NCEPLIBS-g2c
1.8.0
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File functions for the g2c library. More...
#include "grib2_int.h"
Go to the source code of this file.
Macros | |
#define | BYTES_TO_DISCIPLINE 6 |
Number of bytes to discipline field in GRIB2 message. More... | |
#define | G2C_SEEKMSG_BUFSIZE 4092 |
Size of buffer used in g2c_seekmsg(). More... | |
#define | MIN(a, b) ((a) < (b) ? (a) : (b)) |
Find a minimum. More... | |
#define | READ_BUF_SIZE 4092 |
Default size of read-buffer. More... | |
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. More... | |
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. More... | |
static int | determine_dims (G2C_SECTION_INFO_T *sec) |
Determine the dimension information from the section 3 metadata. More... | |
static int | find_available_g2cid (int *g2cid) |
Find a g2cid to use for a newly opened or created file. More... | |
static int | free_metadata (int g2cid) |
Free resources holding the file metadata. More... | |
int | g2c_add_file (const char *path, int mode, int *g2cid) |
Open a GRIB2 file and add it to the list of open files. More... | |
int | g2c_close (int g2cid) |
Close a GRIB2 file, freeing resources. More... | |
int | g2c_find_msg2 (int g2cid, size_t skip_bytes, size_t max_bytes, size_t *bytes_to_msg, size_t *bytes_in_msg) |
Search a file for the next GRIB1 or GRIB2 message. More... | |
int | g2c_get_msg (int g2cid, size_t skip_bytes, size_t max_bytes, size_t *bytes_to_msg, size_t *bytes_in_msg, unsigned char **cbuf) |
Search a file for the next GRIB1 or GRIB2 message, and read it, allocating space in memory to hold the message. More... | |
int | g2c_open (const char *path, int mode, int *g2cid) |
Open an existing GRIB2 file. More... | |
int | g2c_rw_section1_metadata (FILE *f, int rw_flag, G2C_MESSAGE_INFO_T *msg) |
Read Section 1. More... | |
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. More... | |
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. More... | |
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. More... | |
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. More... | |
int | g2c_seekmsg (int g2cid, size_t skip, size_t *offset, size_t *msglen) |
Search a file for the next GRIB2 Message. More... | |
MUTEX (m) | |
Define mutex for thread-safety. More... | |
static int | read_metadata (int g2cid) |
Read metadata from a GRIB2 file being opened with g2c_open(). More... | |
static int | read_msg_metadata (G2C_MESSAGE_INFO_T *msg) |
Read the file to get metadata about a message. More... | |
Variables | |
G2C_FILE_INFO_T | g2c_file [G2C_MAX_FILES+1] |
Global file information. More... | |
int | g2c_next_g2cid = 1 |
Next g2cid file ID - used when opening or creating a file. More... | |
#define BYTES_TO_DISCIPLINE 6 |
#define G2C_SEEKMSG_BUFSIZE 4092 |
Size of buffer used in g2c_seekmsg().
#define MIN | ( | a, | |
b | |||
) | ((a) < (b) ? (a) : (b)) |
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.
file | Pointer to the G2C_FILE_INFO_T for this file. |
msg_num | Number of the message in file (0-based). |
bytes_to_msg | Number of bytes to the start of the message in the file. |
bytes_in_msg | Length of message in bytes. |
read_file | Set to true to cause metadata to be read from a GRIB2 data file. |
msg | Pointer to a pointer that will get the location of the newly created G2C_MESSAGE_INFO_T object. Ignored if NULL. |
Definition at line 1020 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().
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.
f | FILE pointer to open GRIB2 file. |
msg | Pointer to the G2C_MESSAGE_INFO_T struct. |
sec_id | 0-based section ID. |
sec_len | Length of section. |
bytes_to_sec | Number of bytes from start of message to this section. |
sec_num | Section number. |
Definition at line 797 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().
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Determine the dimension information from the section 3 metadata.
See (GRIB2 - SECTION 3 GRID DEFINITION SECTION)[https://www.nco.ncep.noaa.gov/pmb/docs/grib2/grib2_doc/grib2_sect3.shtml].
For a list of grid definitions see [GRIB2 - TABLE 3.1 Grid Definition Template Number](https://www.nco.ncep.noaa.gov/pmb/docs/grib2/grib2_doc/grib2_table3-1.shtml).
sec | G2C_SECTION3_INFO_T struct. |
Definition at line 418 of file g2cfile.c.
References g2c_section3_info::dim, G2C_ENOMEM, G2C_MAX_NAME, G2C_NOERROR, g2c_section3_info::grid_def, LATITUDE, g2c_dim_info::len, LOG, LONGITUDE, g2c_dim_info::name, g2c_section_info::sec_info, g2c_section_info::template, and g2c_dim_info::value.
