[svn-r13491] Description:

	Reduce the size of the value used to store the # of bytes in the
"payload" for chunk 0 of an object header.

Tested on:
	FreeBSD/32 6.2 (duty)

9 files changed, 102 insertions, 29 deletions

diff --git a/src/H5O.c b/src/H5O.c
index 9ac1dd1..775ee4d 100644
--- a/src/H5O.c
+++ b/src/H5O.c
@@ -677,6 +677,8 @@ H5O_create(H5F_t *f, hid_t dxpl_id, size_t size_hint, hid_t ocpl_id,
 
     /* Initialize version-specific fields */
     if(oh->version > H5O_VERSION_1) {
+        size_t tent_oh_size;            /* Tentative size of object header */
+
         /* Initialize all time fields with current time, if we are storing them */
         if(oh->flags & H5O_HDR_STORE_TIMES)
             oh->atime = oh->mtime = oh->ctime = oh->btime = H5_now();
@@ -698,6 +700,30 @@ H5O_create(H5F_t *f, hid_t dxpl_id, size_t size_hint, hid_t ocpl_id,
         /* Check for non-default attribute storage phase change values */
         if(oh->max_compact != H5O_CRT_ATTR_MAX_COMPACT_DEF || oh->min_dense != H5O_CRT_ATTR_MIN_DENSE_DEF)
             oh->flags |= H5O_HDR_ATTR_STORE_PHASE_CHANGE;
+
+        /* Determine correct value for chunk #0 size bits */
+
+        /* See if only 1 byte is enough */
+        tent_oh_size = H5O_SIZEOF_HDR(oh) + size_hint;
+        if(tent_oh_size > 255) {
+            uint8_t old_oh_flags = oh->flags;   /* Temporary object header flags */
+
+            /* Need more than 1 byte, see if 2 bytes is enough */
+            oh->flags |= H5O_HDR_CHUNK0_2;
+            tent_oh_size = H5O_SIZEOF_HDR(oh) + size_hint;
+            if(tent_oh_size > 65535) {
+                /* Need more than 2 bytes, see if 4 bytes is enough */
+                oh->flags = old_oh_flags;
+                oh->flags |= H5O_HDR_CHUNK0_4;
+                tent_oh_size = H5O_SIZEOF_HDR(oh) + size_hint;
+                if(tent_oh_size > 4294967295) {
+                    /* Use 8 bytes */
+                    /* (Should probably have check for using more than 8 bytes... :-) */
+                    oh->flags = old_oh_flags;
+                    oh->flags |= H5O_HDR_CHUNK0_8;
+                } /* end if */
+            } /* end if */
+        } /* end if */
     } /* end if */
     else {
         /* Reset unused time fields */
diff --git a/src/H5Ocache.c b/src/H5Ocache.c
index 706497f..16e6278 100644
--- a/src/H5Ocache.c
+++ b/src/H5Ocache.c
@@ -279,7 +279,7 @@ H5O_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, const void UNUSED * _udata1,
         /* Flags */
         oh->flags = *p++;
         if(oh->flags & ~H5O_HDR_ALL_FLAGS)
-            HGOTO_ERROR(H5E_OHDR, H5E_VERSION, NULL, "unknown object header status flag(s)")
+            HGOTO_ERROR(H5E_OHDR, H5E_BADVALUE, NULL, "unknown object header status flag(s)")
 
         /* Number of messages (to allocate initially) */
         nmesgs = 1;
@@ -324,6 +324,28 @@ H5O_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, const void UNUSED * _udata1,
             oh->max_compact = H5O_CRT_ATTR_MAX_COMPACT_DEF;
             oh->min_dense = H5O_CRT_ATTR_MIN_DENSE_DEF;
         } /* end else */
+
+        /* First chunk size */
+        switch(oh->flags & H5O_HDR_CHUNK0_SIZE) {
+            case 0:     /* 1 byte size */
+                chunk_size = *p++;
+                break;
+
+            case 1:     /* 2 byte size */
+                UINT16DECODE(p, chunk_size);
+                break;
+
+            case 2:     /* 4 byte size */
+                UINT32DECODE(p, chunk_size);
+                break;
+
+            case 3:     /* 8 byte size */
+                UINT64DECODE(p, chunk_size);
+                break;
+
+            default:
+                HGOTO_ERROR(H5E_OHDR, H5E_BADVALUE, NULL, "bad size for chunk 0")
+        } /* end switch */
     } /* end if */
     else {
         /* Reset unused time fields */
@@ -332,10 +354,10 @@ H5O_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, const void UNUSED * _udata1,
         /* Reset unused attribute fields */
         oh->max_compact = 0;
         oh->min_dense = 0;
-    } /* end else */
 
