| /* |
| * Copyright (c) 2018, The OpenThread Authors. |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * 3. Neither the name of the copyright holder nor the |
| * names of its contributors may be used to endorse or promote products |
| * derived from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
| * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE |
| * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| * POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| /** |
| * @file |
| * This file defines OpenThread String class. |
| */ |
| |
| #ifndef STRING_HPP_ |
| #define STRING_HPP_ |
| |
| #include "openthread-core-config.h" |
| |
| #include <stdarg.h> |
| #include <stdint.h> |
| #include <stdio.h> |
| |
| #include "common/binary_search.hpp" |
| #include "common/code_utils.hpp" |
| #include "common/error.hpp" |
| #include "common/num_utils.hpp" |
| |
| namespace ot { |
| |
| /** |
| * @addtogroup core-string |
| * |
| * @brief |
| * This module includes definitions for OpenThread String class. |
| * |
| * @{ |
| * |
| */ |
| |
| /** |
| * Represents comparison mode when matching strings. |
| * |
| */ |
| enum StringMatchMode : uint8_t |
| { |
| kStringExactMatch, ///< Exact match of characters. |
| kStringCaseInsensitiveMatch, ///< Case insensitive match (uppercase and lowercase characters are treated as equal). |
| }; |
| |
| /** |
| * Represents string encoding check when copying string. |
| * |
| */ |
| enum StringEncodingCheck : uint8_t |
| { |
| kStringNoEncodingCheck, ///< Do not check the string encoding. |
| kStringCheckUtf8Encoding, ///< Validate that string follows UTF-8 encoding. |
| }; |
| |
| static constexpr char kNullChar = '\0'; ///< null character. |
| |
| /** |
| * Returns the number of characters that precede the terminating null character. |
| * |
| * @param[in] aString A pointer to the string. |
| * @param[in] aMaxLength The maximum length in bytes. |
| * |
| * @returns The number of characters that precede the terminating null character or @p aMaxLength, |
| * whichever is smaller. `0` if @p aString is `nullptr`. |
| * |
| */ |
| uint16_t StringLength(const char *aString, uint16_t aMaxLength); |
| |
| /** |
| * Finds the first occurrence of a given character in a null-terminated string. |
| * |
| * @param[in] aString A pointer to the string. |
| * @param[in] aChar A char to search for in the string. |
| * |
| * @returns The pointer to first occurrence of the @p aChar in @p aString, or `nullptr` if cannot be found. |
| * |
| */ |
| const char *StringFind(const char *aString, char aChar); |
| |
| /** |
| * Finds the first occurrence of a given sub-string in a null-terminated string. |
| * |
| * @param[in] aString A pointer to the string. |
| * @param[in] aSubString A sub-string to search for. |
| * @param[in] aMode The string comparison mode, exact match or case insensitive match. |
| * |
| * @returns The pointer to first match of the @p aSubString in @p aString (using comparison @p aMode), or `nullptr` if |
| * cannot be found. |
| * |
| */ |
| const char *StringFind(const char *aString, const char *aSubString, StringMatchMode aMode = kStringExactMatch); |
| |
| /** |
| * Checks whether a null-terminated string starts with a given prefix string. |
| * |
| * @param[in] aString A pointer to the string. |
| * @param[in] aPrefixString A prefix string. |
| * @param[in] aMode The string comparison mode, exact match or case insensitive match. |
| * |
| * @retval TRUE If @p aString starts with @p aPrefixString. |
| * @retval FALSE If @p aString does not start with @p aPrefixString. |
| * |
| */ |
| bool StringStartsWith(const char *aString, const char *aPrefixString, StringMatchMode aMode = kStringExactMatch); |
| |
| /** |
| * Checks whether a null-terminated string ends with a given character. |
| * |
| * @param[in] aString A pointer to the string. |
| * @param[in] aChar A char to check. |
