CDF Changes Log, CDF V3.9

V2.0.0   11-Feb-91  Release of CDF V2.0.
V2.1.0    7-Jun-91  Release of CDF V2.1.
V2.2.0   20-May-92  Release of CDF V2.2.
V2.3.0    1-Oct-92  Release of CDF V2.3.
V2.4.0   26-Jan-94  Release of CDF V2.4. 
V2.5.0   21-Dec-94  Release of CDF V2.5.
V2.6.0*  23-Feb-96  Alpha release of CDF V2.6.
V2.6.0#   5-Apr-96  Beta release of CDF V2.6.
V2.6.0&  13-Jun-96  Beta release of CDF V2.6.
V2.6.0$  17-Jun-96  Beta release of CDF V2.6.
V2.6.0@  15-Aug-96  Beta release of CDF V2.6.
V2.6.0   10-Oct-96  Release of CDF V2.6. 
V2.7.0   27-Sep-99  Release of CDF V2.7. 
V2.7.1   16-May-01  Add new ports: Solaris on PC, MacOS X and Linux on 
                       DEC/Alpha. 
                    Correct bugs in CDFDump program.
                    Correct and enhance CDF-Java APIs and Java Native 
                       Interface (JNI).
                    Add new Java-based tool programs for CDFEdit and CDFExport.
                    Add variable name checking in CDFconvert for compression 
                       option.
                    Add Cygwin port for win32 on PC. Create individual tool
                       programs for Windows using Cygwin libraries.
      	 05-Dec-01  Add a new set of APIs: CDFgetrVarsRecordData, 
                    CDFgetzVarsRecordData, CDFputrVarsRecordData and 
                    CDFputzVarsRecordData to allow a full single 
                    record read/write for a group of r/zVariables.  
         26-Jan-02  Correct a bug in cdfcmp.c for showing dimension size 
                    differences between two zVariables. 
         28-Jun-02  Add a new option in cdfcmp.c to allow tolerance checks
                    while comparing two unequal data values.
         22-Jul-02  Handle f77 Fortran for Cygwin. 
         25-Nov-02  Add 64-bit mode for Solaris/sparc64 for sparcv9. Also,
                    gcc for 64-bit is added.
V2.7.2   08-Apr-04  Change the way that current variable select is being
                    handled.  Keep the current variable selected offset as a 
                    reference for any following variable selection. Originally, 
                    each time a selection of a variable or getting a variable's 
                    field data will start the search for that variable ALWAYS 
                    from the beginning of the variable list. It requires too 
                    many I/Os for accessing a sequence of variables. 
         04-May-04  Corrected a bug that caused the f77 to fail under 64-bit
                    environment.
V3.0     07-Jan-05  Changed file offset from type long (32-bit) to off_t 
                       (64-bit) for the platform on which the data type is 
                       supported.  Changed the file I/O functions accordingly. 
                       The CDF internal file structures are changed. Made the 
                       library backward compatible, meaning programs created 
                       from V3.0 can still access (read/update) the CDF files 
                       of older version.
                    Expanded the length of variable and attribute name from
                       64 to 256.  
                    The CDF/Java was modified to ensure that concurrent 
                       accessing a CDF would be thread-safe.
                    Added a new data type, CDF_EPOCH16, to
                       accommodate more refined time resolution within a
                       second. A new set of functions, similar to those
                       of CDF_EPOCH data type, was added.
                    Modified cdfdump tool program to be more efficient in
                       data reading.
         25-Mar-05  Changed JNI and Java-CDF APIs to ensure proper operations 
                    within the multiple-threaded environment.
V3.1.0   27-May-05  Added new sets of APIs to allow Standard Interface to 
                    interact with zVariables and other CDF-related
                    information.
         11-Jul-05  Added MingW port for PC.
         05-Aug-05  Added new functions to allow creating CDF files in
                    older, V2.7, version, not just the default V3.1. 	 
         18-Jan-06  Modified code, including tools, to handle file path
                    that has ".cdf" or ".skt" extension while it is not
                    expected to be there.
         30-Jan-06  Add FreeBSD port for PCs.
          1-Feb-06  Added Intel C++ and Fortran compilers for Linux port on PCs. 
         22-Jun-06  Added support for HPUX and AIX for both 32 and 64-bit mode.
                    Allow Mac OS X to build code for PPC and x386.
V3.1.1   12-Oct-06  Modified to allow upper/lower case CDF name for Windows.
                    Changed Epoch to make 9999-12-31 23:59:999 as encoded date 
                    for the filled value of -1.0E31. For Epoch16, a pair of
                    -1.0E31 filled values is encoded as 
                    9999-12-31 23:59:999:999:999:999.
