Name

String reading (Scilab gateway) — How to read matrices of strings in a gateway.

Calling Sequence

Input argument profile:

SciErr getMatrixOfString(void* _pvCtx, int* _piAddress, int* _piRows, int* _piCols, int* _piLength, char** _pstStrings)
SciErr getMatrixOfWideString(void* _pvCtx, int* _piAddress, int* _piRows, int* _piCols, int* _piLength, wchar_t** _pwstStrings)

Named variable profile:

SciErr createNamedMatrixOfString(void* _pvCtx, char* _pstName, int _iRows, int _iCols, char** _pstStrings)
SciErr createNamedMatrixOfWideString(void* _pvCtx, char* _pstName, int _iRows, int _iCols, wchar_t** _pwstStrings)

Parameters

_pvCtx

Scilab environment pointer, pass in "pvApiCtx" provided by api_scilab.h.

_piAddress

Address of the Scilab variable.

_pstName

Name of the variable for "named" functions.

_piRows

Return number of rows.

_piCols

Return number of columns.

_piLength

Address of array of strings length (must be allocated size: _piRows * _piCols)

_pstStrings

Address of array of char* (must be allocated size: _piRows * _piCols)

_pwstStrings

Address of array of wchar_t* (must be allocated size: _piRows * _piCols)

SciErr

Error structure where is stored errors messages history and first error number.

Description

This help describes how matrix of strings can be handled through the Scilab API.

Gateway Source

	 
int read_string(char *fname,unsigned long fname_len)
{
	SciErr sciErr;
	int i,j;
	int iLen		= 0;
	//variable info
	int iRows		= 0;
	int iCols		= 0;
	int* piAddr		= NULL;
	int* piLen		= NULL;
	char** pstData	= NULL;

	//output variable
	int iRowsOut	= 1;
	int iColsOut	= 1;
	char* pstOut	= NULL;

	//check input and output arguments
	CheckRhs(1,1);
	CheckLhs(1,1);

	//get variable address
	sciErr = getVarAddressFromPosition(pvApiCtx, 1, &piAddr);
	if(sciErr.iErr)
	{
		printError(&sciErr, 0);
		return 0;
	}

	//fisrt call to retrieve dimensions
	sciErr = getMatrixOfString(pvApiCtx, piAddr, &iRows, &iCols, NULL, NULL);
	if(sciErr.iErr)
	{
		printError(&sciErr, 0);
		return 0;
	}

	piLen = (int*)malloc(sizeof(int) * iRows * iCols);
	//second call to retrieve length of each string
	sciErr = getMatrixOfString(pvApiCtx, piAddr, &iRows, &iCols, piLen, NULL);
	if(sciErr.iErr)
	{
		printError(&sciErr, 0);
		return 0;
	}

	pstData = (char**)malloc(sizeof(char*) * iRows * iCols);
	for(i = 0 ; i < iRows * iCols ; i++)
	{
		pstData[i] = (char*)malloc(sizeof(char) * (piLen[i] + 1));//+ 1 for null termination
	}
	//third call to retrieve data
	sciErr = getMatrixOfString(pvApiCtx, piAddr, &iRows, &iCols, piLen, pstData);
	if(sciErr.iErr)
	{
		printError(&sciErr, 0);
		return 0;
	}

	//computer length of all strings
	for(i = 0 ; i < iRows * iCols ; i++)
	{
		iLen += piLen[i];
	}

	//alloc output variable
	pstOut = (char*)malloc(sizeof(char) * (iLen + iRows * iCols));
	//initialize string to 0x00
	memset(pstOut, 0x00, sizeof(char) * (iLen + iRows * iCols));

	//concat input strings in output string
	for(i = 0 ; i < iRows ; i++)
	{
		for(j = 0 ; j < iCols ; j++)
		{
			int iCurLen = strlen(pstOut);
			if(iCurLen)
			{
				strcat(pstOut, " ");
			}
			strcpy(pstOut + strlen(pstOut), pstData[j * iRows + i]);
		}
	}

	//create new variable
	sciErr = createMatrixOfString(pvApiCtx, Rhs + 1, iRowsOut, iColsOut, &pstOut);
	if(sciErr.iErr)
	{
		printError(&sciErr, 0);
		return 0;
	}

	//free memory
	free(piLen);
	for(i = 0 ; i < iRows * iCols ; i++)
	{
		free(pstData[i]);
	}
	free(pstData);
	free(pstOut);

	LhsVar(1) = Rhs + 1;
	return 0;
}

Scilab test script

 
a_ref = ["may the puffin be with you"];
a = ["may", "the", "puffin"; "be","with","you"];
b = read_string(a);
if a_ref <> b then error("failed"), end