-    /* First chunk size */
-    UINT32DECODE(p, chunk_size);
+        /* First chunk size */
+        UINT32DECODE(p, chunk_size);
+    } /* end else */
 
     /* Reserved, in version 1 */
     if(H5O_VERSION_1 == oh->version)
@@ -412,8 +434,7 @@ H5O_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, const void UNUSED * _udata1,
         } /* end if */
         else {
             /* Read the chunk raw data */
-            if(H5F_block_read(f, H5FD_MEM_OHDR, chunk_addr, chunk_size,
-                    dxpl_id, oh->chunk[chunkno].image) < 0)
+            if(H5F_block_read(f, H5FD_MEM_OHDR, chunk_addr, chunk_size, dxpl_id, oh->chunk[chunkno].image) < 0)
                 HGOTO_ERROR(H5E_OHDR, H5E_READERROR, NULL, "unable to read object header data")
 
             /* Point into chunk image to decode */
@@ -649,6 +670,8 @@ H5O_assert(oh);
          * on the entire block of memory needs to be updated if anything is
          * modified */
         if(oh->version > H5O_VERSION_1) {
+            uint64_t chunk0_size = oh->chunk[0].size - H5O_SIZEOF_HDR(oh);  /* Size of chunk 0's data */
+
             /* Verify magic number */
             HDassert(!HDmemcmp(p, H5O_HDR_MAGIC, H5O_SIZEOF_MAGIC));
             p += H5O_SIZEOF_MAGIC;
@@ -676,8 +699,27 @@ H5O_assert(oh);
                 UINT16ENCODE(p, oh->min_dense);
             } /* end if */
 
-            /* Chunk size */
-            UINT32ENCODE(p, (oh->chunk[0].size - H5O_SIZEOF_HDR(oh)));
+            /* First chunk size */
+            switch(oh->flags & H5O_HDR_CHUNK0_SIZE) {
+                case 0:     /* 1 byte size */
+                    *p++ = chunk0_size;
+                    break;
+
+                case 1:     /* 2 byte size */
+                    UINT16ENCODE(p, chunk0_size);
+                    break;
+
+                case 2:     /* 4 byte size */
+                    UINT32ENCODE(p, chunk0_size);
+                    break;
+
+                case 3:     /* 8 byte size */
+                    UINT64ENCODE(p, chunk0_size);
+                    break;
+
+                default:
+                    HGOTO_ERROR(H5E_OHDR, H5E_BADVALUE, FAIL, "bad size for chunk 0")
+            } /* end switch */
         } /* end if */
         else {
             /* Version */
diff --git a/src/H5Opkg.h b/src/H5Opkg.h
index 65d4914..17532e0 100644
--- a/src/H5Opkg.h
+++ b/src/H5Opkg.h
@@ -88,6 +88,12 @@
 #define H5O_CRT_ATTR_MIN_DENSE_DEF      6
 #define H5O_CRT_OHDR_FLAGS_DEF          H5O_HDR_STORE_TIMES
 
+/* Object header status flag definitions */
+#define H5O_HDR_CHUNK0_1                0x00
+#define H5O_HDR_CHUNK0_2                0x01
+#define H5O_HDR_CHUNK0_4                0x02
+#define H5O_HDR_CHUNK0_8                0x03
+
 /*
  * Size of object header prefix.
  */
@@ -114,7 +120,7 @@
                   2 +		/*max compact attributes */		      \
                   2		/*min dense attributes	*/		      \
                 ) : 0) +						      \
-                4 +		/*chunk data size	*/		      \
+                (1 << ((O)->flags & H5O_HDR_CHUNK0_SIZE)) + /*chunk 0 data size */ \
                 H5O_SIZEOF_CHKSUM) /*checksum size	*/		      \
     )
 
