FITS header reading/writing

Functions
qfits_header *	qfits_header_read (const char *filename)
	Read a FITS header from a file to an internal structure.
qfits_header *	qfits_header_read_hdr (const char *filename)
	Read a FITS header from a 'hdr' file.
qfits_header *	qfits_header_read_hdr_string (const unsigned char *hdr_str, int nb_char)
	Read a FITS header from a 'hdr' string.
qfits_header *	qfits_header_readext (const char *filename, int xtnum)
	Read an extension header from a FITS file.
void	qfits_zeropad (const char *filename)
	Pad an existing file with zeros to a multiple of 2880.
int	qfits_is_fits (const char *filename)
	Identify if a file is a FITS file.
int	qfits_get_hdrinfo (const char *filename, int xtnum, int *seg_start, int *seg_size)
	Retrieve offset to start and size of a header in a FITS file.
int	qfits_get_datinfo (const char *filename, int xtnum, int *seg_start, int *seg_size)
	Retrieve offset to start and size of a data section in a file.

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Function Documentation

int qfits_get_datinfo (  const char *  filename, int  xtnum, int *  seg_start, int *  seg_size )

Retrieve offset to start and size of a data section in a file. Parameters: filename  Name of the file to examine. xtnum  Extension number (0 for main). seg_start  Segment start in bytes (output). seg_size  Segment size in bytes (output). Returns: int 0 if Ok, -1 otherwise. This function retrieves the two most important informations about a data section in a FITS file: the offset to its beginning, and the size of the section in bytes. Both values are returned in the passed pointers to ints. It is Ok to pass NULL for any pointer if you do not want to retrieve the associated value. You must provide an extension number for the header, 0 meaning the main header in the file.

int qfits_get_hdrinfo (  const char *  filename, int  xtnum, int *  seg_start, int *  seg_size )

Retrieve offset to start and size of a header in a FITS file. Parameters: filename  Name of the file to examine xtnum  Extension number (0 for main) seg_start  Segment start in bytes (output) seg_size  Segment size in bytes (output) Returns: int 0 if Ok, -1 otherwise. This function retrieves the two most important informations about a header in a FITS file: the offset to its beginning, and the size of the header in bytes. Both values are returned in the passed pointers to ints. It is Ok to pass NULL for any pointer if you do not want to retrieve the associated value. You must provide an extension number for the header, 0 meaning the main header in the file.

qfits_header* qfits_header_read (  const char *  filename  )

Read a FITS header from a file to an internal structure. Parameters: filename  Name of the file to be read Returns: Pointer to newly allocated qfits_header or NULL in error case. This function parses a FITS (main) header, and returns an allocated qfits_header object. The qfits_header object contains a linked-list of key "tuples". A key tuple contains: A keyword A value A comment An original FITS line (as read from the input file) Direct access to the structure is not foreseen, use accessor functions in fits_h.h Value, comment, and original line might be NULL pointers.

qfits_header* qfits_header_read_hdr (  const char *  filename  )

Read a FITS header from a 'hdr' file. Parameters: filename  Name of the file to be read Returns: Pointer to newly allocated qfits_header or NULL in error case This function parses a 'hdr' file, and returns an allocated qfits_header object. A hdr file is an ASCII format were the header is written with a carriage return after each line. The command dfits typically displays a hdr file.

qfits_header* qfits_header_read_hdr_string (  const unsigned char *  hdr_str, int  nb_char )

Read a FITS header from a 'hdr' string. Parameters: hdr_str  String containing the hdr file nb_char  Number of characters in the string Returns: Pointer to newly allocated qfits_header or NULL in error case This function parses a 'hdr' string, and returns an allocated qfits_header object.

qfits_header* qfits_header_readext (  const char *  filename, int  xtnum )

Read an extension header from a FITS file. Parameters: filename  Name of the FITS file to read xtnum  Extension number to read, starting from 0. Returns: Newly allocated qfits_header structure. Strictly similar to qfits_header_read() but reads headers from extensions instead. If the requested xtension is 0, this function returns the main header. Returns NULL in case of error.

int qfits_is_fits (  const char *  filename  )

Identify if a file is a FITS file. Parameters: filename  name of the file to check Returns: int 0, 1, or -1 Returns 1 if the file name looks like a valid FITS file. Returns 0 else. If the file does not exist, returns -1.

void qfits_zeropad (  const char *  filename  )

Pad an existing file with zeros to a multiple of 2880. Parameters: filename  Name of the file to pad. Returns: void This function simply pads an existing file on disk with enough zeros for the file size to reach a multiple of 2880, as required by FITS.