| * |
| * @retval TRUE If @p aString ends with character @p aChar. |
| * @retval FALSE If @p aString does not end with character @p aChar. |
| * |
| */ |
| bool StringEndsWith(const char *aString, char aChar); |
| |
| /** |
| * Checks whether a null-terminated string ends with a given sub-string. |
| * |
| * @param[in] aString A pointer to the string. |
| * @param[in] aSubString A sub-string to check against. |
| * @param[in] aMode The string comparison mode, exact match or case insensitive match. |
| * |
| * @retval TRUE If @p aString ends with sub-string @p aSubString. |
| * @retval FALSE If @p aString does not end with sub-string @p aSubString. |
| * |
| */ |
| bool StringEndsWith(const char *aString, const char *aSubString, StringMatchMode aMode = kStringExactMatch); |
| |
| /** |
| * Checks whether or not two null-terminated strings match. |
| * |
| * @param[in] aFirstString A pointer to the first string. |
| * @param[in] aSecondString A pointer to the second string. |
| * @param[in] aMode The string comparison mode, exact match or case insensitive match. |
| * |
| * @retval TRUE If @p aFirstString matches @p aSecondString using match mode @p aMode. |
| * @retval FALSE If @p aFirstString does not match @p aSecondString using match mode @p aMode. |
| * |
| */ |
| bool StringMatch(const char *aFirstString, const char *aSecondString, StringMatchMode aMode = kStringExactMatch); |
| |
| /** |
| * Copies a string into a given target buffer with a given size if it fits. |
| * |
| * @param[out] aTargetBuffer A pointer to the target buffer to copy into. |
| * @param[out] aTargetSize The size (number of characters) in @p aTargetBuffer array. |
| * @param[in] aSource A pointer to null-terminated string to copy from. Can be `nullptr` which treated as "". |
| * @param[in] aEncodingCheck Specifies the encoding format check (e.g., UTF-8) to perform. |
| * |
| * @retval kErrorNone The @p aSource fits in the given buffer. @p aTargetBuffer is updated. |
| * @retval kErrorInvalidArgs The @p aSource does not fit in the given buffer. |
| * @retval kErrorParse The @p aSource does not follow the encoding format specified by @p aEncodingCheck. |
| * |
| */ |
| Error StringCopy(char *TargetBuffer, uint16_t aTargetSize, const char *aSource, StringEncodingCheck aEncodingCheck); |
| |
| /** |
| * Copies a string into a given target buffer with a given size if it fits. |
| * |
| * @tparam kSize The size of buffer. |
| * |
| * @param[out] aTargetBuffer A reference to the target buffer array to copy into. |
| * @param[in] aSource A pointer to null-terminated string to copy from. Can be `nullptr` which treated as "". |
| * @param[in] aEncodingCheck Specifies the encoding format check (e.g., UTF-8) to perform. |
| * |
| * @retval kErrorNone The @p aSource fits in the given buffer. @p aTargetBuffer is updated. |
| * @retval kErrorInvalidArgs The @p aSource does not fit in the given buffer. |
| * @retval kErrorParse The @p aSource does not follow the encoding format specified by @p aEncodingCheck. |
| * |
| */ |
| template <uint16_t kSize> |
| Error StringCopy(char (&aTargetBuffer)[kSize], |
| const char *aSource, |
| StringEncodingCheck aEncodingCheck = kStringNoEncodingCheck) |
| { |
| return StringCopy(aTargetBuffer, kSize, aSource, aEncodingCheck); |
| } |
| |
| /** |
| * Parses a decimal number from a string as `uint8_t` and skips over the parsed characters. |
| * |
| * If the string does not start with a digit, `kErrorParse` is returned. |
| * |
| * All the digit characters in the string are parsed until reaching a non-digit character. The pointer `aString` is |
| * updated to point to the first non-digit character after the parsed digits. |
| * |
| * If the parsed number value is larger than @p aMaxValue, `kErrorParse` is returned. |
| * |
| * @param[in,out] aString A reference to a pointer to string to parse. |
