[Teem-commit] SF.net SVN: teem:[5704] teem/trunk/src/nrrd

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

Revision: 5704
          http://teem.svn.sourceforge.net/teem/?rev=5704&view=rev
Author:   kindlmann
Date:     2012-10-03 19:05:29 +0000 (Wed, 03 Oct 2012)
Log Message:
-----------
rethinking storage of backwards - must fit in (signed) long because byteSkip fit in the same type, but ultimately have to rethink cast of size_t bsize to long

Modified Paths:
--------------
    teem/trunk/src/nrrd/encodingGzip.c
    teem/trunk/src/nrrd/read.c

Modified: teem/trunk/src/nrrd/encodingGzip.c
===================================================================
--- teem/trunk/src/nrrd/encodingGzip.c	2012-10-03 18:36:38 UTC (rev 5703)
+++ teem/trunk/src/nrrd/encodingGzip.c	2012-10-03 19:05:29 UTC (rev 5704)
@@ -75,7 +75,7 @@
        of memory from "buff" into the given "_data" pointer */
     char *buff;
     airArray *buffArr;
-    unsigned long backwards;
+    long backwards;
       
     /* setting the airArray increment to twice the chunk size means that for
        headers that are small compared to the data, the airArray never
@@ -119,16 +119,16 @@
       return 1;
     }
     /* backwards is (positive) number of bytes AFTER data that we ignore */
-    backwards = AIR_CAST(unsigned long, -nio->byteSkip - 1);
-    if (sizeRed < sizeData + backwards) {
+    backwards = -nio->byteSkip - 1;
+    if (sizeRed < sizeData + AIR_CAST(size_t, backwards)) {
       char stmp1[AIR_STRLEN_SMALL], stmp2[AIR_STRLEN_SMALL];
       biffAddf(NRRD, "%s: expected %s bytes but received only %s", me,
-               airSprintSize_t(stmp1, sizeData + backwards),
+               airSprintSize_t(stmp1, sizeData + AIR_CAST(size_t, backwards)),
                airSprintSize_t(stmp2, sizeRed));
       return 1;
     }
     /* also handles nio->byteSkip == -N-1 signifying extra N bytes at end */
-    memcpy(_data, buff + sizeRed - sizeData - (-nio->byteSkip - 1), sizeData);
+    memcpy(_data, buff + sizeRed - sizeData - backwards, sizeData);
     airArrayNuke(buffArr);
   } else {
     /* no negative byteskip: after byteskipping, we can read directly

Modified: teem/trunk/src/nrrd/read.c
===================================================================
--- teem/trunk/src/nrrd/read.c	2012-10-03 18:36:38 UTC (rev 5703)
+++ teem/trunk/src/nrrd/read.c	2012-10-03 19:05:29 UTC (rev 5704)
@@ -281,7 +281,7 @@
     return 1;
   }
   if (nio->byteSkip < 0) {
-    unsigned long backwards;
+    long backwards;
     if (nrrdEncodingRaw != nio->encoding) {
       biffAddf(NRRD, "%s: can do backwards byte skip only in %s "
                "encoding, not %s", me,
@@ -295,8 +295,9 @@
     bsize = nrrdElementNumber(nrrd)/_nrrdDataFNNumber(nio);
     bsize *= nrrdElementSize(nrrd);
     /* backwards is (positive) number of bytes AFTER data that we ignore */
-    backwards = AIR_CAST(unsigned long, -nio->byteSkip - 1);
-    if (fseek(dataFile, -AIR_CAST(long, bsize + backwards), SEEK_END)) {
+    backwards = -nio->byteSkip - 1;
+    /* HEY what if bsize fits in size_t but not in (signed) long? */
+    if (fseek(dataFile, -AIR_CAST(long, bsize) - backwards, SEEK_END)) {
       char stmp[AIR_STRLEN_SMALL];
       biffAddf(NRRD, "%s: failed to fseek(dataFile, %s, SEEK_END)", me,
                airSprintSize_t(stmp, bsize));

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