From 21055a1e5d34dda1b8151dd46a6bedca22bd73d9 Mon Sep 17 00:00:00 2001
From: Nicholas Noll <nbnoll@eml.cc>
Date: Sat, 18 Apr 2020 13:40:53 -0700
Subject: feat: added prototype of io/buffered io

---
 src/bufio/writer.c | 95 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 95 insertions(+)
 create mode 100644 src/bufio/writer.c

(limited to 'src/bufio/writer.c')

diff --git a/src/bufio/writer.c b/src/bufio/writer.c
new file mode 100644
index 0000000..07573d5
--- /dev/null
+++ b/src/bufio/writer.c
@@ -0,0 +1,95 @@
+#include "impl.h"
+
+struct bufio·Writer
+{
+    io·Writer w;
+    Buffer    buf;
+};
+
+// Constructor/destructor.
+
+bufio·Writer*
+bufio·newwriter(io·Writer w)
+{
+    bufio·Writer* bw = newbuffer(offsetof(bufio·Writer, buf), 0);
+    bw->w            = w;
+    bw->buf.pos      = bw->buf.base;
+
+    return bw;
+}
+
+error
+bufio·freewriter(bufio·Writer* w)
+{
+    free(w);
+
+    return 0;
+}
+
+// Write will write n bytes from the input buffer into the storage buffer.
+// Returns the actual number of bytes written.
+int
+bufio·write(bufio·Writer* w, byte* buf, int count)
+{
+    int   remain = count;
+    byte* wtr    = buf;
+
+    int n, nw;
+    while (remain > 0) {
+        int bdiff = w->buf.end - w->buf.pos;
+        n         = (bdiff > remain) ? remain : bdiff;
+        if (!n) {
+            if (w->buf.eof) break;
+            nw = w->w.write(w->w.impl, buf, count);
+            if (nw < w->buf.size) {
+                w->buf.eof = 1;
+                return BUF·err;
+            }
+            w->buf.off += nw;
+            w->buf.pos = w->buf.base;
+        }
+        memmove(w->buf.pos, wtr, n);
+        wtr += n;
+        w->buf.pos += n;
+        remain -= n;
+    }
+
+    return count - remain;
+}
+
+error
+bufio·put(bufio·Writer* w, byte c)
+{
+    int diff;
+putbyte:
+    diff = w->buf.end - w->buf.pos;
+    if (diff) {
+        *w->buf.pos++ = c;
+        return 0;
+    }
+    if (bufio·flush(w) != BUF·err) goto putbyte;
+
+    return BUF·err;
+}
+
+error
+bufio·flush(bufio·Writer* w)
+{
+    int active = (w->buf.eof == 0);
+
+    int n, nw;
+    if (active && w) {
+        n = w->buf.pos - w->buf.base;
+        if (!n) return 0;
+
+        nw = w->w.write(w->w.impl, w->buf.base, n);
+        if (nw == n) {
+            w->buf.off += n;
+            return 0;
+        }
+        w->buf.eof = 1;
+        w->buf.pos = w->buf.end;
+    }
+
+    return BUF·err;
+}
-- 
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