NCEPLIBS-g2c 2.0.0
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grib2_int.h File Reference

Header file with internal function prototypes NCEPLIBS-g2c library. More...

#include <assert.h>
#include <ctype.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <arpa/inet.h>
#include "grib2.h"

Go to the source code of this file.

Data Structures

struct  g2c_code_table
 A GRIB2 code table. More...
 
struct  g2c_dim_info
 Keep information about dimensions defined in section 3. More...
 
struct  g2c_entry
 An entry in a GRIB2 code table. More...
 
struct  g2c_file_info
 This is the information about each open file. More...
 
struct  g2c_message_info
 This is the information about each message. More...
 
struct  g2c_param
 An entry in the table of NOAA abbreviations for GRIB parameters. More...
 
struct  g2c_section3_info
 Information about Section 3 GRID DEFINITION SECTION. More...
 
struct  g2c_section4_info
 Information about Section 4 PRODUCT DEFINITION SECTION. More...
 
struct  g2c_section5_info
 Information about Section 5 DATA REPRESENTATION SECTION. More...
 
struct  g2c_section6_info
 Information about Section 6 BIT-MAP SECTION. More...
 
struct  gtemplate
 Struct for GRIB template, returned by getgridtemplate(). More...
 

Macros

#define ALOG2   (0.69314718)
 ln(2.0)
 
#define BYTE   8
 Number of bits in a byte.
 
#define EIGHT_BYTES   8
 Eight bytes.
 
#define EXTERN_MUTEX(m)
 Pthreads not enabled, so do nothing.
 
#define FOUR_BYTES   4
 Four bytes.
 
#define G2C_FILE_READ   0
 Read.
 
#define G2C_FILE_WRITE   1
 Write.
 
#define G2C_INDEX1_BDS_VAL_LEN   10
 Length of the binary data section (bds) in index file.
 
#define G2C_INDEX1_BMS_VAL_LEN   5
 Length of the bitmap section (bms) in index file.
 
#define G2C_INDEX1_GDS_VAL2_LEN   27
 Length of the gds in index file.
 
#define G2C_INDEX1_GDS_VAL_LEN   41
 Length of the grid definition section (gds) in index file.
 
#define G2C_INDEX1_PDS_VAL2_LEN   27
 Length of the pds 2 section in the index file.
 
#define G2C_INDEX1_PDS_VAL3_LEN   27
 Length of the pds 3 section in the index file.
 
#define G2C_INDEX1_PDS_VAL_LEN   27
 Length of the product definition section (pds) in index file.
 
#define G2C_JASPER_JPEG_FORMAT_NAME   "jpc"
 Name of JPEG codec in Jasper.
 
#define G2C_MAGIC_HEADER   "GRIB"
 GRIB magic header string.
 
#define G2C_MAGIC_HEADER_LEN   8
 Full length of magic header string (includes GRIB version byte).
 
#define G2C_MAX_MESSAGES   1024
 Maximum number of messages in a file.
 
#define G2C_MIN_MAX_BYTES   16
 Minimum acceptable value for max_bytes parameter of g2c_get_msg().
 
#define hton64(y)   (((uint64_t)htonl(y)) << WORD | htonl(y >> WORD))
 Byte swap 64-bit ints.
 
#define LATITUDE   "Latitude"
 Latitude.
 
#define LOG(e)
 Ignore logging to stdout.
 
#define LONGITUDE   "Longitude"
 Longitude.
 
#define MUTEX(m)
 Pthreads not enabled, so do nothing.
 
#define MUTEX_LOCK(m)
 Pthreads not enabled, so do nothing.
 
#define MUTEX_UNLOCK(m)
 Pthreads not enabled, so do nothing.
 
#define ntoh64(y)   (((uint64_t)ntohl(y)) << WORD | ntohl(y >> WORD))
 Byte swap 64-bit ints.
 
#define ONE_BYTE   1
 One byte.
 
#define TWO_BYTES   2
 Two bytes.
 
#define WORD   32
 Number of bits in four bytes.
 

Typedefs

typedef struct g2c_entry G2C_CODE_ENTRY_T
 An entry in a GRIB2 code table.
 
typedef struct g2c_code_table G2C_CODE_TABLE_T
 A GRIB2 code table.
 
typedef struct g2c_dim_info G2C_DIM_INFO_T
 Keep information about dimensions defined in section 3.
 
typedef struct g2c_file_info G2C_FILE_INFO_T
 This is the information about each open file.
 
typedef struct g2c_message_info G2C_MESSAGE_INFO_T
 This is the information about each message.
 
typedef struct g2c_param G2C_PARAM_T
 An entry in the table of NOAA abbreviations for GRIB parameters.
 
typedef struct g2c_section3_info G2C_SECTION3_INFO_T
 Information about Section 3 GRID DEFINITION SECTION.
 
typedef struct g2c_section4_info G2C_SECTION4_INFO_T
 Information about Section 4 PRODUCT DEFINITION SECTION.
 
typedef struct g2c_section5_info G2C_SECTION5_INFO_T
 Information about Section 5 DATA REPRESENTATION SECTION.
 
typedef struct g2c_section6_info G2C_SECTION6_INFO_T
 Information about Section 6 BIT-MAP SECTION.
 
typedef struct g2c_section_info G2C_SECTION_INFO_T
 Information about a section 3 through 7 in a GRIB2 message.
 
typedef struct gtemplate gtemplate
 Struct for GRIB template.
 

Functions

int add_msg (G2C_FILE_INFO_T *file, int msg_num, size_t bytes_to_msg, size_t bytes_in_msg, int read_file, G2C_MESSAGE_INFO_T **msg)
 Add new message to linked list.
 
int add_section (FILE *f, G2C_MESSAGE_INFO_T *msg, int sec_id, unsigned int sec_len, size_t bytes_to_sec, unsigned char sec_num)
 Add metadata about a new section 3, 4, 5, 6, or 7.
 
void aecpack (float *fld, g2int width, g2int height, g2int *idrstmpl, unsigned char *cpack, g2int *lcpack)
 This function packs up a float array into a AEC code stream.
 
g2int aecunpack (unsigned char *cpack, g2int len, g2int *idrstmpl, g2int ndpts, float *fld)
 Unpack AEC compressed data into an array of floats, using info from the GRIB2 Data Representation Template 5.42.
 
void cmplxpack (float *fld, g2int ndpts, g2int idrsnum, g2int *idrstmpl, unsigned char *cpack, g2int *lcpack)
 Pack up a data field using a complex packing algorithm.
 
void compack (float *fld, g2int ndpts, g2int idrsnum, g2int *idrstmpl, unsigned char *cpack, g2int *lcpack)
 Pack a data field using a complex packing algorithm.
 
int comunpack (unsigned char *cpack, g2int lensec, g2int idrsnum, g2int *idrstmpl, g2int ndpts, float *fld)
 Unpack a data field that was packed using a complex packing algorithm, using info from the GRIB2 Data Representation Template 5.2 or Template 5.3.
 
int dec_aec (unsigned char *cpack, g2int len, g2int nbits, g2int flags, g2int block_size, g2int rsi, unsigned char *cfld, g2int cfldlen)
 Decode an AEC code stream specified in the CCSDS 121.0-B-3 Blue Book.
 
int dec_jpeg2000 (char *injpc, g2int bufsize, g2int *outfld)
 Decode a JPEG2000 code stream specified in the JPEG2000 Part-1 standard (i.e., ISO/IEC 15444-1) using JasPer Software.
 
int dec_png (unsigned char *pngbuf, g2int *width, g2int *height, unsigned char *cout)
 Decode PNG.
 
int enc_aec (unsigned char *data, g2int ctemplen, g2int nbits, g2int flags, g2int block_size, g2int rsi, unsigned char *aecbuf, g2int *aecbuflen)
 Encode data into an AEC code stream specified in the CCSDS 121.0-B-3 Blue Book.
 
int enc_jpeg2000 (unsigned char *cin, g2int width, g2int height, g2int nbits, g2int ltype, g2int ratio, g2int retry, char *outjpc, g2int jpclen)
 Encode a grayscale image into a JPEG2000 code stream specified in the JPEG2000 Part-1 standard (i.e., ISO/IEC 15444-1) using JasPer Software.
 
int enc_png (unsigned char *data, g2int width, g2int height, g2int nbits, unsigned char *pngbuf)
 Encode PNG.
 
gtemplateextdrstemplate (g2int number, g2int *list)
 This subroutine generates the remaining octet map for a given Data Representation Template, if required.
 
gtemplateextgridtemplate (g2int number, g2int *list)
 This subroutine generates the remaining octet map for a given Grid Definition Template, if required.
 
gtemplateextpdstemplate (g2int number, g2int *list)
 This subroutine generates the remaining octet map for a given Product Definition Template, if required.
 
int g2c_add_file (const char *path, int mode, int *g2cid)
 Open a GRIB2 file and add it to the list of open files.
 
int g2c_check_msg (unsigned char *cgrib, g2int *lencurr, int verbose)
 Check for 'GRIB' at the beginning of a GRIB message, and check to see if the message is already terminated with '7777'.
 
int g2c_file_io (FILE *f, int write, int g2ctype, void *var)
 Read or write a big-endian integer type to an open file, with conversion between native and big-endian format.
 
int g2c_file_io_byte (FILE *f, int write, char *var)
 Read or write a big-endian signed byte to an open GRIB2 file, with conversion between native and big-endian format, and special GRIB2 handling of negative numbers.
 
int g2c_file_io_int (FILE *f, int write, int *var)
 Read or write a big-endian 4-byte signed int to an open GRIB2 file, with conversion between native and big-endian format, and special GRIB2 handling of negative numbers.
 
int g2c_file_io_longlong (FILE *f, int write, long long *var)
 Read or write a big-endian signed long long to an open GRIB2 file, with conversion between native and big-endian format, and special GRIB2 handling of negative numbers.
 
int g2c_file_io_short (FILE *f, int write, short *var)
 Read or write a big-endian signed short to an open GRIB2 file, with conversion between native and big-endian format, and special GRIB2 handling of negative numbers.
 
int g2c_file_io_template (FILE *f, int rw_flag, int map, long long int *template_value)
 Read or write a big-endian 4-byte int or unsigned int from or to an open file, with conversion between native and big-endian format, and handling of GRIB negative numbers.
 
int g2c_file_io_ubyte (FILE *f, int write, unsigned char *var)
 Read or write a big-endian unsigned byte to an open GRIB2 file, with conversion between native and big-endian format.
 
int g2c_file_io_uint (FILE *f, int write, unsigned int *var)
 Read or write a big-endian 4-byte unsigned int to an open GRIB2 file, with conversion between native and big-endian format.
 
int g2c_file_io_ulonglong (FILE *f, int write, unsigned long long *var)
 Read or write a big-endian unsigned long long to an open GRIB2 file, with conversion between native and big-endian format.
 
int g2c_file_io_ushort (FILE *f, int write, unsigned short *var)
 Read or write a big-endian unsigned short to an open GRIB2 file, with conversion between native and big-endian format.
 
int g2c_get_datetime (int ipdtn, long long int *ipdtmpl, short year, unsigned char month, unsigned char day, unsigned char hour, unsigned char minute, unsigned char second, char *tabbrev)
 Convert date and time from GRIB2 info to string output.
 
int g2c_get_level_desc (int ipdtn, long long int *ipdtmpl, char *level_desc)
 Determine the string that describes the level information, given the GRIB2 Product Definition Template information.
 
int g2c_log_section1 (G2C_MESSAGE_INFO_T *msg)
 Log section 0 information.
 
int g2c_rw_section1_metadata (FILE *f, int rw_flag, G2C_MESSAGE_INFO_T *msg)
 Read Section 1.
 
int g2c_rw_section3_metadata (FILE *f, int rw_flag, G2C_SECTION_INFO_T *sec)
 Read the metadata from section 3 (Grid Definition Section) of a GRIB2 message.
 
