda )
 {
 m_type = VT_NUMERIC;
 m_lambdaDbl = aLambda;
 m_isDeferredDbl = true;
 }
 
 void SetDeferredEval( std::function<wxString()> aLambda )
 {
 m_type = VT_STRING;
 m_lambdaStr = aLambda;
 m_isDeferredStr = true;
 }
 
 void Set( const wxString& aValue )
 {
 m_type = VT_STRING;
 m_valueStr = aValue;
 }
 
 void Set( const VALUE &val )
 {
 m_type = val.m_type;
 m_valueDbl = val.m_valueDbl;
 
 if( m_type == VT_STRING )
 m_valueStr = val.m_valueStr;
 }
 
private:
 VAR_TYPE_T m_type;
 mutable double m_valueDbl; // mutable to support deferred evaluation
 mutable wxString m_valueStr; // mutable to support deferred evaluation
 bool m_stringIsWildcard;
 
 mutable bool m_isDeferredDbl;
 std::function<double()> m_lambdaDbl;
 
 mutable bool m_isDeferredStr;
 std::function<wxString()> m_lambdaStr;
};
 
class VAR_REF
{
public:
 VAR_REF() {};
 virtual ~VAR_REF() {};
 
 virtual VAR_TYPE_T GetType() const = 0;
 virtual VALUE GetValue( CONTEXT* aCtx ) = 0;
};
 
 
class CONTEXT
{
public:
 CONTEXT() :
 m_stack(),
 m_stackPtr( 0 )
 {
 m_ownedValues.reserve( 20 );
 }
 
 virtual ~CONTEXT()
 {
 for( auto &v : m_ownedValues )
 {
 delete v;
 }
 }
 
 VALUE* AllocValue()
 {
 m_ownedValues.emplace_back( new VALUE );
 return m_ownedValues.back();
 }
 
 void Push( VALUE* v )
 {
 m_stack[ m_stackPtr++ ] = v;
 }
 
 VALUE* Pop()
 {
 if( m_stackPtr == 0 )
 {
 ReportError( _( "Malformed expression" ) );
 return AllocValue();
 }
 
 return m_stack[ --m_stackPtr ];
 }
 
 int SP() const
 {
 return m_stackPtr;
 };
 
 void SetErrorCallback( std::function<void( const wxString& aMessage, int aOffset )> aCallback )
 {
 m_errorCallback = std::move( aCallback );
 }
 
 bool HasErrorCallback() { return m_errorCallback != nullptr; }
 
 void ReportError( const wxString& aErrorMsg );
 
private:
 std::vector<VALUE*> m_ownedValues;
 VALUE* m_stack[100]; // std::stack not performant enough
 int m_stackPtr;
 
 std::function<void( const wxString& aMessage, int aOffset )> m_errorCallback;
};
 
 
class UCODE
{
public:
 virtual ~UCODE();
 
 void AddOp( UOP* uop )
 {
 m_ucode.push_back(uop);
 }
 
 VALUE* Run( CONTEXT* ctx );
 wxString Dump() const;
 
 virtual std::unique_ptr<VAR_REF> CreateVarRef( const wxString& var, const wxString& field )
 {
 return nullptr;
 };
 
 virtual FUNC_CALL_REF CreateFuncCall( const wxString& name )
 {
 return nullptr;
 };
 
protected:
 
 std::vector<UOP*> m_ucode;
};
 
 
class UOP
{
public:
 UOP( int op, std::unique_ptr<VALUE> value ) :
 m_op( op ),
 m_ref(nullptr),
 m_value( std::move( value ) )
 {};
 
 UOP( int op, std::unique_ptr<VAR_REF> vref ) :
 m_op( op ),
 m_ref( std::move( vref ) ),
 m_value(nullptr)
 {};
 
 UOP( int op, FUNC_CALL_REF func, std::unique_ptr<VAR_REF> vref = nullptr ) :
 m_op( op ),
 m_func( std::move( func ) ),
 m_ref( std::move( vref ) ),
 m_value(nullptr)
 {};
 
