geotifffile.c File Reference

GeoTIFF file format detection and operations. More...

#include "config.h"
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <netcdf.h>
#include "geotiffdispatch.h"
#include "nep_nc4.h"

Macros
#define	GEOTIFF_KEY_DIRECTORY_TAG   34735
#define	MAX_IFD_OFFSET   104857600
#define	TIFF_IFD_ENTRY_SIZE   12
#define	MAX_BUFFER_SIZE   1073741824
#define	MAX_IFD_ENTRIES   4096

Functions
static unsigned short	swap16 (unsigned short val)
static unsigned int	swap32 (unsigned int val)
static int	nc4_set_var_type (nc_type xtype, int endianness, size_t type_size, char *type_name, NC_TYPE_INFO_T **typep)
static int	nc4_var_list_add_full (NC_GRP_INFO_T *grp, const char *name, int ndims, nc_type xtype, int endianness, size_t type_size, char *type_name, void *fill_value, int contiguous, size_t *chunksizes, void *format_var_info, NC_VAR_INFO_T **var)
static int	read_tiff_header (FILE *fp, int *is_little_endian, int *is_bigtiff, unsigned int *ifd_offset)
static int	check_geotiff_tags (FILE *fp, unsigned int ifd_offset, int is_little_endian, int is_bigtiff, int *has_geotiff_tags)
int	NC_GEOTIFF_detect_format (const char *path, int *is_geotiff)

Detailed Description

GeoTIFF file format detection and operations.

This file implements GeoTIFF format detection for the NetCDF API. It validates TIFF magic numbers, headers, and GeoTIFF-specific tags to distinguish GeoTIFF files from regular TIFF files.

Author

Edward Hartnett

Date

2025-12-26

Copyright

Intelligent Data Design, Inc. All rights reserved.

Macro Definition Documentation

GEOTIFF_KEY_DIRECTORY_TAG

#define GEOTIFF_KEY_DIRECTORY_TAG   34735

GeoTIFF key directory tag

MAX_BUFFER_SIZE

#define MAX_BUFFER_SIZE   1073741824

Maximum buffer size for reading (1 GB)

MAX_IFD_ENTRIES

#define MAX_IFD_ENTRIES   4096

Maximum number of IFD entries to process

MAX_IFD_OFFSET

#define MAX_IFD_OFFSET   104857600

Maximum reasonable IFD offset (100 MB)

TIFF_IFD_ENTRY_SIZE

#define TIFF_IFD_ENTRY_SIZE   12

TIFF IFD entry size

Function Documentation

check_geotiff_tags()

static int check_geotiff_tags ( FILE *  fp, unsigned int  ifd_offset, int  is_little_endian, int  is_bigtiff, int *  has_geotiff_tags  )

static

Check if IFD contains GeoTIFF tags.

Parameters

fp	File pointer.
ifd_offset	IFD offset.
is_little_endian	1 if little-endian, 0 if big-endian.
is_bigtiff	1 if BigTIFF, 0 if classic TIFF.
has_geotiff_tags	Output: 1 if GeoTIFF tags found, 0 otherwise.

Returns

NC_NOERR on success, error code otherwise.

nc4_set_var_type()

static int nc4_set_var_type ( nc_type  xtype, int  endianness, size_t  type_size, char *  type_name, NC_TYPE_INFO_T **  typep  )

static

nc4_var_list_add_full()

static int nc4_var_list_add_full ( NC_GRP_INFO_T *  grp, const char *  name, int  ndims, nc_type  xtype, int  endianness, size_t  type_size, char *  type_name, void *  fill_value, int  contiguous, size_t *  chunksizes, void *  format_var_info, NC_VAR_INFO_T **  var  )

static

NC_GEOTIFF_detect_format()

int NC_GEOTIFF_detect_format	(	const char *	path,
		int *	is_geotiff
	)

read_tiff_header()

static int read_tiff_header ( FILE *  fp, int *  is_little_endian, int *  is_bigtiff, unsigned int *  ifd_offset  )

static

Read and validate TIFF header.

Parameters

fp	File pointer.
is_little_endian	Output: 1 if little-endian, 0 if big-endian.
is_bigtiff	Output: 1 if BigTIFF, 0 if classic TIFF.
ifd_offset	Output: IFD offset.

Returns

NC_NOERR on success, error code otherwise.

swap16()

static unsigned short swap16 ( unsigned short  val )

static

Byte-swap a 16-bit value.

Parameters

val	Value to swap.

Returns

Swapped value.

swap32()

static unsigned int swap32 ( unsigned int  val )

static

Byte-swap a 32-bit value.

Parameters

val	Value to swap.

Returns

Swapped value.