V3.2.0   21-Oct-06  Added MD5 checksum feature for data integrity check of the
                    CDF.  Modified tools to use the checksum feature.
                    Added a couple of new tool programs: cdfdump and cdfmerge.
                    Renamed the original cdfdump to cdfirsdump.
         25-Apr-07  Changed the default size of cache buffers from 512 to
                    10240 bytes to improve data access performance.
         18-Jun-07  Enhanced READONLY mode to improve metadata access
                    performance. When READONLY mode is selected, all metadata
                    is read and stored in internal data structures which are
                    then accessed whenever metadata is requested.
V3.2.1   24-Apr-08  Modified the library so a potential buffer overflow 
                    vulnerability when reading specially-crafted (invalid) CDF
                    can be avoided. 
V3.2.2   10-Aug-08  A maintenance release. Modified the Java tools so they can
                    handle CDF files with space(s) in the file path. cdfmerge 
                    tool was modified to allow merging "Epoch" variable data 
                    just like other variables. 
V3.2.3   24-Nov-08  Modified CDFdump to add a new output option.
V3.3.0   05-Dec-08  Added an optional process to validate data fields in a CDF
                    when it is open. This process addresses a potential issue 
                    of library becoming vulnerable when a compromised CDF is
                    accessed. A failed validation from a CDF will cause the 
                    application to end gracefully. All CDF tools will have 
                    sanity checks on. A new tool, cdfvalidate, is added.
                    Added an option to cdfdump to allow user-specified 
                    variables to be dumped.
V3.3.1   10-jan-11  Added several new features to the cdfexport tool program:
                    -[include | exclude] "<vars> | varsfile=<file>" 
                    -[epochrange | recordrange] "<ranges>"
 
                    Bug fixed in Java-CDF APIs and a couple of new methods 
                    were added. Added an option to cdfdump to allow a range
                    of records to be dumped.  MingW port was revised to 
                    handle 'pdcurses', if installed, for the curses-based 
                    tools. Fixed cdf validation to allow some V2.0 files to 
                    be valid. Library bugs fixed: read/delete/read scenario,
                    updated alloc/max record number when adding records to
                    a compressed variable before closing the file, modified
                    last record number in VXRs when records are deleted. 
                    Replaced calls to sprintf/vsprintf with snprintf/vsnprintf.
                    Added a new set of functions to allow encode/parse epoch
                    data in ISO 8601 format in the CDF library.
         01-Aug-11  For version 3.3.1.1
                    Modified code to handle 64-bit Fortran on Solaris/Intel
                    port. Minor fixed in the CDF java and cdfml class methods.
V3.3.2   05-Aug-11  Added two new data types:
                    CDF_INT8: 8-byte signed integer
                    CDF_TIME_TT2000: 8-byte integer of epoch from TT2000 with
                                     leap seconds
                    A new tool, cdfleapsecondsinfo, to show the information i
                    of the leap seconds used in the CDF. Change the default
                    CDF encoding to the most popular hardware of 
                    IBMPC_ENCODING. Added an opion to convert epoch between
                    CDF_EPOCH/EPOCH16 and CDF_TIME_TT2000 in cdfconvert tool.
         15-Aug-11  For version 3.3.2.1
                    Fixed the code to handle TT2000 base time.
         01-Sep-11  For version 3.3.2.2
                    Modified code to handle 64-bit Fortran on Solaris/Intel
                    port. Minor fixed in the CDF java and cdfml class methods. 
                    A fixed bug in the library.
         11-Jan-12  For version 3.3.2.3
                    Modified email address for CDFsupport. Modified cdfml: DTD
                    and XSD to add CDF_INT8 and CDF_TIME_TT2000 data types.
                    Changed date/time parameters for compute_TT2000
                    and TT2000_breakdown functions from double to int,
                    similar to compute_epoch and EPOCH_breakdown. Minor change
                    in CDFUtils java code. Revised default pad, dummy and
                    illegal values for TT2000 data type. 
V3.4.0   17-Feb-12  Convert V3.3.2.3 to new version. Reset pad values for
                    INT8 and TT2000 data types.
         10-May-12  For version 3.4.1.0
                    Bugs fixed in core library.  Minor changes in skt2cdf tool
                    program and cdfdump help. Fixed cdfmerge while using text
                    file for input files control. Modified Java CDF class's
                    open method to delay collecting variable and attribute data.
