From 5d93dfbc2cca21806970d3a6a26b488191703f0b Mon Sep 17 00:00:00 2001
From: Paul Sokolovsky <pfalcon@users.sourceforge.net>
Date: Fri, 25 Mar 2016 01:10:49 +0200
Subject: [PATCH] py/modio: Initial implementation of io.BufferedWriter class.

Just .write() method implemented currently.
---
 py/modio.c    | 72 +++++++++++++++++++++++++++++++++++++++++++++++++++
 py/mpconfig.h |  5 ++++
 py/qstrdefs.h |  3 +++
 3 files changed, 80 insertions(+)

diff --git a/py/modio.c b/py/modio.c
index e1c51b9a9d..04d3d79af3 100644
--- a/py/modio.c
+++ b/py/modio.c
@@ -24,13 +24,82 @@
  * THE SOFTWARE.
  */
 
+#include <assert.h>
+#include <string.h>
+
+#include "py/runtime.h"
 #include "py/builtin.h"
+#include "py/stream.h"
 
 #if MICROPY_PY_IO
 
 extern const mp_obj_type_t mp_type_fileio;
 extern const mp_obj_type_t mp_type_textio;
 
+#if MICROPY_PY_IO_BUFFEREDWRITER
+typedef struct _mp_obj_bufwriter_t {
+    mp_obj_base_t base;
+    mp_obj_t stream;
+    size_t alloc;
+    size_t len;
+    byte buf[0];
+} mp_obj_bufwriter_t;
+
+STATIC mp_obj_t bufwriter_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
+    mp_arg_check_num(n_args, n_kw, 2, 2, false);
+    size_t alloc = mp_obj_get_int(args[1]);
+    mp_obj_bufwriter_t *o = m_new_obj_var(mp_obj_bufwriter_t, byte, alloc);
+    o->base.type = type;
+    o->stream = args[0];
+    o->alloc = alloc;
+    o->len = 0;
+    return o;
+}
+
+STATIC mp_uint_t bufwriter_write(mp_obj_t self_in, const void *buf, mp_uint_t size, int *errcode) {
+    mp_obj_bufwriter_t *self = MP_OBJ_TO_PTR(self_in);
+
+    mp_uint_t org_size = size;
+
+    while (size > 0) {
+        mp_uint_t rem = self->alloc - self->len;
+        if (size < rem) {
+            memcpy(self->buf + self->len, buf, size);
+            self->len += size;
+            return org_size;
+        }
+
+        memcpy(self->buf + self->len, buf, rem);
+        buf = (byte*)buf + rem;
+        size -= rem;
+        mp_uint_t out_sz = mp_stream_writeall(self->stream, self->buf, self->alloc, errcode);
+        if (out_sz == MP_STREAM_ERROR) {
+            return MP_STREAM_ERROR;
+        }
+        self->len = 0;
+    }
+
+    return org_size;
+}
+
+STATIC const mp_map_elem_t bufwriter_locals_dict_table[] = {
+    { MP_OBJ_NEW_QSTR(MP_QSTR_write), (mp_obj_t)&mp_stream_write_obj },
+};
+STATIC MP_DEFINE_CONST_DICT(bufwriter_locals_dict, bufwriter_locals_dict_table);
+
+STATIC const mp_stream_p_t bufwriter_stream_p = {
+    .write = bufwriter_write,
+};
+
+STATIC const mp_obj_type_t bufwriter_type = {
+    { &mp_type_type },
+    .name = MP_QSTR_BufferedWriter,
+    .make_new = bufwriter_make_new,
+    .stream_p = &bufwriter_stream_p,
+    .locals_dict = (mp_obj_t)&bufwriter_locals_dict,
+};
+#endif // MICROPY_PY_IO_BUFFEREDWRITER
+
 STATIC const mp_rom_map_elem_t mp_module_io_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR__io) },
     // Note: mp_builtin_open_obj should be defined by port, it's not
@@ -46,6 +115,9 @@ STATIC const mp_rom_map_elem_t mp_module_io_globals_table[] = {
     #if MICROPY_PY_IO_BYTESIO
     { MP_ROM_QSTR(MP_QSTR_BytesIO), MP_ROM_PTR(&mp_type_bytesio) },
     #endif
+    #if MICROPY_PY_IO_BUFFEREDWRITER
+    { MP_ROM_QSTR(MP_QSTR_BufferedWriter), MP_ROM_PTR(&bufwriter_type) },
+    #endif
 };
 
 STATIC MP_DEFINE_CONST_DICT(mp_module_io_globals, mp_module_io_globals_table);
diff --git a/py/mpconfig.h b/py/mpconfig.h
index 67bbba7e1f..6c2db2f1fc 100644
--- a/py/mpconfig.h
+++ b/py/mpconfig.h
@@ -747,6 +747,11 @@ typedef double mp_float_t;
 #define MICROPY_PY_IO_BYTESIO (1)
 #endif
 
+// Whether to provide "io.BufferedWriter" class
+#ifndef MICROPY_PY_IO_BUFFEREDWRITER
+#define MICROPY_PY_IO_BUFFEREDWRITER (0)
+#endif
+
 // Whether to provide "struct" module
 #ifndef MICROPY_PY_STRUCT
 #define MICROPY_PY_STRUCT (1)
diff --git a/py/qstrdefs.h b/py/qstrdefs.h
index 734354b33e..b127537329 100644
--- a/py/qstrdefs.h
+++ b/py/qstrdefs.h
@@ -607,6 +607,9 @@ Q(file)
 Q(mode)
 Q(r)
 Q(encoding)
+#if MICROPY_PY_IO_BUFFEREDWRITER
+Q(BufferedWriter)
+#endif
 #endif
 
 #if MICROPY_PY_GC