Hi Francesco, hi Sylvestre,
this bug has been fixed upstream.
Please find attached a patch tho backport the fix to HDF5 1.8.11.
I should have commit access to the repo of the debian package [2] so
please let me know if you want me to update the package to include the
patch.
[1]
http://mail.lists.hdfgroup.org/pipermail/hdf-forum_lists.hdfgroup.org/2013-September/007137.html
[2] git://git.debian.org/git/pkg-grass/hdf5.git
best regards
--
Antonio Valentino
>From 4707d38bd9994de69dded7e3599b4efd20b13aec Mon Sep 17 00:00:00 2001
From: Antonio Valentino <antonio.valent...@tiscali.it>
Date: Fri, 27 Sep 2013 19:23:52 +0000
Subject: [PATCH] Fix long double detection
---
src/H5detect.c | 67 ++++++++++++++++++++++++++++++++++++++++------------------
1 file changed, 47 insertions(+), 20 deletions(-)
diff --git a/src/H5detect.c b/src/H5detect.c
index d6f6a3b..eedf175 100644
--- a/src/H5detect.c
+++ b/src/H5detect.c
@@ -118,10 +118,12 @@ static volatile int nd_g = 0, na_g = 0;
static void print_results(int nd, detected_t *d, int na, malign_t *m);
static void iprint(detected_t *);
-static int byte_cmp(int, const void *, const void *);
-static int bit_cmp(int, int *, volatile void *, volatile void *);
+static int byte_cmp(int, const void *, const void *, const unsigned char *);
+static int bit_cmp(int, int *, volatile void *, volatile void *,
+ const unsigned char *);
static void fix_order(int, int, int *, const char **);
-static int imp_bit(int, int *, volatile void *, volatile void *);
+static int imp_bit(int, int *, volatile void *, volatile void *,
+ const unsigned char *);
static unsigned long find_bias(int, int, int *, void *);
static void precision (detected_t*);
static void print_header(void);
@@ -293,6 +295,8 @@ precision (detected_t *d)
#define DETECT_F(TYPE,VAR,INFO) { \
volatile TYPE _v1, _v2, _v3; \
unsigned char _buf1[sizeof(TYPE)], _buf3[sizeof(TYPE)]; \
+ unsigned char _pad_mask[sizeof(TYPE)]; \
+ unsigned char _byte_mask; \
int _i, _j, _last = (-1); \
char *_mesg; \
\
@@ -300,11 +304,26 @@ precision (detected_t *d)
INFO.varname = #VAR; \
INFO.size = sizeof(TYPE); \
\
- /* Completely initialize temporary variables, in case the bits used in */ \
- /* the type take less space than the number of bits used to store the type */ \
- memset(&_v3, 0, sizeof(TYPE)); \
- memset(&_v2, 0, sizeof(TYPE)); \
- memset(&_v1, 0, sizeof(TYPE)); \
+ /* Initialize padding mask */ \
+ HDmemset(_pad_mask, 0, sizeof(_pad_mask)); \
+ \
+ /* Padding bits. Set a variable to 4.0, then flip each bit and see if \
+ * the modified variable is equal ("==") to the original. Build a \
+ * padding bitmask to indicate which bits in the type are padding (i.e. \
+ * have no effect on the value and should be ignored by subsequent \
+ * steps). This is necessary because padding bits can change arbitrarily \
+ * and interfere with detection of the various properties below unless we \
+ * know to ignore them. */ \
+ _v1 = 4.0; \
+ HDmemcpy(_buf1, (const void *)&_v1, sizeof(TYPE)); \
+ for(_i = 0; _i < (int)sizeof(TYPE); _i++) \
+ for(_byte_mask = (unsigned char)1; _byte_mask; _byte_mask <<= 1) { \
+ _buf1[_i] ^= _byte_mask; \
+ HDmemcpy((void *)&_v2, (const void *)_buf1, sizeof(TYPE)); \
+ if(_v1 != _v2) \
+ _pad_mask[_i] |= _byte_mask; \
+ _buf1[_i] ^= _byte_mask; \
+ } /* enf for */ \
\
/* Byte Order */ \
for(_i = 0, _v1 = 0.0, _v2 = 1.0; _i < (int)sizeof(TYPE); _i++) { \
@@ -313,7 +332,7 @@ precision (detected_t *d)
_v2 /= 256.0; \
memcpy(_buf1, (const void *)&_v1, sizeof(TYPE)); \
memcpy(_buf3, (const void *)&_v3, sizeof(TYPE)); \
- _j = byte_cmp(sizeof(TYPE), &_buf3, &_buf1); \
+ _j = byte_cmp(sizeof(TYPE), _buf3, _buf1, _pad_mask); \
