Add a buffered writer to stdlib _io module.

1 files changed, 41 insertions, 3 deletions

diff --git a/src/lib/_io.rs b/src/lib/_io.rs
index d78f8835..096c768a 100644
--- a/src/lib/_io.rs
+++ b/src/lib/_io.rs
@@ -2,6 +2,10 @@ type buf_reader = unsafe obj {
   fn read() -> vec[u8];
 };
 
+type buf_writer = unsafe obj {
+  fn write(vec[u8] v);
+};
+
 fn default_bufsz() -> uint {
   ret 4096u;
 }
@@ -10,7 +14,7 @@ fn new_buf() -> vec[u8] {
   ret _vec.alloc[u8](default_bufsz());
 }
 
-fn new_buf_reader(str s) -> buf_reader {
+fn new_buf_reader(str path) -> buf_reader {
 
   unsafe obj fd_buf_reader(int fd, mutable vec[u8] buf) {
 
@@ -39,11 +43,45 @@ fn new_buf_reader(str s) -> buf_reader {
     }
   }
 
-  auto fd = os.libc.open(_str.buf(s), 0);
+  auto fd = os.libc.open(_str.buf(path), 0);
   if (fd < 0) {
-    log "error opening file";
+    log "error opening file for reading";
     log sys.rustrt.last_os_error();
     fail;
   }
   ret fd_buf_reader(fd, new_buf());
 }
+
+fn new_buf_writer(str path) -> buf_writer {
+
+  unsafe obj fd_buf_writer(int fd) {
+
+    fn write(vec[u8] v) {
+      auto len = _vec.len[u8](v);
+      auto count = 0u;
+      auto vbuf;
+      while (count < len) {
+        vbuf = _vec.buf_off[u8](v, count);
+        auto nout = os.libc.write(fd, vbuf, len);
+        if (nout < 0) {
+          log "error dumping buffer";
+          log sys.rustrt.last_os_error();
+          fail;
+        }
+        count += nout as uint;
+      }
+    }
+
+    drop {
+      os.libc.close(fd);
+    }
+  }
+
+  auto fd = os.libc.open(_str.buf(path), 0);
+  if (fd < 0) {
+    log "error opening file for writing";
+    log sys.rustrt.last_os_error();
+    fail;
+  }
+  ret fd_buf_writer(fd);
+}