From eaf189b545dd1184113283f84cbf165d1cdcd4ef Mon Sep 17 00:00:00 2001
From: antifallobst <antifallobst@systemausfall.org>
Date: Thu, 20 Apr 2023 22:10:02 +0200
Subject: [PATCH] feature (utils): implemented streams

---
 kernel/inc/utils/stream.h | 20 ++++++++++++
 kernel/src/utils/stream.c | 64 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 84 insertions(+)
 create mode 100644 kernel/inc/utils/stream.h
 create mode 100644 kernel/src/utils/stream.c

diff --git a/kernel/inc/utils/stream.h b/kernel/inc/utils/stream.h
new file mode 100644
index 0000000..748ed5f
--- /dev/null
+++ b/kernel/inc/utils/stream.h
@@ -0,0 +1,20 @@
+// This file is part of noxos and licensed under the MIT open source license
+
+#ifndef NOX_STREAM_H
+#define NOX_STREAM_H
+
+#include "utils/stdtypes.h"
+
+typedef struct {
+    uint8_t* buffer;
+    uint32_t size;
+    uint32_t pos_sender;
+    uint32_t pos_receiver;
+} stream_T;
+
+stream_T*   stream_alloc    (uint32_t size);
+void        stream_destruct (stream_T* stream);
+uint32_t    stream_write    (stream_T* stream, void* buffer_in, uint32_t n);
+uint32_t    stream_read     (stream_T* stream, void* buffer_out, uint32_t n);
+
+#endif //NOX_STREAM_H
diff --git a/kernel/src/utils/stream.c b/kernel/src/utils/stream.c
new file mode 100644
index 0000000..9ab297c
--- /dev/null
+++ b/kernel/src/utils/stream.c
@@ -0,0 +1,64 @@
+// This file is part of noxos and licensed under the MIT open source license
+
+#include "utils/stream.h"
+#include "utils/memory.h"
+#include "utils/math.h"
+
+stream_T* stream_alloc(uint32_t size) {
+    stream_T* stream = memory_allocate(sizeof(stream_T));
+
+    stream->buffer       = memory_allocate(size);
+    stream->size         = size;
+    stream->pos_sender   = 0;
+    stream->pos_receiver = 0;
+
+    return stream;
+}
+
+void stream_destruct(stream_T* stream) {
+    memory_free(stream->buffer);
+    memory_free(stream);
+}
+
+#include "utils/logger.h"
+
+uint32_t stream_write(stream_T* stream, void* buffer_in, uint32_t n) {
+    uint32_t num_top;
+    uint32_t num_bottom;
+    if (stream->pos_receiver > stream->pos_sender) {
+        num_top    = MIN(n, stream->pos_receiver - stream->pos_sender - 1);
+        num_bottom = 0;
+    } else {
+        num_top    = MIN(n, stream->size - stream->pos_sender);
+        num_bottom = MIN(n - num_top, stream->pos_receiver - 1);
+    }
+
+    memory_copy(buffer_in, &stream->buffer[stream->pos_sender], num_top);
+    memory_copy(&buffer_in[num_top], stream->buffer, num_bottom);
+
+    stream->pos_sender += num_top + num_bottom;
+    stream->pos_sender %= stream->size;
+
+    return num_top + num_bottom;
+}
+
+uint32_t stream_read(stream_T* stream, void* buffer_out, uint32_t n) {
+    uint32_t num_top;
+    uint32_t num_bottom;
+
+    if (stream->pos_sender > stream->pos_receiver) {
+        num_top    = MIN(n, stream->pos_sender - stream->pos_receiver - 1);
+        num_bottom = 0;
+    } else {
+        num_top    = MIN(n, stream->size - stream->pos_receiver);
+        num_bottom = MIN(n - num_top, stream->pos_sender - 1);
+    }
+
+    memory_copy(&stream->buffer[stream->pos_receiver], buffer_out, num_top);
+    memory_copy(stream->buffer, &buffer_out[num_top], num_bottom);
+
+    stream->pos_receiver += num_top + num_bottom;
+    stream->pos_receiver %= stream->size;
+
+    return num_top + num_bottom;
+}
\ No newline at end of file