@@ -188,9 +194,6 @@
         } /* end if */							      \
     } /* end if */
 
-/* All the object header status flags that this version of the library knows about */
-#define H5O_HDR_ALL_FLAGS       (H5O_HDR_ATTR_CRT_ORDER_TRACKED | H5O_HDR_ATTR_CRT_ORDER_INDEXED | H5O_HDR_ATTR_STORE_PHASE_CHANGE | H5O_HDR_STORE_TIMES)
-
 
 /* The "message class" type */
 struct H5O_msg_class_t {
diff --git a/src/H5Opublic.h b/src/H5Opublic.h
index 73c4581..b3d0c36 100644
--- a/src/H5Opublic.h
+++ b/src/H5Opublic.h
@@ -61,10 +61,12 @@
 #define H5O_MESG_ALL_FLAG      (H5O_MESG_SDSPACE_FLAG | H5O_MESG_DTYPE_FLAG | H5O_MESG_FILL_FLAG | H5O_MESG_PLINE_FLAG | H5O_MESG_ATTR_FLAG)
 
 /* Object header status flag definitions */
-#define H5O_HDR_ATTR_CRT_ORDER_TRACKED  0x01    /* Attribute creation order is tracked */
-#define H5O_HDR_ATTR_CRT_ORDER_INDEXED  0x02    /* Attribute creation order has index */
-#define H5O_HDR_ATTR_STORE_PHASE_CHANGE 0x04    /* Non-default attribute storage phase change values stored */
-#define H5O_HDR_STORE_TIMES             0x08    /* Store access, modification, change & birth times for object */
+#define H5O_HDR_CHUNK0_SIZE             0x03    /* 2-bit field indicating # of bytes to store the size of chunk 0's data */
+#define H5O_HDR_ATTR_CRT_ORDER_TRACKED  0x04    /* Attribute creation order is tracked */
+#define H5O_HDR_ATTR_CRT_ORDER_INDEXED  0x08    /* Attribute creation order has index */
+#define H5O_HDR_ATTR_STORE_PHASE_CHANGE 0x10    /* Non-default attribute storage phase change values stored */
+#define H5O_HDR_STORE_TIMES             0x20    /* Store access, modification, change & birth times for object */
+#define H5O_HDR_ALL_FLAGS       (H5O_HDR_CHUNK0_SIZE | H5O_HDR_ATTR_CRT_ORDER_TRACKED | H5O_HDR_ATTR_CRT_ORDER_INDEXED | H5O_HDR_ATTR_STORE_PHASE_CHANGE | H5O_HDR_STORE_TIMES)
 