int g2c_rw_section4_metadata (FILE *f, int rw_flag, G2C_SECTION_INFO_T *sec)
 Read or write the metadata from section 4 (Product Definition Section) of a GRIB2 message.
 
int g2c_rw_section5_metadata (FILE *f, int rw_flag, G2C_SECTION_INFO_T *sec)
 Read or write the metadata from section 5 (Data Representation Section) of a GRIB2 message.
 
int g2c_rw_section6_metadata (FILE *f, int rw_flag, G2C_SECTION_INFO_T *sec)
 Read or write the metadata from section 6 (Data Representation Section) of a GRIB2 message.
 
void gbit (unsigned char *in, g2int *iout, g2int iskip, g2int nbits)
 Get arbitrary size values from a packed bit string, right justifying each value in the unpacked iout array.
 
void gbits (unsigned char *in, g2int *iout, g2int iskip, g2int nbits, g2int nskip, g2int n)
 Unpack arbitrary size values from a packed bit string, right justifying each value in the unpacked iout array.
 
g2int getdim (unsigned char *csec3, g2int *width, g2int *height, g2int *iscan)
 Return the dimensions and scanning mode of a grid definition.
 
gtemplategetdrstemplate (g2int number)
 This subroutine returns DRS template information for a specified Data Representation Template.
 
gtemplategetgridtemplate (g2int number)
 This subroutine returns grid template information for a specified Grid Definition Template for [Section 3 - the Grid Definition Section (GDS)](https://www.nco.ncep.noaa.gov/pmb/docs/grib2/grib2_doc/grib2_sect3.shtml).
 
gtemplategetpdstemplate (g2int number)
 This subroutine returns PDS template information for a specified Product Definition Template.
 
g2int getpoly (unsigned char *csec3, g2int *jj, g2int *kk, g2int *mm)
 This subroutine returns the J, K, and M pentagonal resolution parameters specified in a GRIB Grid Definition Section (GDS) used spherical harmonic coefficients using GDT 5.50 through 5.53.
 
double int_power (double x, g2int y)
 Function similar to C pow() power function.
 
void jpcpack (float *fld, g2int width, g2int height, g2int *idrstmpl, unsigned char *cpack, g2int *lcpack)
 This function packs up a float array into a JPEG2000 code stream.
 
g2int jpcunpack (unsigned char *cpack, g2int len, g2int *idrstmpl, g2int ndpts, float *fld)
 Unpack JPEG2000 compressed data into an array of floats, using info from the GRIB2 Data Representation Template 5.40 or 5.40000.
 
void misspack (float *fld, g2int ndpts, g2int idrsnum, g2int *idrstmpl, unsigned char *cpack, g2int *lcpack)
 Pack a data field using a complex packing algorithm.
 
void mkieee (float *a, g2int *rieee, g2int num)
 Store a list of real values in 32-bit IEEE floating point format.
 
int pack_gp (g2int *kfildo, g2int *ic, g2int *nxy, g2int *is523, g2int *minpk, g2int *inc, g2int *missp, g2int *misss, g2int *jmin, g2int *jmax, g2int *lbit, g2int *nov, g2int *ndg, g2int *lx, g2int *ibit, g2int *jbit, g2int *kbit, g2int *novref, g2int *lbitref, g2int *ier)
 Determines groups of variable size, but at least of size minpk, the associated max (jmax( )) and min (jmin( )), the number of bits necessary to hold the values in each group (lbit( )), the number of values in each group (nov( )), the number of bits necessary to pack the jmin( ) values (ibit), the number of bits necessary to pack the lbit( ) values (jbit), and the number of bits necessary to pack the nov( ) values (kbit).
 
void pngpack (float *fld, g2int width, g2int height, g2int *idrstmpl, unsigned char *cpack, g2int *lcpack)
 This subroutine packs up a float data field into PNG image format.
 
g2int pngunpack (unsigned char *cpack, g2int len, g2int *idrstmpl, g2int ndpts, float *fld)
 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.
 
void rdieee (g2int *rieee, float *a, g2int num)
 Read a list of real values in 32-bit IEEE floating point format.
 
void sbit (unsigned char *out, g2int *in, g2int iskip, g2int nbits)
 Store arbitrary size values into a packed bit string, taking the low order bits from each value in the unpacked array.
 
void sbits (unsigned char *out, g2int *in, g2int iskip, g2int nbits, g2int nskip, g2int n)
 Store arbitrary size values into a packed bit string, taking the low order bits from each value in the unpacked array.
 
void simpack (float *fld, g2int ndpts, g2int *idrstmpl, unsigned char *cpack, g2int *lcpack)
 Packs a data field using the simple packing algorithm.
 
g2int simunpack (unsigned char *cpack, g2int *idrstmpl, g2int ndpts, float *fld)
 Unpack a data field that was packed using a simple packing algorithm, using info from the GRIB2 Data Representation Template 5.0.
 
void specpack (float *fld, g2int ndpts, g2int JJ, g2int KK, g2int MM, g2int *idrstmpl, unsigned char *cpack, g2int *lcpack)
 Pack a spectral data field using the complex packing algorithm for spherical harmonic data as defined in the GRIB2 Data Representation Template 5.51.
 
g2int specunpack (unsigned char *cpack, g2int *idrstmpl, g2int ndpts, g2int JJ, g2int KK, g2int MM, float *fld)
 Unpack 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.
 

Detailed Description

Header file with internal function prototypes NCEPLIBS-g2c library.

Author
Ed Hartnett
Date
2021-11-08

Definition in file grib2_int.h.


Data Type Documentation

◆ g2c_code_table

struct g2c_code_table

A GRIB2 code table.

Definition at line 256 of file grib2_int.h.

Data Fields
G2C_CODE_ENTRY_T * entry
struct g2c_code_table * next
char title[G2C_MAX_GRIB_TITLE_LEN+1]

◆ g2c_dim_info

struct g2c_dim_info

Keep information about dimensions defined in section 3.

Definition at line 185 of file grib2_int.h.

Data Fields
int dimid Dimension ID.
size_t len Length of dimension.
char name[G2C_MAX_NAME+1] Name of dimension.
float * value Array of dimension values.

◆ g2c_entry

struct g2c_entry

An entry in a GRIB2 code table.

Definition at line 247 of file grib2_int.h.

Data Fields
char code[G2C_MAX_GRIB_CODE_LEN+1]
char desc[G2C_MAX_GRIB_DESC_LEN+1]
struct g2c_entry * next
char status[G2C_MAX_GRIB_STATUS_LEN+1]

◆ g2c_file_info

struct g2c_file_info

This is the information about each open file.

Definition at line 237 of file grib2_int.h.

Data Fields
FILE * f FILE pointer to open file.
int g2cid ID of the file.
G2C_MESSAGE_INFO_T * msg Information about each message in the file.
size_t num_messages Number of messages in the file.
char path[G2C_MAX_NAME+1] Path of the file.

◆ g2c_message_info

struct g2c_message_info

This is the information about each message.

Definition at line 135 of file grib2_int.h.

Data Fields
size_t bytes_in_msg Number of bytes in this message.
size_t bytes_to_bms Number of bytes in the message to the bitmap section.
size_t bytes_to_data Number of bytes in the message to the (first) data section.
size_t bytes_to_local Number of bytes in the message before the (first) local section.
size_t bytes_to_msg Number of bytes to skip in the file, to get to this message.
short center Originating center.
unsigned char day Day.
unsigned char discipline Discipline from section 0.
struct g2c_file_info * file Pointer to containing file.
unsigned char hour Hour.
unsigned char local_version Version number of GRIB local tables used to augment Master Tables.
unsigned char master_version GRIB master tables version number.
unsigned char minute Minute.
unsigned char month Month.
size_t msg_num Number of message in file (0-based).
struct g2c_message_info * next Pointer to next in list.
int num_fields Number of fields in the message.
int num_local Number of local sections in the message.
int num_sections Number of sections in the file.
struct g2c_section_info * sec List of section metadata.
int sec1_len Length of section 1.
unsigned char second Second.
int section1[G2C_SECTION1_ARRAY_LEN] Section 1 array.
int * section_number Array (length num_sections) of section numbers.
size_t * section_offset Array (length num_sections) of byte offsets from start of message to section.
unsigned char sig_ref_time Significance of reference time.
unsigned char status Production Status of Processed data in the GRIB message.
short subcenter Originating subcenter.
unsigned char type Type of processed data in this GRIB message.
short year Year.

◆ g2c_param

struct g2c_param

An entry in the table of NOAA abbreviations for GRIB parameters.

Definition at line 264 of file grib2_int.h.

Data Fields
char abbrev[G2C_MAX_NOAA_ABBREV_LEN+1] NOAA abbreviation for this parameter.
int g1num GRIB1 parameter number.
int g1ver GRIB1 table version.
int g2cat GRIB2 category number.
int g2disc GRIB2 discipline.
int g2num GRIB2 parameter number.

◆ g2c_section3_info

struct g2c_section3_info

Information about Section 3 GRID DEFINITION SECTION.

Definition at line 195 of file grib2_int.h.

Data Fields
G2C_DIM_INFO_T dim[2] Dimension information.
unsigned short grid_def Grid definition template number (= N) (See Table 3.1).
unsigned char interp_list Interpetation of list of numbers defining number of points (See Table 3.11).
unsigned int num_data_points Number of data points.
unsigned char num_opt Number of octets for optional list of numbers defining number of points.
int * optional Optional list of numbers defining number of points.
unsigned char source_grid_def Source of grid definition (See Table 3.0).

◆ g2c_section4_info

struct g2c_section4_info

Information about Section 4 PRODUCT DEFINITION SECTION.

Definition at line 208 of file grib2_int.h.

Data Fields
int field_num
unsigned short num_coord Number of coordinate values after template.
int * optional Optional list of numbers defining number of points.
unsigned short prod_def Product definition template number (See Table 4.0).

◆ g2c_section5_info

struct g2c_section5_info

Information about Section 5 DATA REPRESENTATION SECTION.

Definition at line 218 of file grib2_int.h.

Data Fields
unsigned short data_def Data representation template number (See Table 5.0).
unsigned int num_data_points Number of data points where one or more values are specified in Section 7 when a bit map is present, total number of data points when a bit map is absent.

◆ g2c_section6_info

struct g2c_section6_info

Information about Section 6 BIT-MAP SECTION.

Definition at line 229 of file grib2_int.h.

Data Fields
unsigned char indicator Bit map indicator.

See Table 6.0.

◆ g2c_section_info

struct g2c_section_info

Information about a section 3 through 7 in a GRIB2 message.

Definition at line 170 of file grib2_int.h.

Data Fields
size_t bytes_to_sec Number of bytes from start of message to this section.
G2C_MESSAGE_INFO_T * msg Pointer to contianing message.
struct g2c_section_info * next Pointer to next in list.
struct g2c_section_info * prev Pointer to previous in list.
int sec_id ID of the section (0-based).
void * sec_info Pointer to struct specific for section 3, 4, 5, 6, or 7.
unsigned int sec_len Length of the section (in bytes).
unsigned char sec_num Section number.
long long int * template Grid, product, or data template.
int template_len Number of entries in template.

◆ gtemplate

struct gtemplate

Struct for GRIB template, returned by getgridtemplate().

Definition at line 277 of file grib2_int.h.

Data Fields
g2int * ext Number of octets of each entry in the extension part of the template.
g2int extlen Number of entries in the template extension.
g2int * map Number of octets of each entry in the static part of the template.
g2int maplen Number of entries in the static part of the template.
g2int needext Indicates whether or not the template needs to be extended.
g2int num The template number.
g2int type The template type: 3 Grid Defintion Template.

4 Product Defintion Template. 5 Data Representation Template.

Macro Definition Documentation

◆ ALOG2

#define ALOG2   (0.69314718)

ln(2.0)

Definition at line 30 of file grib2_int.h.

