| /* |
| * Copyright (C) 2020 The Android Open Source Project |
| * |
| * 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. |
| */ |
| |
| #pragma once |
| |
| #include <iomanip> |
| #include <sstream> |
| #include <string> |
| #include <vector> |
| |
| namespace android::mediametrics::stringutils { |
| |
| /** |
| * fieldPrint is a helper method that logs to a stringstream a sequence of |
| * field names (in a fixed size array) together with a variable number of arg parameters. |
| * |
| * stringstream << field[0] << ":" << arg0 << " "; |
| * stringstream << field[1] << ":" << arg1 << " "; |
| * ... |
| * stringstream << field[N-1] << ":" << arg{N-1} << " "; |
| * |
| * The number of fields must exactly match the (variable) arguments. |
| * |
| * Example: |
| * |
| * const char * const fields[] = { "integer" }; |
| * std::stringstream ss; |
| * fieldPrint(ss, fields, int(10)); |
| */ |
| template <size_t N, typename... Targs> |
| void fieldPrint(std::stringstream& ss, const char * const (& fields)[N], Targs... args) { |
| static_assert(N == sizeof...(args)); // guarantee #fields == #args |
| auto fptr = fields; // get a pointer to the base of fields array |
| ((ss << *fptr++ << ":" << args << " "), ...); // (fold expression), send to stringstream. |
| } |
| |
| /** |
| * Return string tokens from iterator, separated by spaces and reserved chars. |
| */ |
| std::string tokenizer(std::string::const_iterator& it, |
| const std::string::const_iterator& end, const char *reserved); |
| |
| /** |
| * Splits flags string based on delimeters (or, whitespace which is removed). |
| */ |
| std::vector<std::string> split(const std::string& flags, const char *delim); |
| |
| /** |
| * Parse the devices string and return a vector of device address pairs. |
| * |
| * A failure to parse returns early with the contents that were able to be parsed. |
| */ |
| std::vector<std::pair<std::string, std::string>> getDeviceAddressPairs(const std::string &devices); |
| |
| /** |
| * Replaces targetChars with replaceChar in string, returns number of chars replaced. |
| */ |
| size_t replace(std::string &str, const char *targetChars, const char replaceChar); |
| |
| // RFC 1421, 2045, 2152, 4648(4), 4880 |
| inline constexpr char Base64Table[] = |
| // 0000000000111111111122222222223333333333444444444455555555556666 |
| // 0123456789012345678901234567890123456789012345678901234567890123 |
| "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; |
| |
| // RFC 4648(5) URL-safe Base64 encoding |
| inline constexpr char Base64UrlTable[] = |
| // 0000000000111111111122222222223333333333444444444455555555556666 |
| // 0123456789012345678901234567890123456789012345678901234567890123 |
| "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_"; |
| |
| // An constexpr struct that transposes/inverts a string conversion table. |
| struct Transpose { |
| // constexpr bug, returning char still means -1 == 0xff, so we use unsigned char. |
| using base_char_t = unsigned char; |
| static inline constexpr base_char_t INVALID_CHAR = 0xff; |
| |
| template <size_t N> |
| explicit constexpr Transpose(const char(&string)[N]) { |
| for (auto& e : mMap) { |
| e = INVALID_CHAR; |
| } |
| for (size_t i = 0; string[i] != 0; ++i) { |
| mMap[static_cast<size_t>(string[i]) & 0xff] = i; |
| } |
| } |
| |
| constexpr base_char_t operator[] (size_t n) const { |
| return n < sizeof(mMap) ? mMap[n] : INVALID_CHAR; |
| } |
| |
| constexpr const auto& get() const { |
| return mMap; |
| } |
| |
| private: |
| base_char_t mMap[256]; // construct an inverse character mapping. |
| }; |
| |
| // This table is used to convert an input char to a 6 bit (0 - 63) value. |
| // If the input char is not in the Base64Url charset, Transpose::INVALID_CHAR is returned. |
| inline constexpr Transpose InverseBase64UrlTable(Base64UrlTable); |
| |
| // Returns true if s consists of only valid Base64Url characters (no padding chars allowed). |
| inline constexpr bool isBase64Url(const char *s) { |
| for (; *s != 0; ++s) { |
| if (InverseBase64UrlTable[(unsigned char)*s] == Transpose::INVALID_CHAR) return false; |
| } |
| return true; |
| } |
| |
| // Returns true if s is a valid log session id: exactly 16 Base64Url characters. |
| // |
| // logSessionIds are a web-safe Base64Url RFC 4648(5) encoded string of 16 characters |
| // (representing 96 unique bits 16 * 6). |
| // |
| // The string version is considered the reference representation. However, for ease of |
| // manipulation and comparison, it may be converted to an int128. |
| // |
| // For int128 conversion, some common interpretations exist - for example |
| // (1) the 16 Base64 chars can be converted 6 bits per char to a 96 bit value |
| // (with the most significant 32 bits as zero) as there are only 12 unique bytes worth of data |
| // or (2) the 16 Base64 chars can be used to directly fill the 128 bits of int128 assuming |
| // the 16 chars are 16 bytes, filling the layout of the int128 variable. |
| // Endianness of the data may follow whatever is convenient in the interpretation as long |
| // as it is applied to each such conversion of string to int128 identically. |
| // |
| inline constexpr bool isLogSessionId(const char *s) { |
| return std::char_traits<std::decay_t<decltype(*s)>>::length(s) == 16 && isBase64Url(s); |
| } |
| |
| // Returns either the original string or an empty string if isLogSessionId check fails. |
| inline std::string sanitizeLogSessionId(const std::string& string) { |
| if (isLogSessionId(string.c_str())) return string; |
| return {}; // if not a logSessionId, return an empty string. |
| } |
| |
| inline std::string bytesToString(const std::vector<uint8_t>& bytes, size_t maxSize = SIZE_MAX) { |
| if (bytes.size() == 0) { |
| return "{}"; |
| } |
| std::stringstream ss; |
| ss << "{"; |
| ss << std::hex << std::setfill('0'); |
| maxSize = std::min(maxSize, bytes.size()); |
| for (size_t i = 0; i < maxSize; ++i) { |
| ss << " " << std::setw(2) << (int)bytes[i]; |
| } |
| if (maxSize != bytes.size()) { |
| ss << " ... }"; |
| } else { |
| ss << " }"; |
| } |
| return ss.str(); |
| } |
| |
| } // namespace android::mediametrics::stringutils |