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CPreprocessor Class Reference

This is a simplistic C/C++-like preprocessor. More...

#include <Preprocessor.h>

Collaboration diagram for CPreprocessor:
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Classes

class  Macro
 A macro definition. More...
 
class  Token
 A input token. More...
 

Public Types

typedef void(* ErrorHandlerFunc) (void *iData, int iLine, const char *iError, const char *iToken, size_t iTokenLen)
 An error handler function type. More...
 

Public Member Functions

 CPreprocessor ()
 Create an empty preprocessor object. More...
 
virtual ~CPreprocessor ()
 Destroy the preprocessor object. More...
 
void Define (const char *iMacroName, size_t iMacroNameLen, const char *iMacroValue, size_t iMacroValueLen)
 Define a macro without parameters. More...
 
void Define (const char *iMacroName, size_t iMacroNameLen, long iMacroValue)
 Define a numerical macro. More...
 
void Define (const char *iMacroName, const char *iMacroValue)
 Define a macro without parameters. More...
 
void Define (const char *iMacroName, long iMacroValue)
 Define a numerical macro. More...
 
bool Undef (const char *iMacroName, size_t iMacroNameLen)
 Undefine a macro. More...
 
char * Parse (const char *iSource, size_t iLength, size_t &oLength)
 Parse the input string and return a newly-allocated output string. More...
 

Public Attributes

void * ErrorData
 User-specific storage, passed to Error() More...
 

Static Public Attributes

static ErrorHandlerFunc ErrorHandler = DefaultError
 A pointer to the preprocessor's error handler. More...
 

Private Member Functions

 CPreprocessor (const Token &iToken, int iLine)
 Private constructor to re-parse a single token. More...
 
Token GetToken (bool iExpand)
 Stateless tokenizer: Parse the input text and return the next token. More...
 
Token HandleDirective (Token &iToken, int iLine)
 Handle a preprocessor directive. More...
 
bool HandleDefine (Token &iBody, int iLine)
 Handle a #define directive. More...
 
bool HandleUnDef (Token &iBody, int iLine)
 Undefine a previously defined macro. More...
 
bool HandleIfDef (Token &iBody, int iLine)
 Handle an #ifdef directive. More...
 
bool HandleIf (Token &iBody, int iLine)
 Handle an #if directive. More...
 
bool HandleElse (Token &iBody, int iLine)
 Handle an #else directive. More...
 
bool HandleEndIf (Token &iBody, int iLine)
 Handle an #endif directive. More...
 
Token GetArgument (Token &oArg, bool iExpand)
 Get a single function argument until next ',' or ')'. More...
 
Token GetArguments (int &oNumArgs, Token *&oArgs, bool iExpand)
 Get all the arguments of a macro: '(' arg1 { ',' arg2 { ',' ... More...
 
Token GetExpression (Token &oResult, int iLine, int iOpPriority=0)
 Parse an expression, compute it and return the result. More...
 
bool GetValue (const Token &iToken, long &oValue, int iLine)
 Get the numeric value of a token. More...
 
Token ExpandMacro (const Token &iToken)
 Expand the given macro, if it exists. More...
 
MacroIsDefined (const Token &iToken)
 Check if a macro is defined, and if so, return it. More...
 
Token Parse (const Token &iSource)
 Parse the input string and return a token containing the whole output. More...
 
void Error (int iLine, const char *iError, const Token *iToken=NULL)
 Call the error handler. More...
 

Static Private Member Functions

static Token ExpandDefined (CPreprocessor *iParent, int iNumArgs, Token *iArgs)
 The implementation of the defined() preprocessor function. More...
 

Private Attributes

const char * Source
 The current source text input. More...
 
const char * SourceEnd
 The end of the source text. More...
 
int Line
 Current line number. More...
 
bool BOL
 True if we are at beginning of line. More...
 
unsigned EnableOutput
 A stack of 32 booleans packed into one value :) More...
 
MacroMacroList
 The list of macros defined so far. More...
 

Friends

class CPreprocessor::Macro
 

Detailed Description

This is a simplistic C/C++-like preprocessor.

It takes an non-zero-terminated string on input and outputs a non-zero-terminated string buffer.

This preprocessor was designed specifically for GLSL shaders, so if you want to use it for other purposes you might want to check if the feature set it provides is enough for you.

Here's a list of supported features:

Member Typedef Documentation

typedef void(* CPreprocessor::ErrorHandlerFunc) (void *iData, int iLine, const char *iError, const char *iToken, size_t iTokenLen)

An error handler function type.

The default implementation just drops a note to stderr and then the parser ends, returning NULL.

