forked from RustPython/RustPython
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathpystruct.rs
More file actions
323 lines (294 loc) · 10.3 KB
/
pystruct.rs
File metadata and controls
323 lines (294 loc) · 10.3 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
//! Python struct module.
//!
//! Docs: https://docs.python.org/3/library/struct.html
//!
//! Use this rust module to do byte packing:
//! https://docs.rs/byteorder/1.2.6/byteorder/
pub(crate) use _struct::make_module;
#[pymodule]
pub(crate) mod _struct {
use crate::vm::{
buffer::{new_struct_error, struct_error_type, FormatSpec},
builtins::{PyBytes, PyStr, PyStrRef, PyTupleRef, PyTypeRef},
function::{ArgBytesLike, ArgMemoryBuffer, PosArgs},
match_class,
protocol::PyIterReturn,
types::{Constructor, IterNext, IterNextIterable},
AsObject, Py, PyObjectRef, PyPayload, PyResult, TryFromObject, VirtualMachine,
};
use crossbeam_utils::atomic::AtomicCell;
struct IntoStructFormatBytes(PyStrRef);
impl TryFromObject for IntoStructFormatBytes {
fn try_from_object(vm: &VirtualMachine, obj: PyObjectRef) -> PyResult<Self> {
// CPython turns str to bytes but we do reversed way here
// The only performance difference is this transition cost
let fmt = match_class! {
match obj {
s @ PyStr => if s.is_ascii() {
Some(s)
} else {
None
},
b @ PyBytes => if b.is_ascii() {
Some(unsafe {
PyStr::new_ascii_unchecked(b.as_bytes().to_vec())
}.into_ref(vm))
} else {
None
},
other => return Err(vm.new_type_error(format!("Struct() argument 1 must be a str or bytes object, not {}", other.class().name()))),
}
}.ok_or_else(|| vm.new_unicode_decode_error("Struct format must be a ascii string".to_owned()))?;
Ok(IntoStructFormatBytes(fmt))
}
}
impl IntoStructFormatBytes {
fn format_spec(&self, vm: &VirtualMachine) -> PyResult<FormatSpec> {
FormatSpec::parse(self.0.as_str().as_bytes(), vm)
}
}
fn get_buffer_offset(
buffer_len: usize,
offset: isize,
needed: usize,
is_pack: bool,
vm: &VirtualMachine,
) -> PyResult<usize> {
let offset_from_start = if offset < 0 {
if (-offset) as usize > buffer_len {
return Err(new_struct_error(
vm,
format!(
"offset {} out of range for {}-byte buffer",
offset, buffer_len
),
));
}
buffer_len - (-offset as usize)
} else {
let offset = offset as usize;
let (op, op_action) = if is_pack {
("pack_into", "packing")
} else {
("unpack_from", "unpacking")
};
if offset >= buffer_len {
let msg = format!(
"{op} requires a buffer of at least {required} bytes for {op_action} {needed} \
bytes at offset {offset} (actual buffer size is {buffer_len})",
op = op,
op_action = op_action,
required = needed + offset as usize,
needed = needed,
offset = offset,
buffer_len = buffer_len
);
return Err(new_struct_error(vm, msg));
}
offset
};
if (buffer_len - offset_from_start) < needed {
Err(new_struct_error(
vm,
if is_pack {
format!("no space to pack {} bytes at offset {}", needed, offset)
} else {
format!(
"not enough data to unpack {} bytes at offset {}",
needed, offset
)
},
))
} else {
Ok(offset_from_start)
}
}
#[pyfunction]
fn pack(fmt: IntoStructFormatBytes, args: PosArgs, vm: &VirtualMachine) -> PyResult<Vec<u8>> {
fmt.format_spec(vm)?.pack(args.into_vec(), vm)
}
#[pyfunction]
fn pack_into(
fmt: IntoStructFormatBytes,
buffer: ArgMemoryBuffer,
offset: isize,
args: PosArgs,
vm: &VirtualMachine,
) -> PyResult<()> {
let format_spec = fmt.format_spec(vm)?;
let offset = get_buffer_offset(buffer.len(), offset, format_spec.size, true, vm)?;
buffer.with_ref(|data| format_spec.pack_into(&mut data[offset..], args.into_vec(), vm))
}
#[pyfunction]
fn unpack(
fmt: IntoStructFormatBytes,
buffer: ArgBytesLike,
vm: &VirtualMachine,
) -> PyResult<PyTupleRef> {
let format_spec = fmt.format_spec(vm)?;
buffer.with_ref(|buf| format_spec.unpack(buf, vm))
}
#[derive(FromArgs)]
struct UpdateFromArgs {
buffer: ArgBytesLike,
#[pyarg(any, default = "0")]
offset: isize,
}
#[pyfunction]
