From ad9b9c7621a8a2d85e8056321c3da3287717ec18 Mon Sep 17 00:00:00 2001 From: Paul Sokolovsky Date: Thu, 14 Jul 2016 01:44:50 +0300 Subject: [PATCH] py/stream: Implement 2- and 3-arg write() method as an extension to CPython. 3-arg form: stream.write(data, offset, length) 2-arg form: stream.write(data, length) These allow efficient buffer writing without incurring extra memory allocation for slicing or creating memoryview() object, what is important for low-memory ports. All arguments must be positional. It might be not so bad idea to standardize on 3-arg form, but 2-arg case would need check and raising an exception anyway then, so instead it was just made to work. --- py/stream.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) diff --git a/py/stream.c b/py/stream.c index 4fcc151dca..48f31d401c 100644 --- a/py/stream.c +++ b/py/stream.c @@ -267,12 +267,24 @@ void mp_stream_write_adaptor(void *self, const char *buf, size_t len) { mp_stream_write(MP_OBJ_FROM_PTR(self), buf, len, MP_STREAM_RW_WRITE); } -STATIC mp_obj_t stream_write_method(mp_obj_t self_in, mp_obj_t arg) { +STATIC mp_obj_t stream_write_method(size_t n_args, const mp_obj_t *args) { mp_buffer_info_t bufinfo; - mp_get_buffer_raise(arg, &bufinfo, MP_BUFFER_READ); - return mp_stream_write(self_in, bufinfo.buf, bufinfo.len, MP_STREAM_RW_WRITE); + mp_get_buffer_raise(args[1], &bufinfo, MP_BUFFER_READ); + size_t max_len = (size_t)-1; + size_t off = 0; + if (n_args == 3) { + max_len = mp_obj_get_int_truncated(args[2]); + } else if (n_args == 4) { + off = mp_obj_get_int_truncated(args[2]); + max_len = mp_obj_get_int_truncated(args[3]); + if (off > bufinfo.len) { + off = bufinfo.len; + } + } + bufinfo.len -= off; + return mp_stream_write(args[0], (byte*)bufinfo.buf + off, MIN(bufinfo.len, max_len), MP_STREAM_RW_WRITE); } -MP_DEFINE_CONST_FUN_OBJ_2(mp_stream_write_obj, stream_write_method); +MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_stream_write_obj, 2, 4, stream_write_method); STATIC mp_obj_t stream_write1_method(mp_obj_t self_in, mp_obj_t arg) { mp_buffer_info_t bufinfo;