Parameters
iDataUser-specific pointer from the corresponding CPreprocessor object.
iLineThe line at which the error happened.
iErrorThe error string.
iTokenIf not NULL contains the erroneous token
iTokenLenThe length of iToken. iToken is never zero-terminated!

Constructor & Destructor Documentation

CPreprocessor::CPreprocessor ( const Token iToken,
int  iLine 
)
private

Private constructor to re-parse a single token.

CPreprocessor::CPreprocessor ( )
inline

Create an empty preprocessor object.

CPreprocessor::~CPreprocessor ( )
virtual

Destroy the preprocessor object.

Member Function Documentation

void CPreprocessor::Define ( const char *  iMacroName,
size_t  iMacroNameLen,
const char *  iMacroValue,
size_t  iMacroValueLen 
)

Define a macro without parameters.

Parameters
iMacroNameThe name of the defined macro
iMacroNameLenThe length of the name of the defined macro
iMacroValueThe value of the defined macro
iMacroValueLenThe length of the value of the defined macro
void CPreprocessor::Define ( const char *  iMacroName,
size_t  iMacroNameLen,
long  iMacroValue 
)

Define a numerical macro.

Parameters
iMacroNameThe name of the defined macro
iMacroNameLenThe length of the name of the defined macro
iMacroValueThe value of the defined macro
void CPreprocessor::Define ( const char *  iMacroName,
const char *  iMacroValue 
)

Define a macro without parameters.

Parameters
iMacroNameThe name of the defined macro
iMacroValueThe value of the defined macro
void CPreprocessor::Define ( const char *  iMacroName,
long  iMacroValue 
)

Define a numerical macro.

Parameters
iMacroNameThe name of the defined macro
iMacroValueThe value of the defined macro
void CPreprocessor::Error ( int  iLine,
const char *  iError,
const Token iToken = NULL 
)
private

Call the error handler.

Parameters
iLineThe line at which the error happened.
iErrorThe error string.
iTokenIf not NULL contains the erroneous token
CPreprocessor::Token CPreprocessor::ExpandDefined ( CPreprocessor iParent,
int  iNumArgs,
Token iArgs 
)
staticprivate

The implementation of the defined() preprocessor function.

Parameters
iParentThe parent preprocessor object
iNumArgsNumber of arguments
iArgsThe arguments themselves
Returns
The return value encapsulated in a token
CPreprocessor::Token CPreprocessor::ExpandMacro ( const Token iToken)
private

Expand the given macro, if it exists.

If macro has arguments, they are collected from source stream.

Parameters
iTokenA KEYWORD token containing the (possible) macro name.
Returns
The expanded token or iToken if it is not a macro
CPreprocessor::Token CPreprocessor::GetArgument ( Token oArg,
bool  iExpand 
)
private

Get a single function argument until next ',' or ')'.

Parameters
oArgThe argument is returned in this variable.
iExpandIf false, parameters are not expanded and no expressions are allowed; only a single keyword is expected per argument.
Returns
The first unhandled token after argument.
CPreprocessor::Token CPreprocessor::GetArguments ( int &  oNumArgs,
Token *&  oArgs,
bool  iExpand 
)
private

Get all the arguments of a macro: '(' arg1 { ',' arg2 { ',' ...

}} ')'

Parameters
oNumArgsNumber of parsed arguments is stored into this variable.
oArgsThis is set to a pointer to an array of parsed arguments.
iExpandIf false, parameters are not expanded and no expressions are allowed; only a single keyword is expected per argument.
CPreprocessor::Token CPreprocessor::GetExpression ( Token oResult,
int  iLine,
int  iOpPriority = 0 
)
private

Parse an expression, compute it and return the result.

Operator priority: 0: Whole expression 1: '(' ')' 2: || 3: && 4: | 5: ^ 6: & 7: '==' '!=' 8: '<' '<=' '>' '>=' 9: '<<' '>>' 10: '+' '-' 11: '*' '/' '' 12: unary '+' '-' '!' '~'.

Parameters
oResultA token containing the result of expression
iLineThe line at which the expression starts (for error reports)
iOpPriorityOperator priority (at which operator we will stop if proceeding recursively – used internally. Parser stops when it encounters an operator with higher or equal priority).
Returns
The last unhandled token after the expression
CPreprocessor::Token CPreprocessor::GetToken ( bool  iExpand)
private

Stateless tokenizer: Parse the input text and return the next token.

Parameters
iExpandIf true, macros will be expanded to their values
Returns
The next token from the input stream
bool CPreprocessor::GetValue ( const Token iToken,
long &  oValue,
int  iLine 
)
private

Get the numeric value of a token.

