From cc64a9ae6c4ca7518ba904d6cdf38b3d8dccbbf7 Mon Sep 17 00:00:00 2001
From: Thomas White <taw@physics.org>
Date: Tue, 5 Dec 2017 12:14:44 +0100
Subject: Add const versions of RefList iteration

---
 libcrystfel/src/reflist.c | 113 +++++++++++++++++++++++++++++++++++++++++++++-
 libcrystfel/src/reflist.h |   2 +
 2 files changed, 114 insertions(+), 1 deletion(-)

diff --git a/libcrystfel/src/reflist.c b/libcrystfel/src/reflist.c
index 6f44681d..707c802e 100644
--- a/libcrystfel/src/reflist.c
+++ b/libcrystfel/src/reflist.c
@@ -955,7 +955,8 @@ struct _reflistiterator {
 	int stack_size;
 	int stack_ptr;
 	Reflection **stack;
-
+	const Reflection **stack_const;
+	int is_const;
 };
 
 
@@ -980,6 +981,7 @@ Reflection *first_refl(RefList *list, RefListIterator **piter)
 	iter->stack_size = 32;
 	iter->stack = malloc(iter->stack_size*sizeof(Reflection *));
 	iter->stack_ptr = 0;
+	iter->is_const = 0;
 	*piter = iter;
 
 	if ( list == NULL ) return NULL;
@@ -1013,6 +1015,60 @@ Reflection *first_refl(RefList *list, RefListIterator **piter)
 }
 
 
+/**
+ * first_refl_const:
+ * @list: A %RefList to iterate over
+ * @piter: Address at which to store a %RefListIterator
+ *
+ * As first_refl(), except returns a const %Reflection.
+ * Use this when you don't need to modify any of the reflections.
+ *
+ * Returns: the first reflection in the list.
+ *
+ **/
+const Reflection *first_refl_const(const RefList *list, RefListIterator **piter)
+{
+	const Reflection *refl;
+	RefListIterator *iter;
+
+	iter = malloc(sizeof(struct _reflistiterator));
+	iter->stack_size = 32;
+	iter->stack_const = malloc(iter->stack_size*sizeof(Reflection *));
+	iter->stack_ptr = 0;
+	iter->is_const = 1;
+	*piter = iter;
+
+	if ( list == NULL ) return NULL;
+
+	refl = list->head;
+
+	do {
+
+		if ( refl != NULL ) {
+			iter->stack_const[iter->stack_ptr++] = refl;
+			if ( iter->stack_ptr == iter->stack_size ) {
+				iter->stack_size += 32;
+				iter->stack_const = realloc(iter->stack_const,
+				         iter->stack_size*sizeof(Reflection *));
+			}
+			refl = refl->child[0];
+			continue;
+		}
+
+		if ( iter->stack_ptr == 0 ) {
+			free(iter->stack_const);
+			free(iter);
+			return NULL;
+		}
+
+		refl = iter->stack_const[--iter->stack_ptr];
+
+		return refl;
+
+	} while ( 1 );
+}
+
+
 /**
  * next_refl:
  * @refl: A reflection
@@ -1026,6 +1082,8 @@ Reflection *first_refl(RefList *list, RefListIterator **piter)
  **/
 Reflection *next_refl(Reflection *refl, RefListIterator *iter)
 {
+	assert(!iter->is_const);
+
 	/* Are there more reflections with the same indices? */
 	if ( refl->next != NULL ) {
 		return refl->next;
@@ -1065,6 +1123,59 @@ Reflection *next_refl(Reflection *refl, RefListIterator *iter)
 }
 
 
+/**
+ * next_refl_const:
+ * @refl: A reflection
+ * @iter: A %RefListIterator
+ *
+ * As next_refl(), except returns a const %Reflection.
+ * Use this when you don't need to modify any of the reflections.
+ *
+ * Returns: the next reflection in the list, or NULL if no more.
+ *
+ **/
+const Reflection *next_refl_const(const Reflection *refl, RefListIterator *iter)
+{
+	assert(iter->is_const);
+
+	/* Are there more reflections with the same indices? */
+	if ( refl->next != NULL ) {
+		return refl->next;
+	} else {
+
+		/* No, so rewind back to the head of the list */
+		while ( refl->prev != NULL ) {
+			refl = refl->prev;
+		}
+
+	}
+
+	refl = refl->child[1];
+	do {
+
+		if ( refl != NULL ) {
+
+			iter->stack_const[iter->stack_ptr++] = refl;
+			if ( iter->stack_ptr == iter->stack_size ) {
+				iter->stack_size += 32;
+				iter->stack_const = realloc(iter->stack_const,
+				         iter->stack_size*sizeof(Reflection *));
+			}
+			refl = refl->child[0];
+			continue;
+
+		}
+		if ( iter->stack_ptr == 0 ) {
+			free(iter->stack_const);
+			free(iter);
+			return NULL;
+		}
+
+		return iter->stack_const[--iter->stack_ptr];
+
+	} while ( 1 );
+}
+
 /*********************************** Voodoo ***********************************/
 
 static int recursive_depth(Reflection *refl)
diff --git a/libcrystfel/src/reflist.h b/libcrystfel/src/reflist.h
index 3f0ff783..f2126ac9 100644
--- a/libcrystfel/src/reflist.h
+++ b/libcrystfel/src/reflist.h
@@ -132,6 +132,8 @@ extern void add_refl_to_list(Reflection *refl, RefList *list);
 /* Iteration */
 extern Reflection *first_refl(RefList *list, RefListIterator **piter);
 extern Reflection *next_refl(Reflection *refl, RefListIterator *iter);
+extern const Reflection *first_refl_const(const RefList *list, RefListIterator **piter);
+extern const Reflection *next_refl_const(const Reflection *refl, RefListIterator *iter);
 
 /* Misc */
 extern int num_reflections(RefList *list);
-- 
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