.TH "g2_unpack7.c" 3 "Tue May 3 2022" "Version 1.6.4" "NCEPLIBS-g2c" \" -*- nroff -*-
.ad l
.nh
.SH NAME
g2_unpack7.c \- Unpack Section 7 (Data Section) as defined in GRIB Edition 2\&.  

.SH SYNOPSIS
.br
.PP
\fC#include <stdio\&.h>\fP
.br
\fC#include <stdlib\&.h>\fP
.br
\fC#include <memory\&.h>\fP
.br
\fC#include <string\&.h>\fP
.br
\fC#include 'grib2\&.h'\fP
.br

.SS "Functions"

.in +1c
.ti -1c
.RI "int \fBcomunpack\fP (unsigned char *, \fBg2int\fP, \fBg2int\fP, \fBg2int\fP *, \fBg2int\fP, \fBg2float\fP *)"
.br
.RI "This subroutine unpacks a data field that was packed using a complex packing algorithm as defined in the GRIB2 documention, using info from the GRIB2 Data Representation Template 5\&.2 or 5\&.3\&. "
.ti -1c
.RI "\fBg2int\fP \fBg2_unpack7\fP (unsigned char *cgrib, \fBg2int\fP *iofst, \fBg2int\fP igdsnum, \fBg2int\fP *igdstmpl, \fBg2int\fP idrsnum, \fBg2int\fP *idrstmpl, \fBg2int\fP ndpts, \fBg2float\fP **fld)"
.br
.RI "This subroutine unpacks Section 7 (Data Section) as defined in GRIB Edition 2\&. "
.ti -1c
.RI "\fBg2int\fP \fBjpcunpack\fP (unsigned char *, \fBg2int\fP, \fBg2int\fP *, \fBg2int\fP, \fBg2float\fP *)"
.br
.RI "This subroutine unpacks a data field that was packed into a JPEG2000 code stream using info from the GRIB2 Data Representation Template 5\&.40 or 5\&.40000\&. "
.ti -1c
.RI "\fBg2int\fP \fBpngunpack\fP (unsigned char *, \fBg2int\fP, \fBg2int\fP *, \fBg2int\fP, \fBg2float\fP *)"
.br
.RI "This subroutine unpacks a data field that was packed into a PNG image format using info from the GRIB2 Data Representation Template 5\&.41 or 5\&.40010\&. "
.ti -1c
.RI "\fBg2int\fP \fBsimunpack\fP (unsigned char *, \fBg2int\fP *, \fBg2int\fP, \fBg2float\fP *)"
.br
.RI "This subroutine unpacks a data field that was packed using a simple packing algorithm as defined in the GRIB2 documention, using info from the GRIB2 Data Representation Template 5\&.0\&. "
.ti -1c
.RI "\fBg2int\fP \fBspecunpack\fP (unsigned char *, \fBg2int\fP *, \fBg2int\fP, \fBg2int\fP, \fBg2int\fP, \fBg2int\fP, \fBg2float\fP *)"
.br
.RI "This subroutine unpacks a spectral data field that was packed using the complex packing algorithm for spherical harmonic data as defined in the GRIB2 documention, using info from the GRIB2 Data Representation Template 5\&.51\&. "
.in -1c
.SH "Detailed Description"
.PP 
Unpack Section 7 (Data Section) as defined in GRIB Edition 2\&. 


.PP
\fBAuthor\fP
.RS 4
Stephen Gilbert 
.RE
.PP
\fBDate\fP
.RS 4
2002-10-31 
.RE
.PP

.PP
Definition in file \fBg2_unpack7\&.c\fP\&.
.SH "Function Documentation"
.PP 
.SS "int comunpack (unsigned char * cpack, \fBg2int\fP lensec, \fBg2int\fP idrsnum, \fBg2int\fP * idrstmpl, \fBg2int\fP ndpts, \fBg2float\fP * fld)"

.PP
This subroutine unpacks a data field that was packed using a complex packing algorithm as defined in the GRIB2 documention, using info from the GRIB2 Data Representation Template 5\&.2 or 5\&.3\&. Supports GRIB2 complex packing templates with or without spatial differences (i\&.e\&. DRTs 5\&.2 and 5\&.3)\&.
.PP
PROGRAM HISTORY LOG:
.IP "\(bu" 2
2002-10-29 Gilbert
.IP "\(bu" 2
2004-12-16 Gilbert Added test (provided by Arthur Taylor/MDL) to verify that group widths and lengths are consistent with section length\&.
.PP
.PP
\fBParameters\fP
.RS 4
\fIcpack\fP pointer to the packed data field\&. 
.br
\fIlensec\fP length of section 7 (used for error checking)\&. 
.br
\fIidrsnum\fP Data Representation Template number 5\&.N Must equal 2 or 3\&. 
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\fIidrstmpl\fP pointer to the array of values for Data Representation Template 5\&.2 or 5\&.3 
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\fIndpts\fP The number of data values to unpack 
.br
\fIfld\fP Contains the unpacked data values\&. fld must be allocated with at least ndpts*sizeof(g2float) bytes before calling this routine\&.
.RE
.PP
\fBReturns\fP
.RS 4
0 for success, error code otherwise\&.
.RE
.PP
\fBAuthor\fP
.RS 4
Stephen Gilbert 
.RE
.PP
\fBDate\fP
.RS 4
2002-10-29 
.RE
.PP

