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12.3.8.9 List of gal_data_t ¶

Gnuastro’s generic data container has a next element which enables it to be used as a singly-linked list (see Generic data container (gal_data_t)). The ability to connect the different data containers offers great advantages. For example, each column in a table in an independent dataset: with its own name, units, numeric data type (see Numeric data types). Another application is in Tessellating an input dataset into separate tiles or only studying particular regions, or tiles, of a larger dataset (see Tessellation and Tessellation library (tile.h)). Each independent tile over the dataset can be connected to the others as a linked list and thus any number of tiles can be represented with one variable.

Function:
void
gal_list_data_add (gal_data_t **list, gal_data_t *newnode) ¶

Add an already allocated dataset (newnode) to top of list. Note that if newnode->next!=NULL (newnode is itself a list), then list will be added to its end.

In this example multiple images are linked together as a list:

int quietmmap=1;
size_t minmapsize=-1;
gal_data_t *tmp, *list=NULL;
tmp = gal_fits_img_read("file1.fits", "1", minmapsize, quietmmap,
                        NULL);
gal_list_data_add( &list, tmp );
tmp = gal_fits_img_read("file2.fits", "1", minmapsize, quietmmap,
                        NULL);
gal_list_data_add( &list, tmp );

Function:
void
gal_list_data_add_alloc (gal_data_t **list, void *array, uint8_t type, size_t ndim, size_t *dsize, struct wcsprm *wcs, int clear, size_t minmapsize, int quietmmap, char *name, char *unit, char *comment) ¶

Allocate a new dataset (with gal_data_alloc in Dataset allocation) and put it as the first element of list. Note that if this is the first node to be added to the list, list must be NULL.

Function:
gal_data_t *
gal_list_data_pop (gal_data_t **list) ¶

Pop the top node from list and return it.

Function:
void
gal_list_data_remove (gal_data_t **list, gal_data_t *node) ¶

Remove node from the given list. After finding the given node, this function will just set node->next=NULL and correct the next node of its previous element to its next element (thus “removing” it from the list). If node doesn’t exist in the list, this function won’t make any change to list.

Function:
gal_data_t *
gal_list_data_select_by_name (gal_data_t *list, char *name) ¶

Select the dataset within the list, that has a name element that is identical (case-sensitive) to the given name. If not found, a NULL pointer will be returned.

Note that this dataset will not be popped from the list, only a pointer to it will be returned and if you free it or change its next element, it may harm your original list.

Function:
gal_data_t *
gal_list_data_select_by_id (gal_data_t *table, char *idstr, size_t *index) ¶

Select the dataset within the list that can be identified with the string given to idstr (which can be a counter, starting from 1, or a name). If not found, a NULL pointer will be returned.

Note that this dataset will not be popped from the list, only a pointer to it will be returned and if you free it or change its next element, it may harm your original list.

Function:
void
gal_list_data_reverse (gal_data_t **list) ¶

Reverse the order of the list such that the top node in the list before calling this function becomes the bottom node after it.

Function:
gal_data_t **
gal_list_data_to_array_ptr (gal_data_t *list, size_t *num) ¶

Allocate and return an array of gal_data_t * pointers with the same number of elements as the nodes in list. The pointers will be put in the same order that the list is parsed. Hence the N-th element in the array will point to the same dataset that the N-th node in the list points to.

Function:
size_t
gal_list_data_number (gal_data_t *list) ¶

Return the number of nodes in list.

Function:
gal_data_t *
gal_list_data_last (gal_data_t *list) ¶

Return a pointer to the last node in list.

Function:
void
gal_list_data_free (gal_data_t *list) ¶

Free all the datasets in list along with all the allocated spaces in each.