Gwyddion – Free SPM (AFM, SNOM/NSOM, STM, MFM, …) data analysis software

gwyutils

gwyutils — Various utility functions

Functions

gboolean (*GwySetFractionFunc) ()
gboolean (*GwySetMessageFunc) ()
void gwy_hash_table_to_slist_cb ()
void gwy_hash_table_to_list_cb ()
gchar * gwy_strkill ()
gchar * gwy_strreplace ()
gint gwy_strdiffpos ()
gboolean gwy_strisident ()
gboolean gwy_ascii_strcase_equal ()
guint gwy_ascii_strcase_hash ()
guint gwy_stramong ()
gpointer gwy_memmem ()
gboolean gwy_file_get_contents ()
gboolean gwy_file_abandon_contents ()
gchar * gwy_find_self_dir ()
const gchar * gwy_get_user_dir ()
const gchar * gwy_get_home_dir ()
gchar * gwy_canonicalize_path ()
gboolean gwy_filename_ignore ()
gchar * gwy_sgettext ()
gchar * gwy_str_next_line ()
guint gwy_str_fixed_font_width ()
guint gwy_gstring_replace ()
void gwy_gstring_to_native_eol ()
void gwy_memcpy_byte_swap ()
void gwy_convert_raw_data ()
guint gwy_raw_data_size ()
void gwy_object_set_or_reset ()
gboolean gwy_set_member_object ()
FILE * gwy_fopen ()
gint gwy_fprintf ()

Types and Values

enum GwyRawDataType
enum GwyByteOrder

Includes

#include <libgwyddion/gwyddion.h>

Description

Various utility functions: creating GLib lists from hash tables gwy_hash_table_to_list_cb()), protably finding Gwyddion application directories (gwy_find_self_dir()), string functions (gwy_strreplace()), path manipulation (gwy_canonicalize_path()).

Functions

GwySetFractionFunc ()

gboolean
(*GwySetFractionFunc) (gdouble fraction);

Type of function for reporting progress of a long computation.

Usually you want to use gwy_app_wait_set_fraction().

Parameters

fraction

Progress estimate as a number from the interval [0,1].

 

Returns

TRUE if the computation should continue; FALSE if it should be cancelled.

GwySetMessageFunc ()

gboolean
(*GwySetMessageFunc) (const gchar *message);

Type of function for reporting what a long computation is doing now.

Usually you want to use gwy_app_wait_set_message().

Parameters

message

Message to be shown together with the progress fraction. If the computation has stages the messages should reflect this. Otherwise at least some general message should be set.

 

Returns

TRUE if the computation should continue; FALSE if it should be cancelled.

gwy_hash_table_to_slist_cb ()

void
gwy_hash_table_to_slist_cb (gpointer unused_key,
                            gpointer value,
                            gpointer user_data);

GHashTable to GSList convertor.

Usble in g_hash_table_foreach(), pass a pointer to a GSList* as user data to it.

Parameters

unused_key

Hash key (unused).

 

value

Hash value.

 

user_data

User data (a pointer to GSList*).

 

gwy_hash_table_to_list_cb ()

void
gwy_hash_table_to_list_cb (gpointer unused_key,
                           gpointer value,
                           gpointer user_data);

GHashTable to GList convertor.

Usble in g_hash_table_foreach(), pass a pointer to a GList* as user data to it.

Parameters

unused_key

Hash key (unused).

 

value

Hash value.

 

user_data

User data (a pointer to GList*).

 

gwy_strkill ()

gchar *
gwy_strkill (gchar *s,
             const gchar *killchars);

Removes characters in killchars from string s , modifying it in place.

Use gwy_strkill(g_strdup(s ), killchars ) to get a modified copy.

Parameters

s

A NUL-terminated string.

 

killchars

A string containing characters to kill.

 

Returns

s itself, the return value is to allow function call nesting.

gwy_strreplace ()

gchar *
gwy_strreplace (const gchar *haystack,
                const gchar *needle,
                const gchar *replacement,
                gsize maxrepl);

Replaces occurences of string needle in haystack with replacement .

See gwy_gstring_replace() for a function which does in-place replacement on a GString.

Parameters

haystack

A NUL-terminated string to search in.

 

needle

A NUL-terminated string to search for.

 

replacement

A NUL-terminated string to replace needle with.

 

maxrepl

Maximum number of occurences to replace (use (gsize)-1 to replace all occurences).