◆ BYTE

#define BYTE   8

Number of bits in a byte.

Definition at line 47 of file grib2_int.h.

◆ EIGHT_BYTES

#define EIGHT_BYTES   8

Eight bytes.

Definition at line 53 of file grib2_int.h.

◆ EXTERN_MUTEX

#define EXTERN_MUTEX (   m)

Pthreads not enabled, so do nothing.

Definition at line 113 of file grib2_int.h.

◆ FOUR_BYTES

#define FOUR_BYTES   4

Four bytes.

Definition at line 52 of file grib2_int.h.

◆ G2C_FILE_READ

#define G2C_FILE_READ   0

Read.

Definition at line 131 of file grib2_int.h.

◆ G2C_FILE_WRITE

#define G2C_FILE_WRITE   1

Write.

Definition at line 132 of file grib2_int.h.

◆ G2C_INDEX1_BDS_VAL_LEN

#define G2C_INDEX1_BDS_VAL_LEN   10

Length of the binary data section (bds) in index file.

Definition at line 73 of file grib2_int.h.

◆ G2C_INDEX1_BMS_VAL_LEN

#define G2C_INDEX1_BMS_VAL_LEN   5

Length of the bitmap section (bms) in index file.

Definition at line 70 of file grib2_int.h.

◆ G2C_INDEX1_GDS_VAL2_LEN

#define G2C_INDEX1_GDS_VAL2_LEN   27

Length of the gds in index file.

Definition at line 82 of file grib2_int.h.

◆ G2C_INDEX1_GDS_VAL_LEN

#define G2C_INDEX1_GDS_VAL_LEN   41

Length of the grid definition section (gds) in index file.

Definition at line 67 of file grib2_int.h.

◆ G2C_INDEX1_PDS_VAL2_LEN

#define G2C_INDEX1_PDS_VAL2_LEN   27

Length of the pds 2 section in the index file.

Definition at line 76 of file grib2_int.h.

◆ G2C_INDEX1_PDS_VAL3_LEN

#define G2C_INDEX1_PDS_VAL3_LEN   27

Length of the pds 3 section in the index file.

Definition at line 79 of file grib2_int.h.

◆ G2C_INDEX1_PDS_VAL_LEN

#define G2C_INDEX1_PDS_VAL_LEN   27

Length of the product definition section (pds) in index file.

Definition at line 64 of file grib2_int.h.

◆ G2C_JASPER_JPEG_FORMAT_NAME

#define G2C_JASPER_JPEG_FORMAT_NAME   "jpc"

Name of JPEG codec in Jasper.

Definition at line 33 of file grib2_int.h.

◆ G2C_MAGIC_HEADER

#define G2C_MAGIC_HEADER   "GRIB"

GRIB magic header string.

Definition at line 39 of file grib2_int.h.

◆ G2C_MAGIC_HEADER_LEN

#define G2C_MAGIC_HEADER_LEN   8

Full length of magic header string (includes GRIB version byte).

Definition at line 42 of file grib2_int.h.

◆ G2C_MAX_MESSAGES

#define G2C_MAX_MESSAGES   1024

Maximum number of messages in a file.

Definition at line 45 of file grib2_int.h.

◆ G2C_MIN_MAX_BYTES

#define G2C_MIN_MAX_BYTES   16

Minimum acceptable value for max_bytes parameter of g2c_get_msg().

Definition at line 36 of file grib2_int.h.

◆ hton64

#define hton64 (   y)    (((uint64_t)htonl(y)) << WORD | htonl(y >> WORD))

Byte swap 64-bit ints.

This converts native-endian 8-byte ints into big-endian 8-byte ints.

Definition at line 129 of file grib2_int.h.

◆ LATITUDE

#define LATITUDE   "Latitude"

Latitude.

Definition at line 56 of file grib2_int.h.

◆ LOG

#define LOG (   e)

Ignore logging to stdout.

Library was not built with LOGGING=ON.

Definition at line 428 of file grib2_int.h.

◆ LONGITUDE

#define LONGITUDE   "Longitude"

Longitude.

Definition at line 59 of file grib2_int.h.

◆ MUTEX

#define MUTEX (   m)

Pthreads not enabled, so do nothing.

Definition at line 110 of file grib2_int.h.

◆ MUTEX_LOCK

#define MUTEX_LOCK (   m)

Pthreads not enabled, so do nothing.

Definition at line 116 of file grib2_int.h.

◆ MUTEX_UNLOCK

#define MUTEX_UNLOCK (   m)

Pthreads not enabled, so do nothing.

Definition at line 119 of file grib2_int.h.

◆ ntoh64

#define ntoh64 (   y)    (((uint64_t)ntohl(y)) << WORD | ntohl(y >> WORD))

Byte swap 64-bit ints.

This converts big-endian 8-byte ints into native endian 8-byte ints.

Definition at line 125 of file grib2_int.h.

◆ ONE_BYTE

#define ONE_BYTE   1

One byte.

Definition at line 50 of file grib2_int.h.

◆ TWO_BYTES

#define TWO_BYTES   2

Two bytes.

Definition at line 51 of file grib2_int.h.

◆ WORD

#define WORD   32

Number of bits in four bytes.

Definition at line 48 of file grib2_int.h.

Typedef Documentation

◆ G2C_CODE_ENTRY_T

typedef struct g2c_entry G2C_CODE_ENTRY_T

An entry in a GRIB2 code table.

◆ G2C_CODE_TABLE_T

A GRIB2 code table.

◆ G2C_DIM_INFO_T

typedef struct g2c_dim_info G2C_DIM_INFO_T

Keep information about dimensions defined in section 3.

◆ G2C_FILE_INFO_T

This is the information about each open file.

◆ G2C_MESSAGE_INFO_T

This is the information about each message.

◆ G2C_PARAM_T

typedef struct g2c_param G2C_PARAM_T

An entry in the table of NOAA abbreviations for GRIB parameters.

◆ G2C_SECTION3_INFO_T

◆ G2C_SECTION4_INFO_T

◆ G2C_SECTION5_INFO_T

◆ G2C_SECTION6_INFO_T

◆ G2C_SECTION_INFO_T

Information about a section 3 through 7 in a GRIB2 message.

◆ gtemplate

typedef struct gtemplate gtemplate

Struct for GRIB template.

Definition at line 305 of file grib2_int.h.

Function Documentation

◆ add_msg()

int add_msg ( G2C_FILE_INFO_T file,
int  msg_num,
size_t  bytes_to_msg,
size_t  bytes_in_msg,
int  read_file,
G2C_MESSAGE_INFO_T **  msg 
)

Add new message to linked list.

Parameters
filePointer to the G2C_FILE_INFO_T for this file.
msg_numNumber of the message in file (0-based).
bytes_to_msgNumber of bytes to the start of the message in the file.
bytes_in_msgLength of message in bytes.
read_fileSet to true to cause metadata to be read from a GRIB2 data file.
msgPointer to a pointer that will get the location of the newly created G2C_MESSAGE_INFO_T object. Ignored if NULL.
Returns
Author
Ed Hartnett
Date
Sep 12, 2022

Definition at line 1017 of file g2cfile.c.

References g2c_message_info::bytes_in_msg, g2c_message_info::bytes_to_msg, g2c_message_info::file, G2C_ENOMEM, G2C_NOERROR, LOG, g2c_file_info::msg, g2c_message_info::msg_num, g2c_message_info::next, g2c_file_info::num_messages, and read_msg_metadata().

Referenced by g2c_open_index(), and read_metadata().

◆ add_section()

int add_section ( FILE *  f,
G2C_MESSAGE_INFO_T msg,
int  sec_id,
unsigned int  sec_len,
size_t  bytes_to_sec,
unsigned char  sec_num 
)

Add metadata about a new section 3, 4, 5, 6, or 7.

Parameters
fFILE pointer to open GRIB2 file.
msgPointer to the G2C_MESSAGE_INFO_T struct.
sec_id0-based section ID.
sec_lenLength of section.
bytes_to_secNumber of bytes from start of message to this section.
sec_numSection number.
Returns
Author
Ed Hartnett
Date
Sep 12, 2022

Definition at line 794 of file g2cfile.c.

References g2c_section_info::bytes_to_sec, G2C_EBADSECTION, G2C_ENOMEM, G2C_FILE_READ, G2C_NOERROR, g2c_rw_section3_metadata(), g2c_rw_section4_metadata(), g2c_rw_section5_metadata(), g2c_rw_section6_metadata(), LOG, g2c_section_info::msg, g2c_section_info::next, g2c_message_info::num_local, g2c_section_info::prev, g2c_message_info::sec, g2c_section_info::sec_id, g2c_section_info::sec_len, and g2c_section_info::sec_num.

Referenced by g2c_open_index(), and read_msg_metadata().

◆ aecpack()

void aecpack ( float *  fld,
g2int  width,
g2int  height,
g2int idrstmpl,
unsigned char *  cpack,
g2int lcpack 
)

This function packs up a float array into a AEC code stream.

After the data are scaled, and the reference value is subtracted out, the data are passed to the AEC encoder.

This function also fills in GRIB2 Data Representation Template 5.42 with the appropriate values.

Parameters
fldPointer to the float data values to pack.
widthThe number of points in the x direction.
heightThe number of points in the y direction.
idrstmplContains the array of values for Data Representation Template Table 5.42.
  • 0 Reference value - ignored on input, set by aecpack routine.
  • 1 Binary Scale Factor - used on input, unchanged by aecpack routine.
  • 2 Decimal Scale Factor - used on input, unchanged by aecpack routine.
  • 3 number of bits for each data value - ignored on input
  • 4 Original field type - currently ignored on input Data values assumed to be reals. Set to 0 on output.
  • 5 CCSDS compression options mask.
  • 6 Block size.
  • 7 Reference sample interval. May be modified in this function.
cpackA pointer that will get the packed data field. Must be allocated before this function is called. Pass the allocated size in the lcpack parameter.
lcpackPointer that gets the length of packed field in cpack. This must be set by the calling function to the size available in cpack.
Author
Eric Engle (adapted from jpcpack)

Definition at line 297 of file aecpack.c.

References aecpack_int().

Referenced by g2_addfield().

◆ aecunpack()

g2int aecunpack ( unsigned char *  cpack,
g2int  len,
g2int idrstmpl,
g2int  ndpts,
float *  fld 
)

Unpack AEC compressed data into an array of floats, using info from the GRIB2 Data Representation Template 5.42.

Parameters
cpackThe packed data.
lenThe length of the packed data.
idrstmplPointer to array of values for Data Representation Template 5.42.
ndptsThe number of data values to unpack.
fldA pointer that gets the unpacked data values as an array of float.
Returns
Author
Eric Engle
Date
2023-10-16

Definition at line 161 of file aecunpack.c.

References aecunpack_int(), and LOG.

Referenced by g2c_unpack7_int().

◆ cmplxpack()

void cmplxpack ( float *  fld,
g2int  ndpts,
g2int  idrsnum,
g2int idrstmpl,
unsigned char *  cpack,
g2int lcpack 
)

Pack up a data field using a complex packing algorithm.

This function supports GRIB2 complex packing templates with or without spatial differences (i.e. DRTs 5.2 and 5.3). It also fills in GRIB2 Data Representation Template 5.2 or 5.3 with the appropriate values.

Parameters
fldContains the data values to pack.
ndptsThe number of data values in array fld
idrsnumData Representation Template number. Must equal 2 or 3.
idrstmplContains the array of values for Data Representation Template 5.2 or 5.3
  • 0 Reference value - ignored on input, set by compack routine.
  • 1 Binary Scale Factor
  • 2 Decimal Scale Factor
  • 6 Missing value management
  • 7 Primary missing value
  • 8 Secondary missing value
  • 16 Order of Spatial Differencing ( 1 or 2 )
cpackThe packed data field.
lcpacklength of packed field cpack. Will be set to -1 if missing value management field is not 1 or 2.
Author
Stephen Gilbert
Date
2004-08-27

Definition at line 37 of file cmplxpack.c.