| * @param[out] aUint8 A reference to return the parsed value. |
| * @param[in] aMaxValue Maximum allowed value for the parsed number. |
| * |
| * @retval kErrorNone Successfully parsed the number from string. @p aString and @p aUint8 are updated. |
| * @retval kErrorParse Failed to parse the number from @p aString, or parsed number is larger than @p aMaxValue. |
| * |
| */ |
| Error StringParseUint8(const char *&aString, uint8_t &aUint8, uint8_t aMaxValue); |
| |
| /** |
| * Parses a decimal number from a string as `uint8_t` and skips over the parsed characters. |
| * |
| * If the string does not start with a digit, `kErrorParse` is returned. |
| * |
| * All the digit characters in the string are parsed until reaching a non-digit character. The pointer `aString` is |
| * updated to point to the first non-digit character after the parsed digits. |
| * |
| * If the parsed number value is larger than maximum `uint8_t` value, `kErrorParse` is returned. |
| * |
| * @param[in,out] aString A reference to a pointer to string to parse. |
| * @param[out] aUint8 A reference to return the parsed value. |
| * |
| * @retval kErrorNone Successfully parsed the number from string. @p aString and @p aUint8 are updated. |
| * @retval kErrorParse Failed to parse the number from @p aString, or parsed number is out of range. |
| * |
| */ |
| Error StringParseUint8(const char *&aString, uint8_t &aUint8); |
| |
| /** |
| * Converts all uppercase letter characters in a given string to lowercase. |
| * |
| * @param[in,out] aString A pointer to the string to convert. |
| * |
| */ |
| void StringConvertToLowercase(char *aString); |
| |
| /** |
| * Converts all lowercase letter characters in a given string to uppercase. |
| * |
| * @param[in,out] aString A pointer to the string to convert. |
| * |
| */ |
| void StringConvertToUppercase(char *aString); |
| |
| /** |
| * Converts an uppercase letter character to lowercase. |
| * |
| * If @p aChar is uppercase letter it is converted lowercase. Otherwise, it remains unchanged. |
| * |
| * @param[in] aChar The character to convert |
| * |
| * @returns The character converted to lowercase. |
| * |
| */ |
| char ToLowercase(char aChar); |
| |
| /** |
| * Converts a lowercase letter character to uppercase. |
| * |
| * If @p aChar is lowercase letter it is converted uppercase. Otherwise, it remains unchanged. |
| * |
| * @param[in] aChar The character to convert |
| * |
| * @returns The character converted to uppercase. |
| * |
| */ |
| char ToUppercase(char aChar); |
| |
| /** |
| * Checks whether a given character is an uppercase letter ('A'-'Z'). |
| * |
| * @param[in] aChar The character to check. |
| * |
| * @retval TRUE @p aChar is an uppercase letter. |
| * @retval FALSE @p aChar is not an uppercase letter. |
| * |
| */ |
| bool IsUppercase(char aChar); |
| |
| /** |
| * Checks whether a given character is a lowercase letter ('a'-'z'). |
| * |
| * @param[in] aChar The character to check. |
| * |
| * @retval TRUE @p aChar is a lowercase letter. |
| * @retval FALSE @p aChar is not a lowercase letter. |
| * |
| */ |
| bool IsLowercase(char aChar); |
| |
| /** |
| * Checks whether a given character is a digit character ('0'-'9'). |
| * |
| * @param[in] aChar The character to check. |
| * |
| * @retval TRUE @p aChar is a digit character. |
| * @retval FALSE @p aChar is not a digit character. |
| * |
| */ |
| bool IsDigit(char aChar); |
| |
| /** |
| * Parse a given digit character to its numeric value. |
| * |
| * @param[in] aDigitChar The digit character to parse. |
| * @param[out] aValue A reference to return the parsed value on success. |
| * |
| * @retval kErrorNone Successfully parsed the digit, @p aValue is updated. |
| * @retval kErrorInvalidArgs @p aDigitChar is not a valid digit character. |
| * |
| */ |
| Error ParseDigit(char aDigitChar, uint8_t &aValue); |
| |
| /** |
| * Parse a given hex digit character ('0'-'9', 'A'-'F', or 'a'-'f') to its numeric value. |