V3.5.0   25-Feb-13  The original beta version
                    for version 3.5.0.0
                    Used open source zlib source code to replace CDF's GZIP
                    compression/decompression, which was modified from original
                    code by Jean-loup Gailly and Mark Adler, in the previous
                    versions. Bugs fixed. Modified the default blocking factor
                    for compressed variable data. New features were added in
                    cdfdump.
         15-Sep-13  for version 3.5.0.1 (the official release version)
                    Fixed minor memory leaks in core library and JNI. 
                    Added a new option to cdfdump tool for how to show the
                    floating-point values if FORMAT entry is missing. Added
                    support for Visual Basic on Windows. Pad value is set when
                    a variable is created. Fixed code to save CDFid for 64-bit
                    Fortran when a CDF is open/created, even only 4-byte of it
                    is used in Fortran code. Default pad values are set with
                    rather invalid values, so they can be recognized easily.
         31-Mar-14  for version 3.5.0.2
                    Use the latest zlib version 1.2.8 without code changes.
                    Minor code changes for filling space(s) for writing string
                    type pad value. 64-bit Windows package now distributes
                    64-bit Cygwin-based libraries and tools. Bugs fixed. Added
                    support for nan, inf and -inf for floating point values in
                    the tool programs. 
V3.6.0    5-Feb-15  for version 3.6.0.3
                    Added a new leap second for 2015-07-01 to the leap second
                    table. Added a field "LeapSecondLastUpdated" in GDR to
                    record what leap second table a CDF is based upon. A set of
                    functions to read/write/validate the field is added.
                    Added an option to renumber the sparse variable records
                    after a record(s) is deleted. Added sort and detect options
                    in tool cdfconvert. Skip checking the file/path name's
                    characters when reading a CDF file. Enforce ASCII chars for
                    file name (not including the directory portion) only. Minor
                    bug fixes.
          1-May-15  for version 3.6.0.4
                    Modified cdfjava.jar. Extended status text length.
V3.6.1   20-Sep-15  for version 3.6.1.0
                    Used the preserved system temporary folder, e.g., /tmp
                    for Linux/Unix/MacOSX, to hold the temporary file(s)
                    while doing compression/decompression. Set
                    temporary file name using the random number generator with 
                    process id and current time as the seed. Added support
                    for computing TT2000 from UTC if the passed day is DOY
                    (day of the year from January 1st). Added a few options
                    to cdfconvert tool program. 
V3.6.2   20-Mar-16  for version 3.6.2.0
                    Modified to Makefile and installation process to support
                    Mac OS X El Captain (10.11). Modified the library to handle
                    string data that has a shorter length than defined (number
                    of elements) when reading/writing. It will be filled with
                    spaces, starting from the NUL. 
         13-May-16  for version 3.6.2.1 
                    Bug fixed for handling TT2000 time computing if only
                    year/month/day is given. Speed up the leap second
                    time/table validation.
V3.6.3   20-Oct-16  for version 3.6.3.0
                    Added a new set of C-based APIs for reading the CDF data.
                    Each of these APIs, identified as CDFread..., will return 
                    a pointer to the library allocated space for the data. 
                    Caller is responsible to free the space after use. New
                    features were added to cdfstats and cdfdump tool programs.
                    A new leap second is added for 1/1/2017.
         10-Jan-17  for version 3.6.3.1
                    Updated the leap second last updated header in a CDF from
                    the (latest) leap second table if the CDF is created based
                    on an existing master CDF that has an older leap second
                    table.
V3.6.4   10-Feb-17  for version 3.6.4.0
                    For Unix-based systems, use C's "mkstemp" function to create
                    the temporary files, in the template form of
                    "mycdftmp.XXXXXX". On Windows, use VS's "_mktemp_s" to do
                    the same. Use the random number generator to create the
                    temporary file name as the last resort if C's function 
                    fails to create one. 
                    For Unix-based systems, the temporary files will be
                    created in the current directory if it is writable and
                    neither environment variable CDF_TMP nor TMPDIR is defined.
                    Otherwise, it will try the directory defined by the
                    environment variable CDF_TMP first and then TMPDIR.
                    If the current directory is not writable, then system's 
                    "/tmp" is used. On Windows, both "TMP" and "TEMP" directory
                    will be tried if CDF_TMP is not defined. If all fail,
                    the last resort is to use the current directory. 
                    Modified cdfexport to not truncate variable name while 
                    displaying its data.  Have a separate patch for supporting
                    IDL 8.6.
V3.7.0   11-May-18  for version 3.7.0.0
                    For variable attribute, multi-strings are allowed. A header
                    field in the internal data structure for entry is used to
                    stored the number of strings. A function to free the 
                    retrieved strings, when reading, is created. The data
                    validation control process, thru CDF_VALIDATE environment
                    variable, is modified to also skip the checksum
                    verification, in addition to the data sanity check, if the
                    validation is turned off. cdfconvert tool allows the output
                    of the converted file to replace the source file.