References compack(), and misspack().

Referenced by g2_addfield().

◆ compack()

void compack ( float *  fld,
g2int  ndpts,
g2int  idrsnum,
g2int idrstmpl,
unsigned char *  cpack,
g2int lcpack 
)

Pack a data field using a complex packing algorithm.

This function supports GRIB2 complex packing templates with or without spatial differences (i.e. DRTs 5.2 and 5.3). It also fills in GRIB2 Data Representation Template 5.2 or Template 5.3 with the appropriate values.

Parameters
fldContains the data values to pack.
ndptsThe number of data values in array fld.
idrsnumData Representation Template number. Must equal 2 or 3.
idrstmplContains the array of values for Data Representation Template 5.2 or 5.3.
  • 0 Reference value - ignored on input, set my compack().
  • 1 Binary Scale Factor
  • 2 Decimal Scale Factor
  • 6 Missing value management
  • 7 Primary missing value
  • 8 Secondary missing value
  • 16 Order of Spatial Differencing (1 or 2)
cpackThe packed data field.
lcpacklength of packed field cpack.
Author
Stephen Gilbert
Date
2002-11-07

Definition at line 42 of file compack.c.

References ALOG2, int_power(), mkieee(), pack_gp(), sbit(), and sbits().

Referenced by cmplxpack().

◆ comunpack()

int comunpack ( unsigned char *  cpack,
g2int  lensec,
g2int  idrsnum,
g2int idrstmpl,
g2int  ndpts,
float *  fld 
)

Unpack a data field that was packed using a complex packing algorithm, using info from the GRIB2 Data Representation Template 5.2 or Template 5.3.

Supports GRIB2 complex packing templates with or without spatial differences (i.e. DRTs 5.2 and 5.3).

Program History Log

Date Programmer Comments
2002-10-29 Gilbert Initial
2004-12-16 Gilbert Added test (from Arthur Taylor/MDL) verifying group widths/lengths
Parameters
cpackpointer to the packed data field.
lenseclength of section 7 (used for error checking).
idrsnumData Representation Template number. Must equal 2 or 3.
idrstmplpointer to the array of values for Data Representation Template 5.2 or 5.3
ndptsThe number of data values to unpack
fldContains the unpacked data values. Must be allocated with at least ndpts * sizeof(float) bytes before calling this routine.
Returns
0 for success, error code otherwise.
Author
Stephen Gilbert
Date
2002-10-29

Definition at line 41 of file comunpack.c.

References gbit(), gbits(), int_power(), LOG, and rdieee().

Referenced by g2c_unpack7_int().

◆ dec_aec()

int dec_aec ( unsigned char *  cpack,
g2int  len,
g2int  nbits,
g2int  flags,
g2int  block_size,
g2int  rsi,
unsigned char *  cfld,
g2int  cfldlen 
)

Decode an AEC code stream specified in the CCSDS 121.0-B-3 Blue Book.

Parameters
cpackPointer to buffer that holds the input AEC code stream.
lenLength (in bytes) of the buffer that holds the input AEC code stream.
nbitsCCSDS bits per sample.
flagsCCSDS compression options mask.
block_sizeCCSDS block size.
rsiCCSDS reference sample interval.
cfldPointer to output buffer from the AEC decoder.
cfldlenlength of output buffer.
Returns
  • >0 Length of data from AEC decoder
  • 0 Successful decode (AEC_OK)
  • -1 AEC_CONF_ERROR
  • -2 AEC_STREAM_ERROR
  • -3 AEC_DATA_ERROR
  • -4 AEC_MEM_ERROR
  • -5 AEC_RSI_OFFSETS_ERROR
Author
Eric Engle
Date
2023-10-16

Definition at line 38 of file decenc_aec.c.

References LOG.

Referenced by aecunpack_int().

◆ dec_jpeg2000()

int dec_jpeg2000 ( char *  injpc,
g2int  bufsize,
g2int outfld 
)

Decode a JPEG2000 code stream specified in the JPEG2000 Part-1 standard (i.e., ISO/IEC 15444-1) using JasPer Software.

Parameters
injpcPointer to buffer that holds the input JPEG2000 code stream.
bufsizeLength (in bytes) of the buffer that holds the input JPEG2000 code stream.
outfldPointer to g2int array, already allocated, that gets the unpacked data.
Returns
Author
Stephen Gilbert, Ed Hartnett

Definition at line 376 of file decenc_jpeg2000.c.

References int_dec_jpeg2000().

Referenced by jpcunpack_int().

◆ dec_png()

int dec_png ( unsigned char *  pngbuf,
g2int width,
g2int height,
unsigned char *  cout 
)

Decode PNG.

Parameters
pngbufPointer to PNG buffer.
widthPointer to width.
heightPointer to height.
coutOutput buffer.
Returns
0 for success, error code otherwise.
Author
Stephen Gilbert

Definition at line 100 of file decenc_png.c.

References user_read_data().

Referenced by pngunpack_int().

◆ enc_aec()

int enc_aec ( unsigned char *  data,
g2int  ctemplen,
g2int  nbits,
g2int  flags,
g2int  block_size,
g2int  rsi,
unsigned char *  aecbuf,
g2int aecbuflen 
)

Encode data into an AEC code stream specified in the CCSDS 121.0-B-3 Blue Book.

Parameters
dataPointer to buffer that holds the input data.
ctemplenLength (in bytes) of the buffer that holds the input data..
nbitsCCSDS bits per sample.
flagsCCSDS compression options mask.
block_sizeCCSDS block size.
rsiCCSDS reference sample interval.
aecbufPointer to buffer holding the AEC encoded stream.
aecbuflenLength of AEC code stream.
Returns
  • >0 Exact length of AEC encoded data.
  • 0 Successful decode (AEC_OK)
  • -1 AEC_CONF_ERROR
  • -2 AEC_STREAM_ERROR
  • -3 AEC_DATA_ERROR
  • -4 AEC_MEM_ERROR
  • -5 AEC_RSI_OFFSETS_ERROR
Author
Eric Engle
Date
2023-10-16

Definition at line 108 of file decenc_aec.c.

References LOG.

Referenced by aecpack_int().

◆ enc_jpeg2000()

int enc_jpeg2000 ( unsigned char *  cin,
g2int  width,
g2int  height,
g2int  nbits,
g2int  ltype,
g2int  ratio,
g2int  retry,
char *  outjpc,
g2int  jpclen 
)

Encode a grayscale image into a JPEG2000 code stream specified in the JPEG2000 Part-1 standard (i.e., ISO/IEC 15444-1) using JasPer Software.

  • ### Program History Log
    Date Programmer Comments
    2002-12-02 Gilbert Initial
    2004-12-16 Gilbert Added retry argument allowing increased guard bits.
    2022-04-15 Hartnett Converted to use jas_ instead of jpc_ functions.
Parameters
cinPacked matrix of Grayscale image values to encode.
widthwidth of image.
heightheight of image.
nbitsdepth (in bits) of image. i.e number of bits used to hold each data value.
ltypeindicator of lossless or lossy compression.
  • 1, for lossy compression
  • != 1, for lossless compression
ratiotarget compression ratio. (ratio:1) Used only when ltype == 1.
retryIf 1 try increasing number of guard bits.
outjpcOutput encoded JPEG2000 code stream.
jpclenNumber of bytes allocated for the output JPEG2000 code stream in outjpc.
Returns
  • > 0 = Length in bytes of encoded JPEG2000 code stream
  • G2_JASPER_INIT Error initializing jasper library.
  • G2_JASPER_ENCODE Error encode jpeg2000 code stream.
Note
Requires JasPer Software version 1.500.4 or 1.700.2 or later.
Author
Stephen Gilbert
Date
2002-12-02
Author
Ed Hartnett

Definition at line 94 of file decenc_jpeg2000.c.

References G2_JASPER_ENCODE, G2_JASPER_INIT, G2C_JASPER_JPEG_FORMAT_NAME, LOG, and MAXOPTSSIZE.

Referenced by g2c_enc_jpeg2000(), and jpcpack_int().

◆ enc_png()

int enc_png ( unsigned char *  data,
g2int  width,
g2int  height,
g2int  nbits,
unsigned char *  pngbuf 
)

Encode PNG.

Parameters
datadata.
widthwidth.
heightheight.
nbitsnumber of bits.
pngbufPNG buffer.
Returns
PNG length, or negative number for error.
Author
Stephen Gilbert

Definition at line 207 of file decenc_png.c.

References user_flush_data(), and user_write_data().

Referenced by pngpack_int().

◆ extdrstemplate()

gtemplate * extdrstemplate ( g2int  number,
g2int list 
)

This subroutine generates the remaining octet map for a given Data Representation Template, if required.

Some Templates can vary depending on data values given in an earlier part of the Template, and it is necessary to know some of the earlier entry values to generate the full octet map of the Template.

Parameters
numberThe number of the Data Representation Template that is being requested.
listThe list of values for each entry in the the Data Representation Template.
Returns
Pointer to the returned template struct. Returns NULL pointer, if template not found.
Author
Stephen Gilbert
Date
2000-05-11

Definition at line 213 of file drstemplates.c.

References getdrsindex(), and getdrstemplate().

Referenced by g2_unpack5().

◆ extgridtemplate()

gtemplate * extgridtemplate ( g2int  number,
g2int template 
)

This subroutine generates the remaining octet map for a given Grid Definition Template, if required.

Some Templates can vary depending on data values given in an earlier part of the Template, and it is necessary to know some of the earlier entry values to generate the full octet map of the Template.

This function allocates memory for the extension. The pointer ext in the gtemplate struct must be freed to prevent memory leaks.

Parameters
numberThe number of the Grid Definition Template that is being requested.
templateThe grid definition template array.
Returns
Pointer to the returned template struct. Returns NULL pointer, if template not found.
Author
Stephen Gilbert
Date
2000-05-09

Definition at line 225 of file gridtemplates.c.

References getgridindex(), and getgridtemplate().

Referenced by g2_addgrid(), g2_unpack3(), and g2c_get_grid_template_extension().

◆ extpdstemplate()

gtemplate * extpdstemplate ( g2int  number,
g2int list 
)

This subroutine generates the remaining octet map for a given Product Definition Template, if required.

Some Templates can vary depending on data values given in an earlier part of the Template, and it is necessary to know some of the earlier entry values to generate the full octet map of the Template.

This function allocates memory in the ext field of the gtemplate struct. This memory must be freed by the caller.

Parameters
numbernumber of the Product Definition Template 4.NN that is being requested.
listThe list of values for each entry in the the Product Definition Template.
Returns
Pointer to the returned template struct. Returns NULL pointer if template not found.
Author
Stephen Gilbert
Date
2000-05-11

Definition at line 326 of file pdstemplates.c.

References getpdsindex(), and getpdstemplate().

Referenced by g2_addfield(), g2_unpack4(), and g2c_get_pds_template_extension().

◆ g2c_add_file()

int g2c_add_file ( const char *  path,
int  mode,
int *  g2cid 
)

Open a GRIB2 file and add it to the list of open files.

Parameters
pathPath of the file.
modeOpen mode flags.
g2cidPointer that gets an indentifier for the file.
Returns
Author
Ed Hartnett
Date
Aug 16, 2022

Definition at line 1143 of file g2cfile.c.

References find_available_g2cid(), G2C_EFILE, G2C_EINVAL, G2C_ENAMETOOLONG, g2c_file, G2C_MAX_NAME, G2C_NOERROR, G2C_WRITE, g2c_file_info::g2cid, LOG, g2c_file_info::msg, and g2c_file_info::num_messages.

Referenced by g2c_open(), and g2c_open_index().