fn unpack_from(
fmt: IntoStructFormatBytes,
args: UpdateFromArgs,
vm: &VirtualMachine,
) -> PyResult<PyTupleRef> {
let format_spec = fmt.format_spec(vm)?;
let offset =
get_buffer_offset(args.buffer.len(), args.offset, format_spec.size, false, vm)?;
args.buffer
.with_ref(|buf| format_spec.unpack(&buf[offset..][..format_spec.size], vm))
}
#[pyattr]
#[pyclass(name = "unpack_iterator")]
#[derive(Debug, PyPayload)]
struct UnpackIterator {
format_spec: FormatSpec,
buffer: ArgBytesLike,
offset: AtomicCell<usize>,
}
impl UnpackIterator {
fn new(
vm: &VirtualMachine,
format_spec: FormatSpec,
buffer: ArgBytesLike,
) -> PyResult<UnpackIterator> {
if format_spec.size == 0 {
Err(new_struct_error(
vm,
"cannot iteratively unpack with a struct of length 0".to_owned(),
))
} else if buffer.len() % format_spec.size != 0 {
Err(new_struct_error(
vm,
format!(
"iterative unpacking requires a buffer of a multiple of {} bytes",
format_spec.size
),
))
} else {
Ok(UnpackIterator {
format_spec,
buffer,
offset: AtomicCell::new(0),
})
}
}
}
#[pyimpl(with(IterNext))]
impl UnpackIterator {
#[pymethod(magic)]
fn length_hint(&self) -> usize {
self.buffer.len().saturating_sub(self.offset.load()) / self.format_spec.size
}
}
impl IterNextIterable for UnpackIterator {}
impl IterNext for UnpackIterator {
fn next(zelf: &Py<Self>, vm: &VirtualMachine) -> PyResult<PyIterReturn> {
let size = zelf.format_spec.size;
let offset = zelf.offset.fetch_add(size);
zelf.buffer.with_ref(|buf| {
if let Some(buf) = buf.get(offset..offset + size) {
zelf.format_spec
.unpack(buf, vm)
.map(|x| PyIterReturn::Return(x.into()))
} else {
Ok(PyIterReturn::StopIteration(None))
}
})
}
}
#[pyfunction]
fn iter_unpack(
fmt: IntoStructFormatBytes,
buffer: ArgBytesLike,
vm: &VirtualMachine,
) -> PyResult<UnpackIterator> {
let format_spec = fmt.format_spec(vm)?;
UnpackIterator::new(vm, format_spec, buffer)
}
#[pyfunction]
fn calcsize(fmt: IntoStructFormatBytes, vm: &VirtualMachine) -> PyResult<usize> {
Ok(fmt.format_spec(vm)?.size)
}
#[pyattr]
#[pyclass(name = "Struct")]
#[derive(Debug, PyPayload)]
struct PyStruct {
spec: FormatSpec,
format: PyStrRef,
}
impl Constructor for PyStruct {
type Args = IntoStructFormatBytes;
fn py_new(cls: PyTypeRef, fmt: Self::Args, vm: &VirtualMachine) -> PyResult {
let spec = fmt.format_spec(vm)?;
let format = fmt.0;
PyStruct { spec, format }
.into_ref_with_type(vm, cls)
.map(Into::into)
}
}
#[pyimpl(with(Constructor))]
impl PyStruct {
#[pyproperty]
fn format(&self) -> PyStrRef {
self.format.clone()
}
#[pyproperty]
#[inline]
fn size(&self) -> usize {
self.spec.size
}
#[pymethod]
fn pack(&self, args: PosArgs, vm: &VirtualMachine) -> PyResult<Vec<u8>> {
self.spec.pack(args.into_vec(), vm)
}
#[pymethod]
fn pack_into(
&self,
buffer: ArgMemoryBuffer,
offset: isize,
args: PosArgs,
vm: &VirtualMachine,
) -> PyResult<()> {
let offset = get_buffer_offset(buffer.len(), offset, self.size(), true, vm)?;
buffer.with_ref(|data| {
self.spec
.pack_into(&mut data[offset..], args.into_vec(), vm)
})
}
#[pymethod]
fn unpack(&self, data: ArgBytesLike, vm: &VirtualMachine) -> PyResult<PyTupleRef> {
data.with_ref(|buf| self.spec.unpack(buf, vm))
}
#[pymethod]
fn unpack_from(&self, args: UpdateFromArgs, vm: &VirtualMachine) -> PyResult<PyTupleRef> {
let offset = get_buffer_offset(args.buffer.len(), args.offset, self.size(), false, vm)?;
args.buffer
.with_ref(|buf| self.spec.unpack(&buf[offset..][..self.size()], vm))
}
#[pymethod]
fn iter_unpack(
&self,
buffer: ArgBytesLike,
vm: &VirtualMachine,
) -> PyResult<UnpackIterator> {
UnpackIterator::new(vm, self.spec.clone(), buffer)
}
}
// seems weird that this is part of the "public" API, but whatever
// TODO: implement a format code->spec cache like CPython does?
#[pyfunction]
fn _clearcache() {}
#[pyattr(name = "error")]
fn error_type(vm: &VirtualMachine) -> PyTypeRef {
struct_error_type(vm).clone()
}
}