 /* Maximum shared message values.  Number of indexes is 8 to allow room to add
  * new types of messages.
diff --git a/test/stab.c b/test/stab.c
index 5275454..b8044ae 100644
--- a/test/stab.c
+++ b/test/stab.c
@@ -427,9 +427,9 @@ lifecycle(hid_t fapl)
     /* Check that the object header is only one chunk and the space has been allocated correctly */
     if(H5Gget_objinfo(gid, ".", FALSE, &obj_stat) < 0) TEST_ERROR
 #ifdef H5_HAVE_LARGE_HSIZET
-    if(obj_stat.ohdr.size != 190) TEST_ERROR
+    if(obj_stat.ohdr.size != 187) TEST_ERROR
 #else /* H5_HAVE_LARGE_HSIZET */
-    if(obj_stat.ohdr.size != 170) TEST_ERROR
+    if(obj_stat.ohdr.size != 167) TEST_ERROR
 #endif /* H5_HAVE_LARGE_HSIZET */
     if(obj_stat.ohdr.free != 0) TEST_ERROR
     if(obj_stat.ohdr.nmesgs != 6) TEST_ERROR
@@ -453,9 +453,9 @@ lifecycle(hid_t fapl)
     /* Check that the object header is still one chunk and the space has been allocated correctly */
     if(H5Gget_objinfo(gid, ".", FALSE, &obj_stat) < 0) TEST_ERROR
 #ifdef H5_HAVE_LARGE_HSIZET
-    if(obj_stat.ohdr.size != 190) TEST_ERROR
+    if(obj_stat.ohdr.size != 187) TEST_ERROR
 #else /* H5_HAVE_LARGE_HSIZET */
-    if(obj_stat.ohdr.size != 170) TEST_ERROR
+    if(obj_stat.ohdr.size != 167) TEST_ERROR
 #endif /* H5_HAVE_LARGE_HSIZET */
     if(obj_stat.ohdr.free != 112) TEST_ERROR
     if(obj_stat.ohdr.nmesgs != 3) TEST_ERROR
diff --git a/tools/testfiles/h5mkgrp_nested_latest.ls b/tools/testfiles/h5mkgrp_nested_latest.ls
index 4ac4374..efe8551 100644
--- a/tools/testfiles/h5mkgrp_nested_latest.ls
+++ b/tools/testfiles/h5mkgrp_nested_latest.ls
@@ -3,10 +3,10 @@ Expected output for 'h5ls ../testfiles/h5mkgrp_nested_latest.h5'
 #############################
 Opened "../testfiles/h5mkgrp_nested_latest.h5" with sec2 driver.
 /one                     Group
-    Location:  1:428
+    Location:  1:422
     Links:     1
     Modified:  XXXX-XX-XX XX:XX:XX XXX
 /one/two                 Group
-    Location:  1:238
+    Location:  1:235
     Links:     1
     Modified:  XXXX-XX-XX XX:XX:XX XXX
diff --git a/tools/testfiles/h5mkgrp_nested_mult_latest.ls b/tools/testfiles/h5mkgrp_nested_mult_latest.ls
index 54ca444..2771497 100644
--- a/tools/testfiles/h5mkgrp_nested_mult_latest.ls
+++ b/tools/testfiles/h5mkgrp_nested_mult_latest.ls
@@ -3,18 +3,18 @@ Expected output for 'h5ls ../testfiles/h5mkgrp_nested_mult_latest.h5'
 #############################
 Opened "../testfiles/h5mkgrp_nested_mult_latest.h5" with sec2 driver.
 /one                     Group
-    Location:  1:428
+    Location:  1:422
     Links:     1
     Modified:  XXXX-XX-XX XX:XX:XX XXX
 /one/two                 Group
-    Location:  1:238
+    Location:  1:235
     Links:     1
     Modified:  XXXX-XX-XX XX:XX:XX XXX
 /three                   Group
-    Location:  1:808
+    Location:  1:796
     Links:     1
     Modified:  XXXX-XX-XX XX:XX:XX XXX
 /three/four              Group
-    Location:  1:618
+    Location:  1:609
     Links:     1
     Modified:  XXXX-XX-XX XX:XX:XX XXX
diff --git a/tools/testfiles/h5mkgrp_several_latest.ls b/tools/testfiles/h5mkgrp_several_latest.ls
index 9e238ba..fbe9aa5 100644
--- a/tools/testfiles/h5mkgrp_several_latest.ls
+++ b/tools/testfiles/h5mkgrp_several_latest.ls
@@ -3,10 +3,10 @@ Expected output for 'h5ls ../testfiles/h5mkgrp_several_latest.h5'
 #############################
 Opened "../testfiles/h5mkgrp_several_latest.h5" with sec2 driver.
 /one                     Group
-    Location:  1:238
+    Location:  1:235
     Links:     1
     Modified:  XXXX-XX-XX XX:XX:XX XXX
 /two                     Group
-    Location:  1:428
+    Location:  1:422
     Links:     1
     Modified:  XXXX-XX-XX XX:XX:XX XXX
diff --git a/tools/testfiles/h5mkgrp_single_latest.ls b/tools/testfiles/h5mkgrp_single_latest.ls
index 085d182..4838dfc 100644
--- a/tools/testfiles/h5mkgrp_single_latest.ls
+++ b/tools/testfiles/h5mkgrp_single_latest.ls
@@ -3,6 +3,6 @@ Expected output for 'h5ls ../testfiles/h5mkgrp_single_latest.h5'
 #############################
 Opened "../testfiles/h5mkgrp_single_latest.h5" with sec2 driver.
 /latest                  Group
-    Location:  1:238
+    Location:  1:235
     Links:     1
     Modified:  XXXX-XX-XX XX:XX:XX XXX