getg2ir.f File Reference

This subroutine read a GRIB file and return its index content. More...

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Functions/Subroutines
subroutine	getg2ir (LUGB, MSK1, MSK2, MNUM, CBUF, NLEN, NNUM, NMESS, IRET)
	This subroutine read a GRIB file and return its index content. More...

Detailed Description

This subroutine read a GRIB file and return its index content.

Author

Mark Iredell

Date

1995-10-31

Definition in file getg2ir.f.

Function/Subroutine Documentation

getg2ir()

subroutine getg2ir	(	integer, intent(in)	LUGB,
		integer, intent(in)	MSK1,
		integer, intent(in)	MSK2,
		integer, intent(in)	MNUM,
		character(len=1), dimension(:), pointer	CBUF,
		integer, intent(out)	NLEN,
		integer, intent(out)	NNUM,
		integer, intent(out)	NMESS,
		integer, intent(out)	IRET
	)

This subroutine read a GRIB file and return its index content.

the index buffer returned contains index records with the internal format:

• byte 001 - 004 length of index record
• byte 005 - 008 bytes to skip in data file before grib message
• byte 009 - 012 bytes to skip in message before lus (local use) set = 0, if no local use section in grib2 message.
• byte 013 - 016 bytes to skip in message before gds
• byte 017 - 020 bytes to skip in message before pds
• byte 021 - 024 bytes to skip in message before drs
• byte 025 - 028 bytes to skip in message before bms
• byte 029 - 032 bytes to skip in message before data section
• byte 033 - 040 bytes total in the message
• byte 041 - 041 grib version number (currently 2)
• byte 042 - 042 message discipline
• byte 043 - 044 field number within grib2 message
• byte 045 - ii identification section (ids)
• byte ii+1- jj grid definition section (gds)
• byte jj+1- kk product definition section (pds)
• byte kk+1- ll the data representation section (drs)
• byte ll+1-ll+6 first 6 bytes of the bit map section (bms)

Program history log:

• 1995-10-31 mark iredell
• 1996-10-31 mark iredell augmented optional definitions to byte 320
• 2002-01-02 stephen gilbert modified from getgir to create grib2 indexes

Parameters

[in]	lugb	integer unit of the unblocked grib file
[in]	msk1	integer number of bytes to search for first message
[in]	msk2	integer number of bytes to search for other messages
[in]	mnum	integer number of grib messages to skip (usually 0) output arguments:
[out]	cbuf	character*1 pointer to a buffer that contains index records. users should free memory that cbuf points to, using deallocate(cbuf) when cbuf is no longer needed.
[out]	nlen	integer total length of index record buffer in bytes
[out]	nnum	integer number of index records, =0 if no grib messages are found)
[out]	nmess	last grib message in file successfully processed
[out]	iret	integer return code 0 all ok 1 not enough memory available to hold full index buffer 2 not enough memory to allocate initial index buffer

subprograms called:

• skgb seek next grib message
• ixgb2 make index record

Note

subprogram can be called from a multiprocessing environment. do not engage the same logical unit from more than one processor.

Author

Mark Iredell

Date

1995-10-31

Definition at line 60 of file getg2ir.f.