Ogre::CPreprocessor Class Reference

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

#include <OgreGLSLPreprocessor.h>

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...
char *	Parse (const char *iSource, size_t iLength, size_t &oLength)
	Parse the input string and return a newly-allocated output string. More...
bool	Undef (const char *iMacroName, size_t iMacroNameLen)
	Undefine a macro. More...

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

Static Public Attributes
static ErrorHandlerFunc	ErrorHandler
	A pointer to the preprocessor's error handler. 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:

• 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.

Member Typedef Documentation

ErrorHandlerFunc

typedef void(* Ogre::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!

Constructor & Destructor Documentation

CPreprocessor()

Ogre::CPreprocessor::CPreprocessor ( )

inline

Create an empty preprocessor object.

References Define(), Undef(), and ~CPreprocessor().

~CPreprocessor()

virtual Ogre::CPreprocessor::~CPreprocessor ( )

virtual

Destroy the preprocessor object.

Referenced by CPreprocessor().

Member Function Documentation

Define() [1/2]

void Ogre::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

Referenced by CPreprocessor().

Define() [2/2]

void Ogre::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

Undef()

bool Ogre::CPreprocessor::Undef	(	const char *	iMacroName,
		size_t	iMacroNameLen
	)

Undefine a macro.

Parameters

iMacroName	The name of the macro to undefine
iMacroNameLen	The length of the name of the macro to undefine

Returns

true if the macro has been undefined, false if macro doesn't exist

Referenced by CPreprocessor().

Parse()

char* Ogre::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.

Friends And Related Function Documentation

CPreprocessor::Macro

friend class CPreprocessor::Macro

friend

Member Data Documentation

ErrorHandler

ErrorHandlerFunc Ogre::CPreprocessor::ErrorHandler

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).

ErrorData

void* Ogre::CPreprocessor::ErrorData

User-specific storage, passed to Error()

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

• OgreGLSLPreprocessor.h