wasmparser/readers/core/
memories.rs

1/* Copyright 2018 Mozilla Foundation
2 *
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at
6 *
7 *     http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
14 */
15
16use crate::{BinaryReader, FromReader, MemoryType, Result, SectionLimited};
17
18/// A reader for the memory section of a WebAssembly module.
19pub type MemorySectionReader<'a> = SectionLimited<'a, MemoryType>;
20
21impl<'a> FromReader<'a> for MemoryType {
22    fn from_reader(reader: &mut BinaryReader<'a>) -> Result<Self> {
23        let pos = reader.original_position();
24        let flags = reader.read_u8()?;
25
26        if (flags & !0b1111) != 0 {
27            bail!(pos, "invalid memory limits flags");
28        }
29
30        let memory64 = flags & 0b0100 != 0;
31        let shared = flags & 0b0010 != 0;
32        let has_max = flags & 0b0001 != 0;
33        let has_page_size = flags & 0b1000 != 0;
34
35        Ok(MemoryType {
36            memory64,
37            shared,
38            initial: if reader.memory64() {
39                reader.read_var_u64()?
40            } else {
41                reader.read_var_u32()?.into()
42            },
43            maximum: if !has_max {
44                None
45            } else if reader.memory64() {
46                Some(reader.read_var_u64()?)
47            } else {
48                Some(reader.read_var_u32()?.into())
49            },
50            page_size_log2: if has_page_size {
51                let val = reader.read_var_u32()?;
52                if val >= 64 {
53                    bail!(pos, "invalid custom page size");
54                }
55                Some(val)
56            } else {
57                None
58            },
59        })
60    }
61}
wasmparser/readers/core/memories.rs

wasmparser/readers/core/
memories.rs
