Bug in Mat_VarGetStructsLinear()

[Takumi Kamioka]

Hi,

I  utilize matio1.3.4.
Thanks a lot for this great library.
I found a bug in Mat_VarGetStructsLinear().
The function only return structures starting from the first  structure.
I modified the function as follows (add one line):

matvar_t *
Mat_VarGetStructsLinear(matvar_t *matvar,int start,int stride,int edge,
    int copy_fields)
{
    int i, I = 0, field, nfields;
    matvar_t *struct_slab, **fields;

    /* FIXME: Check allocations */
    if ( matvar == NULL || matvar->rank > 10 ) {
       struct_slab = NULL;
    } else {

        struct_slab = Mat_VarDuplicate(matvar,0);
        if ( !copy_fields )
            struct_slab->mem_conserve = 1;

        nfields = matvar->nbytes / matvar->data_size;
        for ( i = 0; i < matvar->rank; i++ )
            nfields = nfields / matvar->dims_;

        struct_slab->nbytes = edge*nfields*sizeof(matvar_t *);
        struct_slab->data = malloc(struct_slab->nbytes);
        fields = struct_slab->data;
        I = start*nfields;  /* ADD this line */
        for ( i = 0; i < edge; i++ ) {
            if ( copy_fields ) {
                for ( field = 0; field < nfields; field++ ) {
                    fields =
                        Mat_VarDuplicate(*((matvar_t **)matvar->data+I),1);
                    I++;
                }
            } else {
                for ( field = 0; field < nfields; field++ ) {
                    fields = *((matvar_t **)matvar->data + I);
                    I++;
                }
            }
            I += stride;
        }
    }
    return struct_slab;
}

That works fine for my usage.
Thanks,_

[cch]

Thanks!

Chris

[Takumi Kamioka]

Hi, Chris!

I found an another bug in the same function. Multiple fields could not be read from a structure obtained by this function. Because the number of fields was not set correctly.
I modified it as follows. It's working but It might be the wrong modification.

@@ -1291,8 +1291,9 @@ Mat_VarGetStructsLinear(matvar_t *matvar,int start,int str

         struct_slab->nbytes = edge*nfields*sizeof(matvar_t *);
         struct_slab->data = malloc(struct_slab->nbytes);
          fields = struct_slab->data;
+        struct_slab->dims = edge;   
         I = start*nfields;
         for ( i = 0; i < edge; i++ ) {
             if ( copy_fields ) {
                 for ( field = 0; field < nfields; field++ ) {
@@ -1309,6 +1310,7 @@ Mat_VarGetStructsLinear(matvar_t *matvar,int start,int str
             I += stride;
         }
     }
     return struct_slab;
}