Source code
Revision control
Copy as Markdown
Other Tools
/* Copyright 2018 Mozilla Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
use crate::{BinaryReader, FromReader, MemoryType, Result, SectionLimited};
/// A reader for the memory section of a WebAssembly module.
pub type MemorySectionReader<'a> = SectionLimited<'a, MemoryType>;
impl<'a> FromReader<'a> for MemoryType {
fn from_reader(reader: &mut BinaryReader<'a>) -> Result<Self> {
let pos = reader.original_position();
let flags = reader.read_u8()?;
if (flags & !0b1111) != 0 {
bail!(pos, "invalid memory limits flags");
}
let memory64 = flags & 0b0100 != 0;
let shared = flags & 0b0010 != 0;
let has_max = flags & 0b0001 != 0;
let has_page_size = flags & 0b1000 != 0;
Ok(MemoryType {
memory64,
shared,
initial: if memory64 {
reader.read_var_u64()?
} else {
reader.read_var_u32()?.into()
},
maximum: if !has_max {
None
} else if memory64 {
Some(reader.read_var_u64()?)
} else {
Some(reader.read_var_u32()?.into())
},
page_size_log2: if has_page_size {
Some(reader.read_var_u32()?)
} else {
None
},
})
}
}