[svn-r27770] Bring r27428 from trunk

Reverts the following changes:

    27737, 27742, 27743

These involve double conversions that cause problems with the IBM
XL compiler.

Tested on: h5committest
           ostrich w/ XL C compiler

3 files changed, 123 insertions, 0 deletions

diff --git a/config/cmake/ConfigureChecks.cmake b/config/cmake/ConfigureChecks.cmake
index e223553..09f1caf 100644
--- a/config/cmake/ConfigureChecks.cmake
+++ b/config/cmake/ConfigureChecks.cmake
@@ -33,6 +33,18 @@ endif (HDF5_METADATA_TRACE_FILE)
 MARK_AS_ADVANCED (HDF5_METADATA_TRACE_FILE)
 
 # ----------------------------------------------------------------------
+# Decide whether the data accuracy has higher priority during data
+# conversions.  If not, some hard conversions will still be prefered even
+# though the data may be wrong (for example, some compilers don't
+# support denormalized floating values) to maximize speed.
+#
+option (HDF5_WANT_DATA_ACCURACY "IF data accuracy is guaranteed during data conversions" ON)
+if (HDF5_WANT_DATA_ACCURACY)
+  set (H5_WANT_DATA_ACCURACY 1)
+endif (HDF5_WANT_DATA_ACCURACY)
+MARK_AS_ADVANCED (HDF5_WANT_DATA_ACCURACY)
+
+# ----------------------------------------------------------------------
 # Decide whether the presence of user's exception handling functions is
 # checked and data conversion exceptions are returned.  This is mainly
 # for the speed optimization of hard conversions.  Soft conversions can
@@ -220,6 +232,24 @@ H5ConversionTests (H5_LDOUBLE_TO_LONG_SPECIAL  "Checking IF your system converts
 #
 H5ConversionTests (H5_LONG_TO_LDOUBLE_SPECIAL "Checking IF your system can convert (unsigned) long to long double values with special algorithm")
 # ----------------------------------------------------------------------
+# Set the flag to indicate that the machine can accurately convert
+# 'long double' to '(unsigned) long long' values.  (This flag should be set for
+# all machines, except for Mac OS 10.4 and SGI IRIX64 6.5.  When the bit sequence
+# of long double is 0x4351ccf385ebc8a0bfcc2a3c..., the values of (unsigned)long long
+# start to go wrong on these two machines.  Adjusting it higher to
+# 0x4351ccf385ebc8a0dfcc... or 0x4351ccf385ebc8a0ffcc... will make the converted
+# values wildly wrong.  This test detects this wrong behavior and disable the test.
+#
+H5ConversionTests (H5_LDOUBLE_TO_LLONG_ACCURATE "Checking IF correctly converting long double to (unsigned) long long values")
+# ----------------------------------------------------------------------
+# Set the flag to indicate that the machine can accurately convert
+# '(unsigned) long long' to 'long double' values.  (This flag should be set for
+# all machines, except for Mac OS 10.4, when the bit sequences are 003fff...,
+# 007fff..., 00ffff..., 01ffff..., ..., 7fffff..., the converted values are twice
+# as big as they should be.
+#
+H5ConversionTests (H5_LLONG_TO_LDOUBLE_CORRECT "Checking IF correctly converting (unsigned) long long to long double values")
+# ----------------------------------------------------------------------
 # Check if pointer alignments are enforced
 #
 H5ConversionTests (H5_NO_ALIGNMENT_RESTRICTIONS "Checking IF alignment restrictions are strictly enforced")
diff --git a/config/cmake/ConversionTests.c b/config/cmake/ConversionTests.c
index cd2e8bb..d964bf8 100644
--- a/config/cmake/ConversionTests.c
+++ b/config/cmake/ConversionTests.c
@@ -116,6 +116,88 @@ done:
 