 

Returns

A newly allocated string.

gwy_strdiffpos ()

gint
gwy_strdiffpos (const gchar *s1,
                const gchar *s2);

Finds position where two strings differ.

Parameters

s1

A string.

 

s2

A string.

 

Returns

The last position where the strings do not differ yet. Particularly, -1 is returned if either string is NULL, zero-length, or they differ in the very first character.

gwy_strisident ()

gboolean
gwy_strisident (const gchar *s,
                const gchar *more,
                const gchar *startmore);

Checks whether a string is valid identifier.

Valid identifier must start with an alphabetic character or a character from startmore , and it must continue with alphanumeric characters or characters from more .

Note underscore is not allowed by default, you have to pass it in more and/or startmore .

Parameters

s

A NUL-terminated string.

 

more

List of additional ASCII characters allowed inside identifier, empty list can be passed as NULL.

 

startmore

List of additional ASCII characters allowed as the first identifier characters, empty list can be passed as NULL.

 

Returns

TRUE if s is valid identifier, FALSE otherwise.

gwy_ascii_strcase_equal ()

gboolean
gwy_ascii_strcase_equal (gconstpointer v1,
                         gconstpointer v2);

Compares two strings for equality, ignoring case.

The case folding is performed only on ASCII characters.

This function is intended to be passed to g_hash_table_new() as key_equal_func , namely in conjuction with gwy_ascii_strcase_hash() hashing function.

Parameters

v1

String key.

 

v2

String key to compare with v1 .

 

Returns

TRUE if the two string keys match, ignoring case.

Since: 2.26

gwy_ascii_strcase_hash ()

guint
gwy_ascii_strcase_hash (gconstpointer v);

Converts a string to a hash value, ignoring case.

The case folding is performed only on ASCII characters.

This function is intended to be passed to g_hash_table_new() as hash_func , namely in conjuction with gwy_ascii_strcase_equal() comparison function.

Parameters

v

String key.

 

Returns

The hash value corresponding to the key v .

Since: 2.26

gwy_stramong ()

guint
gwy_stramong (const gchar *str,
              ...);

Checks whether a string is equal to any from given list.

Parameters

str

A string to find.

 

...

NULL-terminated list of string to compare str with.

 

Returns

Zero if str does not equal to any string from the list, nozero othwerise. More precisely, the position + 1 of the first string str equals to is returned in the latter case.

Since: 2.11

gwy_memmem ()

gpointer
gwy_memmem (gconstpointer haystack,
            gsize haystack_len,
            gconstpointer needle,
            gsize needle_len);

Find a block of memory in another block of memory.

This function is very similar to strstr(), except that it works with arbitrary memory blocks instead of NUL-terminated strings.

If needle_len is zero, haystack is always returned.

On GNU systems with glibc at least 2.1 this is a just a trivial memmem() wrapper. On other systems it emulates memmem() behaviour.

Parameters

haystack

Memory block to search in.

 

haystack_len

Size of haystack , in bytes.

 

needle

Memory block to find.

 

needle_len

Size of needle , in bytes.

 

Returns

Pointer to the first byte of memory block in haystack that matches needle ; NULL if no such block exists.

Since: 2.12

gwy_file_get_contents ()

gboolean
gwy_file_get_contents (const gchar *filename,
                       guchar **buffer,
                       gsize *size,
                       GError **error);

Reads or mmaps file filename into memory.

The buffer must be treated as read-only and must be freed with gwy_file_abandon_contents(). It is NOT guaranteed to be NUL-terminated, use size to find its end.

Parameters

filename

A file to read contents of.

 

buffer

Buffer to store the file contents.

 

size

Location to store buffer (file) size.

 

error

Return location for a GError.

 

Returns

Whether it succeeded. In case of failure buffer and size are reset too.

gwy_file_abandon_contents ()

gboolean
gwy_file_abandon_contents (guchar *buffer,
                           gsize size,
                           GError **error);

Frees or unmmaps memory allocated by gwy_file_get_contents().

Parameters

buffer

Buffer with file contents as created by gwy_file_get_contents().

 

size

Buffer size.

 

error

Return location for a GError. Since 2.22 no error can occur; safely pass NULL.

 

Returns

Whether it succeeded. Since 2.22 it always return TRUE.

gwy_find_self_dir ()

gchar *
gwy_find_self_dir (const gchar *dirname);

Finds a system Gwyddion directory.

On Unix, a compiled-in path is returned, unless it's overriden with environment variables (see gwyddion manual page).