◆ g2c_check_msg()

int g2c_check_msg ( unsigned char *  cgrib,
g2int lencurr,
int  verbose 
)

Check for 'GRIB' at the beginning of a GRIB message, and check to see if the message is already terminated with '7777'.

Parameters
cgribBuffer that contains the GRIB message.
lencurrPointer that gets the length of the GRIB message.
verboseIf non-zero, print any error messages to stdout.
Returns
Author
Ed Hartnett
Date
Nov 11, 2021

Definition at line 26 of file util.c.

References G2C_EMSGCOMPLETE, G2C_ENOTGRIB, G2C_NOERROR, and gbit().

Referenced by g2_addfield(), g2_addgrid(), g2_addlocal(), and g2_gribend().

◆ g2c_file_io()

int g2c_file_io ( FILE *  f,
int  write,
int  g2ctype,
void *  var 
)

Read or write a big-endian integer type to an open file, with conversion between native and big-endian format.

GRIB2 handles negative numbers in a special way. Instead of storing two-compliments, like every other programmer and computing organization in the world, GRIB2 flips the first bit, then stores the rest of the int as an unsigned number in the remaining 31 bits. How exciting!

This function takes the excitement out of GRIB2 negative numbers.

Parameters
fPointer to the open FILE.
writeNon-zero if function should write, otherwise function will read.
g2ctypeThe type to be read or written.
varPointer to the int to be written, or pointer to the storage that gets the int read.
Returns
  • :: G2C_NOERROR No error.
  • :: G2C_EINVAL Invalid input.
  • :: G2C_EFILE Error reading/writing file.
Author
Ed Hartnett
Date
11/7/22

Definition at line 41 of file g2cio.c.

References BITSHIFT_15, BITSHIFT_31, BITSHIFT_63, BITSHIFT_7, EIGHT_BYTES, FOUR_BYTES, G2C_BYTE, G2C_EBADTYPE, G2C_EFILE, G2C_EINVAL, G2C_INT, G2C_INT64, G2C_NOERROR, G2C_SHORT, G2C_UBYTE, G2C_UINT, G2C_UINT64, G2C_USHORT, hton64, ntoh64, ONE_BYTE, and TWO_BYTES.

Referenced by g2c_file_io_byte(), g2c_file_io_int(), g2c_file_io_longlong(), g2c_file_io_short(), g2c_file_io_ubyte(), g2c_file_io_uint(), g2c_file_io_ulonglong(), and g2c_file_io_ushort().

◆ g2c_file_io_byte()

int g2c_file_io_byte ( FILE *  f,
int  write,
char *  var 
)

Read or write a big-endian signed byte to an open GRIB2 file, with conversion between native and big-endian format, and special GRIB2 handling of negative numbers.

Parameters
fPointer to the open GRIB2 FILE.
writeNon-zero to write, zero to read.
varPointer to the byte.
Returns
  • :: G2C_NOERROR No error.
  • :: G2C_EINVAL Invalid input.
  • :: G2C_EFILE Error reading/writing file.
Author
Ed Hartnett 11/13/22

Definition at line 316 of file g2cio.c.

References G2C_BYTE, and g2c_file_io().

Referenced by g2c_file_io_template().

◆ g2c_file_io_int()

int g2c_file_io_int ( FILE *  f,
int  write,
int *  var 
)

Read or write a big-endian 4-byte signed int to an open GRIB2 file, with conversion between native and big-endian format, and special GRIB2 handling of negative numbers.

Parameters
fPointer to the open GRIB2 FILE.
writeNon-zero to write, zero to read.
varPointer to the int.
Returns
  • :: G2C_NOERROR No error.
  • :: G2C_EINVAL Invalid input.
  • :: G2C_EFILE Error reading/writing file.
Author
Ed Hartnett 11/7/22

Definition at line 230 of file g2cio.c.

References g2c_file_io(), and G2C_INT.

Referenced by g2c_file_io_template().

◆ g2c_file_io_longlong()

int g2c_file_io_longlong ( FILE *  f,
int  write,
long long *  var 
)

Read or write a big-endian signed long long to an open GRIB2 file, with conversion between native and big-endian format, and special GRIB2 handling of negative numbers.

Parameters
fPointer to the open GRIB2 FILE.
writeNon-zero to write, zero to read.
varPointer to the long long.
Returns
  • :: G2C_NOERROR No error.
  • :: G2C_EINVAL Invalid input.
  • :: G2C_EFILE Error reading/writing file.
Author
Ed Hartnett 11/13/22

Definition at line 359 of file g2cio.c.

References g2c_file_io(), and G2C_INT64.

◆ g2c_file_io_short()

int g2c_file_io_short ( FILE *  f,
int  write,
short *  var 
)

Read or write a big-endian signed short to an open GRIB2 file, with conversion between native and big-endian format, and special GRIB2 handling of negative numbers.

Parameters
fPointer to the open GRIB2 FILE.
writeNon-zero to write, zero to read.
varPointer to the short.
Returns
  • :: G2C_NOERROR No error.
  • :: G2C_EINVAL Invalid input.
  • :: G2C_EFILE Error reading/writing file.
Author
Ed Hartnett 11/13/22

Definition at line 273 of file g2cio.c.

References g2c_file_io(), and G2C_SHORT.

Referenced by g2c_file_io_template(), g2c_rw_section1_metadata(), g2c_start_index_record(), and g2c_start_index_record_lf().

◆ g2c_file_io_template()

int g2c_file_io_template ( FILE *  f,
int  rw_flag,
int  map,
long long int *  template_value 
)

Read or write a big-endian 4-byte int or unsigned int from or to an open file, with conversion between native and big-endian format, and handling of GRIB negative numbers.

This is for template values.

With template values, if the map value is negative, then the template value may be negative.

Parameters
fPointer to the open FILE.
rw_flagNon-zero if function should write, otherwise function will read.
mapThe map value for this template item.
template_valuePointer to the template value to be written, or pointer to the storage that gets the templage value read.
Returns
  • :: G2C_NOERROR No error.
  • :: G2C_EINVAL Invalid input.
  • :: G2C_EFILE Error reading/writing file.
Author
Ed Hartnett 11/7/22

Definition at line 408 of file g2cio.c.

References FOUR_BYTES, G2C_EBADTEMPLATE, g2c_file_io_byte(), g2c_file_io_int(), g2c_file_io_short(), g2c_file_io_ubyte(), g2c_file_io_uint(), g2c_file_io_ushort(), G2C_NOERROR, ONE_BYTE, and TWO_BYTES.

Referenced by g2c_rw_section3_metadata(), g2c_rw_section4_metadata(), and g2c_rw_section5_metadata().

◆ g2c_file_io_ubyte()

int g2c_file_io_ubyte ( FILE *  f,
int  write,
unsigned char *  var 
)

Read or write a big-endian unsigned byte to an open GRIB2 file, with conversion between native and big-endian format.

Parameters
fPointer to the open GRIB2 FILE.
writeNon-zero to write, zero to read.
varPointer to the unsigned byte.
Returns
  • :: G2C_NOERROR No error.
  • :: G2C_EINVAL Invalid input.
  • :: G2C_EFILE Error reading/writing file.
Author
Ed Hartnett 11/13/22

Definition at line 337 of file g2cio.c.

References g2c_file_io(), and G2C_UBYTE.

Referenced by g2c_file_io_template(), g2c_open_index(), g2c_rw_section1_metadata(), g2c_rw_section3_metadata(), g2c_rw_section6_metadata(), g2c_start_index1_record(), g2c_start_index_record(), g2c_start_index_record_lf(), g2c_write_index(), and read_msg_metadata().

◆ g2c_file_io_uint()

int g2c_file_io_uint ( FILE *  f,
int  write,
unsigned int *  var 
)

Read or write a big-endian 4-byte unsigned int to an open GRIB2 file, with conversion between native and big-endian format.

Parameters
fPointer to the open GRIB2 FILE.
writeNon-zero to write, zero to read.
varPointer to the unsigned int.
Returns
  • :: G2C_NOERROR No error.
  • :: G2C_EINVAL Invalid input.
  • :: G2C_EFILE Error reading/writing file.
Author
Ed Hartnett 11/7/22

Definition at line 251 of file g2cio.c.

References g2c_file_io(), and G2C_UINT.

Referenced by g2c_file_io_template(), g2c_open_index(), g2c_rw_section1_metadata(), g2c_rw_section3_metadata(), g2c_rw_section5_metadata(), g2c_start_index1_record(), g2c_start_index_record(), g2c_start_index_record_lf(), g2c_write_index(), and read_msg_metadata().

◆ g2c_file_io_ulonglong()

int g2c_file_io_ulonglong ( FILE *  f,
int  write,
unsigned long long *  var 
)

Read or write a big-endian unsigned long long to an open GRIB2 file, with conversion between native and big-endian format.

Parameters
fPointer to the open GRIB2 FILE.
writeNon-zero to write, zero to read.
varPointer to the unsigned long long.
Returns
  • :: G2C_NOERROR No error.
  • :: G2C_EINVAL Invalid input.
  • :: G2C_EFILE Error reading/writing file.
Author
Ed Hartnett 11/13/22

Definition at line 380 of file g2cio.c.

References g2c_file_io(), and G2C_UINT64.

Referenced by g2c_start_index_record(), and g2c_start_index_record_lf().

◆ g2c_file_io_ushort()

int g2c_file_io_ushort ( FILE *  f,
int  write,
unsigned short *  var 
)

Read or write a big-endian unsigned short to an open GRIB2 file, with conversion between native and big-endian format.

Parameters
fPointer to the open GRIB2 FILE.
writeNon-zero to write, zero to read.
varPointer to the unsigned short.
Returns
  • :: G2C_NOERROR No error.
  • :: G2C_EINVAL Invalid input.
  • :: G2C_EFILE Error reading/writing file.
Author
Ed Hartnett 11/13/22

Definition at line 294 of file g2cio.c.

References g2c_file_io(), and G2C_USHORT.

Referenced by g2c_file_io_template(), g2c_rw_section3_metadata(), g2c_rw_section4_metadata(), and g2c_rw_section5_metadata().

◆ g2c_get_datetime()

int g2c_get_datetime ( int  ipdtn,
long long int *  ipdtmpl,
short  year,
unsigned char  month,
unsigned char  day,
unsigned char  hour,
unsigned char  minute,
unsigned char  second,
char *  tabbrev 
)

Convert date and time from GRIB2 info to string output.

Note
This function is based on the prvtime() function in NCEPLIBS-grib_utils.
Parameters
[in]ipdtnProduct Definition Template Number ([Code Table 4.0] (https://www.nco.ncep.noaa.gov/pmb/docs/grib2/grib2_doc/grib2_table4-0.shtml)).
ipdtmplArray of data values for the Product Definition Template specified by ipdtn.
yearyear
monthmonth
dayday
hourhour
minuteminute
secondsecond
tabbrevCharacter array that will get the date and time string. Must be of length 100.
Returns
Author
Ed Hartnett
Date
Sep 28, 2022

Definition at line 49 of file g2cdegrib2.c.

References G2C_DATE_TIME_LEN, and G2C_NOERROR.

Referenced by g2c_degrib2().

◆ g2c_get_level_desc()

int g2c_get_level_desc ( int  ipdtn,
long long int *  ipdtmpl,
char *  level_desc 
)

Determine the string that describes the level information, given the GRIB2 Product Definition Template information.

This subroutine finds the "Type of first fixed surface" (see [Code table 4.5](https://www.nco.ncep.noaa.gov/pmb/docs/grib2/grib2_doc/grib2_temp4-0.shtml)) using the product definition template value and product template array. The location in the template array varies depending on the template number.

