GwyFileDetectFunc()

gint
(*GwyFileDetectFunc) (const GwyFileDetectInfo *fileinfo,
                      gboolean only_name);

The type of file type detection function.

When called with TRUE only_name it should not try to access the file.

A basic scale for the returned values is:

GwyFileLoadFunc()

GwyFile *
(*GwyFileLoadFunc) (const gchar *filename,
                    GwyRunModeFlags mode,
                    GError **error);

The type of file loading function.

The function can create the file as being in construction with gwy_file_new_in_construction() to avoid signals being emitted during construction. If the returned object is still marked in construction, it will be finished by the module system.

GwyFileSaveFunc()

gboolean
(*GwyFileSaveFunc) (GwyFile *file,
                    const gchar *filename,
                    GwyRunModeFlags mode,
                    GError **error);

The type of file saving function.

gwy_file_func_register()

gboolean
gwy_file_func_register (const gchar *name,
                        const gchar *description,
                        GwyFileDetectFunc detect,
                        GwyFileLoadFunc load_file,
                        GwyFileSaveFunc save_file,
                        GwyFileSaveFunc export_file);

Registers a file format and defines which file operations it supports.

At least one of load_file , save_file , and export_file must be non-NULL. See GwyFileOperationType for differences between save and export.

Note: the string arguments are not copied as modules are not expected to vanish. If they are constructed (non-constant) strings, do not free them. Should modules ever become unloadable they will get chance to clean-up.

It is possible to register the same routines such as load_file for multiple file types (as distinguished by name ). In such case they must use gwy_file_func_current() to see under which name they are called. It may be easier to register different routines which then call the same function within the module with some distinguishing argument.

gwy_file_func_run_detect()

gint
gwy_file_func_run_detect (const gchar *name,
                          const gchar *filename,
                          gboolean only_name);

Runs a file type detection function identified by name .

Value of only_name should be TRUE if the file doesn't exist (is to be written) so its contents can't be used for file type detection.

This is a low-level function, consider using gwy_file_detect() if you simply want to detect a file type.

gwy_file_func_run_load()

GwyFile *
gwy_file_func_run_load (const gchar *name,
                        const gchar *filename,
                        GwyRunModeFlags mode,
                        GError **error);

Runs a file load function identified by name .

This is a low-level function, consider using gwy_file_load() if you simply want to load a file.

The returned object is never marked as in construction; it is always already finished.

gwy_file_func_run_save()

gboolean
gwy_file_func_run_save (const gchar *name,
                        GwyFile *file,
                        const gchar *filename,
                        GwyRunModeFlags mode,
                        GError **error);

Runs a file save function identified by name .

It guarantees the container lifetime spans through the actual file saving, so the module function doesn't have to care about it.

This is a low-level function, consider using gwy_file_save() if you simply want to save a file.

gwy_file_func_run_export()

gboolean
gwy_file_func_run_export (const gchar *name,
                          GwyFile *file,
                          const gchar *filename,
                          GwyRunModeFlags mode,
                          GError **error);

Runs a file export function identified by name .

It guarantees the container lifetime spans through the actual file saving, so the module function doesn't have to care about it.

This is a low-level function, consider using gwy_file_save() if you simply want to save a file.

gwy_file_func_exists()

gboolean
gwy_file_func_exists (const gchar *name);

Checks whether a file type function exists.

gwy_file_func_get_operations()

GwyFileOperationType
gwy_file_func_get_operations (const gchar *name);

Returns operations supported by a file type function.

gwy_file_func_get_description()

const gchar *
gwy_file_func_get_description (const gchar *name);

Gets file function description.

That is, the description argument of gwy_file_func_register() .

gwy_file_func_foreach()

void
gwy_file_func_foreach (GwyNameFunc function,
                       gpointer user_data);

Calls a function for each file function.

gwy_file_func_current()

const gchar *
gwy_file_func_current (void);

Obtains the name of currently running file type function.

All file functions are taken into account: detect, load, save and export.

If no file type function is currently running, NULL is returned.

If multiple nested file functions are running (which is not usual but technically possible), the innermost function name is returned. If nested function of different types are running (which is not usual but technically possible) the other types do not affect the returned value; only file functions are taken into account.

gwy_file_func_get_is_detectable()

gboolean
gwy_file_func_get_is_detectable (const gchar *name);

Reports if the file format is reasonably detectable.

This is TRUE for all file types that define a detection method unless they explicitly call gwy_file_func_set_is_detectable() to set the file format non-detectable in spite of providing a detection method.

If files that can be actually loaded as a given type form a subset of files that are detected as this format, which is normaly the case, it makes no sense to let the user explicitly choose between these formats. Hence, detectable formats normally are not explicitly offered.

gwy_file_func_set_is_detectable()

void
gwy_file_func_set_is_detectable (const gchar *name,
                                 gboolean is_detectable);

Sets the detectability status of a file format.