                    Added support for ARM ports, little or big-endian. The
                    string-typed data for attribute entry or variable data can
                    be Nul-terminated. The default pad value can also be empty.
                    Previously, space(s) is filled if the data length is
                    shorter than the defined number of elements. Added openVMS
                    on Itanium (IA64) ports: IA64VMSi, IA64VMSd and IA64VMSg.
                    Added cdfj.jar, the pure Java package for CDF read and 
                    write without needing CDF library and JNI. A revised cdf
                    schema is included for CDF's XML support.
V3.7.1   21-Aug-18  for version 3.7.1.0
                    Modified to make the encoded date/time string for CDF_EPOCH
                    and CDF_EPOCH16 in the form of ISO 8601 as the default, as 
                    yyyy-mm-ddThh:mm:ss.ccc or yyyy-mm-ddThh:mm:ss.cccuuunnnppp
                    respectively. Enhanced the CDFML xsd schema. Do not throw
                    an error if the ILLEGAL_TT2000_VALUE is encountered. When 
                    encoding its value into date/time string, it is presented
                    as 1707-09-22T12:12:10.961224195. (Read CDF's C document.)
                    Add a set of general encoding/parsing functions for each
                    of the CDF epoch data type. Added a set of time conversion
                    functions between CDF_EPOCH/CDF_EPOCH16/CDF_TIME_TT2000 time
                    and unix time. Reset the rVariables' dimension to zero if
                    a cdf is converted, by cdfconvert, with "zMode 2".
V3.8.0   27-Oct-19  for version 3.8.0.0
                    Modified the code to use a variable's FILLVAL, replacing
                    its PAD value, for all record varying variable's virtual
                    record data if it exists. To use FILLVAL, it must have a
                    data type equivalent to its variable's. String typed
                    variable's pad value is filled with a single space and
                    followed by NUL(s), instead of multiple spaces.  
                    Changed skt2cdf tool program to allow handling a skeleton 
                    table directly from Windows (with \r\n at the end in each
                    line) on non-Windows systems. Added new options to 
                    cdfconvert tool program to 
                      1. remove non-varying dimension(s) from the source 
                         zVariable(s) if it does not have DEPEND_* attribute
                         defined to the destination variable. 
                      2. replace any pad value(s) in a variable's data by its
                         FILLVAL value, if FILLVAL attribute exists and has
                         an equivalent data type as variable's. 
                    Modified the tool programs to use FORMAT attribute to encode
                    both data and metadata if the format is to be used. These
                    include all C-based and Java-based tools. A new option is
                    added to cdf2skt tool to allow users to choose how to
                    display variable's metadata and data, either with or without
                    format. 
          7-Jul-20  for version 3.8.0.1
                    Modified CDF epoch breakdown functions that might cause
                    incorrect day being returned.
V3.8.1   22-Mar-22  for version 3.8.1.0
                    Added a set of easy-to-use read functions: READCDF and 
                    READVARIABLE, to read CDF and variable information for 
                    Java, C#, Perl and IDL interface in a single call. 
                    Allowed building the fat JNI from the main CDF Makefile
                    build. Modified TT2000 type handling routine in C/Java to
                    accept minus leap second in the future. Added Json-CDF
                    converters in Java package. Enhanced netCDF-to-CDF 
                    converter. Support characters in UTF-8 encoding. Dynamic
                    space allocation is no longer placed into a linked list.
                    Modified TT2000 handling function to handle reverse 
                    leap second (no 59 second). Added support for Apple M1
                    processor.
V3.9.0   22-Jan-23  for version 3.9.0.0
                    Increased the regular cache buffer size to improve the
                    hit rate for getting the CDF internal information.
                    Modified the variable compression section to avoid making
                    a temporary file by increasing the number of cache buffers,
                    and flushing out the old caches when they
                    reach a point that processing the next variable's compressed
                    data would cause a temporary file to be created as the
                    remaining caches will not be enough. The blocking factor is
                    limited to a value, computed from CDF's maximum caches, so
                    variable's compression operation will not trigger a
                    temporary file(s) being created. A bug fixed for variable's
                    allocated from/to operation for a compressed or sparse 
                    variable. Increased the cache buffer size for Linux/Mac to
                    improve the performance. Bugs fixed for curses-based tool
                    programs. Moved src/tests directory to cdf_tests directly
                    within the cdf home to make test programs there more 
                    visible.