Parameters
ipdtnProduct Definition Template Number ([Code Table 4.0] (https://www.nco.ncep.noaa.gov/pmb/docs/grib2/grib2_doc/grib2_table4-0.shtml)).
ipdtmplArray of data values for the Product Definition Template specified by ipdtn.
level_descCharacter array which gets the string describing the level. Must be of length 40.
Returns
Author
Ed Hartnett
Date
Sep 28, 2022

Definition at line 309 of file g2cdegrib2.c.

References format_level(), and G2C_NOERROR.

Referenced by g2c_degrib2().

◆ g2c_log_section1()

◆ g2c_rw_section1_metadata()

int g2c_rw_section1_metadata ( FILE *  f,
int  rw_flag,
G2C_MESSAGE_INFO_T msg 
)

Read Section 1.

Parameters
fPointer to open file.
rw_flagG2C_FILE_WRITE if function should write, G2C_FILE_READ if it should read.
msgPointer to G2C_MESSAGE_INFO_T which will be populated with the values of section 0.
Returns
-G2C_NOERROR No error.
Author
Ed Hartnett
Date
10/16/22

Definition at line 874 of file g2cfile.c.

References g2c_message_info::center, g2c_message_info::day, G2C_ENOSECTION, g2c_file_io_short(), g2c_file_io_ubyte(), g2c_file_io_uint(), G2C_NOERROR, G2C_SECTION1_BYTES, g2c_message_info::hour, g2c_message_info::local_version, LOG, g2c_message_info::master_version, g2c_message_info::minute, g2c_message_info::month, g2c_message_info::sec1_len, g2c_message_info::second, g2c_message_info::sig_ref_time, g2c_message_info::status, g2c_message_info::subcenter, g2c_message_info::type, and g2c_message_info::year.

Referenced by g2c_open_index(), g2c_write_index(), and read_msg_metadata().

◆ g2c_rw_section3_metadata()

int g2c_rw_section3_metadata ( FILE *  f,
int  rw_flag,
G2C_SECTION_INFO_T sec 
)

Read the metadata from section 3 (Grid Definition Section) of a GRIB2 message.

When this function is called, the file cursor is positioned just after the section number field in the section. The size of the section, and the section number, have already been read when this function is called.

Parameters
fFILE pointer to open GRIB2 file.
rw_flagG2C_FILE_WRITE if function should write, G2C_FILE_READ (0) if it should read.
secPointer to the G2C_SECTION_INFO_T struct.
Returns
Author
Ed Hartnett
Date
Sep 15, 2022

Definition at line 478 of file g2cfile.c.

References determine_dims(), G2C_EINVAL, G2C_ENOMEM, g2c_file_io_template(), g2c_file_io_ubyte(), g2c_file_io_uint(), g2c_file_io_ushort(), g2c_get_grid_template(), G2C_MAX_GDS_TEMPLATE_MAPLEN, G2C_NOERROR, g2c_section3_info::grid_def, g2c_section3_info::interp_list, LOG, g2c_section3_info::num_data_points, g2c_section3_info::num_opt, g2c_section_info::sec_info, g2c_section_info::sec_num, g2c_section3_info::source_grid_def, g2c_section_info::template, and g2c_section_info::template_len.

Referenced by add_section(), and g2c_write_index().

◆ g2c_rw_section4_metadata()

int g2c_rw_section4_metadata ( FILE *  f,
int  rw_flag,
G2C_SECTION_INFO_T sec 
)

Read or write the metadata from section 4 (Product Definition Section) of a GRIB2 message.

When this function is called, the file cursor is positioned just after the section number field in the section. The size of the section, and the section number, have already been read/written when this function is called.

Parameters
fFILE pointer to open GRIB2 file.
rw_flagG2C_FILE_WRITE if function should write, G2C_FILE_READ if it should read.
secPointer to the G2C_SECTION_INFO_T struct.
Returns
Author
Ed Hartnett
Date
Sep 16, 2022

Definition at line 574 of file g2cfile.c.

References G2C_EINVAL, G2C_ENOMEM, g2c_file_io_template(), g2c_file_io_ushort(), g2c_get_pds_template(), G2C_MAX_PDS_TEMPLATE_MAPLEN, G2C_NOERROR, LOG, g2c_section_info::msg, g2c_section4_info::num_coord, g2c_message_info::num_fields, g2c_section4_info::prod_def, g2c_section_info::sec_info, g2c_section_info::sec_num, g2c_section_info::template, and g2c_section_info::template_len.

Referenced by add_section(), and g2c_write_index().

◆ g2c_rw_section5_metadata()

int g2c_rw_section5_metadata ( FILE *  f,
int  rw_flag,
G2C_SECTION_INFO_T sec 
)

Read or write the metadata from section 5 (Data Representation Section) of a GRIB2 message.

When this function is called, the file cursor is positioned just after the section number field in the section. The size of the section, and the section number, have already been read when this function is called.

Parameters
fFILE pointer to open GRIB2 file.
rw_flagG2C_FILE_WRITE if function should write, G2C_FILE_READ if it should read.
secPointer to the G2C_SECTION_INFO_T struct.
Returns
Author
Ed Hartnett
Date
Sep 16, 2022

Definition at line 663 of file g2cfile.c.

References g2c_section5_info::data_def, G2C_EINVAL, G2C_ENOMEM, g2c_file_io_template(), g2c_file_io_uint(), g2c_file_io_ushort(), g2c_get_drs_template(), G2C_MAX_PDS_TEMPLATE_MAPLEN, G2C_NOERROR, LOG, g2c_section5_info::num_data_points, g2c_section_info::sec_info, g2c_section_info::template, and g2c_section_info::template_len.

Referenced by add_section(), and g2c_write_index().

◆ g2c_rw_section6_metadata()

int g2c_rw_section6_metadata ( FILE *  f,
int  rw_flag,
G2C_SECTION_INFO_T sec 
)

Read or write the metadata from section 6 (Data Representation Section) of a GRIB2 message.

When this function is called, the file cursor is positioned just after the section number field in the section. The size of the section, and the section number, have already been read when this function is called.

Parameters
fFILE pointer to open GRIB2 file.
rw_flagG2C_FILE_WRITE if function should write, G2C_FILE_READ if it should read.
secPointer to the G2C_SECTION_INFO_T struct.
Returns
Author
Ed Hartnett
Date
Sep 16, 2022

Definition at line 745 of file g2cfile.c.

References G2C_EINVAL, G2C_ENOMEM, g2c_file_io_ubyte(), G2C_NOERROR, g2c_section6_info::indicator, LOG, and g2c_section_info::sec_info.

Referenced by add_section().

◆ gbit()

void gbit ( unsigned char *  in,
g2int iout,
g2int  iskip,
g2int  nbits 
)

Get arbitrary size values from a packed bit string, right justifying each value in the unpacked iout array.

Parameters
inpointer to character array input.
ioutpointer that gets the unpacked array output.
iskipinitial number of bits to skip.
nbitsnumber of bits to take.
Author
NOAA Programmer

Definition at line 20 of file gbits.c.

References gbits().

Referenced by comunpack(), g2_addfield(), g2_addgrid(), g2_addlocal(), g2_getfld(), g2_gribend(), g2_info(), g2_unpack1(), g2_unpack2(), g2_unpack3(), g2_unpack4(), g2_unpack5(), g2_unpack6(), g2c_check_msg(), g2c_unpack7_int(), and seekgb().

◆ gbits()

void gbits ( unsigned char *  in,
g2int iout,
g2int  iskip,
g2int  nbits,
g2int  nskip,
g2int  n 
)

Unpack arbitrary size values from a packed bit string, right justifying each value in the unpacked iout array.

Parameters
inPointer to character array input.
ioutPointer that gets the unpacked array output.
iskipInitial number of bits to skip.
nbitsNumber of bits to take.
nskipAdditional number of bits to skip on each iteration.
nNumber of iterations.
Author
NOAA Programmer

Definition at line 57 of file gbits.c.

Referenced by aecunpack_int(), comunpack(), g2_unpack3(), g2_unpack4(), g2_unpack6(), g2c_gbits_int(), gbit(), pngunpack_int(), simunpack(), and specunpack().

◆ getdim()

g2int getdim ( unsigned char *  csec3,
g2int width,
g2int height,
g2int iscan 
)

Return the dimensions and scanning mode of a grid definition.

Parameters
csec3Character array that contains the packed GRIB2 GDS.
widthx (or i) dimension of the grid. 0 if grid is not recognized.
heighty (or j) dimension of the grid. 0 if grid is not recognized.
iscanScanning mode (see Table 3.4). 0 of grid not recognized.
Returns
Always returns 0.
Author
Stephen Gilbert
Date
2002-12-11

Definition at line 27 of file getdim.c.

References g2_unpack3().

Referenced by g2_addfield().

◆ getdrstemplate()

gtemplate * getdrstemplate ( g2int  number)

This subroutine returns DRS template information for a specified Data Representation Template.

The number of entries in the template is returned along with a map of the number of octets occupied by each entry. Also, a flag is returned to indicate whether the template would need to be extended.

Parameters
numberThe number of the Data Representation Template that is being requested.
Returns
Pointer to the returned template struct. Returns NULL if template not found.
Author
Stephen Gilbert
Date
2000-05-11

Definition at line 167 of file drstemplates.c.

References getdrsindex(), and templatesdrs.

Referenced by extdrstemplate(), g2_addfield(), and g2_unpack5().

◆ getgridtemplate()

gtemplate * getgridtemplate ( g2int  number)

This subroutine returns grid template information for a specified Grid Definition Template for [Section 3 - the Grid Definition Section (GDS)](https://www.nco.ncep.noaa.gov/pmb/docs/grib2/grib2_doc/grib2_sect3.shtml).

The number of entries in the template is returned along with a map of the number of octets occupied by each entry. Also, a flag is returned to indicate whether the template would need to be extended.

This function allocates storage for the template. The returned pointer must be freed by the caller.

Parameters
numberThe number of the Grid Definition Template that is being requested.
Returns
Pointer to the returned template struct (must be freed by caller). Returns NULL pointer, if template not found.
Author
Stephen Gilbert
Date
2000-05-09

Definition at line 177 of file gridtemplates.c.

References getgridindex(), and templatesgrid.

Referenced by extgridtemplate(), g2_addgrid(), and g2_unpack3().

◆ getpdstemplate()

gtemplate * getpdstemplate ( g2int  number)

This subroutine returns PDS template information for a specified Product Definition Template.

The number of entries in the template is returned along with a map of the number of octets occupied by each entry. Also, a flag is returned to indicate whether the template would need to be extended.

This function allocates memory for the gtemplate struct, which must be freed by the caller.

Parameters
numberthe number of the Product Definition Template that is being requested.
Returns
Pointer to the returned template struct. Returns NULL pointer if template not found.
Author
Stephen Gilbert
Date
2000-05-11

Definition at line 277 of file pdstemplates.c.

References getpdsindex(), and templatespds.

Referenced by extpdstemplate(), g2_addfield(), and g2_unpack4().

◆ getpoly()

g2int getpoly ( unsigned char *  csec3,
g2int jj,
g2int kk,
g2int mm 
)

This subroutine returns the J, K, and M pentagonal resolution parameters specified in a GRIB Grid Definition Section (GDS) used spherical harmonic coefficients using GDT 5.50 through 5.53.

If 51 - complex data spectral packing is used as the data representation template number (see Table 5.0), then the Grid Definition Template Number in section 3 should be one of:

  • 50: Spherical Harmonic Coefficients (See Template 3.50)
  • 51: Rotated Spherical Harmonic Coefficients (See Template 3.51)
  • 52: Stretched Spherical Harmonic Coefficients (See Template 3.52)
  • 53: Rotated and Stretched Spherical Harmonic Coefficients (See Template 3.53)
Parameters
csec3Character array that contains the packed GRIB2 GDS.
jjJ pentagonal resolution parameter.
kkK pentagonal resolution parameter.
mmM pentagonal resolution parameter.
Returns
always returns 0.
Note
Returns jj, kk, and mm set to zero, if grid template not recognized.
Author
Stephen Gilbert
Date
2002-12-11

Definition at line 40 of file getpoly.c.

