Squashed 'external/toxcore/c-toxcore/' content from commit 67badf69

git-subtree-dir: external/toxcore/c-toxcore
git-subtree-split: 67badf69416a74e74f6d7eb51dd96f37282b8455

toxav/ring_buffer.c

@@ -0,0 +1,115 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later
+ * Copyright © 2016-2018 The TokTok team.
+ * Copyright © 2013 Tox project.
+ * Copyright © 2013 plutooo
+ */
+#include "ring_buffer.h"
+
+#include <stdlib.h>
+
+#include "../toxcore/ccompat.h"
+
+struct RingBuffer {
+    uint16_t size; /* Max size */
+    uint16_t start;
+    uint16_t end;
+    void   **data;
+};
+
+bool rb_full(const RingBuffer *b)
+{
+    return (b->end + 1) % b->size == b->start;
+}
+
+bool rb_empty(const RingBuffer *b)
+{
+    return b->end == b->start;
+}
+
+/**
+ * @retval NULL on success
+ * @return input value "p" on failure, so caller can free on failed rb_write
+ */
+void *rb_write(RingBuffer *b, void *p)
+{
+    if (b == nullptr) {
+        return p;
+    }
+
+    void *rc = nullptr;
+
+    if ((b->end + 1) % b->size == b->start) { /* full */
+        rc = b->data[b->start];
+    }
+
+    b->data[b->end] = p;
+    b->end = (b->end + 1) % b->size;
+
+    if (b->end == b->start) {
+        b->start = (b->start + 1) % b->size;
+    }
+
+    return rc;
+}
+
+bool rb_read(RingBuffer *b, void **p)
+{
+    if (b->end == b->start) { /* Empty */
+        *p = nullptr;
+        return false;
+    }
+
+    *p = b->data[b->start];
+    b->start = (b->start + 1) % b->size;
+    return true;
+}
+
+RingBuffer *rb_new(int size)
+{
+    RingBuffer *buf = (RingBuffer *)calloc(1, sizeof(RingBuffer));
+
+    if (buf == nullptr) {
+        return nullptr;
+    }
+
+    buf->size = size + 1; /* include empty elem */
+    buf->data = (void **)calloc(buf->size, sizeof(void *));
+
+    if (buf->data == nullptr) {
+        free(buf);
+        return nullptr;
+    }
+
+    return buf;
+}
+
+void rb_kill(RingBuffer *b)
+{
+    if (b != nullptr) {
+        free(b->data);
+        free(b);
+    }
+}
+
+uint16_t rb_size(const RingBuffer *b)
+{
+    if (rb_empty(b)) {
+        return 0;
+    }
+
+    return
+        b->end > b->start ?
+        b->end - b->start :
+        (b->size - b->start) + b->end;
+}
+
+uint16_t rb_data(const RingBuffer *b, void **dest)
+{
+    uint16_t i;
+
+    for (i = 0; i < rb_size(b); ++i) {
+        dest[i] = b->data[(b->start + i) % b->size];
+    }
+
+    return i;
+}