On Win32, the directory where the libgwyddion DLL from which this function was called resides is taken as the base and the location of other Gwyddion directories is calculated from it.

The returned value is not actually tested for existence, it's up to caller.

To obtain the Gwyddion user directory see gwy_get_user_dir().

Parameters

dirname

A gwyddion directory name: "modules", "plugins", "pixmaps", "locale", or "data".

 

Returns

The path as a newly allocated string.

gwy_get_user_dir ()

const gchar *
gwy_get_user_dir (void);

Returns the directory where Gwyddion user settings and data should be stored.

On Unix this is usually a dot-directory in user's home directory. On modern Win32 the returned directory resides in user's Documents and Settings. On silly platforms or silly occasions, silly locations (namely a temporary directory) can be returned as fallback.

To obtain a Gwyddion system directory see gwy_find_self_dir().

Returns

The directory as a constant string that should not be freed.

gwy_get_home_dir ()

const gchar *
gwy_get_home_dir (void);

Returns home directory, or temporary directory as a fallback.

Under normal circumstances the same string as g_get_home_dir() would return is returned. But on MS Windows, something like "C:\Windows\Temp" can be returned too, as it is as good as anything else (we can write there).

Returns

Something usable as user home directory. It may be silly, but never NULL or empty.

gwy_canonicalize_path ()

gchar *
gwy_canonicalize_path (const gchar *path);

Canonicalizes a filesystem path.

Particularly it makes the path absolute, resolves ..' and .', and fixes slash sequences to single slashes. On Win32 it also converts all backslashes to slashes along the way.

Note this function does NOT resolve symlinks, use g_file_read_link() for that.

Parameters

path

A filesystem path.

 

Returns

The canonical path, as a newly created string.

gwy_filename_ignore ()

gboolean
gwy_filename_ignore (const gchar *filename_sys);

Checks whether file should be ignored.

This function checks for common file names indicating files that should be normally ignored. Currently it means backup files (ending with ~ or .bak) and Unix hidden files (starting with a dot).

Parameters

filename_sys

File name in GLib encoding.

 

Returns

TRUE to ignore this file, FALSE otherwise.

gwy_sgettext ()

gchar *
gwy_sgettext (const gchar *msgid);

Translate a message id containing disambiguating prefix ending with `|'.

Parameters

msgid

Message id to translate, containing `|'-separated prefix.

 

Returns

Translated message, or msgid itself with all text up to the last `|' removed if there is no translation.

gwy_str_next_line ()

gchar *
gwy_str_next_line (gchar **buffer);

Extracts a next line from a character buffer, modifying it in place.

buffer is updated to point after the end of the line and the "\n" (or "\r" or "\r\n") is replaced with "\0", if present.

The final line may or may not be terminated with an EOL marker, its contents is returned in either case. Note, however, that the empty string "" is not interpreted as an empty unterminated line. Instead, NULL is immediately returned.

The typical usage of gwy_str_next_line() is:

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gchar *p = text;
for (gchar *line = gwy_str_next_line(&p);
     line;
     line = gwy_str_next_line(&p)) {
    g_strstrip(line);
    // Do something more with line
}

Parameters

buffer

Text buffer.

 

Returns

The start of the line. NULL if the buffer is empty or NULL. The return value is not a new string; the normal return value is the previous value of buffer .

gwy_str_fixed_font_width ()

guint
gwy_str_fixed_font_width (const gchar *str);

Measures the width of UTF-8 encoded string in fixed-width font.

This corresponds to width of the string displayed on a text terminal, for instance. Zero and double width characters are taken into account. It is not guaranteed all terminals display the string with the calculated width.

Parameters

str

UTF-8 encoded string.

 

Returns

String width in fixed font, in character cells.

Since: 2.52

gwy_gstring_replace ()

guint
gwy_gstring_replace (GString *str,
                     const gchar *old,
                     const gchar *replacement,
                     gint count);

Replaces non-overlapping occurrences of one string with another in a GString.

Passing NULL or the empty string for replacement will cause the occurrences of old to be removed.

Passing NULL or the empty string for old means a match occurs at every position in the string, including after the last character. So replacement will be inserted at every position in this case.

See gwy_strreplace() for a function which creates a new plain C string with substring replacement.

Parameters

str

A GString string to modify in place.

 

old

The character sequence to find and replace. Passing NULL is the same as passing the empty string.

 

replacement

The character sequence that should replace old . Passing NULL is the same as passing the empty string.

 

count

The maximum number of replacements to make. A negative number means replacing all occurrences of old . Note zero means just zero, i.e. no replacements are made.