References g2_unpack3().

Referenced by g2_addfield().

◆ int_power()

double int_power ( double  x,
g2int  y 
)

Function similar to C pow() power function.

Parameters
xThe base value whose power is to be calculated.
yThe power value.
Returns
x**y
Author
Wesley Ebisuzaki

Definition at line 18 of file int_power.c.

Referenced by aecpack_int(), aecunpack_int(), compack(), comunpack(), jpcpack_int(), jpcunpack_int(), misspack(), mkieee(), pngpack_int(), pngunpack_int(), rdieee(), simpack(), simunpack(), and specunpack().

◆ jpcpack()

void jpcpack ( float *  fld,
g2int  width,
g2int  height,
g2int idrstmpl,
unsigned char *  cpack,
g2int lcpack 
)

This function packs up a float array into a JPEG2000 code stream.

After the data are scaled, and the reference value is subtracted out, the data are treated as a grayscale image and passed to a JPEG2000 encoder.

This function also fills in GRIB2 Data Representation Template 5.40 or 5.40000 with the appropriate values.

Parameters
fldPointer to the float data values to pack.
widthThe number of points in the x direction.
heightThe number of points in the y direction.
idrstmplContains the array of values for Data Representation Template Table 5.40 or 5.40000.
  • 0 Reference value - ignored on input, set by jpcpack routine.
  • 1 Binary Scale Factor - used on input, unchanged by jpcpack routine.
  • 2 Decimal Scale Factor - used on input, unchanged by jpcpack routine.
  • 3 number of bits for each data value - ignored on input
  • 4 Original field type - currently ignored on input Data values assumed to be reals. Set to 0 on output.
  • 5 if 0 use lossless compression, if 1 use lossy compression.
  • 6 Desired compression ratio, if idrstmpl[5]=1. Set to 255, if idrstmpl[5]=0. May be modified in this function.
cpackA pointer that will get the packed data field. Must be allocated before this function is called. Pass the allocated size in the lcpack parameter.
lcpackPointer that gets the length of packed field in cpack. This must be set by the calling function to the size available in cpack.
Author
Stephen Gilbert, Ed Hartnett

Definition at line 269 of file jpcpack.c.

References jpcpack_int().

Referenced by g2_addfield().

◆ jpcunpack()

g2int jpcunpack ( unsigned char *  cpack,
g2int  len,
g2int idrstmpl,
g2int  ndpts,
float *  fld 
)

Unpack JPEG2000 compressed data into an array of floats, using info from the GRIB2 Data Representation Template 5.40 or 5.40000.

Parameters
cpackThe packed data.
lenThe length of the packed data.
idrstmplPointer to array of values for Data Representation Template 5.40 or 5.40000.
ndptsThe number of data values to unpack.
fldA pointer that gets the unpacked data values as an array of float.
Returns
Author
Stephem Gilbert
Date
2003-08-27

Definition at line 123 of file jpcunpack.c.

References G2_JPCUNPACK_MEM, jpcunpack_int(), and LOG.

Referenced by g2c_unpack7_int().

◆ misspack()

void misspack ( float *  fld,
g2int  ndpts,
g2int  idrsnum,
g2int idrstmpl,
unsigned char *  cpack,
g2int lcpack 
)

Pack a data field using a complex packing algorithm.

This funciton supports GRIB2 complex packing templates with or without spatial differences (See Template 5.2 and Template 5.3).

This function fills in GRIB2 Data Representation template arrays with the appropriate values.

Parameters
fldContains the data values to pack
ndptsThe number of data values in array fld
idrsnumData Representation Template number. Must equal 2 or 3.
idrstmplContains the array of values for Data Representation Template 5.2 or 5.3.
  • 0 Reference value - ignored on input, set by misspack routine.
  • 1 Binary Scale Factor - used on input.
  • 2 Decimal Scale Factor- used on input.
  • 6 Missing value management.
  • 7 Primary missing value.
  • 8 Secondary missing value.
  • 16 Order of Spatial Differencing (1 or 2).
cpackThe packed data field (character*1 array).
lcpacklength of packed field cpack.
Author
Stephen Gilbert
Date
2000-06-21

Definition at line 43 of file misspack.c.

References ALOG2, int_power(), mkieee(), pack_gp(), rdieee(), sbit(), and sbits().

Referenced by cmplxpack().

◆ mkieee()

void mkieee ( float *  a,
g2int rieee,
g2int  num 
)

Store a list of real values in 32-bit IEEE floating point format.

Parameters
aInput array of floating point values.
numNumber of floating point values to convert.
rieeeOutput array of data values in 32-bit IEEE format stored in g2int integer array. rieee must be allocated with at least 4*num bytes of memory before calling this function.
Author
Stephen Gilbert
Date
2002-10-29

Definition at line 22 of file mkieee.c.

References int_power().

Referenced by aecpack_int(), compack(), g2_addfield(), jpcpack_int(), misspack(), pngpack_int(), simpack(), and specpack().

◆ pack_gp()

int pack_gp ( g2int kfildo,
g2int ic,
g2int nxy,
g2int is523,
g2int minpk,
g2int inc,
g2int missp,
g2int misss,
g2int jmin,
g2int jmax,
g2int lbit,
g2int nov,
g2int ndg,
g2int lx,
g2int ibit,
g2int jbit,
g2int kbit,
g2int novref,
g2int lbitref,
g2int ier 
)

Determines groups of variable size, but at least of size minpk, the associated max (jmax( )) and min (jmin( )), the number of bits necessary to hold the values in each group (lbit( )), the number of values in each group (nov( )), the number of bits necessary to pack the jmin( ) values (ibit), the number of bits necessary to pack the lbit( ) values (jbit), and the number of bits necessary to pack the nov( ) values (kbit).

The routine is designed to determine the groups such that a small number of bits is necessary to pack the data without excessive computations. If all values in the group are zero, the number of bits to use in packing is defined as zero when there can be no missing values; when there can be missing values, the number of bits must be at least 1 to have the capability to recognize the missing value. However, if all values in a group are missing, the number of bits needed is 0, and the unpacker recognizes this. All variables are g2int. Even though the groups are initially of size minpk or larger, an adjustment between two groups (the lookback procedure) may make a group smaller than minpk. The control on group size is that the sum of the sizes of the two consecutive groups, each of size minpk or larger, is not decreased. When determining the number of bits necessary for packing, the largest value that can be accommodated in, say, mbits, is 2**mbits-1; this largest value (and the next smallest value) is reserved for the missing value indicator (only) when is523 ne 0. If the dimension ndg is not large enough to hold all the groups, the local value of minpk is increased by 50 percent. This is repeated until ndg will suffice. A diagnostic is printed whenever this happens, which should be very rarely. If it happens often, ndg in subroutine pack should be increased and a corresponding increase in subroutine unpack made. Considerable code is provided so that no more checking for missing values within loops is done than necessary; the added efficiency of this is relatively minor, but does no harm. For grib2, the reference value for the length of groups in nov( ) and for the number of bits necessary to pack group values are determined, and subtracted before jbit and kbit are determined.

When 1 or more groups are large compared to the others, the width of all groups must be as large as the largest. A subroutine reduce breaks up large groups into 2 or more to reduce total bits required. If reduce should abort, pack_gp will be executed again without the call to reduce.

PROGRAM HISTORY LOG:

  • February 1994 Glahn tdl mos-2000
  • June 1995 Glahn modified for lmiss error.
  • July 1996 Glahn added misss
  • February 1997 Glahn removed 4 redundant tests for missp.eq.0; inserted a test to better handle a string of 9999's
  • February 1997 Glahn added loops to eliminate test for misss when misss = 0
  • March 1997 Glahn corrected for secondary missing value
  • March 1997 Glahn corrected for use of local value of minpk
  • March 1997 Glahn corrected for secondary missing value
  • March 1997 Glahn changed calculating number of bits through exponents to an array (improved overall packing performance by about 35 percent!). allowed 0 bits for packing jmin( ), lbit( ), and nov( ).
  • May 1997 Glahn a number of changes for efficiency. mod functions eliminated and one ifthen added. jount removed. recomputation of bits not made unless necessary after moving points from one group to another. nendb adjusted to eliminate possibility of very small group at the end. about 8 percent improvement in overall packing. iskipa removed; there is always a group b that can become group a. control on size of group b (statement below 150) added. added adda, and use of ge and le instead of gt and lt in loops between 150 and 160. ibitbs added to shorten trips through loop.
  • March 2000 Glahn modified for grib2; changed name from packgp
  • january 2001 Glahn comments; ier = 706 substituted for stops; added return1; removed statement number 110; added ier and * return
  • November 2001 Glahn changed some diagnostic formats to allow printing larger numbers
  • November 2001 Glahn added misslx( ) to put maximum value into jmin( ) when all values missing to agree with grib standard.
  • November 2001 Glahn changed two tests on missp and misss eq 0 to tests on is523. however, missp and misss cannot in general be = 0.
  • November 2001 Glahn added call to reduce; defined itest before loops to reduce computation; started large group when all same value
  • December 2001 Glahn modified and added a few comments
  • January 2002 Glahn removed loop before 150 to determine a group of all same value
  • January 2002 Glahn changed mallow from 9999999 to 2**30+1, and made it a parameter
  • March 2002 Glahn added non fatal ier = 716, 717; removed nendb=nxy above 150; added iersav=0; comments

