From eedb2c3c5286a10ba059640ca84a34c488186e37 Mon Sep 17 00:00:00 2001
From: Pierre Curto <pierre.curto@gmail.com>
Date: Fri, 25 Aug 2023 12:48:53 +0200
Subject: [PATCH] std/collections: add RingBuffer.popc()

Signed-off-by: Pierre Curto <pierre.curto@gmail.com>
---
 lib/std/collections/ringbuffer.c3          | 15 +++++++++++++++
 test/unit/stdlib/collections/ringbuffer.c3 |  5 ++++-
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/lib/std/collections/ringbuffer.c3 b/lib/std/collections/ringbuffer.c3
index 45fa28a6f..507dd9116 100644
--- a/lib/std/collections/ringbuffer.c3
+++ b/lib/std/collections/ringbuffer.c3
@@ -37,6 +37,21 @@ fn Type RingBuffer.getc(&self, usz index)
 	return self.buf[index - avail];
 }
 
+fn Type! RingBuffer.popc(&self)
+{
+	switch
+	{
+		case self.written == 0:
+			return SearchResult.MISSING?;
+		case self.written < SIZE:
+			self.written--;
+			return self.buf[self.written];
+		default:
+			self.head = (self.head - 1) % SIZE;
+			return self.buf[self.head];
+	}
+}
+
 fn usz RingBuffer.get(&self, usz index, Type[] buffer)
 {
 	index %= SIZE;
diff --git a/test/unit/stdlib/collections/ringbuffer.c3 b/test/unit/stdlib/collections/ringbuffer.c3
index cd6b8c047..158c732e7 100644
--- a/test/unit/stdlib/collections/ringbuffer.c3
+++ b/test/unit/stdlib/collections/ringbuffer.c3
@@ -4,7 +4,7 @@ import std::io;
 
 def Buffer = RingBuffer(<char, 4>);
 
-fn void putc_getc()
+fn void! putc_getc()
 {
 	Buffer rb;
 	rb.init();
@@ -23,4 +23,7 @@ fn void putc_getc()
 	assert(rb.getc(1) == 3);
 	assert(rb.getc(2) == 4);
 	assert(rb.getc(3) == 5);
+
+	char c = rb.popc()!;
+	assert(c == 5);
 }
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