circuitpython/py/stream.c

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#include <string.h>
#include "nlr.h"
#include "misc.h"
#include "mpconfig.h"
#include "mpqstr.h"
#include "obj.h"
#include "stream.h"
// This file defines generic Python stream read/write methods which
// dispatch to the underlying stream interface of an object.
static mp_obj_t stream_read(mp_obj_t self_in, mp_obj_t arg) {
struct _mp_obj_base_t *o = (struct _mp_obj_base_t *)self_in;
if (o->type->stream_p.read == NULL) {
// CPython: io.UnsupportedOperation, OSError subclass
nlr_jump(mp_obj_new_exception_msg(MP_QSTR_OSError, "Operation not supported"));
}
machine_int_t sz = mp_obj_get_int(arg);
// +1 because so far we mark end of string with \0
char *buf = m_new(char, sz + 1);
int error;
machine_int_t out_sz = o->type->stream_p.read(self_in, buf, sz, &error);
if (out_sz == -1) {
nlr_jump(mp_obj_new_exception_msg_varg(MP_QSTR_OSError, "[Errno %d]", error));
} else {
buf[out_sz] = 0;
return mp_obj_new_str(qstr_from_str_take(buf, /*out_sz,*/ sz + 1));
}
}
static mp_obj_t stream_write(mp_obj_t self_in, mp_obj_t arg) {
struct _mp_obj_base_t *o = (struct _mp_obj_base_t *)self_in;
if (o->type->stream_p.write == NULL) {
// CPython: io.UnsupportedOperation, OSError subclass
nlr_jump(mp_obj_new_exception_msg(MP_QSTR_OSError, "Operation not supported"));
}
const char *buf = qstr_str(mp_obj_get_qstr(arg));
machine_int_t sz = strlen(buf);
int error;
machine_int_t out_sz = o->type->stream_p.write(self_in, buf, sz, &error);
if (out_sz == -1) {
nlr_jump(mp_obj_new_exception_msg_varg(MP_QSTR_OSError, "[Errno %d]", error));
} else {
// http://docs.python.org/3/library/io.html#io.RawIOBase.write
// "None is returned if the raw stream is set not to block and no single byte could be readily written to it."
// Do they mean that instead of 0 they return None?
return MP_OBJ_NEW_SMALL_INT(out_sz);
}
}
MP_DEFINE_CONST_FUN_OBJ_2(mp_stream_read_obj, stream_read);
MP_DEFINE_CONST_FUN_OBJ_2(mp_stream_write_obj, stream_write);