modio: Implement io.StringIO class.

py/modio.c

@@ -11,6 +11,8 @@ STATIC const mp_map_elem_t mp_module_io_globals_table[] = {
     // Note: mp_builtin_open_obj should be defined by port, it's not
     // part of the core.
     { MP_OBJ_NEW_QSTR(MP_QSTR_open), (mp_obj_t)&mp_builtin_open_obj },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_BytesIO), (mp_obj_t)&mp_type_stringio },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_StringIO), (mp_obj_t)&mp_type_stringio },
 };
 
 STATIC const mp_obj_dict_t mp_module_io_globals = {

py/obj.h

@@ -292,6 +292,7 @@ extern const mp_obj_type_t mp_type_module;
 extern const mp_obj_type_t mp_type_staticmethod;
 extern const mp_obj_type_t mp_type_classmethod;
 extern const mp_obj_type_t mp_type_property;
+extern const mp_obj_type_t mp_type_stringio;
 
 // Exceptions
 extern const mp_obj_type_t mp_type_BaseException;

py/objstringio.c

@@ -0,0 +1,119 @@
+#include <stdio.h>
+#include <string.h>
+
+#include "nlr.h"
+#include "misc.h"
+#include "mpconfig.h"
+#include "qstr.h"
+#include "obj.h"
+#include "runtime.h"
+#include "stream.h"
+
+typedef struct _mp_obj_stringio_t {
+    mp_obj_base_t base;
+    vstr_t *vstr;
+    // StringIO has single pointer used for both reading and writing
+    machine_uint_t pos;
+} mp_obj_stringio_t;
+
+STATIC void stringio_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in, mp_print_kind_t kind) {
+    mp_obj_stringio_t *self = self_in;
+    print(env, "<io.StringIO 0x%x>", self->vstr);
+}
+
+STATIC machine_int_t stringio_read(mp_obj_t o_in, void *buf, machine_uint_t size, int *errcode) {
+    mp_obj_stringio_t *o = o_in;
+    machine_uint_t remaining = o->vstr->len - o->pos;
+    if (size > remaining) {
+        size = remaining;
+    }
+    memcpy(buf, o->vstr->buf + o->pos, size);
+    o->pos += size;
+    return size;
+}
+
+STATIC machine_int_t stringio_write(mp_obj_t o_in, const void *buf, machine_uint_t size, int *errcode) {
+    mp_obj_stringio_t *o = o_in;
+    machine_uint_t remaining = o->vstr->alloc - o->pos;
+    if (size > remaining) {
+        // Take all what's already allocated...
+        o->vstr->len = o->vstr->alloc;
+        // ... and add more
+        vstr_add_len(o->vstr, size - remaining);
+    }
+    memcpy(o->vstr->buf + o->pos, buf, size);
+    o->pos += size;
+    if (o->pos > o->vstr->len) {
+        o->vstr->len = o->pos;
+    }
+    return size;
+}
+
+STATIC mp_obj_t stringio_getvalue(mp_obj_t self_in) {
+    mp_obj_stringio_t *self = self_in;
+    return mp_obj_new_str((byte*)self->vstr->buf, self->vstr->len, false);
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(stringio_getvalue_obj, stringio_getvalue);
+
+STATIC mp_obj_t stringio_close(mp_obj_t self_in) {
+    mp_obj_stringio_t *self = self_in;
+    vstr_free(self->vstr);
+    self->vstr = NULL;
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(stringio_close_obj, stringio_close);
+
+mp_obj_t stringio___exit__(uint n_args, const mp_obj_t *args) {
+    return stringio_close(args[0]);
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(stringio___exit___obj, 4, 4, stringio___exit__);
+
+STATIC mp_obj_stringio_t *stringio_new() {
+    mp_obj_stringio_t *o = m_new_obj(mp_obj_stringio_t);
+    o->base.type = &mp_type_stringio;
+    o->vstr = vstr_new();
+    o->pos = 0;
+    return o;
+}
+
+STATIC mp_obj_t stringio_make_new(mp_obj_t type_in, uint n_args, uint n_kw, const mp_obj_t *args) {
+    mp_obj_stringio_t *o = stringio_new();
+
+    if (n_args > 0) {
+        mp_buffer_info_t bufinfo;
+        mp_get_buffer_raise(args[0], &bufinfo, MP_BUFFER_READ);
+        stringio_write(o, bufinfo.buf, bufinfo.len, NULL);
+        // Cur ptr is always at the beginning of buffer at the construction
+        o->pos = 0;
+    }
+    return o;
+}
+
+STATIC const mp_map_elem_t stringio_locals_dict_table[] = {
+    { MP_OBJ_NEW_QSTR(MP_QSTR_read), (mp_obj_t)&mp_stream_read_obj },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_readall), (mp_obj_t)&mp_stream_readall_obj },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_readline), (mp_obj_t)&mp_stream_unbuffered_readline_obj},
+    { MP_OBJ_NEW_QSTR(MP_QSTR_write), (mp_obj_t)&mp_stream_write_obj },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_close), (mp_obj_t)&stringio_close_obj },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_getvalue), (mp_obj_t)&stringio_getvalue_obj },
+    { MP_OBJ_NEW_QSTR(MP_QSTR___enter__), (mp_obj_t)&mp_identity_obj },
+    { MP_OBJ_NEW_QSTR(MP_QSTR___exit__), (mp_obj_t)&stringio___exit___obj },
+};
+
+STATIC MP_DEFINE_CONST_DICT(stringio_locals_dict, stringio_locals_dict_table);
+
+STATIC const mp_stream_p_t stringio_stream_p = {
+    .read = stringio_read,
+    .write = stringio_write,
+};
+
+const mp_obj_type_t mp_type_stringio = {
+    { &mp_type_type },
+    .name = MP_QSTR_StringIO,
+    .print = stringio_print,
+    .make_new = stringio_make_new,
+    .getiter = mp_identity,
+    .iternext = mp_stream_unbuffered_iter,
+    .stream_p = &stringio_stream_p,
+    .locals_dict = (mp_obj_t)&stringio_locals_dict,
+};

py/py.mk

@@ -74,6 +74,7 @@ PY_O_BASENAME = \
 	objset.o \
 	objslice.o \
 	objstr.o \
+	objstringio.o \
 	objtuple.o \
 	objtype.o \
 	objzip.o \

py/qstrdefs.h

@@ -118,7 +118,6 @@ Q(hash)
 Q(hex)
 Q(%#x)
 Q(id)
-Q(io)
 Q(int)
 Q(isinstance)
 Q(issubclass)
@@ -308,6 +307,13 @@ Q(pack)
 Q(unpack)
 #endif
 
+#if MICROPY_ENABLE_MOD_IO
+Q(io)
+Q(StringIO)
+Q(BytesIO)
+Q(getvalue)
+#endif
+
 #if MICROPY_ENABLE_PROPERTY
 Q(property)
 Q(getter)

tests/io/stringio1.py

@@ -0,0 +1,30 @@
+import io
+
+a = io.StringIO()
+print(a.getvalue())
+print(a.read())
+
+a = io.StringIO("foobar")
+print(a.getvalue())
+print(a.read())
+print(a.read())
+
+a = io.StringIO()
+a.write("foo")
+print(a.getvalue())
+
+a = io.StringIO("foo")
+a.write("12")
+print(a.getvalue())
+
+a = io.StringIO("foo")
+a.write("123")
+print(a.getvalue())
+
+a = io.StringIO("foo")
+a.write("1234")
+print(a.getvalue())
+
+a = io.StringIO()
+a.write("foo")
+print(a.read())