Tidy up ringbuf and make tests

src/ringbuf.c

@@ -0,0 +1,93 @@
+#ifdef __linux
+#define _GNU_SOURCE
+#include <unistd.h>
+#include <sys/mman.h>
+#include <errno.h>
+#include <string.h>
+#include <stdio.h>
+#include "ucore/ringbuf.h"
+
+
+int uc_ringbuf_init(UCRingBuf *rb, uint32_t sz)
+{
+
+    uint32_t pagesz = getpagesize();
+    // Round up to page size
+    sz = ((sz + pagesz - 1) / pagesz) * pagesz;
+    /* Reserve contiguous address space*/
+    void *base = mmap(NULL, sz * 2, PROT_NONE, MAP_POPULATE|MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
+    if (base == NULL) {
+        return -errno;
+    }
+    /* MAP_PRIVATE doesn't work */
+    base = mmap(base, sz * 1, PROT_READ|PROT_WRITE, MAP_POPULATE|MAP_ANONYMOUS|MAP_FIXED|MAP_SHARED, -1, 0);
+    if (base == MAP_FAILED) {
+        return -errno;
+    }
+    void *mbase = mremap(base, sz * 1, sz, MREMAP_FIXED|MREMAP_MAYMOVE|MREMAP_DONTUNMAP, base + sz);
+    if (mbase == MAP_FAILED) {
+        munmap(base, sz);
+        return -errno;
+
+    }
+
+    rb->base = base;
+    rb->sz = sz;
+    rb->read_idx = 0;
+    rb->write_idx = 0;
+
+    return 0;
+}
+
+int uc_ringbuf_destroy(UCRingBuf *rb)
+{
+    int rc = munmap(rb->base, rb->sz);
+    if (rc != 0) {
+        return -errno;
+    }
+
+    rc = munmap(rb->base + rb->sz, rb->sz);
+    if (rc != 0) {
+        return -errno;
+    }
+
+    rb->base = NULL;
+
+    return 0;
+}
+
+uint32_t uc_ringbuf_available(const UCRingBuf *rb)
+{
+    return rb->sz - rb->write_idx + rb->read_idx;
+}
+
+int uc_ringbuf_write(UCRingBuf *rb, const void *restrict data, uint32_t len)
+{
+    if (rb->write_idx - rb->read_idx + len > rb->sz) {
+        return -ENOMEM;
+    }
+    memcpy(&rb->base[rb->write_idx], data, len);
+    rb->write_idx += len;
+
+    return 0;
+}
+
+int uc_ringbuf_read(UCRingBuf *rb, void *restrict data, uint32_t len)
+{
+    if (uc_ringbuf_len(rb) < len) {
+        return -ENOMEM;
+    }
+
+    memcpy(data, &rb->base[rb->read_idx], len);
+
+    rb->read_idx += len;
+    if (rb->read_idx == rb->write_idx) {
+        rb->read_idx = rb->write_idx = 0;
+    } else if (rb->read_idx > rb->sz) {
+        rb->read_idx -= rb->sz;
+        rb->write_idx -= rb->sz;
+    }
+    return 0;
+}
+
+#endif