 #endif
 
+#ifdef H5_LDOUBLE_TO_LLONG_ACCURATE_TEST
+int main(void)
+{
+    long double         ld = 20041683600089727.779961L;
+    long long           ll;
+    unsigned long long  ull;
+    unsigned char       s[16];
+    int                 ret = 0;
+
+    if(sizeof(long double) == 16) {
+        /*make sure the long double type is the same as the failing type
+         *which has 16 bytes in size and 11 bits of exponent.  If it is,
+         *the bit sequence should be like below.  It's not
+         *a decent way to check but this info isn't available. */
+        memcpy(s, &ld, 16);
+        if(s[0]==0x43 && s[1]==0x51 && s[2]==0xcc && s[3]==0xf3 &&
+            s[4]==0x85 && s[5]==0xeb && s[6]==0xc8 && s[7]==0xa0 &&
+            s[8]==0xbf && s[9]==0xcc && s[10]==0x2a && s[11]==0x3c) {
+
+            /*slightly adjust the bit sequence (s[8]=0xdf).  The converted
+             *values will go wild on Mac OS 10.4 and IRIX64 6.5.*/
+            s[0]=0x43; s[1]=0x51; s[2]=0xcc; s[3]=0xf3;
+            s[4]=0x85; s[5]=0xeb; s[6]=0xc8; s[7]=0xa0;
+            s[8]=0xdf; s[9]=0xcc; s[10]=0x2a; s[11]=0x3c;
+            s[12]=0x3d; s[13]=0x85; s[14]=0x56; s[15]=0x20;
+
+            memcpy(&ld, s, 16);
+            ll = (long long)ld;
+            ull = (unsigned long long)ld;
+
+            if(ll != 20041683600089728 || ull != 20041683600089728)
+                ret = 1;
+        }
+    }
+done:
+    exit(ret);
+}
+#endif
+
+#ifdef H5_LLONG_TO_LDOUBLE_CORRECT_TEST
+int main(void)
+{
+    long double         ld;
+    long long           ll;
+    unsigned long long  ull;
+    unsigned char       s[16];
+    int                 flag=0, ret=0;
+
+    /*Determine if long double has 16 byte in size, 11 bit exponent, and
+     *the bias is 0x3ff */
+    if(sizeof(long double) == 16) {
+        ld = 1.0L;
+        memcpy(s, &ld, 16);
+        if(s[0]==0x3f && s[1]==0xf0 && s[2]==0x00 && s[3]==0x00 &&
+            s[4]==0x00 && s[5]==0x00 && s[6]==0x00 && s[7]==0x00)
+            flag = 1;
+    }
+
+    if(flag==1 && sizeof(long long)==8) {
+        ll = 0x01ffffffffffffffLL;
+        ld = (long double)ll;
+        memcpy(s, &ld, 16);
+        /*Check if the bit sequence is as supposed to be*/
+        if(s[0]!=0x43 || s[1]!=0x7f || s[2]!=0xff || s[3]!=0xff ||
+            s[4]!=0xff || s[5]!=0xff || s[6]!=0xff || s[7]!=0xff ||
+            s[8]!=0xf0 || s[9]!=0x00 || s[10]!=0x00 || s[11]!=0x00)
+            ret = 1;
+    }
+    if(flag==1 && sizeof(unsigned long long)==8) {
+        ull = 0x01ffffffffffffffULL;
+        ld = (long double)ull;
+        memcpy(s, &ld, 16);
+        if(s[0]!=0x43 || s[1]!=0x7f || s[2]!=0xff || s[3]!=0xff ||
+            s[4]!=0xff || s[5]!=0xff || s[6]!=0xff || s[7]!=0xff ||
+            s[8]!=0xf0 || s[9]!=0x00 || s[10]!=0x00 || s[11]!=0x00)
+            ret = 1;
+    }
+done:
+    exit(ret);
+}
+#endif
+
 #ifdef H5_NO_ALIGNMENT_RESTRICTIONS_TEST
 
 #include <stdlib.h>
diff --git a/config/cmake/H5pubconf.h.in b/config/cmake/H5pubconf.h.in
index 10cf1bc..874c8f0 100644
--- a/config/cmake/H5pubconf.h.in
+++ b/config/cmake/H5pubconf.h.in
@@ -362,10 +362,18 @@
 /* Define if HDF5's high-level library headers should be included in hdf5.h */
 #cmakedefine H5_INCLUDE_HL @H5_INCLUDE_HL@
 
+/* Define if your system can convert long double to (unsigned) long long
+   values correctly. */
+#cmakedefine H5_LDOUBLE_TO_LLONG_ACCURATE @H5_LDOUBLE_TO_LLONG_ACCURATE@
+
 /* Define if your system converts long double to (unsigned) long values with
    special algorithm. */
 #cmakedefine H5_LDOUBLE_TO_LONG_SPECIAL @H5_LDOUBLE_TO_LONG_SPECIAL@
 
+/* Define if your system can convert (unsigned) long long to long double
+   values correctly. */
+#cmakedefine H5_LLONG_TO_LDOUBLE_CORRECT @H5_LLONG_TO_LDOUBLE_CORRECT@
+
 /* Define if your system can convert (unsigned) long to long double values
    with special algorithm. */
 #cmakedefine H5_LONG_TO_LDOUBLE_SPECIAL @H5_LONG_TO_LDOUBLE_SPECIAL@
@@ -567,6 +575,9 @@
 /* Version number of package */
 #define H5_VERSION "@HDF5_PACKAGE_VERSION_STRING@"
 
+/* Data accuracy is prefered to speed during data conversions */
+#cmakedefine H5_WANT_DATA_ACCURACY @H5_WANT_DATA_ACCURACY@
+
 /* Check exception handling functions during data conversions */
 #cmakedefine H5_WANT_DCONV_EXCEPTION @H5_WANT_DCONV_EXCEPTION@