.PP
Definition at line 39 of file comunpack\&.c\&.
.PP
References gbit(), gbits(), int_power(), and rdieee()\&.
.PP
Referenced by g2_unpack7()\&.
.SS "\fBg2int\fP g2_unpack7 (unsigned char * cgrib, \fBg2int\fP * iofst, \fBg2int\fP igdsnum, \fBg2int\fP * igdstmpl, \fBg2int\fP idrsnum, \fBg2int\fP * idrstmpl, \fBg2int\fP ndpts, \fBg2float\fP ** fld)"

.PP
This subroutine unpacks Section 7 (Data Section) as defined in GRIB Edition 2\&. PROGRAM HISTORY LOG:
.IP "\(bu" 2
2002-10-31 Gilbert
.IP "\(bu" 2
2002-12-20 Gilbert - Added GDT info to arguments and added 5\&.51 processing\&.
.IP "\(bu" 2
2003-08-29 Gilbert - Added support for new templates using PNG and JPEG2000 algorithms/templates\&.
.IP "\(bu" 2
2004-11-29 Gilbert - JPEG2000 now allowed to use WMO Template no\&. 5\&.40 PNG now allowed to use WMO Template no\&. 5\&.41
.IP "\(bu" 2
2004-12-16 Taylor - Added check on comunpack return code\&.
.IP "\(bu" 2
2008-12-23 Wesley - Initialize Number of data points unpacked
.PP
.PP
\fBParameters\fP
.RS 4
\fIcgrib\fP char array containing Section 7 of the GRIB2 message 
.br
\fIiofst\fP Bit offset of the beginning of Section 7 in cgrib\&. 
.br
\fIigdsnum\fP Grid Definition Template Number (see Code Table 3\&.0) (Only used for DRS Template 5\&.51) 
.br
\fIigdstmpl\fP Pointer to an integer array containing the data values for the specified Grid Definition Template (N=igdsnum)\&. Each element of this integer array contains an entry (in the order specified) of Grid Definition Template 3\&.N\&. (Only used for DRS Template 5\&.51)\&. 
.br
\fIidrsnum\fP Data Representation Template Number (see Code Table 5\&.0) 
.br
\fIidrstmpl\fP Pointer to an integer array containing the data values for the specified Data Representation Template (N=idrsnum)\&. Each element of this integer array contains an entry (in the order specified) of Data Representation Template 5\&.N 
.br
\fIndpts\fP Number of data points unpacked and returned\&. 
.br
\fIfld\fP Pointer to a float array containing the unpacked data field\&.
.RE
.PP
\fBReturns\fP
.RS 4
.IP "\(bu" 2
0 no error
.IP "\(bu" 2
2 Not section 7
.IP "\(bu" 2
4 Unrecognized Data Representation Template
.IP "\(bu" 2
5 need one of GDT 3\&.50 through 3\&.53 to decode DRT 5\&.51
.IP "\(bu" 2
6 memory allocation error
.IP "\(bu" 2
7 corrupt section 7\&.
.PP
.RE
.PP
\fBAuthor\fP
.RS 4
Stephen Gilbert 
.RE
.PP
\fBDate\fP
.RS 4
2002-10-31 
.RE
.PP

.PP
Definition at line 66 of file g2_unpack7\&.c\&.
.PP
References comunpack(), gbit(), jpcunpack(), pngunpack(), rdieee(), simunpack(), and specunpack()\&.
.PP
Referenced by g2_getfld()\&.
.SS "\fBg2int\fP jpcunpack (unsigned char * cpack, \fBg2int\fP len, \fBg2int\fP * idrstmpl, \fBg2int\fP ndpts, \fBg2float\fP * fld)"

.PP
This subroutine unpacks a data field that was packed into a JPEG2000 code stream using info from the GRIB2 Data Representation Template 5\&.40 or 5\&.40000\&. 
.PP
\fBParameters\fP
.RS 4
\fIcpack\fP The packed data field (character*1 array)\&. 
.br
\fIlen\fP length of packed field cpack\&. 
.br
\fIidrstmpl\fP Pointer to array of values for Data Representation Template 5\&.40 or 5\&.40000\&. 
.br
\fIndpts\fP The number of data values to unpack\&. 
.br
\fIfld\fP Contains the unpacked data values\&.
.RE
.PP
\fBReturns\fP
.RS 4
0 for success, 1 for memory allocation error\&.
.RE
.PP
\fBAuthor\fP
.RS 4
Stephem Gilbert 
.RE
.PP
\fBDate\fP
.RS 4
2003-08-27 
.RE
.PP

