matlab与C++以.mat文件方式进行数据相互流动-优快云博客

本文介绍了一个C++程序如何读取并处理Matlab的MAT文件中的数据结构，并将处理后的结果存回MAT文件的方法。该过程涉及到了C++中使用mat.h库对MAT文件的操作，包括获取字段名、数据类型一致性检查及数据复制等步骤。

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年前，放假回家之前，使用了C++与matlab之间的数据的互动的一个实验，感觉效果挺好。初步达到了目的，所以整理下来方便大家使用。减少大家编程学习的时间。
希望对你们有用。

#include "mat.h"<br data-filtered="filtered"><br data-filtered="filtered">void example8()
{

　　 const char **fnames;       /* pointers to field names */

    const mwSize *dims;

    mxArray    *tmp, *fout;

    char       *pdata=NULL;

    int        i_field, nfields;

    mxClassID  *classIDflags;

    mwIndex    j_struct;

    mwSize     NumStructRecords;

    mwSize     ndim;

    MATFile *pMF;

    mxArray *pRoad, *pOut;

    int status;

    const char *file = "ContourRoadResults_AfterWidthEtcCorrect_4_ZY.mat";

    printf("Opening file %s...\n\n", file);

    pMF = matOpen(file, "u");

    pRoad=matGetVariable(pMF, "ContourRoadResults");

    /* get input arguments */

    nfields = mxGetNumberOfFields(pRoad);

    NumStructRecords = mxGetNumberOfElements(pRoad);

    /* allocate memory  for storing classIDflags */

    classIDflags = (mxClassID*) mxCalloc(nfields, sizeof(mxClassID));

    /* check empty field, proper data type, and data type consistency;

     * and get classID for each field. */

    for(i_field=0; i_field<nfields; i_field++)

    {

        for(j_struct = 0; j_struct < NumStructRecords; j_struct++)

        {

            tmp = mxGetFieldByNumber(pRoad, j_struct, i_field);

            if(tmp == NULL)

            {

                printf("%s%d\t%s%d\n", "FIELD: ", i_field+1, "STRUCT INDEX :", j_struct+1);

                //mexErrMsgIdAndTxt( "MATLAB:phonebook:fieldEmpty", "Above field is empty!");

            }
 
            if(j_struct==0)

            {

                if( (!mxIsChar(tmp) && !mxIsNumeric(tmp)) || mxIsSparse(tmp)) {

                    printf("%s%d\t%s%d\n", "FIELD: ", i_field+1, "STRUCT INDEX :", j_struct+1);

                   // mexErrMsgIdAndTxt( "MATLAB:phonebook:invalidField",

                   //         "Above field must have either string or numeric non-sparse data.");

                }

                classIDflags[i_field]=mxGetClassID(tmp);

            }

            else

            {

                if (mxGetClassID(tmp) != classIDflags[i_field])

                {

                    printf("%s%d\t%s%d\n", "FIELD: ", i_field+1, "STRUCT INDEX :", j_struct+1);

                    //mexErrMsgIdAndTxt( "MATLAB:phonebook:invalidFieldType",

                    //        "Inconsistent data type in above field!");

                } else if(!mxIsChar(tmp) &&

                        ((mxIsComplex(tmp) || mxGetNumberOfElements(tmp)!=1))){

                    printf("%s%d\t%s%d\n", "FIELD: ", i_field+1, "STRUCT INDEX :", j_struct+1);

                    //mexErrMsgIdAndTxt( "MATLAB:phonebook:fieldNotRealScalar",

                    //        "Numeric data in above field must be scalar and noncomplex!");

                }

            }

        }

    }

    /* allocate memory  for storing pointers */

    fnames = (const char **)mxCalloc(nfields, sizeof(*fnames));

    /* get field name pointers */

    for (i_field=0; i_field< nfields; i_field++){

        fnames[i_field] = (char*)mxGetFieldNameByNumber(pRoad,i_field);

    }
 
    /* create a 1x1 struct matrix for output  */

    pOut = mxCreateStructMatrix(1,1,nfields, fnames);

    mxFree((void *)fnames);

    ndim = mxGetNumberOfDimensions(pRoad);

    dims = mxGetDimensions(pRoad);

    for(i_field=0; i_field<nfields; i_field++) {

        /* create cell/numeric array */

        if(classIDflags[i_field] == mxCHAR_CLASS) {

            fout = mxCreateCellArray(ndim, dims);

        }else {

            fout = mxCreateNumericArray(ndim, dims, classIDflags[i_field], mxREAL);

            pdata = (char*)mxGetData(fout);

        }

        /* copy data from input structure array */

        for (j_struct=0; j_struct<NumStructRecords; j_struct++) {

            tmp = mxGetFieldByNumber(pRoad,j_struct,i_field);

            if( mxIsChar(tmp)) {

                mxSetCell(fout, j_struct, mxDuplicateArray(tmp));

            }else {

                mwSize     sizebuf;

                sizebuf = mxGetElementSize(tmp);

                memcpy(pdata, mxGetData(tmp), sizebuf);

                pdata += sizebuf;

            }

        }

        /* set each field in output structure */

        mxSetFieldByNumber(pOut, 0, i_field, fout);

    }
 
    matPutVariable(pMF, "OutputResult_Convert",pOut);

    mxFree(classIDflags);

    if (matClose(pMF) != 0) {

        printf("Error closing file %s\n",file);

        return;

    }

    printf("Done\n");

    return;
}