From 1de5d4e330563d1cfd889534ba3c81979af607b7 Mon Sep 17 00:00:00 2001
From: Vicki Pfau <vi@endrift.com>
Date: Tue, 21 Mar 2017 22:30:30 -0700
Subject: [PATCH] Util: Add CircleBufferWrite

---
 include/mgba-util/circle-buffer.h |  1 +
 src/util/circle-buffer.c          | 28 ++++++++++++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/include/mgba-util/circle-buffer.h b/include/mgba-util/circle-buffer.h
index 28d436e03..6bce02e61 100644
--- a/include/mgba-util/circle-buffer.h
+++ b/include/mgba-util/circle-buffer.h
@@ -29,6 +29,7 @@ int CircleBufferWrite32(struct CircleBuffer* buffer, int32_t value);
 int CircleBufferRead8(struct CircleBuffer* buffer, int8_t* value);
 int CircleBufferRead16(struct CircleBuffer* buffer, int16_t* value);
 int CircleBufferRead32(struct CircleBuffer* buffer, int32_t* value);
+size_t CircleBufferWrite(struct CircleBuffer* buffer, const void* input, size_t length);
 size_t CircleBufferRead(struct CircleBuffer* buffer, void* output, size_t length);
 size_t CircleBufferDump(const struct CircleBuffer* buffer, void* output, size_t length);
 
diff --git a/src/util/circle-buffer.c b/src/util/circle-buffer.c
index deb426473..53a3087ed 100644
--- a/src/util/circle-buffer.c
+++ b/src/util/circle-buffer.c
@@ -205,6 +205,34 @@ int CircleBufferRead32(struct CircleBuffer* buffer, int32_t* value) {
 	return 4;
 }
 
+size_t CircleBufferWrite(struct CircleBuffer* buffer, const void* input, size_t length) {
+	int8_t* data = buffer->writePtr;
+	if (buffer->size + length > buffer->capacity) {
+		return 0;
+	}
+	size_t remaining = buffer->capacity - ((int8_t*) data - (int8_t*) buffer->data);
+	if (length <= remaining) {
+		memcpy(data, input, length);
+		if (length == remaining) {
+			buffer->writePtr = buffer->data;
+		} else {
+			buffer->writePtr = (int8_t*) data + length;
+		}
+	} else {
+		memcpy(data, input, remaining);
+		memcpy(buffer->data, (int8_t*) input + remaining, length - remaining);
+		buffer->writePtr = (int8_t*) buffer->data + length - remaining;
+	}
+
+	buffer->size += length;
+#ifndef NDEBUG
+	if (!_checkIntegrity(buffer)) {
+		abort();
+	}
+#endif
+	return length;
+}
+
 size_t CircleBufferRead(struct CircleBuffer* buffer, void* output, size_t length) {
 	int8_t* data = buffer->readPtr;
 	if (buffer->size == 0) {