See gwy_file_func_get_is_detectable() for details. The only rare case when it makes sense to call this function is when a detection function is provided for some reason, however, this function is not really able to detect the format. For instance, the fallback detection method of the Gwyddion rawfile module.

gwy_file_func_get_is_unfinished()

gboolean
gwy_file_func_get_is_unfinished (const gchar *name);

Reports if the file format implementation is unfinished.

gwy_file_func_set_is_unfinished()

void
gwy_file_func_set_is_unfinished (const gchar *name,
                                 gboolean is_unfinished);

Sets the unfinished status of a file format.

Marking a file format as unfinished is informative.

It should be done under two conditions. The file module can actually read the files and create some images (or other data); if it cannot it should not register the file loading function. But the data it creates are wrong and possibly misleading. For example it is known the conversion from raw to physical values just does not work. It should not be marked when the support for some features is simply missing or the import mostly works fine, but it might not in some specific cases due to the file format complexity.

Gwyddion can then warn when users are opening such files.

gwy_file_detect()

const gchar *
gwy_file_detect (const gchar *filename,
                 gboolean only_name,
                 GwyFileOperationType operations,
                 gint *score);

Detects the type of a file and gives the score.

gwy_file_load()

GwyFile *
gwy_file_load (const gchar *filename,
               GwyRunModeFlags mode,
               GError **error);

Loads a data file, autodetecting its type.

The returned object is never marked as in construction; it is always already finished.

gwy_file_load_with_func()

GwyFile *
gwy_file_load_with_func (const gchar *filename,
                         GwyRunModeFlags mode,
                         const gchar **name,
                         GError **error);

Loads a data file, autodetecting its type.

The returned object is never marked as in construction; it is always already finished.

gwy_file_save()

GwyFileOperationType
gwy_file_save (GwyFile *file,
               const gchar *filename,
               GwyRunModeFlags mode,
               GError **error);

Saves a data file, deciding to save as what type from the file name.

It tries to find a module implementing GWY_FILE_OPERATION_SAVE first, when it does not succeed, it falls back to GWY_FILE_OPERATION_EXPORT.

gwy_file_save_with_func()

GwyFileOperationType
gwy_file_save_with_func (GwyFile *file,
                         const gchar *filename,
                         GwyRunModeFlags mode,
                         const gchar **name,
                         GError **error);

Saves a data file, deciding to save as what type from the file name.

It tries to find a module implementing GWY_FILE_OPERATION_SAVE first, when it does not succeed, it falls back to GWY_FILE_OPERATION_EXPORT.

gwy_module_file_error_quark()

GQuark
gwy_module_file_error_quark (void);

Returns error domain for file module functions.

See and use GWY_MODULE_FILE_ERROR.

GWY_FILE_DETECT_BUFFER_SIZE

#define GWY_FILE_DETECT_BUFFER_SIZE 4096U

The size of GwyFileDetectInfo buffer for initial part of file. It should be enough for any normal kind of magic header test.

This is the maximum size. If the file is tiny the buffer contains less data. Always use buffer_len in the info structure for the actual size.

GWY_MODULE_FILE_ERROR

#define GWY_MODULE_FILE_ERROR gwy_module_file_error_quark()

Error domain for file module operations. Errors in this domain will be from the GwyModuleFileError enumeration. See GError for information on error domains.

enum GwyFileOperationType

File type function file operations (capabilities).

The difference between save and export is that save is supposed to create a file containing fairly complete representation of the container, while export is the possibility to write some information to given file type. Generally only native file format module implements GWY_FILE_OPERATION_SAVE, all others implement GWY_FILE_OPERATION_EXPORT.

enum GwyModuleFileError

Error codes returned by file module operations.

File module functions can return any of these codes, except GWY_MODULE_FILE_ERROR_UNIMPLEMENTED which is normally only returned by high-level functions gwy_file_load() and gwy_file_save(). Module functions can return it only when they are called with a wrong function name.

GwyFileDetectInfo

typedef struct {
    const gchar *name;
    const gchar *name_lowercase;
    gsize file_size;
    guint buffer_len;
    const guchar *head;
    const guchar *tail;
} GwyFileDetectInfo;

File detection data for GwyFileDetectFunc.

It contains the common information file type detection routines need to obtain. It is shared between file detection functions and they must not modify its contents. Some fields are set only when the detection routines are to check the file contents, these are marked `Undefined if only_name '.

The head and tail buffers are always nul-terminated and thus safely usable with string functions. When file is shorter than GWY_FILE_DETECT_BUFFER_SIZE bytes, '\0' is appended to the end (therefore buffer_len = file_size + 1), otherwise the last byte is overwritten with '\0'. In either case the last byte of head and tail cannot be assumed to be identical as in the file (or being a part of the file at all).