 

Returns

The number of replacements made. A non-zero value means the string has been modified, no-op replacements do not count.

Since: 2.36

gwy_gstring_to_native_eol ()

void
gwy_gstring_to_native_eol (GString *str);

Converts "\n" in a string to operating system native line terminators.

Text files are most easily written by opening them in the text mode. This function can be useful for writing text files using functions such as g_file_set_contents() that do not permit the conversion to happen automatically.

It is a no-op on all POSIX systems, including OS X. So at present, it actually performs any conversion at all only on MS Windows.

Parameters

str

A GString string to modify in place.

 

Since: 2.36

gwy_memcpy_byte_swap ()

void
gwy_memcpy_byte_swap (const guint8 *source,
                      guint8 *dest,
                      gsize item_size,
                      gsize nitems,
                      gsize byteswap);

Copies a block of memory swapping bytes along the way.

The bits in byteswap correspond to groups of bytes to swap: if j-th bit is set, adjacent groups of 2j bits are swapped. For example, value 3 means items will be divided into couples (bit 1) of bytes and adjacent couples of bytes swapped, and then divided into single bytes (bit 0) and adjacent bytes swapped. The net effect is reversal of byte order in groups of four bytes. More generally, if you want to reverse byte order in groups of size 2j, use byte swap pattern j-1.

When byteswap is zero, this function reduces to plain memcpy().

Parameters

source

Source memory block.

 

dest

Destination memory location.

 

item_size

Size of one copied item, it should be a power of two.

 

nitems

Number of items of size item_size to copy.

 

byteswap

Byte swap pattern.

 

Since: 2.1

gwy_convert_raw_data ()

void
gwy_convert_raw_data (gconstpointer data,
                      gsize nitems,
                      gssize stride,
                      GwyRawDataType datatype,
                      GwyByteOrder byteorder,
                      gdouble *target,
                      gdouble scale,
                      gdouble offset);

Converts a block of raw data items to doubles.

Note that conversion from 64bit integral types may lose information as they have more bits than the mantissa of doubles. All other conversions should be precise.

Parameters

data

Pointer to the input raw data to be converted to doubles. The data type is given by datatype and byteorder .

 

nitems

Data block length, i.e. the number of consecutive items to convert.

 

stride

Item stride in the raw data, measured in raw values. Pass 1 for consecutive raw data. For backward reading, pass -1 and point data to the last raw item instead of the first.

 

datatype

Type of the raw data items.

 

byteorder

Byte order of the raw data.

 

target

Array of nitems to store the converted input data to.

 

scale

Factor to multiply the data with.

 

offset

Constant to add to the data after multiplying with scale .

 

Since: 2.25

gwy_raw_data_size ()

guint
gwy_raw_data_size (GwyRawDataType datatype);

Reports the size of a single raw data item.

Parameters

datatype

Raw data type.

 

Returns

The size of a single raw data item of type datatype .

Since: 2.25

gwy_object_set_or_reset ()

void
gwy_object_set_or_reset (gpointer object,
                         GType type,
                         ...);

Sets object properties, resetting other properties to defaults.

All explicitly specified properties are set. In addition, all unspecified settable properties of type type (or all unspecified properties if type is 0) are reset to defaults. Settable means the property is writable and not construction-only.

The order in which properties are set is undefined beside keeping the relative order of explicitly specified properties, therefore this function is not generally usable for objects with interdependent properties.

Unlike g_object_set(), it does not set properties that already have the requested value, as a consequences notifications are emitted only for properties which actually change.

Parameters

object

A GObject.

 

type

The type whose properties are to reset, may be zero for all types. The object must be of this type (more precisely object is-a type must hold).

 

...

NULL-terminated list of name/value pairs of properties to set as in g_object_set(). It can be NULL alone to only reset properties to defaults.

 

gwy_set_member_object ()

gboolean
gwy_set_member_object (gpointer instance,
                       gpointer member_object,
                       GType expected_type,
                       gpointer member_field,
                       ...);

Replaces a member object of another object, handling signal connection and disconnection.

If member_object is not NULL a reference is taken, sinking any floating objects (and conversely, the reference to the previous member object is released).

The purpose is to simplify bookkeeping in classes that have settable member objects and (usually but not necessarily) need to connect to some signals of these member objects. Since this function both connects and disconnects signals it must be always called with the same set of signals, including callbacks and flags, for a specific member object.

