Macros

Macros

The Crosswalk SDK provides a number of helpful macros which fall under the these categories:

String Manipulation Wrappers

Some macros can facilitate writing cross-platform code using string functions. _SI_TEXT is used to wrap string constants so that it is compatible with both Unicode and ANSI code. For example, rather than use the following code:

 _SI_PRINTF("Hello World\n");

Use this instead:

 _SI_PRINTF(_SI_TEXT("Hello World\n"));

These macros wrap string manipulation functions. See any ANSI C documentation for more details:

Macro Name	Description
_SI_STRCMP	Macro for the strcmp function
_SI_STRDUP	Macro for the strdup function
_SI_STRCPY	Macro for the strcpy function
_SI_STRCAT	Macro for the strcat function
_SI_SPRINTF	Macro for the sprintf function
_SI_STRLEN	Macro for the strlen function
_SI_PRINTF	Macro for the printf function
_SI_STRTOK	Macro for the strtok function
_SI_STRSTR	Macro for the strstr function
_SI_STRCHR	Macro for the strchr function
_SI_ATOI	Macro for the atoi function

Since the XSI Viewer does not have a console to output to, the XSI Viewer redirects the output of the _SI_PRINTF macro to a log file which you can find under the launch directory for the XSI Viewer application. You use your own log file by using the CSIBCUtil::Open and CSIBCutil::Close functions.

Example (String Manipulation)

SI_Error result = SI_SUCCESS;

_SI_CALL(CSIBCUtil::Open("foo"),_SI_TEXT("Opening File Failed"));
if (result == SI_SUCCESS)
{
   _SI_PRINTF(_SI_TEXT(“Hello World\n”);
}
_SI_CALL(CSIBCutil::Close(), _SI_TEXT(“Closing file”));

Math Function Wrappers

These macros wrap common math functions. See any ANSI C documentation for more details.

Macro Name	Description
_SI_RAND	Macro for the rand function
_SI_SQRT	Macro for the sqrt function
_SI_SQRTF	Macro for the sqrtf function
_SI_ASIN	Macro for the asin function
_SI_ASINF	Macro for the asinf function
_SI_ACOS	Macro for the acos function
_SI_ACOSF	Macro for the acosf function
_SI_FLOOR	Macro for the floor function
_SI_FLOORF	Macro for the floorf function
_SI_COS	Macro for the cos function
_SI_COSF	Macro for the cosf function
_SI_SIN	Macro for the sin function
_SI_SINF	Macro for the sinf function
_SI_TAN	Macro for the tan function
_SI_TANF	Macro for the tanf function
_SI_ATANF	Macro for the atanf function
_SI_ATAN	Macro for the atan function

File Access (I/O) Wrappers

Since file systems may differ from platform to platform, some macros are also provided to facilitate file access. _SI_FILE is the XSI Viewer file handle. It is used by all file access macros. See any ANSI C documentation for more details.

These are the wrapped file access functions:

Functions	Descriptions
_SI_FOPEN( name, mode )	Opens a file using a file name and an access mode. The access mode can be either one of _SI_FILE_READ_TEXT (to open a file in text mode) or _SI_FILE_READ_BINARY (to open a file in binary mode). It returns _SI_FILE_NULL if the file cannot be opened. Otherwise, if successful, it returns an _SI_FILE handle.
_SI_FCLOSE(handle)	Closes a file described by the file handle.
_SI_FREAD( buffer, size, count, handle )	Reads from a file. See the fread function in the ANSI C documentation for more details.
_SI_FWRITE( buffer, size, count, handle )	Writes to a file. See the fread function in the ANSI C documentation for more details.
_SI_FPRINTF(handle, string)	Prints the string to a file.
_SI_FSEEK( handle, count, type )	Sets the file at a specific position according to these rules: • If type is set to _SI_FILE_SET then count is used as the offset from the beginning of the file. • If type is set to _SI_FILE_CUR, then count is used as the offset from the current file position. • If type is set to _SI_FILE_END, then count is used as a negative offset from the end of the file. See the fseek function in the ANSI C documentation for more details.
_SI_FTELL( handle )	Returns the current position in bytes of the file. See the ftell function in the ANSI C documentation for more details.
_SI_FGETC( handle )	Gets the next character in the file. See the getc function in the ANSI C documentation for more details.
_SI_FEOF( handle )	Checks if the end of the file has been reached.
_SI_FERROR( handle )	Checks if there is an error on the file. See the ferror function in the ANSI C documentation for more details.
_SI_FFLUSH( x )	Flushes the buffered content of the file on disk. See the fflush function in the ANSI C documentation for more details.
_SI_UNGETC( character, handle )	Pushes a character back into the file. See the ungetc function in the ANSI C documentation for more details.

Example (File Access)

Here is an example of reading 10 bytes from a file called "foo"

_SI_FILE filePtr;
SI_Byte buffer[10];

filePtr = _SI_Open(_SI_TEXT("foo"), _SI_FILE_READ_BINARY);
if(filePtr != _SI_FILE_NULL)
{
   _SI_FREAD(buffer,sizeof(SI_Byte), 10, filePtr);
   _SI_FCLOSE(filePtr);
}

Memory Allocation

Some macros facilitate memory allocation and error checking. These include:

• _SI_NEW(instance pointer, class constructor)

• _SI_DELETE(instance pointer)

Example (Memory Allocation)

CSIBCVector3D* pVec3D;
 
_SI_NEW(pVec3D, CSIBCVector3D());
_SI_DELETE(pVec3D);

Exported Functions

You can use the XSIEXPORT macro to export functions. This macro maps to __desclspec(dllexport) when the _XSI_PLUGIN_ macro is defined.

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