forked from BigfootDev/flatbuffers
83 lines
2.3 KiB
Rust
83 lines
2.3 KiB
Rust
/*
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* Copyright 2018 Google Inc. All rights reserved.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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use core::cmp::max;
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use core::mem::{align_of, size_of};
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use crate::endian_scalar::emplace_scalar;
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/// Trait to abstract over functionality needed to write values (either owned
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/// or referenced). Used in FlatBufferBuilder and implemented for generated
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/// types.
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pub trait Push: Sized {
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type Output;
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fn push(&self, dst: &mut [u8], _rest: &[u8]);
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#[inline]
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fn size() -> usize {
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size_of::<Self::Output>()
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}
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#[inline]
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fn alignment() -> PushAlignment {
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PushAlignment::new(align_of::<Self::Output>())
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}
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}
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/// Ensure Push alignment calculations are typesafe (because this helps reduce
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/// implementation issues when using FlatBufferBuilder::align).
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pub struct PushAlignment(usize);
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impl PushAlignment {
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#[inline]
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pub fn new(x: usize) -> Self {
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PushAlignment { 0: x }
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}
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#[inline]
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pub fn value(&self) -> usize {
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self.0
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}
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#[inline]
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pub fn max_of(&self, o: usize) -> Self {
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PushAlignment::new(max(self.0, o))
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}
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}
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/// Macro to implement Push for EndianScalar types.
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macro_rules! impl_push_for_endian_scalar {
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($ty:ident) => {
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impl Push for $ty {
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type Output = $ty;
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#[inline]
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fn push(&self, dst: &mut [u8], _rest: &[u8]) {
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unsafe {
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emplace_scalar::<$ty>(dst, *self);
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}
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}
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}
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};
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}
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impl_push_for_endian_scalar!(bool);
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impl_push_for_endian_scalar!(u8);
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impl_push_for_endian_scalar!(i8);
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impl_push_for_endian_scalar!(u16);
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impl_push_for_endian_scalar!(i16);
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impl_push_for_endian_scalar!(u32);
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impl_push_for_endian_scalar!(i32);
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impl_push_for_endian_scalar!(u64);
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impl_push_for_endian_scalar!(i64);
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impl_push_for_endian_scalar!(f32);
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impl_push_for_endian_scalar!(f64);
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