DATA SET USE

  • kfildo - unit number for output (print) file. (output)
Parameters
kfildounit number for output (print) file. (input)
icarray to hold data for packing. the values do not have to be positive at this point, but must be in the range -2**30 to +2**30 (the the value of mallow). these g2int values will be retained exactly through packing and unpacking. (input)
nxynumber of values in ic( ). also treated as its dimension. (input)
is523missing value management 0=data contains no missing values 1=data contains primary missing values 2=data contains primary and secondary missing values (input)
minpkthe minimum size of each group, except possibly the last one. (input)
incthe number of values to add to an already existing group in determining whether or not to start a new group. ideally, this would be 1, but each time inc values are attempted, the max and min of the next minpk values must be found. this is "a loop within a loop," and a slightly larger value may give about as good results with slightly less computational time. if inc is le 0, 1 is used, and a diagnostic is output. note: it is expected that inc will equal 1. the code uses inc primarily in the loops starting at statement 180. if inc were 1, there would not need to be loops as such. however, kinc (the local value of inc) is set ge 1 when near the end of the data to forestall a very small group at the end. (input)
misspwhen missing points can be present in the data, they will have the value missp or misss. missp is the primary missing value and misss is the secondary missing value . these must not be values that would occur with subtracting the minimum (reference) value or scaling. for example, missp = 0 would not be advisable. (input)
missssecondary missing value indicator (see missp). (input)
jminthe minimum of each group (j=1,lx). (output)
jmaxthe maximum of each group (j=1,lx). this is not really needed, but since the max of each group must be found, saving it here is cheap in case the user wants it. (output)
lbitthe number of bits necessary to pack each group (j=1,lx). it is assumed the minimum of each group will be removed before packing, and the values to pack will, therefore, all be positive. however, ic( ) does not necessarily contain all positive values. if the overall minimum has been removed (the usual case), then ic( ) will contain only positive values. (output)
novthe number of values in each group (j=1,lx). (output)
ndgthe dimension of jmin, jmax, lbit, and nov. (input)
lxthe number of groups determined. (output)
ibitthe number of bits necessary to pack the jmin(j) values, j=1,lx. (output)
jbitthe number of bits necessary to pack the lbit(j) values, j=1,lx. (output)
kbitthe number of bits necessary to pack the nov(j) values, j=1,lx. (output)
novrefreference value for nov( ). (output)
lbitrefreference value for lbit( ). (output)
ierError code
  • 0 No error.
  • 706 value will not pack in 30 bits–fatal
  • 714 error in reduce–non-fatal
  • 715 ngp not large enough in reduce–non-fatal
  • 716 minpk inceased–non-fatal
  • 717 inc set
  • 1–non-fatal
  • alternate return when ier ne 0 and fatal error.
Returns
0 - check ier for error code.
   INTERNAL VARIABLES
              cfeed = contains the character representation
                      of a printer form feed.
              ifeed = contains the g2int value of a printer
                      form feed.
               kinc = working copy of inc. may be modified.
               mina = minimum value in group a.
               maxa = maximum value in group a.
              nenda = the place in ic( ) where group a ends.
             kstart = the place in ic( ) where group a starts.
              ibita = number of bits needed to hold values in group a.
               minb = minimum value in group b.
               maxb = maximum value in group b.
              nendb = the place in ic( ) where group b ends.
              ibitb = number of bits needed to hold values in group b.
               minc = minimum value in group c.
               maxc = maximum value in group c.
             ktotal = count of number of values in ic( ) processed.
              nount = number of values added to group a.
              lmiss = 0 when is523 = 0. when packing into a
                      specific number of bits, say mbits,
                      the maximum value that can be handled is
                      2**mbits-1. when is523 = 1, indicating
                      primary missing values, this maximum value
                      is reserved to hold the primary missing value
                      indicator and lmiss = 1. when is523 = 2,
                      the value just below the maximum i.e.,
                      2**mbits-2 is reserved to hold the secondary
                      missing value indicator and lmiss = 2.
             lminpk = local value of minpk. this will be adjusted
                      upward whenever ndg is not large enough to hold
                      all the groups.
             mallow = the largest allowable value for packing.
             mislla = set to 1 when all values in group a are missing.
                      this is used to distinguish between a real
                      minimum when all values are not missing
                      and a minimum that has been set to zero when
                      all values are missing. 0 otherwise.
                      note that this does not distinguish between
                      primary and secondary missings when secondary
                      missings are present. this means that
                      lbit( ) will not be zero with the resulting
                      compression efficiency when secondary missings
                      are present. also note that a check has been
                      made earlier to determine that secondary
                      missings are really there.
             misllb = set to 1 when all values in group b are missing.
                      this is used to distinguish between a real
                      minimum when all values are not missing
                      and a minimum that has been set to zero when
                      all values are missing. 0 otherwise.
             misllc = performs the same function for group c that
                      mislla and misllb do for groups b and c,
                      respectively.
           ibxx2(j) = an array that when this routine is first entered
                      is set to 2**j, j=0,30. ibxx2(30) = 2**30, which
                      is the largest value packable, because 2**31
                      is larger than the g2int word size.
             ifirst = set by data statement to 0. changed to 1 on
                      first
                      entry when ibxx2( ) is filled.
              minak = keeps track of the location in ic( ) where the
                      minimum value in group a is located.
              maxak = does the same as minak, except for the maximum.
              minbk = the same as minak for group b.
              maxbk = the same as maxak for group b.
              minck = the same as minak for group c.
              maxck = the same as maxak for group c.
               adda = keeps track whether or not an attempt to add
                      points to group a was made. if so, then adda
                      keeps from trying to put one back into b.
                      (g2int)
             ibitbs = keeps current value if ibitb so that loop
                      ending at 166 doesn't have to start at
                      ibitb = 0 every time.
          misslx(j) = mallow except when a group is all one value (and
                      lbit(j) = 0) and that value is missing. in
                      that case, misslx(j) is missp or misss. this
                      gets inserted into jmin(j) later as the
                      missing indicator; it can't be put in until
                      the end, because jmin( ) is used to calculate
                      the maximum number of bits (ibits) needed to
                      pack jmin( ).

Definition at line 255 of file pack_gp.c.

References FALSE_, reduce(), and TRUE_.

Referenced by compack(), and misspack().

◆ pngpack()

void pngpack ( float *  fld,
g2int  width,
g2int  height,
g2int idrstmpl,
unsigned char *  cpack,
g2int lcpack 
)

This subroutine packs up a float data field into PNG image format.

After the data field is scaled, and the reference value is subtracted out, it is treated as a grayscale image and passed to a PNG encoder. It also fills in GRIB2 Data Representation Template 5.41 or 5.40010 with the appropriate values.

Parameters
fldPointer to array of float that contains the data values to pack.
widthNumber of points in the x direction.
heightNumber of points in the y direction.
idrstmplContains the array of values for Data Representation Template 5.41 or 5.40010.
  • 0 Reference value - ignored on input, set by pngpack routine.
  • 1 Binary Scale Factor - used on input.
  • 2 Decimal Scale Factor - used on input.
  • 3 number of bits for each grayscale pixel value - ignored on input.
  • 4 Original field type - currently ignored on input, set = 0 on output. Data values assumed to be reals.
cpackThe packed data field.
lcpacklength of packed field cpack.
Author
Stephen Gilbert
Date
2003-08-27
Author
Ed Hartnett

Definition at line 254 of file pngpack.c.

References pngpack_int().

Referenced by g2_addfield().

◆ pngunpack()

g2int pngunpack ( unsigned char *  cpack,
g2int  len,
g2int idrstmpl,
g2int  ndpts,
float *  fld 
)

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.

Parameters
cpackThe packed data field (character*1 array).
lenlength of packed field cpack().
idrstmplPointer to array of values for Data Representation Template 5.41 or 5.40010.
ndptsThe number of data values to unpack.
fldContains the unpacked data values.
Returns
Author
Stephen Gilbert
Date
2003-08-27
Author
Ed Hartnett

Definition at line 126 of file pngunpack.c.

References G2_JPCUNPACK_MEM, G2C_ENOMEM, and pngunpack_int().

Referenced by g2c_unpack7_int().

◆ rdieee()

void rdieee ( g2int rieee,
float *  a,
g2int  num 
)

Read a list of real values in 32-bit IEEE floating point format.

Parameters
rieeeg2int array of floating point values in 32-bit IEEE format.
numNumber of floating point values to convert.
afloat array of real values. a must be allocated with at least 4*num bytes of memory before calling this function.
Author
Stephen Gilbert
Date
2002-10-25

Definition at line 20 of file rdieee.c.

References int_power().

Referenced by aecunpack_int(), comunpack(), g2_miss(), g2_unpack4(), g2c_unpack7_int(), jpcunpack_int(), misspack(), pngunpack_int(), simunpack(), and specunpack().

◆ sbit()

void sbit ( unsigned char *  out,
g2int in,
g2int  iskip,
g2int  nbits 
)

Store arbitrary size values into a packed bit string, taking the low order bits from each value in the unpacked array.

Parameters
outPointer to packed array output. Must be allocated large enough to hold output.
inPointer that gets the unpacked array input.
iskipInitial number of bits to skip.
nbitsNumber of bits to pack.
Author
NOAA Programmer

Definition at line 38 of file gbits.c.

References sbits().

Referenced by compack(), g2_addfield(), g2_addgrid(), g2_addlocal(), g2_create(), g2_gribend(), misspack(), and simpack().

◆ sbits()

void sbits ( unsigned char *  out,
g2int in,
g2int  iskip,
g2int  nbits,
g2int  nskip,
g2int  n 
)

Store arbitrary size values into a packed bit string, taking the low order bits from each value in the unpacked array.

Parameters
outPointer to packed array output. Must be allocated large enough to hold output.
inPointer that gets the unpacked array input.
iskipInitial number of bits to skip.
nbitsNumber of bits to pack.
nskipAdditional number of bits to skip on each iteration.
nNumber of iterations.
Author
NOAA Programmer

Definition at line 178 of file gbits.c.

Referenced by aecpack_int(), compack(), g2_addfield(), g2_addgrid(), jpcpack_int(), misspack(), pngpack_int(), sbit(), and simpack().

◆ simpack()

void simpack ( float *  fld,
g2int  ndpts,
g2int idrstmpl,
unsigned char *  cpack,
g2int lcpack 
)

Packs a data field using the simple packing algorithm.

This function also fills in GRIB2 Data Representation Template 5.0 with the appropriate values.

Parameters
fldContains the data values to pack.
ndptsThe number of data values in array fld.
idrstmplContains the array of values for [Data Representation Template 5.0](https://www.nco.ncep.noaa.gov/pmb/docs/grib2/grib2_doc/grib2_temp5-0.shtml).
  • 0 Reference value - ignored on input - set by simpack routine.
  • 1 Binary Scale Factor - unchanged from input.
  • 2 Decimal Scale Factor - unchanged from input.
  • 3 Number of bits used to pack data, if value is > 0 and <= 31. If this input value is 0 or outside above range then the num of bits is calculated based on given data and scale factors.
  • 4 Original field type - currently ignored on input. Data values assumed to be reals. Set to 0 by simpack routine.
cpackThe packed data field
lcpacklength of packed field starting at cpack.
Author
Stephen Gilbert
Date
2002-11-06

Definition at line 36 of file simpack.c.

References ALOG2, int_power(), LOG, mkieee(), sbit(), and sbits().

Referenced by g2_addfield(), and specpack().

◆ simunpack()

g2int simunpack ( unsigned char *  cpack,
g2int idrstmpl,
g2int  ndpts,
float *  fld 
)

Unpack a data field that was packed using a simple packing algorithm, using info from the GRIB2 Data Representation Template 5.0.

Parameters
cpackpointer to the packed data field.
idrstmplpointer to the array of values for Data Representation Template 5.0.
ndptsThe number of data values to unpack.
fldA pointer that gets the unpacked data values. fld must be `* allocated with at least ndpts * sizeof(float) bytes before calling this routine.
Returns
0 for success, error code otherwise.
Author
Stephen Gilbert
Date
2002-10-29

Definition at line 28 of file simunpack.c.

References G2_JPCUNPACK_MEM, G2_NO_ERROR, gbits(), int_power(), LOG, and rdieee().

Referenced by g2c_unpack7_int().

◆ specpack()

void specpack ( float *  fld,
g2int  ndpts,
g2int  JJ,
g2int  KK,
g2int  MM,
g2int idrstmpl,
unsigned char *  cpack,
g2int lcpack 
)

Pack a spectral data field using the complex packing algorithm for spherical harmonic data as defined in the GRIB2 Data Representation Template 5.51.

Parameters
fldContains the data values to be packed.
ndptsThe number of data values to pack.
JJJ - pentagonal resolution parameter.
KKK - pentagonal resolution parameter.
MMM - pentagonal resolution parameter.
idrstmplContains the array of 10 values for [Data Representation Template 5.51](https://www.nco.ncep.noaa.gov/pmb/docs/grib2/grib2_doc/grib2_temp5-51.shtml).
cpackPointer that gets the packed data field. Must be allocated by caller.
lcpacklength of packed field cpack.
Author
Stephen Gilbert
Date
2002-12-19

Definition at line 33 of file specpack.c.

References mkieee(), and simpack().

Referenced by g2_addfield().

◆ specunpack()

g2int specunpack ( unsigned char *  cpack,
g2int idrstmpl,
g2int  ndpts,
g2int  JJ,
g2int  KK,
g2int  MM,
float *  fld 
)

Unpack 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.

Parameters
cpackpointer to the packed data field.
idrstmplpointer to the array of values for Data Representation Template 5.51.
ndptsThe number of data values to unpack (real and imaginary parts).
JJpentagonal resolution parameter.
KKpentagonal resolution parameter.
MMpentagonal resolution parameter.
fldContains the unpacked data values. fld must be allocated with at least ndpts * sizeof(float) bytes before calling this routine.
Returns
0 for success, -3 for wrong type.
Author
Stephen Gilbert
Date
2000-06-21

Definition at line 35 of file specunpack.c.

References G2_NO_ERROR, G2_SPECUNPACK_TYPE, gbits(), int_power(), and rdieee().

Referenced by g2c_unpack7_int().