From 353b7ebf536c3a516c7bd8ae0f2fea1136354d12 Mon Sep 17 00:00:00 2001
From: Dennis Heimbigner <dmh@unidata.ucar.edu>
Date: Thu, 12 Apr 2012 02:06:28 +0000
Subject: [PATCH] fix bug in memio.c realloc code

---
 cf                         |  4 +--
 libsrc/memio.c             | 59 +++++++++++++++++++++++---------------
 nc_test4/tst_files6.c      |  3 +-
 nc_test4/tst_h_many_atts.c |  1 -
 4 files changed, 40 insertions(+), 27 deletions(-)

diff --git a/cf b/cf
index 2725c01e4..e7b391258 100644
--- a/cf
+++ b/cf
@@ -6,7 +6,7 @@ cmds=$@
 fi
 
 #HDF5=1
-#DAP=1
+DAP=1
 #CDMR=1
 #RPC=1
 #PGI=1
@@ -19,7 +19,7 @@ cmds=""
 #cmds="all"
 #cmds="all check"
 #cmds="all dist"
-cmds="all distcheck"
+#cmds="all distcheck"
 #cmds="$cmds install"
 fi
 
diff --git a/libsrc/memio.c b/libsrc/memio.c
index c268462d8..688e2db0c 100644
--- a/libsrc/memio.c
+++ b/libsrc/memio.c
@@ -18,6 +18,12 @@
 #endif
 #include "nc.h"
 
+#undef DEBUG
+
+#ifdef DEBUG
+#include <stdio.h>
+#endif
+
 #ifndef HAVE_SSIZE_T
 #define ssize_t int
 #endif
@@ -60,13 +66,6 @@
 #undef X_ALIGN
 #endif
 
-/* Define the amount by which memory is incremented on realloc */
-#define DEFAULT_BLOCKSIZE (0x2000)
-
-#define TACTIC_INCR 1
-#define TACTIC_DOUBLE 2
-#define TACTIC TACTIC_DOUBLE
-
 /* Private data for memio */
 
 typedef struct NCMEMIO {
@@ -90,6 +89,8 @@ static int memio_close(ncio* nciop, int);
 /* Mnemonic */
 #define DOOPEN 1
 
+static long pagesize = 0;
+
 /* Create a new ncio struct to hold info about the file. */
 static int
 memio_new(const char* path, int ioflags, off_t initialsize, ncio** nciopp, NCMEMIO** memiop)
@@ -98,13 +99,17 @@ memio_new(const char* path, int ioflags, off_t initialsize, ncio** nciopp, NCMEM
     ncio* nciop = NULL;
     NCMEMIO* memio = NULL;
     int openfd = -1;
+
+    if(pagesize == 0) {
 #if defined HAVE_SYSCONF
-    long pagesize = sysconf(_SC_PAGE_SIZE);
+        pagesize = sysconf(_SC_PAGE_SIZE);
 #elif defined HAVE_GETPAGESIZE
-    long pagesize = getpagesize();
+        pagesize = getpagesize();
 #else
-    long pagesize = 4096; /* good guess */
+        pagesize = 4096; /* good guess */
 #endif
+    }
+
     errno = 0;
 
     /* Always force the allocated size to be a multiple of pagesize */
@@ -218,6 +223,10 @@ memio_create(const char* path, int ioflags,
 	if(memio->memory == NULL) {status = NC_ENOMEM; goto unwind_open;}
     } /*!persist*/
 
+#ifdef DEBUG
+fprintf(stderr,"memio_create: initial memory: %lu/%lu\n",(unsigned long)memio->memory,(unsigned long)memio->alloc);
+#endif
+
     fd = nc__pseudofd();
     *((int* )&nciop->fd) = fd; 
 
@@ -234,7 +243,7 @@ memio_create(const char* path, int ioflags,
     }
 
     /* Pick a default sizehint */
-    if(sizehintp) *sizehintp = DEFAULT_BLOCKSIZE;
+    if(sizehintp) *sizehintp = pagesize;
 
     *nciopp = nciop;
     return NC_NOERR;
@@ -309,6 +318,10 @@ memio_open(const char* path,
     memio->memory = (char*)malloc(memio->alloc);
     if(memio->memory == NULL) {status = NC_ENOMEM; goto unwind_open;}
 
+#ifdef DEBUG
+fprintf(stderr,"memio_open: initial memory: %lu/%lu\n",(unsigned long)memio->memory,(unsigned long)memio->alloc);
+#endif
+
     /* Read the file into the memio memory */
     /* We need to do multiple reads because there is no
        guarantee that the amount read will be the full amount */
@@ -383,28 +396,28 @@ memio_pad_length(ncio* nciop, off_t length)
     if(!fIsSet(nciop->ioflags, NC_WRITE))
         return EPERM; /* attempt to write readonly file*/
 
-    /* Realloc the allocated memory */
     if(memio->locked > 0)
 	return NC_EDISKLESS;
 
     if(length > memio->alloc) {
-	off_t newsize;
-	char* newmem;
-	switch(TACTIC) {
-	case TACTIC_DOUBLE:
-	    newsize = (memio->alloc * 2);
-	    break;
-	case TACTIC_INCR:
-	default:
-	    newsize = length + (length % DEFAULT_BLOCKSIZE);
-	    break;
-	}
+        /* Realloc the allocated memory to a multiple of the pagesize*/
+	off_t newsize = length;
+	void* newmem = NULL;
+	/* Round to a multiple of pagesize */
+	if((newsize % pagesize) != 0)
+	    newsize += (pagesize - (newsize % pagesize));
 
         newmem = (char*)realloc(memio->memory,newsize);
         if(newmem == NULL) return NC_ENOMEM;
+
 	/* zero out the extra memory */
         memset((void*)(newmem+memio->alloc),0,(newsize - memio->alloc));
 
+#ifdef DEBUG
+fprintf(stderr,"realloc: %lu/%lu -> %lu/%lu\n",
+(unsigned long)memio->memory,(unsigned long)memio->alloc,
+(unsigned long)newmem,(unsigned long)newsize);
+#endif
 	memio->memory = newmem;
 	memio->alloc = newsize;
     }  
diff --git a/nc_test4/tst_files6.c b/nc_test4/tst_files6.c
index ab75dd5d7..cb6276859 100644
--- a/nc_test4/tst_files6.c
+++ b/nc_test4/tst_files6.c
@@ -17,7 +17,8 @@ main(int argc, char **argv)
    printf("\n*** Testing netcdf file functions some more.\n");
 #ifdef USE_DAP
 #ifdef ENABLE_DAP_REMOTE_TESTS
-   printf("*** testing simple opendap open/close...");
+    printf("*** testing simple opendap open/close...");
+    printf("    url=%s\n",URL);
    {
       int ncid;
 
diff --git a/nc_test4/tst_h_many_atts.c b/nc_test4/tst_h_many_atts.c
index 2ec8ba218..9cb42a10d 100644
--- a/nc_test4/tst_h_many_atts.c
+++ b/nc_test4/tst_h_many_atts.c
@@ -6,7 +6,6 @@
    but they use HDF5 the same way that netCDF-4 does, so if these
    tests don't work, than netCDF-4 won't work either.
 
-   $Id$
 */
 #include <config.h>
 #include <nc_tests.h>