From 1598c2a362fec3de547616cb8020a315631a4c15 Mon Sep 17 00:00:00 2001
From: Ralph Ronnquist <ralph.ronnquist@gmail.com>
Date: Mon, 11 Jul 2022 00:38:51 +1000
Subject: [PATCH] revise hashvector_contents to optionally create the target
 vector

---
 vector/hashvector.c | 35 ++++++++++++++++++++---------------
 vector/hashvector.h | 19 +++++++++++++------
 2 files changed, 33 insertions(+), 21 deletions(-)

diff --git a/vector/hashvector.c b/vector/hashvector.c
index b39ef5e..8b88135 100644
--- a/vector/hashvector.c
+++ b/vector/hashvector.c
@@ -158,23 +158,28 @@ int hashvector_delete(hashvector *hv,void *item) {
     return 1;
 }
 
-// Copy items into a vector. Returns 0 on success and -1 on failure.
-int hashvector_contents(hashvector *hv,vector *pv) {
-    if ( vector_resize( pv, hv->fill, 0, 0 ) ) {
-	return -1;
-    }
-    unsigned long from = 0;
-    unsigned long to = 0;
-    for ( ; to < hv->fill; from++ ) {
-	void **slot = vector_next_used( &hv->table, &from );
-	if ( slot == 0 ) {
-	    break;
-	}
-	if ( *slot != HV_HOLE ) {
-	    vector_set( pv, to++, *slot );
+vector *hashvector_contents(
+    hashvector *hv,enum vector_variant variant,vector *v)
+{
+    if ( v == 0 ) {
+	if ( hv->fill == 0 ) {
+	    return 0;
 	}
+	v = (vector*) malloc( sizeof( vector ) );
+    } else {
+	vector_resize( v, 0, vector_clear_any, 0 );
     }
-    return 0;
+    (*v) = (vector) { .variant = variant, 0, 0 };
+    if ( hv->fill == 0 ) {
+	return v;
+    }
+    vector_resize( v, hv->fill, 0, 0 );
+    vector_index i;
+    vector_index j = 0;
+    for ( i = 0; i < v->size; i++, j++ ) {
+	vector_set( v, i, hashvector_next( hv, &j, 0 ) );
+    }
+    return v;
 }
 
 // A simple binary hashcode, (before modulo table size)
diff --git a/vector/hashvector.h b/vector/hashvector.h
index 2754fb1..b57aede 100644
--- a/vector/hashvector.h
+++ b/vector/hashvector.h
@@ -134,16 +134,23 @@ extern int hashvector_delete(hashvector *hv,void *item);
  * 
  * \param hv is the \ref hashvector concerned.
  *
- * \param pv is the \ref vector to copy the content into.
+ * \param variant is the desired vector variant.
  *
- * \returns \b -1 if the required resizing of the \ref vector to the
- * \ref hashvector \b fill fails, otherwise \b 0 after having copied
- * the hashvector items in their internal order of appearance into the
- * \ref vector.
+ * \param pv is the optional \ref vector to copy the content into.
+ *
+ * \returns the \ref vector with the \ref hashvector content
+ *
+ * If \pv is null, then a new vector is allocated and handed out for
+ * the caller to reclaim unless the hashvector is empty in which case
+ * this function returns 0.
+ *
+ * If \b pv is not null, it is first cleared, and then populated with
+ * the content from the hashvector. The populated vector is returned.
  *
  * \related hashvector
  */
-extern int hashvector_contents(hashvector *hv,vector *pv);
+extern vector *hashvector_contents(
+    hashvector *hv,enum vector_variant variant,vector *pv);
 
 /**
  * \brief This is a utility function to compute and return a hashcode
-- 
2.39.2