add circuitpython code

1 files changed, 170 insertions, 0 deletions

diff --git a/circuitpython/py/ringbuf.c b/circuitpython/py/ringbuf.c
new file mode 100644
index 0000000..fe47b50
--- /dev/null
+++ b/circuitpython/py/ringbuf.c
@@ -0,0 +1,170 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2016 Paul Sokolovsky
+ * Copyright (c) 2019 Jim Mussared
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "ringbuf.h"
+
+bool ringbuf_init(ringbuf_t *r, uint8_t *buf, size_t capacity) {
+    r->buf = buf;
+    r->size = capacity;
+    r->iget = r->iput = 0;
+    return r->buf != NULL;
+}
+
+// Dynamic initialization. This should be accessible from a root pointer.
+// capacity is the number of bytes the ring buffer can hold. The actual
+// size of the buffer is one greater than that, due to how the buffer
+// handles empty and full statuses.
+bool ringbuf_alloc(ringbuf_t *r, size_t capacity, bool long_lived) {
+    r->buf = gc_alloc(capacity + 1, false, long_lived);
+    r->size = capacity + 1;
+    r->iget = r->iput = 0;
+    return r->buf != NULL;
+}
+
+void ringbuf_free(ringbuf_t *r) {
+    // Free buf by letting gc take care of it. If the VM has finished already,
+    // this will be safe.
+    r->buf = (uint8_t *)NULL;
+    r->size = 0;
+    ringbuf_clear(r);
+}
+
+size_t ringbuf_capacity(ringbuf_t *r) {
+    return r->size - 1;
+}
+
+// Returns -1 if buffer is empty, else returns byte fetched.
+int ringbuf_get(ringbuf_t *r) {
+    if (r->iget == r->iput) {
+        return -1;
+    }
+    uint8_t v = r->buf[r->iget++];
+    if (r->iget >= r->size) {
+        r->iget = 0;
+    }
+    return v;
+}
+
+int ringbuf_get16(ringbuf_t *r) {
+    int v = ringbuf_peek16(r);
+    if (v == -1) {
+        return v;
+    }
+    r->iget += 2;
+    if (r->iget >= r->size) {
+        r->iget -= r->size;
+    }
+    return v;
+}
+
+// Returns -1 if no room in buffer, else returns 0.
+int ringbuf_put(ringbuf_t *r, uint8_t v) {
+    uint32_t iput_new = r->iput + 1;
+    if (iput_new >= r->size) {
+        iput_new = 0;
+    }
+    if (iput_new == r->iget) {
+        return -1;
+    }
+    r->buf[r->iput] = v;
+    r->iput = iput_new;
+    return 0;
+}
+
+void ringbuf_clear(ringbuf_t *r) {
+    r->iput = r->iget = 0;
+}
+
+// Number of free slots that can be written.
+size_t ringbuf_num_empty(ringbuf_t *r) {
+    return (r->size + r->iget - r->iput - 1) % r->size;
+}
+
+// Number of bytes available to read.
+size_t ringbuf_num_filled(ringbuf_t *r) {
+    return (r->size + r->iput - r->iget) % r->size;
+}
+
+// If the ring buffer fills up, not all bytes will be written.
+// Returns how many bytes were successfully written.
+size_t ringbuf_put_n(ringbuf_t *r, const uint8_t *buf, size_t bufsize) {
+    for (size_t i = 0; i < bufsize; i++) {
+        if (ringbuf_put(r, buf[i]) < 0) {
+            // If ringbuf is full, give up and return how many bytes
+            // we wrote so far.
+            return i;
+        }
+    }
+    return bufsize;
+}
+
+// Returns how many bytes were fetched.
+size_t ringbuf_get_n(ringbuf_t *r, uint8_t *buf, size_t bufsize) {
+    for (size_t i = 0; i < bufsize; i++) {
+        int b = ringbuf_get(r);
+        if (b < 0) {
+            return i;
+        }
+        buf[i] = b;
+    }
+    return bufsize;
+}
+
+int ringbuf_peek16(ringbuf_t *r) {
+    if (r->iget == r->iput) {
+        return -1;
+    }
+    uint32_t iget_a = r->iget + 1;
+    if (iget_a == r->size) {
+        iget_a = 0;
+    }
+    if (iget_a == r->iput) {
+        return -1;
+    }
+    return (r->buf[r->iget] << 8) | (r->buf[iget_a]);
+}
+
+int ringbuf_put16(ringbuf_t *r, uint16_t v) {
+    uint32_t iput_a = r->iput + 1;
+    if (iput_a == r->size) {
+        iput_a = 0;
+    }
+    if (iput_a == r->iget) {
+        return -1;
+    }
+    uint32_t iput_b = iput_a + 1;
+    if (iput_b == r->size) {
+        iput_b = 0;
+    }
+    if (iput_b == r->iget) {
+        return -1;
+    }
+    r->buf[r->iput] = (v >> 8) & 0xff;
+    r->buf[iput_a] = v & 0xff;
+    r->iput = iput_b;
+    return 0;
+}