gwyutils

gwyutils — Various utility functions

Synopsis

#include <libgwyddion/gwyddion.h>

enum                GwyRawDataType;
enum                GwyByteOrder;
void                gwy_hash_table_to_slist_cb          (gpointer unused_key,
                                                         gpointer value,
                                                         gpointer user_data);
void                gwy_hash_table_to_list_cb           (gpointer unused_key,
                                                         gpointer value,
                                                         gpointer user_data);
gchar *             gwy_strkill                         (gchar *s,
                                                         const gchar *killchars);
gchar *             gwy_strreplace                      (const gchar *haystack,
                                                         const gchar *needle,
                                                         const gchar *replacement,
                                                         gsize maxrepl);
gint                gwy_strdiffpos                      (const gchar *s1,
                                                         const gchar *s2);
gboolean            gwy_strisident                      (const gchar *s,
                                                         const gchar *more,
                                                         const gchar *startmore);
gboolean            gwy_ascii_strcase_equal             (gconstpointer v1,
                                                         gconstpointer v2);
guint               gwy_ascii_strcase_hash              (gconstpointer v);
guint               gwy_stramong                        (const gchar *str,
                                                         ...);
gpointer            gwy_memmem                          (gconstpointer haystack,
                                                         gsize haystack_len,
                                                         gconstpointer needle,
                                                         gsize needle_len);
gboolean            gwy_file_get_contents               (const gchar *filename,
                                                         guchar **buffer,
                                                         gsize *size,
                                                         GError **error);
gboolean            gwy_file_abandon_contents           (guchar *buffer,
                                                         gsize size,
                                                         GError **error);
gchar *             gwy_find_self_dir                   (const gchar *dirname);
const gchar *       gwy_get_user_dir                    (void);
const gchar *       gwy_get_home_dir                    (void);
gchar *             gwy_canonicalize_path               (const gchar *path);
gboolean            gwy_filename_ignore                 (const gchar *filename_sys);
gchar *             gwy_sgettext                        (const gchar *msgid);
gchar *             gwy_str_next_line                   (gchar **buffer);
void                gwy_memcpy_byte_swap                (const guint8 *source,
                                                         guint8 *dest,
                                                         gsize item_size,
                                                         gsize nitems,
                                                         gsize byteswap);
void                gwy_convert_raw_data                (gconstpointer data,
                                                         gsize nitems,
                                                         gssize stride,
                                                         GwyRawDataType datatype,
                                                         GwyByteOrder byteorder,
                                                         gdouble *target,
                                                         gdouble scale,
                                                         gdouble offset);
guint               gwy_raw_data_size                   (GwyRawDataType datatype);
void                gwy_object_set_or_reset             (gpointer object,
                                                         GType type,
                                                         ...);

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()).

Details

enum GwyRawDataType

typedef enum {
    GWY_RAW_DATA_SINT8,
    GWY_RAW_DATA_UINT8,
    GWY_RAW_DATA_SINT16,
    GWY_RAW_DATA_UINT16,
    GWY_RAW_DATA_SINT32,
    GWY_RAW_DATA_UINT32,
    GWY_RAW_DATA_SINT64,
    GWY_RAW_DATA_UINT64,
    GWY_RAW_DATA_HALF,
    GWY_RAW_DATA_FLOAT,
    GWY_RAW_DATA_REAL,
    GWY_RAW_DATA_DOUBLE,
} GwyRawDataType;

Types of raw data.

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

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

typedef enum {
    GWY_BYTE_ORDER_NATIVE        = 0,
    GWY_BYTE_ORDER_LITTLE_ENDIAN = G_LITTLE_ENDIAN,
    GWY_BYTE_ORDER_BIG_ENDIAN    = G_BIG_ENDIAN,
} GwyByteOrder;

Type of byte order.

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


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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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().

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().

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.

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).

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 `|'.

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
}

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_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().

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.

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.

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.

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.

See Also

gwymacros -- utility macros