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Diffstat (limited to 'src/encoding.cc')
-rw-r--r-- | src/encoding.cc | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/src/encoding.cc b/src/encoding.cc new file mode 100644 index 0000000..93773a6 --- /dev/null +++ b/src/encoding.cc @@ -0,0 +1,84 @@ +// Copyright 2016 Benjamin Barenblat +// +// 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 +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// 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. + +#include "encoding.h" + +#include <array> +#include <cstdlib> +#include <sstream> +#include <string> + +namespace scoville { + +namespace { + +void WriteAsciiAsHex(const char c, std::ostringstream* const out) { + if (1 < sizeof(c) && 0x100 <= c) { + // Not ASCII! + throw EncodingFailure("could not encode non-ASCII character '" + + std::string(1, c) + "'"); + } + *out << std::hex << static_cast<int>(c); +} + +char ReadHexAsAscii(std::istringstream* const in) { + std::array<char, 3> hex_str; + in->get(hex_str.data(), hex_str.size()); + char* decoded_end; + const char result = + static_cast<char>(std::strtol(hex_str.data(), &decoded_end, 16)); + if (decoded_end == hex_str.data()) { + throw DecodingFailure("could not decode invalid hex"); + } + return result; +} + +bool IsVfatBadCharacter(const char c) noexcept { + return (0 <= c && c < 0x20) || c == '*' || c == '?' || c == '<' || c == '>' || + c == '|' || c == '"' || c == ':' || c == '/' || c == '\\'; +} + +} // namespace + +void Encode(std::istringstream* const in, std::ostringstream* const out) { + char c; + while (!in->get(c).eof()) { + if (IsVfatBadCharacter(c)) { + *out << '%'; + WriteAsciiAsHex(c, out); + } else if (c == '%') { + *out << "%%"; + } else { + *out << c; + } + } +} + +void Decode(std::istringstream* const in, std::ostringstream* const out) { + char c; + while (!in->get(c).eof()) { + if (c == '%') { + if (in->peek() == '%') { + in->ignore(); + *out << "%"; + } else { + *out << ReadHexAsAscii(in); + } + } else { + *out << c; + } + } +} + +} // scoville |