mirror of
https://github.com/pezkuwichain/pezkuwi-subxt.git
synced 2026-04-27 06:57:58 +00:00
Shawn Tabrizi
60 lines
2.0 KiB
Rust
60 lines
2.0 KiB
Rust
// Copyright 2019-2020 Parity Technologies (UK) Ltd.
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// This file is part of Substrate.
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// Substrate is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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// Substrate is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License
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// along with Substrate. If not, see <http://www.gnu.org/licenses/>.
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//! Various utilities that help interfacing with wasm runtime code.
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/// Pack a pointer and length into an `u64`.
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pub fn pack_ptr_and_len(ptr: u32, len: u32) -> u64 {
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// The static assertions from above are changed into a runtime check.
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#[cfg(all(not(feature = "std"), feature = "disable_target_static_assertions"))]
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assert_eq!(4, sp_std::mem::size_of::<usize>());
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(u64::from(len) << 32) | u64::from(ptr)
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}
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/// Unpacks an `u64` into the pointer and length.
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///
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/// Runtime API functions return a 64-bit value which encodes a pointer in the least-significant
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/// 32-bits and a length in the most-significant 32 bits. This interprets the returned value as a pointer,
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/// length tuple.
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pub fn unpack_ptr_and_len(val: u64) -> (u32, u32) {
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// The static assertions from above are changed into a runtime check.
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#[cfg(all(not(feature = "std"), feature = "disable_target_static_assertions"))]
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assert_eq!(4, sp_std::mem::size_of::<usize>());
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let ptr = (val & (!0u32 as u64)) as u32;
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let len = (val >> 32) as u32;
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(ptr, len)
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}
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#[cfg(test)]
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mod tests {
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use super::{pack_ptr_and_len, unpack_ptr_and_len};
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#[test]
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fn ptr_len_packing_unpacking() {
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const PTR: u32 = 0x1337;
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const LEN: u32 = 0x7f000000;
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let packed = pack_ptr_and_len(PTR, LEN);
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let (ptr, len) = unpack_ptr_and_len(packed);
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assert_eq!(PTR, ptr);
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assert_eq!(LEN, len);
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}
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}
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