[Teem-commit] teemdoc/html/nrrd lib.html,1.5,1.6

[<kin...@us...>]

Update of /cvsroot/teem/teemdoc/html/nrrd
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv21253/nrrd

Modified Files:
	lib.html 
Log Message:
various updates

Index: lib.html
===================================================================
RCS file: /cvsroot/teem/teemdoc/html/nrrd/lib.html,v
retrieving revision 1.5
retrieving revision 1.6
diff -C2 -d -r1.5 -r1.6
*** lib.html	9 Jan 2004 19:46:46 -0000	1.5
--- lib.html	19 Feb 2004 22:51:12 -0000	1.6
***************
*** 127,131 ****
    ** Comments.  Read from, and written to, header.
    ** The comment array "cmt" is NOT NULL-terminated.
!   ** The number of comments is cmtArr->len.
    */
    char **cmt;
--- 127,131 ----
    ** Comments.  Read from, and written to, header.
    ** The comment array "cmt" is NOT NULL-terminated.
!   ** The number of comments is cmtArr->len.
    */
    char **cmt;
***************
*** 310,313 ****
--- 310,368 ----
  </ul>
  
+ <h2>Reading a NRRD with a different memory allocator</h2>
+ 
+ In some cases you want to read a NRRD in, but you want to do the
+ memory allocation, instead of the nrrd library doing it for you.  This
+ is supported in nrrd, but you have to read the nrrd in two steps: the
+ first time reads the nrrd header so that you can figure out how much
+ memory to allocate, and the second time reads in the data (as well
+ as re-reading the header).  This function demonstrates this:
+ 
+ <blockquote><pre>
+ Nrrd *
+ customLoad(char *filename) {
+   char me[]="demoIO", *err;
+   NrrdIoState *nios;
+   Nrrd *nin;
+   void *data;
+   
+   /* create a new nrrd */
+   nin = nrrdNew();
+   
+   /* tell nrrdLoad to only read the header, not the data */
+   nios = nrrdIoStateNew();
+   nrrdIoStateSet(nios, nrrdIoStateSkipData, AIR_TRUE);
+   
+   /* read in the nrrd header from file */
+   if (nrrdLoad(nin, filename, nios)) {
+     err = biffGetDone(NRRD);
+     fprintf(stderr, "%s: trouble reading \"%s\" header:\n%s",
+             me, filename, err);
+     free(err); nios = nrrdIoStateNix(nios);
+     return NULL;
+   }
+   
+   /* we're done with the nrrdIoState, this sets it to NULL */
+   nios = nrrdIoStateNix(nios);
+   
+   /* load the nrrd again, this time the data will be read, but 
+      the existing nin-&gt;data memory will be used, because nrrdRead
+      (called by nrrdLoad) remembers the address and size of incoming
+      allocated data, and eventually it will get used, instead of
+      nrrd allocating new memory */
+   if (nrrdLoad(nin, filename, NULL)) {
+     err = biffGetDone(NRRD);
+     fprintf(stderr, "%s: trouble reading \"%s\" data:\n%s",
+ 	    me, filename, err);
+     free(err);
+     return NULL;
+   }
+ 
+   /* return the nrrd.  Remember that you probably want to nrrdNix this
+      nrrd, and not nrrdNuke, since nrrdNuke will free(nin-&gt;data) */
+   return nin;
+ }
+ </pre></blockquote>
+ 
  <h2>Getting data into and out of nrrds</h2>
  
***************
*** 378,382 ****
  nval = nrrdNew();
  nrrdAlloc(nval, nrrdTypeDouble, 3, sx, sy, sz);
! val = (double*)nval->data;
  val[10 + sx*(20 + sy*30)] = 42;     /* val[x=10,y=20,z=30] = 42 */
  ...
--- 433,437 ----
  nval = nrrdNew();
  nrrdAlloc(nval, nrrdTypeDouble, 3, sx, sy, sz);
! val = (double*)nval-&gt;data;
  val[10 + sx*(20 + sy*30)] = 42;     /* val[x=10,y=20,z=30] = 42 */
  ...
***************
*** 650,654 ****
  <td align=right><tt>nrrdContentSet</tt>
  <td><b>-</b>
! <td align=left>printf-style setting of the nrrd->content field
  <tr>
  <td align=right><tt>nrrdCheck</tt>
--- 705,709 ----
  <td align=right><tt>nrrdContentSet</tt>
  <td><b>-</b>
! <td align=left>printf-style setting of the nrrd-&gt;content field
  <tr>
  <td align=right><tt>nrrdCheck</tt>
***************
*** 740,747 ****
  <td><b>-</b>
  <td align=left>reverses the byte-ordering of the data in memory
- <tr>
- <td align=right><tt></tt>
- <td><b>-</b>
- <td align=left>
  </table>
  </center>
--- 795,798 ----
***************
*** 761,766 ****
    size_t I, N;
    
!   lup = nrrdDLookup[nrrd->type];
!   ins = nrrdDInsert[nrrd->type];
    N = nrrdElementNumber(nrrd);
    for (I=0; I&lt;N; I++) {
--- 812,817 ----
    size_t I, N;
    
!   lup = nrrdDLookup[nrrd-&gt;type];
!   ins = nrrdDInsert[nrrd-&gt;type];
    N = nrrdElementNumber(nrrd);
    for (I=0; I&lt;N; I++) {