pngunpack.c File Reference

Contains a function to unpack data packed with PNG compression. More...

#include <stdio.h>
#include <stdlib.h>
#include "grib2_int.h"

Go to the source code of this file.

Functions
int	g2c_pngunpackd (unsigned char *cpack, size_t len, int *idrstmpl, size_t ndpts, double *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. More...
int	g2c_pngunpackf (unsigned char *cpack, size_t len, int *idrstmpl, size_t 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. More...
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. More...
static int	pngunpack_int (unsigned char *cpack, g2int len, g2int *idrstmpl, g2int ndpts, void *fld, int fld_is_double, int verbose)
	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. More...

Detailed Description

Contains a function to unpack data packed with PNG compression.

Author

Stephen Gilbert

Date

2003-08-27

Definition in file pngunpack.c.

Function Documentation

g2c_pngunpackd()

int g2c_pngunpackd	(	unsigned char *	cpack,
		size_t	len,
		int *	idrstmpl,
		size_t	ndpts,
		double *	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

cpack	The packed data field (character*1 array).
len	length of packed field cpack().
idrstmpl	Pointer to array of values for Data Representation Template 5.41 or 5.40010.
ndpts	The number of data values to unpack.
fld	Contains the unpacked data values.

Returns

• G2C_NOERROR No Error.
• G2C_ENOMEM Out of memory.

Author

Ed Hartnett

Date

Aug 8, 2022

Definition at line 179 of file pngunpack.c.

References G2C_PNG_DRS_TEMPLATE_LEN, and pngunpack_int().

g2c_pngunpackf()

int g2c_pngunpackf	(	unsigned char *	cpack,
		size_t	len,
		int *	idrstmpl,
		size_t	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

cpack	The packed data field (character*1 array).
len	length of packed field cpack().
idrstmpl	Pointer to array of values for Data Representation Template 5.41 or 5.40010.
ndpts	The number of data values to unpack.
fld	Contains the unpacked data values.

Returns

• G2C_NOERROR No Error.
• G2C_ENOMEM Out of memory.

Author

Ed Hartnett

Date

Sep 8, 2022

Definition at line 147 of file pngunpack.c.

References G2C_PNG_DRS_TEMPLATE_LEN, and pngunpack_int().

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

cpack	The packed data field (character*1 array).
len	length of packed field cpack().
idrstmpl	Pointer to array of values for Data Representation Template 5.41 or 5.40010.
ndpts	The number of data values to unpack.
fld	Contains the unpacked data values.

Returns

• G2C_NOERROR No error.
• G2_JPCUNPACK_MEM Out of memory.

Author

Stephen Gilbert

Date

2003-08-27

Author

Ed Hartnett

Definition at line 117 of file pngunpack.c.

References G2_JPCUNPACK_MEM, G2C_ENOMEM, and pngunpack_int().

Referenced by g2c_unpack7_int().

pngunpack_int()

static int pngunpack_int ( unsigned char *  cpack, g2int  len, g2int *  idrstmpl, g2int  ndpts, void *  fld, int  fld_is_double, int  verbose  )

static

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

cpack	The packed data field (character*1 array).
len	The length of packed field cpack().
idrstmpl	Pointer to array of values for Data Representation Template 5.41 or 5.40010.
ndpts	The number of data values to unpack.
fld	Pointer that will get the unpacked data values.
fld_is_double	If non-zero, then fld will get data as double, otherwise float.
verbose	If non-zero, error messages will be printed in case of error. Otherwise, error codes will be return but no error messages printed. Calls to the original g2c API may cause error messages to be printed in case of error. For the new g2c_ API, no error messages will be printed - instead an error code will be returned. Call g2c_strerror() to get the error message for any error code.

Returns

• G2C_NOERROR No Error.
• G2C_ENOMEM Out of memory.

Author

Stephen Gilbert, Ed Hartnett

Date

Aug 8, 2022

Definition at line 41 of file pngunpack.c.

References dec_png(), G2C_ENOMEM, gbits(), int_power(), LOG, and rdieee().

Referenced by g2c_pngunpackd(), g2c_pngunpackf(), and pngunpack().