[svn-r6825] Purpose:

    New feature/enhancement

Description:
    Chunked datasets are handled poorly in several circumstances involving
certain selections and chunks that are too large for the chunk cache and/or
chunks with filters, causing the chunk to be read from disk multiple times.

Solution:
    Rearrange raw data I/O infrastructure to handle chunked datasets in a much
more friendly way by creating a selection in memory and on disk for each chunk
in a chunked dataset and performing all of the I/O on that chunk at one time.

    There are still some scalability (the current code attempts to
create a selection for all the chunks in the dataset, instead of just the
chunks that are accessed, requiring portions of the istore.c and fillval.c
tests to be commented out) and performance issues, but checking this in will
allow the changes to be tested by a much wider audience while I address the
remaining issues.


Platforms tested:
    h5committested, FreeBSD 4.8 (sleipnir) serial & parallel, Linux 2.4 (eirene)

1 files changed, 16 insertions, 30 deletions

diff --git a/src/H5Dprivate.h b/src/H5Dprivate.h
index e69b0ad..38c13b7 100644
--- a/src/H5Dprivate.h
+++ b/src/H5Dprivate.h
@@ -21,13 +21,7 @@
 #include "H5Dpublic.h"
 
 /* Private headers needed by this file */
-#include "H5private.h"
-#include "H5Fprivate.h"		/*for the H5F_t type			     */
-#include "H5Gprivate.h"		/*symbol tables				     */
-#include "H5MMpublic.h"		/*for H5MM_allocate_t and H5MM_free_t types  */
-#include "H5Oprivate.h"		/*object Headers			     */
-#include "H5Sprivate.h"		/*for the H5S_t type			     */
-#include "H5Tprivate.h"		/*for the H5T_t type			     */
+#include "H5Oprivate.h"		/* Object headers		  	*/
 
 /*
  * Feature: Define H5D_DEBUG on the compiler command line if you want to
@@ -38,11 +32,6 @@
 #  undef H5D_DEBUG
 #endif
 
-#define H5D_RESERVED_ATOMS  0
-
-/* Set the minimum object header size to create objects with */
-#define H5D_MINHDR_SIZE 256
-
 /* ========  Dataset creation properties ======== */
 /* Definitions for storage layout property */
 #define H5D_CRT_LAYOUT_NAME        "layout"
@@ -50,7 +39,7 @@
 #define H5D_CRT_LAYOUT_DEF         H5D_CONTIGUOUS    
 /* Definitions for chunk dimensionality property */
 #define H5D_CRT_CHUNK_DIM_NAME     "chunk_ndims"
-#define H5D_CRT_CHUNK_DIM_SIZE     sizeof(int)
+#define H5D_CRT_CHUNK_DIM_SIZE     sizeof(unsigned)
 #define H5D_CRT_CHUNK_DIM_DEF      1
 /* Definitions for chunk size */
 #define H5D_CRT_CHUNK_SIZE_NAME    "chunk_size"
@@ -155,23 +144,20 @@
 #define H5D_XFER_FILTER_CB_SIZE       sizeof(H5Z_cb_t)
 #define H5D_XFER_FILTER_CB_DEF        {NULL,NULL}
 
-/*
- * A dataset is the following struct.
- */
-typedef struct H5D_t {
-    H5G_entry_t         ent;            /* cached object header stuff   */
-    H5T_t              *type;           /* datatype of this dataset     */
-    H5S_t              *space;          /* dataspace of this dataset    */
-    hid_t               dcpl_id;        /* dataset creation property id */
-    H5O_layout_t        layout;         /* data layout                  */
-    /* Cache some frequently accessed values from the DCPL */
-    H5O_efl_t           efl;            /* External file list information */
-    H5D_alloc_time_t    alloc_time;     /* Dataset allocation time      */
-    H5D_fill_time_t	fill_time;	/* Dataset fill value writing time */
-    H5O_fill_t          fill;           /* Dataset fill value information */
-} H5D_t;
-  
-/* Functions defined in H5D.c */
+/****************************/
+/* Library Private Typedefs */
+/****************************/
+
+/* Typedef for reference counted string (defined in H5Dpkg.h) */
+typedef struct H5D_t H5D_t;
+
+/* Typedef for dataset storage information */
+typedef union H5D_storage_t {
+    H5O_efl_t   efl;            /* External file list information for dataset */
+    hssize_t    *chunk_coords;  /* chunk's coordinates in file chunks */
+} H5D_storage_t;
+
+/* Library-private functions defined in H5D package */
 H5_DLL herr_t H5D_init(void);
 H5_DLL hid_t H5D_open(H5G_entry_t *ent, hid_t dxpl_id);
 H5_DLL htri_t H5D_isa(H5G_entry_t *ent, hid_t dxpl_id);