| * |
| * @param[in] aHexChar The hex digit character to parse. |
| * @param[out] aValue A reference to return the parsed value on success. |
| * |
| * @retval kErrorNone Successfully parsed the digit, @p aValue is updated. |
| * @retval kErrorInvalidArgs @p aHexChar is not a valid hex digit character. |
| * |
| */ |
| Error ParseHexDigit(char aHexChar, uint8_t &aValue); |
| |
| /** |
| * Coverts a boolean to "yes" or "no" string. |
| * |
| * @param[in] aBool A boolean value to convert. |
| * |
| * @returns The converted string representation of @p aBool ("yes" for TRUE and "no" for FALSE). |
| * |
| */ |
| const char *ToYesNo(bool aBool); |
| |
| /** |
| * Validates whether a given byte sequence (string) follows UTF-8 encoding. |
| * Control characters are not allowed. |
| * |
| * @param[in] aString A null-terminated byte sequence. |
| * |
| * @retval TRUE The sequence is a valid UTF-8 string. |
| * @retval FALSE The sequence is not a valid UTF-8 string. |
| * |
| */ |
| bool IsValidUtf8String(const char *aString); |
| |
| /** |
| * Validates whether a given byte sequence (string) follows UTF-8 encoding. |
| * Control characters are not allowed. |
| * |
| * @param[in] aString A byte sequence. |
| * @param[in] aLength Length of the sequence. |
| * |
| * @retval TRUE The sequence is a valid UTF-8 string. |
| * @retval FALSE The sequence is not a valid UTF-8 string. |
| * |
| */ |
| bool IsValidUtf8String(const char *aString, size_t aLength); |
| |
| /** |
| * This `constexpr` function checks whether two given C strings are in order (alphabetical order). |
| * |
| * This is intended for use from `static_assert`, e.g., checking if a lookup table entries are sorted. It is not |
| * recommended to use this function in other situations as it uses recursion so that it can be `constexpr`. |
| * |
| * @param[in] aFirst The first string. |
| * @param[in] aSecond The second string. |
| * |
| * @retval TRUE If first string is strictly before second string (alphabetical order). |
| * @retval FALSE If first string is not strictly before second string (alphabetical order). |
| * |
| */ |
| inline constexpr bool AreStringsInOrder(const char *aFirst, const char *aSecond) |
| { |
| return (*aFirst < *aSecond) |
| ? true |
| : ((*aFirst > *aSecond) || (*aFirst == '\0') ? false : AreStringsInOrder(aFirst + 1, aSecond + 1)); |
| } |
| |
| /** |
| * Implements writing to a string buffer. |
| * |
| */ |
| class StringWriter |
| { |
| public: |
| /** |
| * Initializes the object as cleared on the provided buffer. |
| * |
| * @param[in] aBuffer A pointer to the char buffer to write into. |
| * @param[in] aSize The size of @p aBuffer. |
| * |
| */ |
| StringWriter(char *aBuffer, uint16_t aSize); |
| |
| /** |
| * Clears the string writer. |
| * |
| * @returns The string writer. |
| * |
| */ |
| StringWriter &Clear(void); |
| |
| /** |
| * Returns whether the output is truncated. |
| * |
| * @note If the output is truncated, the buffer is still null-terminated. |
| * |
| * @retval true The output is truncated. |
| * @retval false The output is not truncated. |
| * |
| */ |
| bool IsTruncated(void) const { return mLength >= mSize; } |
| |
| /** |
| * Gets the length of the wanted string. |
| * |
| * Similar to `strlen()` the length does not include the null character at the end of the string. |
| * |
| * @returns The string length. |
| * |
| */ |
| uint16_t GetLength(void) const { return mLength; } |
| |
| /** |
| * Returns the size (number of chars) in the buffer. |
| * |
| * @returns The size of the buffer. |
| * |
| */ |
| uint16_t GetSize(void) const { return mSize; } |
| |
| /** |
| * Appends `printf()` style formatted data to the buffer. |
| * |
| * @param[in] aFormat A pointer to the format string. |
| * @param[in] ... Arguments for the format specification. |
| * |
| * @returns The string writer. |