.PP
Definition at line 29 of file jpcunpack\&.c\&.
.PP
References dec_jpeg2000(), int_power(), and rdieee()\&.
.PP
Referenced by g2_unpack7()\&.
.SS "\fBg2int\fP pngunpack (unsigned char * cpack, \fBg2int\fP len, \fBg2int\fP * idrstmpl, \fBg2int\fP ndpts, \fBg2float\fP * fld)"

.PP
This subroutine unpacks a data field that was packed into a PNG image format using info from the GRIB2 Data Representation Template 5\&.41 or 5\&.40010\&. 
.PP
\fBParameters\fP
.RS 4
\fIcpack\fP The packed data field (character*1 array)\&. 
.br
\fIlen\fP length of packed field cpack()\&. 
.br
\fIidrstmpl\fP Pointer to array of values for Data Representation Template 5\&.41 or 5\&.40010\&. 
.br
\fIndpts\fP The number of data values to unpack\&. 
.br
\fIfld\fP Contains the unpacked data values\&.
.RE
.PP
\fBReturns\fP
.RS 4
0 for success, 1 for memory allocation error\&.
.RE
.PP
\fBAuthor\fP
.RS 4
Stephen Gilbert 
.RE
.PP
\fBDate\fP
.RS 4
2003-08-27 
.RE
.PP

.PP
Definition at line 27 of file pngunpack\&.c\&.
.PP
References dec_png(), gbits(), int_power(), and rdieee()\&.
.PP
Referenced by g2_unpack7()\&.
.SS "\fBg2int\fP simunpack (unsigned char * cpack, \fBg2int\fP * idrstmpl, \fBg2int\fP ndpts, \fBg2float\fP * fld)"

.PP
This subroutine unpacks a data field that was packed using a simple packing algorithm as defined in the GRIB2 documention, using info from the GRIB2 Data Representation Template 5\&.0\&. 
.PP
\fBParameters\fP
.RS 4
\fIcpack\fP pointer to the packed data field\&. 
.br
\fIidrstmpl\fP pointer to the array of values for Data Representation Template 5\&.0\&. 
.br
\fIndpts\fP The number of data values to unpack\&. 
.br
\fIfld\fP Contains the unpacked data values\&. fld must be allocated with at least ndpts*sizeof(g2float) bytes before calling this routine\&.
.RE
.PP
\fBReturns\fP
.RS 4
0 for success, error code otherwise\&.
.RE
.PP
\fBAuthor\fP
.RS 4
Stephen Gilbert 
.RE
.PP
\fBDate\fP
.RS 4
2002-10-29 
.RE
.PP

.PP
Definition at line 26 of file simunpack\&.c\&.
.PP
References gbits(), int_power(), and rdieee()\&.
.PP
Referenced by g2_unpack7()\&.
.SS "\fBg2int\fP specunpack (unsigned char * cpack, \fBg2int\fP * idrstmpl, \fBg2int\fP ndpts, \fBg2int\fP JJ, \fBg2int\fP KK, \fBg2int\fP MM, \fBg2float\fP * fld)"

.PP
This subroutine unpacks a spectral data field that was packed using the complex packing algorithm for spherical harmonic data as defined in the GRIB2 documention, using info from the GRIB2 Data Representation Template 5\&.51\&. 
.PP
\fBParameters\fP
.RS 4
\fIcpack\fP pointer to the packed data field\&. 
.br
\fIidrstmpl\fP pointer to the array of values for Data Representation Template 5\&.51\&. 
.br
\fIndpts\fP The number of data values to unpack (real and imaginary parts)\&. 
.br
\fIJJ\fP pentagonal resolution parameter\&. 
.br
\fIKK\fP pentagonal resolution parameter\&. 
.br
\fIMM\fP pentagonal resolution parameter\&. 
.br
\fIfld\fP Contains the unpacked data values\&. fld must be allocated with at least ndpts*sizeof(g2float) bytes before calling this routine\&.
.RE
.PP
\fBReturns\fP
.RS 4
0 for success, -3 for wrong type\&.
.RE
.PP
\fBAuthor\fP
.RS 4
Stephen Gilbert 
.RE
.PP
\fBDate\fP
.RS 4
2000-06-21 
.RE
.PP

.PP
Definition at line 34 of file specunpack\&.c\&.
.PP
References gbits(), int_power(), and rdieee()\&.
.PP
Referenced by g2_unpack7()\&.
.SH "Author"
.PP 
Generated automatically by Doxygen for NCEPLIBS-g2c from the source code\&.