circuitpython/py/stream.c

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#include <string.h>
#include "nlr.h"
#include "misc.h"
#include "mpconfig.h"
#include "qstr.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_readall(mp_obj_t self_in);
STATIC mp_obj_t stream_read(uint n_args, const mp_obj_t *args) {
struct _mp_obj_base_t *o = (struct _mp_obj_base_t *)args[0];
if (o->type->stream_p == NULL || o->type->stream_p->read == NULL) {
// CPython: io.UnsupportedOperation, OSError subclass
nlr_raise(mp_obj_new_exception_msg(&mp_type_OSError, "Operation not supported"));
}
machine_int_t sz;
if (n_args == 1 || ((sz = mp_obj_get_int(args[1])) == -1)) {
return stream_readall(args[0]);
}
byte *buf = m_new(byte, sz);
int error;
machine_int_t out_sz = o->type->stream_p->read(o, buf, sz, &error);
if (out_sz == -1) {
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_OSError, "[Errno %d]", error));
} else {
mp_obj_t s = mp_obj_new_str(buf, out_sz, false); // will reallocate to use exact size
m_free(buf, sz);
return s;
}
}
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 == NULL || o->type->stream_p->write == NULL) {
// CPython: io.UnsupportedOperation, OSError subclass
nlr_raise(mp_obj_new_exception_msg(&mp_type_OSError, "Operation not supported"));
}
mp_buffer_info_t bufinfo;
mp_get_buffer_raise(arg, &bufinfo, MP_BUFFER_READ);
int error;
machine_int_t out_sz = o->type->stream_p->write(self_in, bufinfo.buf, bufinfo.len, &error);
if (out_sz == -1) {
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_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);
}
}
// TODO: should be in mpconfig.h
#define READ_SIZE 256
STATIC mp_obj_t stream_readall(mp_obj_t self_in) {
struct _mp_obj_base_t *o = (struct _mp_obj_base_t *)self_in;
if (o->type->stream_p == NULL || o->type->stream_p->read == NULL) {
// CPython: io.UnsupportedOperation, OSError subclass
nlr_raise(mp_obj_new_exception_msg(&mp_type_OSError, "Operation not supported"));
}
int total_size = 0;
vstr_t *vstr = vstr_new_size(READ_SIZE);
char *buf = vstr_str(vstr);
char *p = buf;
int error;
int current_read = READ_SIZE;
while (true) {
machine_int_t out_sz = o->type->stream_p->read(self_in, p, current_read, &error);
if (out_sz == -1) {
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_OSError, "[Errno %d]", error));
}
if (out_sz == 0) {
break;
}
total_size += out_sz;
if (out_sz < current_read) {
current_read -= out_sz;
p += out_sz;
} else {
current_read = READ_SIZE;
p = vstr_extend(vstr, current_read);
if (p == NULL) {
// TODO
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_OSError/*&mp_type_RuntimeError*/, "Out of memory"));
}
}
}
mp_obj_t s = mp_obj_new_str((byte*)vstr->buf, total_size, false);
vstr_free(vstr);
return s;
}
// Unbuffered, inefficient implementation of readline() for raw I/O files.
STATIC mp_obj_t stream_unbuffered_readline(uint n_args, const mp_obj_t *args) {
struct _mp_obj_base_t *o = (struct _mp_obj_base_t *)args[0];
if (o->type->stream_p == NULL || o->type->stream_p->read == NULL) {
// CPython: io.UnsupportedOperation, OSError subclass
nlr_raise(mp_obj_new_exception_msg(&mp_type_OSError, "Operation not supported"));
}
machine_int_t max_size = -1;
if (n_args > 1) {
max_size = MP_OBJ_SMALL_INT_VALUE(args[1]);
}
vstr_t *vstr;
if (max_size != -1) {
vstr = vstr_new_size(max_size);
} else {
vstr = vstr_new();
}
int error;
while (max_size == -1 || max_size-- != 0) {
char *p = vstr_add_len(vstr, 1);
if (p == NULL) {
// TODO
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_OSError/*&mp_type_RuntimeError*/, "Out of memory"));
}
machine_int_t out_sz = o->type->stream_p->read(o, p, 1, &error);
if (out_sz == -1) {
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_OSError, "[Errno %d]", error));
}
if (out_sz == 0) {
// Back out previously added byte
// TODO: This is a bit hacky, does it supported by vstr API contract?
// Consider, what's better - read a char and get OutOfMemory (so read
// char is lost), or allocate first as we do.
vstr_add_len(vstr, -1);
break;
}
if (*p == '\n') {
break;
}
}
// TODO don't intern this string
vstr_shrink(vstr);
return MP_OBJ_NEW_QSTR(qstr_from_strn_take(vstr_str(vstr), vstr->alloc, vstr_len(vstr)));
}
mp_obj_t mp_stream_unbuffered_iter(mp_obj_t self) {
mp_obj_t l_in = stream_unbuffered_readline(1, &self);
uint sz;
mp_obj_str_get_data(l_in, &sz);
if (sz != 0) {
return l_in;
}
return MP_OBJ_STOP_ITERATION;
}
MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_stream_read_obj, 1, 2, stream_read);
MP_DEFINE_CONST_FUN_OBJ_1(mp_stream_readall_obj, stream_readall);
MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_stream_unbuffered_readline_obj, 1, 2, stream_unbuffered_readline);
MP_DEFINE_CONST_FUN_OBJ_2(mp_stream_write_obj, stream_write);