| * |
| */ |
| StringWriter &Append(const char *aFormat, ...) OT_TOOL_PRINTF_STYLE_FORMAT_ARG_CHECK(2, 3); |
| |
| /** |
| * Appends `printf()` style formatted data to the buffer. |
| * |
| * @param[in] aFormat A pointer to the format string. |
| * @param[in] aArgs Arguments for the format specification (as `va_list`). |
| * |
| * @returns The string writer. |
| * |
| */ |
| StringWriter &AppendVarArgs(const char *aFormat, va_list aArgs); |
| |
| /** |
| * Appends an array of bytes in hex representation (using "%02x" style) to the buffer. |
| * |
| * @param[in] aBytes A pointer to buffer containing the bytes to append. |
| * @param[in] aLength The length of @p aBytes buffer (in bytes). |
| * |
| * @returns The string writer. |
| * |
| */ |
| StringWriter &AppendHexBytes(const uint8_t *aBytes, uint16_t aLength); |
| |
| /** |
| * Appends a given character a given number of times. |
| * |
| * @param[in] aChar The character to append. |
| * @param[in] aCount Number of times to append @p aChar. |
| * |
| */ |
| StringWriter &AppendCharMultipleTimes(char aChar, uint16_t aCount); |
| |
| /** |
| * Converts all uppercase letter characters in the string to lowercase. |
| * |
| */ |
| void ConvertToLowercase(void) { StringConvertToLowercase(mBuffer); } |
| |
| /** |
| * Converts all lowercase letter characters in the string to uppercase. |
| * |
| */ |
| void ConvertToUppercase(void) { StringConvertToUppercase(mBuffer); } |
| |
| private: |
| char *mBuffer; |
| uint16_t mLength; |
| const uint16_t mSize; |
| }; |
| |
| /** |
| * Defines a fixed-size string. |
| * |
| */ |
| template <uint16_t kSize> class String : public StringWriter |
| { |
| static_assert(kSize > 0, "String buffer cannot be empty."); |
| |
| public: |
| /** |
| * Initializes the string as empty. |
| * |
| */ |
| String(void) |
| : StringWriter(mBuffer, sizeof(mBuffer)) |
| { |
| } |
| |
| /** |
| * Returns the string as a null-terminated C string. |
| * |
| * @returns The null-terminated C string. |
| * |
| */ |
| const char *AsCString(void) const { return mBuffer; } |
| |
| private: |
| char mBuffer[kSize]; |
| }; |
| |
| /** |
| * Provides helper methods to convert from a set of `uint16_t` values (e.g., a non-sequential `enum`) to |
| * string using binary search in a lookup table. |
| * |
| */ |
| class Stringify : public BinarySearch |
| { |
| public: |
| /** |
| * Represents a entry in the lookup table. |
| * |
| */ |
| class Entry |
| { |
| friend class BinarySearch; |
| |
| public: |
| uint16_t mKey; ///< The key value. |
| const char *mString; ///< The associated string. |
| |
| private: |
| int Compare(uint16_t aKey) const { return ThreeWayCompare(aKey, mKey); } |
| |
| constexpr static bool AreInOrder(const Entry &aFirst, const Entry &aSecond) |
| { |
| return aFirst.mKey < aSecond.mKey; |
| } |
| }; |
| |
| /** |
| * Looks up a key in a given sorted table array (using binary search) and return the associated |
| * strings with the key. |
| * |
| * @note This method requires the array to be sorted, otherwise its behavior is undefined. |
| * |
| * @tparam kLength The array length (number of entries in the array). |
| * |
| * @param[in] aKey The key to search for within the table. |
| * @param[in] aTable A reference to an array of `kLength` entries. |
| * @param[in] aNotFound A C string to return if @p aKey was not found in the table. |
| * |
| * @returns The associated string with @p aKey in @p aTable if found, or @p aNotFound otherwise. |
| * |
| */ |
| template <uint16_t kLength> |
| static const char *Lookup(uint16_t aKey, const Entry (&aTable)[kLength], const char *aNotFound = "unknown") |
| { |
| const Entry *entry = BinarySearch::Find(aKey, aTable); |
| |
| return (entry != nullptr) ? entry->mString : aNotFound; |
| } |
| |
| Stringify(void) = delete; |
| }; |
| |
| /** |
| * @} |
| * |
| */ |
| |
| } // namespace ot |
| |
| #endif // STRING_HPP_ |