[gnuastro-commits] master 1fba94b: Library (data.h): two functions to allocate and free gal_data_t **

[Mohammad Akhlaghi]

branch: master
commit 1fba94b33cb9e7ae51a3944418d7ebc4464be44b
Author: Mohammad Akhlaghi <mohammad@akhlaghi.org>
Commit: Mohammad Akhlaghi <mohammad@akhlaghi.org>

    Library (data.h): two functions to allocate and free gal_data_t **
    
    In many contexts, it is necessary to pre-allocate a list of pointers to
    datasets which are then filled at later stages of the processing. With the
    two new 'gal_data_array_ptr_calloc' and 'gal_data_array_ptr_free'
    functions, it is now very easy to allocate such an array and later free it.
---
 NEWS                |  2 ++
 doc/gnuastro.texi   |  9 +++++++++
 lib/data.c          | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 lib/gnuastro/data.h |  5 +++++
 4 files changed, 65 insertions(+)

diff --git a/NEWS b/NEWS
index 19f398d..a1b57c6 100644
--- a/NEWS
+++ b/NEWS
@@ -72,6 +72,8 @@ See the end of the file for license conditions.
    - Spectral lines library: SiIII, OIII, CIV, NV and rest of Lyman series.
    - GAL_CONFIG_HAVE_WCSLIB_DIS_H: if the host's WCSLIB supports distortions.
    - GAL_CONFIG_HAVE_WCSLIB_MJDREF: if the host's WCSLIB reads MJDREF keyword.
+   - gal_data_array_ptr_calloc: Allocate array of pointers to gal_data_t
+   - gal_data_array_ptr_free: Free all the datasets within the array and 
itself.
    - gal_fits_key_list_title_add: Add a title key word to the list.
    - gal_fits_key_list_title_add_end: Add a title key word to the list's end.
    - GAL_INTERPOLATE_NEIGHBORS_METRIC_RADIAL: Radial metric for interpolation.
diff --git a/doc/gnuastro.texi b/doc/gnuastro.texi
index fd168cb..f7e1b37 100644
--- a/doc/gnuastro.texi
+++ b/doc/gnuastro.texi
@@ -20213,6 +20213,15 @@ element of all the datasets will also be freed, see 
@ref{Generic data
 container}.
 @end deftypefun
 
+@deftypefun {gal_data_t **} gal_data_array_ptr_calloc (size_t @code{size})
+Allocate an array of pointers to Gnuastro's generic data structure and 
initalize all pointers to @code{NULL}.
+This is useful when you want to allocate individual datasets later (for 
example with @code{gal_data_alloc}).
+@end deftypefun
+
+@deftypefun void gal_data_array_ptr_free (gal_data_t @code{**dataptr}, size_t 
@code{size}, int @code{free_array});
+Free all the individual datasets within the elements of @code{dataptr}, then 
free @code{dataptr} itself (the array of pointers that was probably allocated 
with @code{gal_data_array_ptr_calloc}.
+@end deftypefun
+
 @node Copying datasets,  , Arrays of datasets, Library data container
 @subsubsection Copying datasets
 
diff --git a/lib/data.c b/lib/data.c
index a487bcf..f41e29e 100644
--- a/lib/data.c
+++ b/lib/data.c
@@ -391,6 +391,55 @@ gal_data_array_free(gal_data_t *dataarr, size_t size, int 
free_array)
 
 
 
+/* Create an array of gal_data_t pointers and initializes them. */
+gal_data_t **
+gal_data_array_ptr_calloc(size_t size)
+{
+  size_t i;
+  gal_data_t **out;
+
+  /* Allocate the array to keep the pointers. */
+  errno=0;
+  out=malloc(size*sizeof *out);
+  if(out==NULL)
+    error(EXIT_FAILURE, errno, "%s: %zu bytes for 'out'", __func__,
+          size*sizeof *out);
+
+  /* Initialize all the pointers to NULL and return. */
+  for(i=0;i<size;++i) out[i]=NULL;
+  return out;
+}
+
+
+
+
+
+/* Assuming that we have an array of pointers to data structures, this
+   function frees them. */
+void
+gal_data_array_ptr_free(gal_data_t **dataptr, size_t size, int free_array)
+{
+  size_t i;
+  for(i=0;i<size;++i)
+    {
+      /* If the user doesn't want to free the array, it must be because
+         they are keeping its pointer somewhere else (that their own
+         responsability!), so we can just set it to NULL for the
+         'gal_data_free' to not free it. */
+      if(free_array==0)
+        dataptr[i]->array=NULL;
+
+      /* Free this data structure. */
+      gal_data_free(dataptr[i]);
+    }
+
+  /* Free the 'gal_data_t **'. */
+  free(dataptr);
+}
+
+
+
+
 
 
 
diff --git a/lib/gnuastro/data.h b/lib/gnuastro/data.h
index 0d8d2f7..63c6967 100644
--- a/lib/gnuastro/data.h
+++ b/lib/gnuastro/data.h
@@ -263,6 +263,11 @@ gal_data_array_calloc(size_t size);
 void
 gal_data_array_free(gal_data_t *dataarr, size_t num, int free_array);
 
+gal_data_t **
+gal_data_array_ptr_calloc(size_t size);
+
+void
+gal_data_array_ptr_free(gal_data_t **dataptr, size_t size, int free_array);