MATLAB: I could’t compile the function unravel.c from DIP using MATLAB book by Rafael Gonzalez and Richard Woods

mex compiler

I typed the function unravel.c in the book DIP using MATLAB book by Rafael Gonzalez and Richard Woods Second Edition as following
/*=========================================================================
   * unravel.c
   * Decodes a variable length codes bit sequence (a vector of
   * 16-bit integers) using a binary sort from the MSB to the LSB
   * (across word boundaries) based on a transition table.
   *=======================================================================*/
#include "mex.h"
void unravel(unit16_T *hx,double *link,double *x,
    double xsz,int hxsz)  
{
    int i=15, j = 0, k = 0, n = 0;           /* Start at root node, 1st */
                                              /* hx bit and x element */
      while (xsz - k)  {                      /* Do until x is filled */
          if (*(link + n) > 0) {              /* Is there a link? */
              if ((*(hx + j) >> i) & 0x0001)  /* Is bit a 1? */
                  n = *(link + n);             /* Yes, get new node */
              else n = *(link + n) - 1;       /* It's 0 so get new node */
              if (i) i--; else {j++; i = 15;} /* Set i, j to next bit */
              if (j > hxsz)                   /* Bits left to decode? */
                  mexErrMsgTxt("Out of code bits ???");
          }
          else {                              /* It must be a leaf node */
              *(x + k++) = -*(link + n);      /* Output value */
              n = 0; }                        /* Start over at root */
      }
      if (k == xsz - 1)                       /* Is one left over? */
          *(x + k++) = -*(link + n);
}
void mexFunction( int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
{
    double *link, *x, xsz;
      uint16_T *hx;
      int hxsz;
      /* Check inputs for reasonableness */
      if (nrhs != 3)
          mexErrMsgTxt("Three inputs required.");
      else if (nlhs > 1)
          mexErrMsgTxt("Too many output arguments.");
      /* Is last input argument a scalar? */
      if(!mxIsDouble(prhs[2])  || mxIsComplex(prhs[2])  || mxGetN(prhs[2]) * mxGetM(prhs[2]) != 1)
          mexErrMsgTxt("Input XSIZE must be a scalar.");
      /* Create input matrix pointers and get scalar */
      hx = (uint16_T *) mxGetData(prhs[0]);
      link = (double *) mxGetData(prhs[1]);
      xsz = mxGetScalar(prhs[2]);     /* returns DOUBLE */
      /* Get the number of elemnts in hx */
      hxsz = mxGetM(prhs[0]);
      /* Create 'xsz' x 1 output matrix */
      plhs[0] = mxCreateDoubleMatrix(xsz, 1, mxREAL);
      /* Get C pointer to a copy of the output matrix */
      x = (double *) mxGetData(plhs[0]);
      /* Call the C subroutine */
      unravel(hx, link, x, xsz, hxsz);
}
on MATLAB i typed the command
>> mex unravel.c
to get the following error
======================================================
unravel.c 
D:\Documents and Settings\COOLAdmin\Desktop\Matlab\unravel.c(8) : error C2143: syntax error : missing ')' before '*' 
D:\Documents and Settings\COOLAdmin\Desktop\Matlab\unravel.c(8) : error C2143: syntax error : missing '{' before '*' 
D:\Documents and Settings\COOLAdmin\Desktop\Matlab\unravel.c(8) : error C2059: syntax error : 'type' 
D:\Documents and Settings\COOLAdmin\Desktop\Matlab\unravel.c(9) : error C2059: syntax error : ')' 
D:\Documents and Settings\COOLAdmin\Desktop\Matlab\unravel.c(55) : warning C4244: 'function' : conversion from 'double ' to 'int ', possible loss of data 
D:\Documents and Settings\COOLAdmin\Desktop\Matlab\unravel.c(61) : warning C4013: 'unravel' undefined; assuming extern returning int 
    C:\PROGRA~1\MATLAB\R2008A\BIN\MEX.PL: Error: Compile of 'unravel.c' failed. 
??? Error using ==> mex at 207
Unable to complete successfully.
=======================================================
Could you please help me on that?

Best Answer

You have a typo in the line:
void unravel(unit16_T *hx,double *link,double *x, double xsz,int hxsz)
It is uint16_T, not unit16_T:
void unravel(uint16_T *hx,double *link,double *x, double xsz,int hxsz)
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