If the token was produced by expanding a macro, we will get an TEXT token which can contain a whole expression; in this case we will call GetExpression to parse it. Otherwise we just call the token's GetValue() method.

Parameters
iTokenThe token to get the numeric value of
oValueThe variable to put the value into
iLineThe line where the directive begins (for error reports)
Returns
true if ok, false if not
bool CPreprocessor::HandleDefine ( Token iBody,
int  iLine 
)
private

Handle a #define directive.

Parameters
iBodyThe body of the directive (everything after the directive until end of line).
iLineThe line where the directive begins (for error reports)
Returns
true if everything went ok, false if not
CPreprocessor::Token CPreprocessor::HandleDirective ( Token iToken,
int  iLine 
)
private

Handle a preprocessor directive.

Parameters
iTokenThe whole preprocessor directive line (until EOL)
iLineThe line where the directive begins (for error reports)
Returns
The last input token that was not proceeded.
bool CPreprocessor::HandleElse ( Token iBody,
int  iLine 
)
private

Handle an #else directive.

Parameters
iBodyThe body of the directive (everything after the directive until end of line).
iLineThe line where the directive begins (for error reports)
Returns
true if everything went ok, false if not
bool CPreprocessor::HandleEndIf ( Token iBody,
int  iLine 
)
private

Handle an #endif directive.

Parameters
iBodyThe body of the directive (everything after the directive until end of line).
iLineThe line where the directive begins (for error reports)
Returns
true if everything went ok, false if not
bool CPreprocessor::HandleIf ( Token iBody,
int  iLine 
)
private

Handle an #if directive.

Parameters
iBodyThe body of the directive (everything after the directive until end of line).
iLineThe line where the directive begins (for error reports)
Returns
true if everything went ok, false if not
bool CPreprocessor::HandleIfDef ( Token iBody,
int  iLine 
)
private

Handle an #ifdef directive.

Parameters
iBodyThe body of the directive (everything after the directive until end of line).
iLineThe line where the directive begins (for error reports)
Returns
true if everything went ok, false if not
bool CPreprocessor::HandleUnDef ( Token iBody,
int  iLine 
)
private

Undefine a previously defined macro.

Parameters
iBodyThe body of the directive (everything after the directive until end of line).
iLineThe line where the directive begins (for error reports)
Returns
true if everything went ok, false if not
CPreprocessor::Macro * CPreprocessor::IsDefined ( const Token iToken)
private

Check if a macro is defined, and if so, return it.

Parameters
iTokenMacro name
Returns
The macro object or NULL if a macro with this name does not exist
CPreprocessor::Token CPreprocessor::Parse ( const Token iSource)
private

Parse the input string and return a token containing the whole output.

Parameters
iSourceThe source text enclosed in a token
Returns
The output text enclosed in a token
char * CPreprocessor::Parse ( const char *  iSource,
size_t  iLength,
size_t &  oLength 
)

Parse the input string and return a newly-allocated output string.

Note
The returned preprocessed string is NOT zero-terminated (just like the input string).
Parameters
iSourceThe source text
iLengthThe length of the source text in characters
oLengthThe length of the output string.
Returns
The output from preprocessor, allocated with malloc(). The parser can actually allocate more than needed for performance reasons, but this should not be a problem unless you will want to store the returned pointer for long time in which case you might want to realloc() it. If an error has been encountered, the function returns NULL. In some cases the function may return an unallocated address that's inside the source buffer. You must free() the result string only if the returned address is not inside the source text.
bool CPreprocessor::Undef ( const char *  iMacroName,
size_t  iMacroNameLen 
)

Undefine a macro.

Parameters
iMacroNameThe name of the macro to undefine
iMacroNameLenThe length of the name of the macro to undefine
Returns
true if the macro has been undefined, false if macro doesn't exist

Friends And Related Function Documentation

friend class CPreprocessor::Macro
friend

Member Data Documentation

bool CPreprocessor::BOL
private

True if we are at beginning of line.

unsigned CPreprocessor::EnableOutput
private

A stack of 32 booleans packed into one value :)

void* CPreprocessor::ErrorData

User-specific storage, passed to Error()

CPreprocessor::ErrorHandlerFunc CPreprocessor::ErrorHandler = DefaultError
static

A pointer to the preprocessor's error handler.

You can assign the address of your own function to this variable and implement your own error handling (e.g. throwing an exception etc).

int CPreprocessor::Line
private

Current line number.

Macro* CPreprocessor::MacroList
private

The list of macros defined so far.

const char* CPreprocessor::Source
private

The current source text input.

const char* CPreprocessor::SourceEnd
private

The end of the source text.


The documentation for this class was generated from the following files: