feat: nearly complete POSIX.1-2008 compliant terminal interface implementation

[lunaix-os.git] / lunaix-os / kernel / ds / rbuffer.c

diff --git a/lunaix-os/kernel/ds/rbuffer.c b/lunaix-os/kernel/ds/rbuffer.c
new file mode 100644 (file)
index 0000000..bfcc3a5
--- /dev/null
+++ b/lunaix-os/kernel/ds/rbuffer.c
@@ -0,0 +1,100 @@
+#include <lunaix/ds/rbuffer.h>
+#include <lunaix/mm/valloc.h>
+#include <lunaix/spike.h>
+
+#include <klibc/string.h>
+
+struct rbuffer*
+rbuffer_create(char* buf, size_t maxsz)
+{
+    struct rbuffer* rb = valloc(sizeof(struct rbuffer));
+    rbuffer_init(rb, buf, maxsz);
+
+    return rb;
+}
+
+int
+rbuffer_erase(struct rbuffer* rb)
+{
+    if (rb->len == 0) {
+        return 0;
+    }
+    rb->ptr = (rb->ptr - 1) % rb->maxsz;
+    rb->len--;
+
+    return 1;
+}
+
+int
+rbuffer_put(struct rbuffer* rb, char c)
+{
+    rb->buffer[rb->ptr] = c;
+    rb->ptr = (rb->ptr + 1) % rb->maxsz;
+    rb->len = MIN(rb->len + 1, rb->maxsz);
+
+    return 1;
+}
+
+int
+rbuffer_puts(struct rbuffer* rb, char* buf, size_t len)
+{
+    if (!len)
+        return 0;
+
+    size_t ptr = (rb->ptr + len) % rb->maxsz;
+    size_t nlen = MIN(len, rb->maxsz);
+    size_t ptr_start = (ptr - nlen) % rb->maxsz;
+
+    buf = &buf[nlen];
+    if (ptr_start >= ptr) {
+        size_t llen = rb->maxsz - ptr_start;
+        memcpy(&rb->buffer[ptr_start], &buf[-nlen], llen);
+        memcpy(&rb->buffer[0], &buf[-nlen + llen], ptr + 1);
+    } else {
+        memcpy(&rb->buffer[ptr_start], &buf[-nlen], nlen);
+    }
+
+    rb->ptr = ptr;
+    rb->len = nlen;
+
+    return nlen;
+}
+
+int
+rbuffer_gets(struct rbuffer* rb, char* buf, size_t len)
+{
+    if (!len)
+        return 0;
+
+    size_t nlen = MIN(len, rb->len);
+    size_t ptr_start = (rb->ptr - rb->len) % rb->maxsz;
+    size_t ptr_end = (ptr_start + nlen) % rb->maxsz;
+
+    buf = &buf[nlen];
+    if (ptr_start >= ptr_end) {
+        size_t llen = rb->maxsz - ptr_start;
+        memcpy(&buf[-nlen], &rb->buffer[ptr_start], llen);
+        memcpy(&buf[-nlen + llen], &rb->buffer[0], ptr_end + 1);
+    } else {
+        memcpy(&buf[-nlen], &rb->buffer[ptr_start], nlen);
+    }
+
+    rb->len -= nlen;
+
+    return nlen;
+}
+
+int
+rbuffer_get(struct rbuffer* rb, char* c)
+{
+    if (rb->len == 0) {
+        return 0;
+    }
+
+    size_t ptr_start = (rb->ptr - rb->len) % rb->maxsz;
+    rb->len--;
+
+    *c = rb->buffer[ptr_start];
+
+    return 1;
+}
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