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

#include <OgreGLSLPreprocessor.h>

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.
Public Member Functions
	CPreprocessor ()
	Create an empty preprocessor object.
virtual	~CPreprocessor ()
	Destroy the preprocessor object.
void	Define (const char iMacroName, size_t iMacroNameLen, const char iMacroValue, size_t iMacroValueLen)
	Define a macro without parameters.
void	Define (const char *iMacroName, size_t iMacroNameLen, long iMacroValue)
	Define a numerical macro.
char *	Parse (const char *iSource, size_t iLength, size_t &oLength)
	Parse the input string and return a newly-allocated output string.
bool	Undef (const char *iMacroName, size_t iMacroNameLen)
	Undefine a macro.
Public Attributes
void *	ErrorData
	User-specific storage, passed to Error()
Static Public Attributes
static ErrorHandlerFunc	ErrorHandler
	A pointer to the preprocessor's error handler.
Private Member Functions
	CPreprocessor (const Token &iToken, int iLine)
	Private constructor to re-parse a single token.
void	Error (int iLine, const char iError, const Token iToken=NULL)
	Call the error handler.
Token	ExpandMacro (const Token &iToken)
	Expand the given macro, if it exists.
Token	GetArgument (Token &oArg, bool iExpand)
	Get a single function argument until next ',' or ')'.
Token	GetArguments (int &oNumArgs, Token *&oArgs, bool iExpand)
	Get all the arguments of a macro: '(' arg1 { ',' arg2 { ',' ...
Token	GetExpression (Token &oResult, int iLine, int iOpPriority=0)
	Parse an expression, compute it and return the result.
Token	GetToken (bool iExpand)
	Stateless tokenizer: Parse the input text and return the next token.
bool	GetValue (const Token &iToken, long &oValue, int iLine)
	Get the numeric value of a token.
bool	HandleDefine (Token &iBody, int iLine)
	Handle a #define directive.
Token	HandleDirective (Token &iToken, int iLine)
	Handle a preprocessor directive.
bool	HandleElse (Token &iBody, int iLine)
	Handle an #else directive.
bool	HandleEndIf (Token &iBody, int iLine)
	Handle an #endif directive.
bool	HandleIf (Token &iBody, int iLine)
	Handle an #if directive.
bool	HandleIfDef (Token &iBody, int iLine)
	Handle an #ifdef directive.
bool	HandleUnDef (Token &iBody, int iLine)
	Undefine a previously defined macro.
Macro *	IsDefined (const Token &iToken)
	Check if a macro is defined, and if so, return it.
Token	Parse (const Token &iSource)
	Parse the input string and return a token containing the whole output.
Static Private Member Functions
static Token	ExpandDefined (CPreprocessor iParent, int iNumArgs, Token iArgs)
	The implementation of the defined() preprocessor function.
Private Attributes
bool	BOL
	True if we are at beginning of line.
unsigned	EnableOutput
	A stack of 32 booleans packed into one value :)
int	Line
	Current line number.
Macro *	MacroList
	The list of macros defined so far.
const char *	Source
	The current source text input.
const char *	SourceEnd
	The end of the source text.
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:

Fast memory allocation-less operation (mostly).
Line continuation (backslash-newline) is swallowed.
Line numeration is fully preserved by inserting empty lines where required. This is crucial if, say, GLSL compiler reports you an error with a line number.
#define: Parametrized and non-parametrized macros. Invoking a macro with less arguments than it takes assignes empty values to missing arguments.
#undef: Forget defined macros
#ifdef/#ifndef/#else/#endif: Conditional suppression of parts of code.
#if: Supports numeric expression of any complexity, also supports the defined() pseudo-function.

Definition at line 62 of file src/GLSL/include/OgreGLSLPreprocessor.h.

Member Typedef Documentation

typedef void(* Ogre::GLSL::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:

iData	User-specific pointer from the corresponding CPreprocessor object.
iLine	The line at which the error happened.
iError	The error string.
iToken	If not NULL contains the erroneous token
iTokenLen	The length of iToken. iToken is never zero-terminated!

Definition at line 508 of file src/GLSL/include/OgreGLSLPreprocessor.h.

Constructor & Destructor Documentation

Ogre::GLSL::CPreprocessor::CPreprocessor	(	const Token &	iToken,
		int	iLine
	)		`[private]`

Private constructor to re-parse a single token.

Ogre::GLSL::CPreprocessor::CPreprocessor ( )

Create an empty preprocessor object.

Definition at line 427 of file src/GLSL/include/OgreGLSLPreprocessor.h.

virtual Ogre::GLSL::CPreprocessor::~CPreprocessor ( ) [virtual]

Destroy the preprocessor object.

Member Function Documentation

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

Define a macro without parameters.

Parameters:

iMacroName	The name of the defined macro
iMacroNameLen	The length of the name of the defined macro
iMacroValue	The value of the defined macro
iMacroValueLen	The length of the value of the defined macro

void Ogre::GLSL::CPreprocessor::Define	(	const char *	iMacroName,
		size_t	iMacroNameLen,
		long	iMacroValue
	)

Define a numerical macro.