Referenced by g2c_rw_section3_metadata().
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Find a g2cid to use for a newly opened or created file.
g2cid | Pointer that gets the next available g2cid. |
Definition at line 365 of file g2cfile.c.
References G2C_EINVAL, G2C_ETOOMANYFILES, g2c_file, G2C_MAX_FILES, g2c_next_g2cid, and G2C_NOERROR.
Referenced by g2c_add_file().
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Free resources holding the file metadata.
g2cid | Indentifier for the file. |
Definition at line 1294 of file g2cfile.c.
References G2C_EBADID, g2c_file, G2C_MAX_FILES, G2C_NOERROR, LOG, g2c_file_info::msg, g2c_message_info::next, g2c_section_info::next, g2c_message_info::sec, g2c_section_info::sec_info, g2c_section_info::sec_num, and g2c_section_info::template.
Referenced by g2c_close().
int g2c_add_file | ( | const char * | path, |
int | mode, | ||
int * | g2cid | ||
) |
Open a GRIB2 file and add it to the list of open files.
path | Path of the file. |
mode | Open mode flags. |
g2cid | Pointer that gets an indentifier for the file. |
Definition at line 1146 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().
int g2c_close | ( | int | g2cid | ) |
Close a GRIB2 file, freeing resources.
g2cid | Indentifier for the file. |
Definition at line 1357 of file g2cfile.c.
References g2c_file_info::f, free_metadata(), G2C_EBADID, G2C_EFILE, g2c_file, G2C_MAX_FILES, G2C_NOERROR, g2c_file_info::g2cid, LOG, MUTEX_LOCK, MUTEX_UNLOCK, g2c_file_info::num_messages, and g2c_file_info::path.
Referenced by main().
int g2c_find_msg2 | ( | int | g2cid, |
size_t | skip_bytes, | ||
size_t | max_bytes, | ||
size_t * | bytes_to_msg, | ||
size_t * | bytes_in_msg | ||
) |
Search a file for the next GRIB1 or GRIB2 message.
A grib message is identified by its indicator section, i.e. an 8-byte sequence with 'GRIB' in bytes 1-4 and a '1' or '2' in byte 8. If found, the length of the message is decoded from bytes 5-7. The search is done over a given section of the file. The search is terminated if an eof or i/o error is encountered.
g2cid | ID of the opened grib file, returned by g2c_open(). |
skip_bytes | Number of bytes to skip before search. |
max_bytes | Maximum number of bytes to search. |
bytes_to_msg | Pointer that gets the number of bytes to skip before message. |
bytes_in_msg | Pointer that gets the number of bytes in message (or 0 if no message found) |
Definition at line 164 of file g2cfile.c.
References G2C_EBADID, G2C_EFILE, G2C_EINVAL, G2C_EMSG, G2C_ENOMEM, G2C_ERROR, g2c_file, G2C_MAGIC_HEADER_LEN, G2C_NOERROR, LOG, MIN, and READ_BUF_SIZE.
int g2c_get_msg | ( | int | g2cid, |
size_t | skip_bytes, | ||
size_t | max_bytes, | ||
size_t * | bytes_to_msg, | ||
size_t * | bytes_in_msg, | ||
unsigned char ** | cbuf | ||
) |
Search a file for the next GRIB1 or GRIB2 message, and read it, allocating space in memory to hold the message.
A grib message is identified by its indicator section, i.e. an 8-byte sequence with 'GRIB' in bytes 1-4 and a '1' or '2' in byte 8. If found, the length of the message is decoded from bytes 5-7. The search is done over a given section of the file. The search is terminated if an EOF or I/O error is encountered.
g2cid | ID of the opened grib file, returned by g2c_open(). |
skip_bytes | The number of bytes to skip before search. |
max_bytes | The maximum number of bytes to search. Must be at least 16. |
bytes_to_msg | A pointer that gets the number of bytes to skip before message. |
bytes_in_msg | A pointer that gets the number of bytes in message (or 0 if no message found) |
cbuf | A pointer that gets allocation of memory, into which the message is copied. This memory must be freed by the caller. |
Definition at line 293 of file g2cfile.c.
References G2C_EBADID, G2C_EFILE, G2C_EINVAL, G2C_ENOMEM, G2C_ENOMSG, G2C_ERROR, g2c_file, G2C_MIN_MAX_BYTES, G2C_NOERROR, LOG, and seekgb().
int g2c_open | ( | const char * | path, |
int | mode, | ||
int * | g2cid | ||
) |
Open an existing GRIB2 file.
path | Path of the file. |
mode | Open mode flags. |
g2cid | Pointer that gets an indentifier for the file. |
Definition at line 1193 of file g2cfile.c.
