From f024ba4245b37c80dce976c77b519c90115fd205 Mon Sep 17 00:00:00 2001
From: Thomas Schmucker <ts@its1.de>
Date: Fri, 14 Aug 2020 18:28:32 +0200
Subject: Implement deque_push_front()

---
 deque.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

(limited to 'deque.c')

diff --git a/deque.c b/deque.c
index 56df165..5800997 100644
--- a/deque.c
+++ b/deque.c
@@ -164,6 +164,22 @@ deque_push_back(struct deque *d, T data)
 	++d->size;
 }
 
+void
+deque_push_front(struct deque *d, T data)
+{
+	if ( d->offset == 0 ) { // Im ersten Element ist kein Platz mehr frei!
+		map_prepend_chunk(d);
+		d->offset = CHUNK_CAPACITY;
+	}
+
+	--d->offset;
+
+	size_t chunk_num = (d->offset / CHUNK_CAPACITY + d->map_begin) % d->map_capacity;
+
+	d->map[chunk_num][d->offset] = data;
+	++d->size;
+}
+
 bool
 deque_pop_front(struct deque *d, T *data)
 {
@@ -209,6 +225,10 @@ main(void)
 		//deque_show(&c);
 	}
 
+	for ( int i = 0; i != 100; ++i ) {
+		deque_push_front(&c, 1000 + i);
+	}
+
 	T data;
 	while ( deque_pop_front(&c, &data) ) {
 		printf("%u, ", data);
-- 
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