Parameters:

iMacroName	The name of the defined macro
iMacroNameLen	The length of the name of the defined macro
iMacroValue	The value of the defined macro

void Ogre::GLSL::CPreprocessor::Error	(	int	iLine,
		const char *	iError,
		const Token *	iToken = `NULL`
	)		`[private]`

Call the error handler.

Parameters:

iLine	The line at which the error happened.
iError	The error string.
iToken	If not NULL contains the erroneous token

static Token Ogre::GLSL::CPreprocessor::ExpandDefined	(	CPreprocessor *	iParent,
		int	iNumArgs,
		Token *	iArgs
	)		`[static, private]`

The implementation of the defined() preprocessor function.

Parameters:

iParent	The parent preprocessor object
iNumArgs	Number of arguments
iArgs	The arguments themselves

Returns:: The return value encapsulated in a token

Token Ogre::GLSL::CPreprocessor::ExpandMacro ( const Token & iToken ) [private]

Expand the given macro, if it exists.

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

Parameters:

iToken A KEYWORD token containing the (possible) macro name.

Returns:: The expanded token or iToken if it is not a macro

Token Ogre::GLSL::CPreprocessor::GetArgument	(	Token &	oArg,
		bool	iExpand
	)		`[private]`

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

Parameters:

oArg	The argument is returned in this variable.
iExpand	If 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.

Token Ogre::GLSL::CPreprocessor::GetArguments	(	int &	oNumArgs,
		Token *&	oArgs,
		bool	iExpand
	)		`[private]`

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

}} ')'

Parameters:

oNumArgs	Number of parsed arguments is stored into this variable.
oArgs	This is set to a pointer to an array of parsed arguments.
iExpand	If false, parameters are not expanded and no expressions are allowed; only a single keyword is expected per argument.

Token Ogre::GLSL::CPreprocessor::GetExpression	(	Token &	oResult,
		int	iLine,
		int	iOpPriority = `0`
	)		`[private]`

Parse an expression, compute it and return the result.

Parameters:

oResult	A token containing the result of expression
iLine	The line at which the expression starts (for error reports)
iOpPriority	Operator 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

Token Ogre::GLSL::CPreprocessor::GetToken ( bool iExpand ) [private]

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

Parameters:

iExpand If true, macros will be expanded to their values

Returns:: The next token from the input stream

bool Ogre::GLSL::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:

iToken	The token to get the numeric value of
oValue	The variable to put the value into
iLine	The line where the directive begins (for error reports)

Returns:: true if ok, false if not

bool Ogre::GLSL::CPreprocessor::HandleDefine	(	Token &	iBody,
		int	iLine
	)		`[private]`

Handle a #define directive.

Parameters:

iBody	The body of the directive (everything after the directive until end of line).
iLine	The line where the directive begins (for error reports)

Returns:: true if everything went ok, false if not

Token Ogre::GLSL::CPreprocessor::HandleDirective	(	Token &	iToken,
		int	iLine
	)		`[private]`

Handle a preprocessor directive.

Parameters:

iToken	The whole preprocessor directive line (until EOL)
iLine	The line where the directive begins (for error reports)

Returns:: The last input token that was not proceeded.

bool Ogre::GLSL::CPreprocessor::HandleElse	(	Token &	iBody,
		int	iLine
	)		`[private]`

Handle an #else directive.

Parameters:

iBody	The body of the directive (everything after the directive until end of line).
iLine	The line where the directive begins (for error reports)

Returns:: true if everything went ok, false if not

bool Ogre::GLSL::CPreprocessor::HandleEndIf	(	Token &	iBody,
		int	iLine
	)		`[private]`

Handle an #endif directive.

Parameters:

iBody	The body of the directive (everything after the directive until end of line).
iLine	The line where the directive begins (for error reports)

Returns:: true if everything went ok, false if not

bool Ogre::GLSL::CPreprocessor::HandleIf	(	Token &	iBody,
		int	iLine
	)		`[private]`

Handle an #if directive.

Parameters:

iBody	The body of the directive (everything after the directive until end of line).
iLine	The line where the directive begins (for error reports)

Returns:: true if everything went ok, false if not

bool Ogre::GLSL::CPreprocessor::HandleIfDef	(	Token &	iBody,
		int	iLine
	)		`[private]`

Handle an #ifdef directive.

Parameters:

iBody	The body of the directive (everything after the directive until end of line).
iLine	The line where the directive begins (for error reports)

Returns:: true if everything went ok, false if not

bool Ogre::GLSL::CPreprocessor::HandleUnDef	(	Token &	iBody,
		int	iLine
	)		`[private]`

Undefine a previously defined macro.

Parameters:

iBody	The body of the directive (everything after the directive until end of line).
iLine	The line where the directive begins (for error reports)

Returns:: true if everything went ok, false if not

Macro* Ogre::GLSL::CPreprocessor::IsDefined ( const Token & iToken ) [private]

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

Parameters:

iToken Macro name

Returns:: The macro object or NULL if a macro with this name does not exist

Token Ogre::GLSL::CPreprocessor::Parse ( const Token & iSource ) [private]

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

Parameters:

iSource The source text enclosed in a token

Returns:: The output text enclosed in a token

char* Ogre::GLSL::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:

iSource	The source text
iLength	The length of the source text in characters
oLength	The 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.