 ~UOP()
 {
 }
 
 void Exec( CONTEXT* ctx );
 
 wxString Format() const;
 
private:
 int m_op;
 
 FUNC_CALL_REF m_func;
 std::unique_ptr<VAR_REF> m_ref;
 std::unique_ptr<VALUE> m_value;
};
 
class TOKENIZER
{
public:
 void Restart( const wxString& aStr )
 {
 m_str = aStr;
 m_pos = 0;
 }
 
 void Clear()
 {
 m_str = "";
 m_pos = 0;
 }
 
 int GetChar() const
 {
 if( m_pos >= m_str.length() )
 return 0;
 
 return m_str[m_pos];
 }
 
 bool Done() const
 {
 return m_pos >= m_str.length();
 }
 
 void NextChar( int aAdvance = 1 )
 {
 m_pos += aAdvance;
 }
 
 size_t GetPos() const
 {
 return m_pos;
 }
 
 wxString GetChars( const std::function<bool( wxUniChar )>& cond ) const;
 
 bool MatchAhead( const wxString& match,
 const std::function<bool( wxUniChar )>& stopCond ) const;
 
private:
 wxString m_str;
 size_t m_pos = 0;
};
 
 
class COMPILER
{
public:
 COMPILER();
 virtual ~COMPILER();
 
 /*
 * clear() should be invoked by the client if a new input string is to be processed. It
 * will reset the parser. User defined variables are retained.
 */
 void Clear();
 
 /* Used by the lemon parser */
 void parseError( const char* s );
 void parseOk();
 
 int GetSourcePos() const { return m_sourcePos; }
 
 void setRoot( LIBEVAL::TREE_NODE *root );
 void freeTree( LIBEVAL::TREE_NODE *tree );
 
 bool Compile( const wxString& aString, UCODE* aCode, CONTEXT* aPreflightContext );
 
 void SetErrorCallback( std::function<void( const wxString& aMessage, int aOffset )> aCallback )
 {
 m_errorCallback = std::move( aCallback );
 }
 
 bool IsErrorPending() const { return m_errorStatus.pendingError; }
 const ERROR_STATUS& GetError() const { return m_errorStatus; }
 
 void GcItem( TREE_NODE* aItem ) { m_gcItems.push_back( aItem ); }
 void GcItem( wxString* aItem ) { m_gcStrings.push_back( aItem ); }
 
protected:
 enum LEXER_STATE
 {
 LS_DEFAULT = 0,
 LS_STRING = 1,
 };
 
 LEXER_STATE m_lexerState;
 
 bool generateUCode( UCODE* aCode, CONTEXT* aPreflightContext );
 
 void reportError( COMPILATION_STAGE stage, const wxString& aErrorMsg, int aPos = -1 );
 
 /* Begin processing of a new input string */
 void newString( const wxString& aString );
 
 /* Tokenizer: Next token/value taken from input string. */
 T_TOKEN getToken();
 bool lexDefault( T_TOKEN& aToken );
 bool lexString( T_TOKEN& aToken );
 
 int resolveUnits();
 
protected:
 /* Token state for input string. */
 void* m_parser; // the current lemon parser state machine
 TOKENIZER m_tokenizer;
 char m_localeDecimalSeparator;
 
 std::unique_ptr<UNIT_RESOLVER> m_unitResolver;
 
 int m_sourcePos;
 bool m_parseFinished;
 ERROR_STATUS m_errorStatus;
 
 std::function<void( const wxString& aMessage, int aOffset )> m_errorCallback;
 
 TREE_NODE* m_tree;
 
 std::vector<TREE_NODE*> m_gcItems;
 std::vector<wxString*> m_gcStrings;
};
 
 
} // namespace LIBEVAL
 
#endif /* LIBEVAL_COMPILER_H_ */