References g2c_add_file(), MUTEX_LOCK, MUTEX_UNLOCK, and read_metadata().
Referenced by main().
int g2c_rw_section1_metadata | ( | FILE * | f, |
int | rw_flag, | ||
G2C_MESSAGE_INFO_T * | msg | ||
) |
Read Section 1.
f | Pointer to open file. |
rw_flag | G2C_FILE_WRITE if function should write, G2C_FILE_READ if it should read. |
msg | Pointer to G2C_MESSAGE_INFO_T which will be populated with the values of section 0. |
Definition at line 877 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().
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.
f | FILE pointer to open GRIB2 file. |
rw_flag | G2C_FILE_WRITE if function should write, G2C_FILE_READ (0) if it should read. |
sec | Pointer to the G2C_SECTION_INFO_T struct. |
Definition at line 481 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().
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.
f | FILE pointer to open GRIB2 file. |
rw_flag | G2C_FILE_WRITE if function should write, G2C_FILE_READ if it should read. |
sec | Pointer to the G2C_SECTION_INFO_T struct. |
Definition at line 577 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().
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.
f | FILE pointer to open GRIB2 file. |
rw_flag | G2C_FILE_WRITE if function should write, G2C_FILE_READ if it should read. |
sec | Pointer to the G2C_SECTION_INFO_T struct. |
Definition at line 666 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().
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.
f | FILE pointer to open GRIB2 file. |
rw_flag | G2C_FILE_WRITE if function should write, G2C_FILE_READ if it should read. |
sec | Pointer to the G2C_SECTION_INFO_T struct. |
Definition at line 748 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().
int g2c_seekmsg | ( | int | g2cid, |
size_t | skip, | ||
size_t * | offset, | ||
size_t * | msglen | ||
) |
Search a file for the next GRIB2 Message.
The search is terminated when a GRIB2 message is found, or the end of the file is reached.
g2cid | ID of an open GRIB2 file, returned from g2c_open()/g2c_create(). |
skip | The number of bytes in the file to skip before starting the search. |
offset | Pointer that gets the number of bytes to skip from the beggining of the file to where the GRIB message starts. Ignored if NULL. |
msglen | Pointer that gets the number of bytes in message (set to 0, if no message found). Ignored if NULL. |
Definition at line 56 of file g2cfile.c.
References G2C_EBADID, G2C_EFILE, G2C_ENOMEM, g2c_file, G2C_MAGIC_HEADER, G2C_NOERROR, G2C_SEEKMSG_BUFSIZE, hton64, and LOG.
Referenced by read_metadata().
MUTEX | ( | m | ) |
Define mutex for thread-safety.
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Read metadata from a GRIB2 file being opened with g2c_open().
g2cid | The indentifier for the file. |
Definition at line 1082 of file g2cfile.c.
References add_msg(), G2C_EBADID, G2C_ENOMSG, g2c_file, g2c_log_file(), G2C_NOERROR, g2c_seekmsg(), and LOG.
Referenced by g2c_open().
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Read the file to get metadata about a message.
msg | Pointer to the G2C_MESSAGE_INFO_T struct for this message. |
Definition at line 940 of file g2cfile.c.
References add_section(), BYTES_TO_DISCIPLINE, g2c_message_info::bytes_to_msg, g2c_message_info::discipline, g2c_file_info::f, g2c_message_info::file, FOUR_BYTES, G2C_EBADSECTION, G2C_EFILE, g2c_file_io_ubyte(), g2c_file_io_uint(), G2C_FILE_READ, G2C_NOERROR, g2c_rw_section1_metadata(), G2C_SECTION0_BYTES, LOG, ONE_BYTE, and g2c_message_info::sec1_len.
Referenced by add_msg().
G2C_FILE_INFO_T g2c_file[G2C_MAX_FILES+1] |
Global file information.
Definition at line 10 of file g2cfile.c.
Referenced by find_available_g2cid(), free_metadata(), g2c_add_file(), g2c_close(), g2c_compare(), g2c_degrib2(), g2c_find_msg2(), g2c_get_msg(), g2c_get_prod(), g2c_inq(), g2c_inq_dim(), g2c_inq_msg(), g2c_inq_msg_time(), g2c_inq_prod(), g2c_log_file(), g2c_open_index(), g2c_seekmsg(), g2c_write_index(), and read_metadata().
int g2c_next_g2cid = 1 |
Next g2cid file ID - used when opening or creating a file.
Definition at line 13 of file g2cfile.c.
Referenced by find_available_g2cid().