if(_j >= 0) { \
INFO.perm[_i] = _j; \
_last = _i; \
@@ -327,19 +346,19 @@ precision (detected_t *d)
/* Implicit mantissa bit */ \
_v1 = 0.5; \
_v2 = 1.0; \
- INFO.imp = imp_bit (sizeof(TYPE), INFO.perm, &_v1, &_v2); \
+ INFO.imp = imp_bit (sizeof(TYPE), INFO.perm, &_v1, &_v2, _pad_mask); \
\
/* Sign bit */ \
_v1 = 1.0; \
_v2 = -1.0; \
- INFO.sign = bit_cmp (sizeof(TYPE), INFO.perm, &_v1, &_v2); \
+ INFO.sign = bit_cmp (sizeof(TYPE), INFO.perm, &_v1, &_v2, _pad_mask); \
\
/* Mantissa */ \
INFO.mpos = 0; \
\
_v1 = 1.0; \
_v2 = 1.5; \
- INFO.msize = bit_cmp (sizeof(TYPE), INFO.perm, &_v1, &_v2); \
+ INFO.msize = bit_cmp (sizeof(TYPE), INFO.perm, &_v1, &_v2, _pad_mask); \
INFO.msize += 1 + (INFO.imp?0:1) - INFO.mpos; \
\
/* Exponent */ \
@@ -879,7 +898,8 @@ iprint(detected_t *d)
*
* Purpose: Compares two chunks of memory A and B and returns the
* byte index into those arrays of the first byte that
- * differs between A and B.
+ * differs between A and B. Ignores differences where the
+ * corresponding bit in pad_mask is set to 0.
*
* Return: Success: Index of differing byte.
*
@@ -894,13 +914,16 @@ iprint(detected_t *d)
*-------------------------------------------------------------------------
*/
static int
-byte_cmp(int n, const void *_a, const void *_b)
+byte_cmp(int n, const void *_a, const void *_b, const unsigned char *pad_mask)
{
int i;
const unsigned char *a = (const unsigned char *) _a;
const unsigned char *b = (const unsigned char *) _b;
- for (i = 0; i < n; i++) if (a[i] != b[i]) return i;
+ for(i = 0; i < n; i++)
+ if((a[i] & pad_mask[i]) != (b[i] & pad_mask[i]))
+ return i;
+
return -1;
}
@@ -911,7 +934,8 @@ byte_cmp(int n, const void *_a, const void *_b)
* Purpose: Compares two bit vectors and returns the index for the
* first bit that differs between the two vectors. The
* size of the vector is NBYTES. PERM is a mapping from
- * actual order to little endian.
+ * actual order to little endian. Ignores differences where
+ * the corresponding bit in pad_mask is set to 0.
*
* Return: Success: Index of first differing bit.
*
@@ -926,7 +950,8 @@ byte_cmp(int n, const void *_a, const void *_b)
*-------------------------------------------------------------------------
*/
static int
-bit_cmp(int nbytes, int *perm, volatile void *_a, volatile void *_b)
+bit_cmp(int nbytes, int *perm, volatile void *_a, volatile void *_b,
+ const unsigned char *pad_mask)
{
int i, j;
volatile unsigned char *a = (volatile unsigned char *) _a;
@@ -935,7 +960,8 @@ bit_cmp(int nbytes, int *perm, volatile void *_a, volatile void *_b)
for (i = 0; i < nbytes; i++) {
assert(perm[i] < nbytes);
- if ((aa = a[perm[i]]) != (bb = b[perm[i]])) {
+ if ((aa = a[perm[i]] & pad_mask[perm[i]])
+ != (bb = b[perm[i]] & pad_mask[perm[i]])) {
for (j = 0; j < 8; j++, aa >>= 1, bb >>= 1) {
if ((aa & 1) != (bb & 1)) return i * 8 + j;
}
@@ -1050,7 +1076,8 @@ fix_order(int n, int last, int *perm, const char **mesg)
*-------------------------------------------------------------------------
*/
static int
-imp_bit(int n, int *perm, volatile void *_a, volatile void *_b)
+imp_bit(int n, int *perm, volatile void *_a, volatile void *_b,
+ const unsigned char *pad_mask)
{
volatile unsigned char *a = (volatile unsigned char *) _a;
volatile unsigned char *b = (volatile unsigned char *) _b;
@@ -1061,7 +1088,7 @@ imp_bit(int n, int *perm, volatile void *_a, volatile void *_b)
* Look for the least significant bit that has changed between
* A and B. This is the least significant bit of the exponent.
*/
- changed = bit_cmp(n, perm, a, b);
+ changed = bit_cmp(n, perm, a, b, pad_mask);
assert(changed >= 0);
/*
--
1.8.4.rc3
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