decode_rust_punycode.h (2049B)
1 // Copyright 2024 The Abseil Authors 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 // https://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 #ifndef ABSL_DEBUGGING_INTERNAL_DECODE_RUST_PUNYCODE_H_ 16 #define ABSL_DEBUGGING_INTERNAL_DECODE_RUST_PUNYCODE_H_ 17 18 #include "absl/base/config.h" 19 #include "absl/base/nullability.h" 20 21 namespace absl { 22 ABSL_NAMESPACE_BEGIN 23 namespace debugging_internal { 24 25 struct DecodeRustPunycodeOptions { 26 const char* punycode_begin; 27 const char* punycode_end; 28 char* out_begin; 29 char* out_end; 30 }; 31 32 // Given Rust Punycode in `punycode_begin .. punycode_end`, writes the 33 // corresponding UTF-8 plaintext into `out_begin .. out_end`, followed by a NUL 34 // character, and returns a pointer to that final NUL on success. On failure 35 // returns a null pointer, and the contents of `out_begin .. out_end` are 36 // unspecified. 37 // 38 // Failure occurs in precisely these cases: 39 // - Any input byte does not match [0-9a-zA-Z_]. 40 // - The first input byte is an underscore, but no other underscore appears in 41 // the input. 42 // - The delta sequence does not represent a valid sequence of code-point 43 // insertions. 44 // - The plaintext would contain more than 256 code points. 45 // 46 // DecodeRustPunycode is async-signal-safe with bounded runtime and a small 47 // stack footprint, making it suitable for use in demangling Rust symbol names 48 // from a signal handler. 49 absl::Nullable<char*> DecodeRustPunycode(DecodeRustPunycodeOptions options); 50 51 } // namespace debugging_internal 52 ABSL_NAMESPACE_END 53 } // namespace absl 54 55 #endif // ABSL_DEBUGGING_INTERNAL_DECODE_RUST_PUNYCODE_H_