Example for a GwyFoo class owning a GwyGradient member object, assuming the usual conventions:

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typedef struct _GwyFooPrivate GwyFooPrivate;

struct _GwyFooPrivate {
    GwyGradient *gradient;
    gulong gradient_data_changed_id;
};

static gboolean
set_gradient(GwyFoo *foo)
{
    GwyFooPrivate *priv = G_TYPE_INSTANCE_GET_PRIVATE(foo, GWY_TYPE_FOO,
                                                      GwyFooPrivate);
    if (!gwy_set_member_object(foo, gradient, GWY_TYPE_GRADIENT,
                               &priv->gradient,
                               "data-changed", &foo_gradient_data_changed,
                               &priv->gradient_data_changed_id,
                               G_CONNECT_SWAPPED,
                               NULL))
        return FALSE;

    // Do whatever else needs to be done if the gradient changes.
    return TRUE;
}

The gradient setter then usually only calls set_gradient() and disposing of the member object again only calls set_gradient() but with NULL gradient.

Parameters

instance

An object instance.

 

member_object

Another object to be owned by instanced , or NULL.

 

expected_type

The type of member_object . It is checked and a critical message is emitted if it does not conform.

 

member_field

Pointer to location storing the current member object to be replaced by member_object .

 

...

List of quadruplets of the form signal name, GCallback callback, gulong pointer to location to hold the signal handler id, and GConnectFlags connection flags.

 

Returns

TRUE if member_field was changed. FALSE means the new member is identical to the current one and the function reduced to no-op (or that an assertion faled).

Since: 2.49

gwy_fopen ()

FILE *
gwy_fopen (const gchar *filename,
           const gchar *mode);

A wrapper for the stdio fopen() function. The fopen() function opens a file and associates a new stream with it.

Because file descriptors are specific to the C library on Windows, and a file descriptor is part of the FILE struct, the FILE* returned by this function makes sense only to functions in the same C library. Thus if the GLib-using code uses a different C library than GLib does, the FILE* returned by this function cannot be passed to C library functions like fprintf() or fread().

See your C library manual for more details about fopen().

Parameters

filename

a pathname in the GLib file name encoding (UTF-8 on Windows)

 

mode

a string describing the mode in which the file should be opened

 

Returns

A FILE* if the file was successfully opened, or NULL if an error occurred.

Since: 2.43

gwy_fprintf ()

gint
gwy_fprintf (FILE *file,
             gchar const *format,
             ...);

An implementation of the standard fprintf() function which supports positional parameters, as specified in the Single Unix Specification.

Parameters

file

the stream to write to.

 

format

a standard printf() format string, but notice

string precision pitfalls
 

...

the arguments to insert in the output.

 

Returns

the number of bytes printed.

Since: 2.43

Types and Values

enum GwyRawDataType

Types of raw data.

Multibyte types usually need to be complemented with GwyByteOrder to get a full type specification.

Members

GWY_RAW_DATA_SINT8

Signed 8bit integer (one byte).

 

GWY_RAW_DATA_UINT8

Unsigned 8bit integer (one byte).

 

GWY_RAW_DATA_SINT16

Signed 16bit integer (two bytes).

 

GWY_RAW_DATA_UINT16

Unsigned 16bit integer (two bytes).

 

GWY_RAW_DATA_SINT32

Signed 32bit integer (four bytes).

 

GWY_RAW_DATA_UINT32

Unsigned 32bit integer (four bytes).

 

GWY_RAW_DATA_SINT64

Signed 64bit integer (eight bytes).

 

GWY_RAW_DATA_UINT64

Unsigned 64bit integer (eight bytes).

 

GWY_RAW_DATA_HALF

Half-precision floating point number (two bytes).

 

GWY_RAW_DATA_FLOAT

Single-precision floating point number (four bytes).

 

GWY_RAW_DATA_REAL

Pascal ‘real’ floating point number (six bytes).

 

GWY_RAW_DATA_DOUBLE

Double-precision floating point number (eight bytes).

 

Since: 2.25

enum GwyByteOrder

Type of byte order.

Members

GWY_BYTE_ORDER_NATIVE

Native byte order.

 

GWY_BYTE_ORDER_LITTLE_ENDIAN

Little endian byte order (the same as G_LITTLE_ENDIAN).

 

GWY_BYTE_ORDER_BIG_ENDIAN

Big endian byte order (the same as G_BIG_ENDIAN).

 

Since: 2.25

See Also

gwymacros --

utility macros

© David Nečas and Petr Klapetek

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