src/string_func.h

   1 /*
   2  * This file is part of OpenTTD.
   3  * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
   4  * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
   5  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
   6  */
   7
   8 /**
   9  * @file string_func.h Functions related to low-level strings.
  10  *
  11  * @note Be aware of "dangerous" string functions; string functions that
  12  * have behaviour that could easily cause buffer overruns and such:
  13  * - strncpy: does not '\0' terminate when input string is longer than
  14  *   the size of the output string. Use strecpy instead.
  15  * - [v]snprintf: returns the length of the string as it would be written
  16  *   when the output is large enough, so it can be more than the size of
  17  *   the buffer and than can underflow size_t (uint-ish) which makes all
  18  *   subsequent snprintf alikes write outside of the buffer. Use
  19  *   [v]seprintf instead; it will return the number of bytes actually
  20  *   added so no [v]seprintf will cause outside of bounds writes.
  21  * - [v]sprintf: does not bounds checking: use [v]seprintf instead.
  22  */
  23
  24 #ifndef STRING_FUNC_H
  25 #define STRING_FUNC_H
  26
  27 #include <stdarg.h>
  28 #include <iosfwd>
  29
  30 #include "core/bitmath_func.hpp"
  31 #include "string_type.h"
  32
  33 char *strecat(char *dst, const char *src, const char *last) NOACCESS(3);
  34 char *strecpy(char *dst, const char *src, const char *last) NOACCESS(3);
  35 char *stredup(const char *src, const char *last = nullptr) NOACCESS(2);
  36
  37 int CDECL seprintf(char *str, const char *last, const char *format, ...) WARN_FORMAT(3, 4) NOACCESS(2);
  38 int CDECL vseprintf(char *str, const char *last, const char *format, va_list ap) WARN_FORMAT(3, 0) NOACCESS(2);
  39
  40 char *CDECL str_fmt(const char *str, ...) WARN_FORMAT(1, 2);
  41
  42 void StrMakeValidInPlace(char *str, const char *last, StringValidationSettings settings = SVS_REPLACE_WITH_QUESTION_MARK) NOACCESS(2);
  43 [[nodiscard]] std::string StrMakeValid(const std::string &str, StringValidationSettings settings = SVS_REPLACE_WITH_QUESTION_MARK);
  44 void StrMakeValidInPlace(char *str, StringValidationSettings settings = SVS_REPLACE_WITH_QUESTION_MARK);
  45
  46 void str_fix_scc_encoded(char *str, const char *last) NOACCESS(2);
  47 void str_strip_colours(char *str);
  48 bool strtolower(char *str);
  49 bool strtolower(std::string &str, std::string::size_type offs = 0);
  50
  51 bool StrValid(const char *str, const char *last) NOACCESS(2);
  52 void StrTrimInPlace(std::string &str);
  53
  54 bool StrStartsWith(const std::string_view str, const std::string_view prefix);
  55 bool StrEndsWith(const std::string_view str, const std::string_view suffix);
  56
  57 /**
  58  * Check if a string buffer is empty.
  59  *
  60  * @param s The pointer to the first element of the buffer
  61  * @return true if the buffer starts with the terminating null-character or
  62  *         if the given pointer points to nullptr else return false
  63  */
  64 static inline bool StrEmpty(const char *s)
  65 {
  66         return s == nullptr || s[0] == '\0';
  67 }
  68
  69 /**
  70  * Get the length of a string, within a limited buffer.
  71  *
  72  * @param str The pointer to the first element of the buffer
  73  * @param maxlen The maximum size of the buffer
  74  * @return The length of the string
  75  */
  76 static inline size_t ttd_strnlen(const char *str, size_t maxlen)
  77 {
  78         const char *t;
  79         for (t = str; (size_t)(t - str) < maxlen && *t != '\0'; t++) {}
  80         return t - str;
  81 }
  82
  83 char *md5sumToString(char *buf, const char *last, const uint8 md5sum[16]);
  84
  85 bool IsValidChar(WChar key, CharSetFilter afilter);
  86
  87 size_t Utf8Decode(WChar *c, const char *s);
  88 size_t Utf8Encode(char *buf, WChar c);
  89 size_t Utf8Encode(std::ostreambuf_iterator<char> &buf, WChar c);
  90 size_t Utf8TrimString(char *s, size_t maxlen);
  91
  92
  93 static inline WChar Utf8Consume(const char **s)
  94 {
  95         WChar c;
  96         *s += Utf8Decode(&c, *s);
  97         return c;
  98 }
  99
 100 template <class Titr>
 101 static inline WChar Utf8Consume(Titr &s)
 102 {
 103         WChar c;
 104         s += Utf8Decode(&c, &*s);
 105         return c;
 106 }
 107
 108 /**
 109  * Return the length of a UTF-8 encoded character.
 110  * @param c Unicode character.
 111  * @return Length of UTF-8 encoding for character.
 112  */
 113 static inline int8 Utf8CharLen(WChar c)
 114 {
 115         if (c < 0x80)       return 1;
 116         if (c < 0x800)      return 2;
 117         if (c < 0x10000)    return 3;
 118         if (c < 0x110000)   return 4;
 119
 120         /* Invalid valid, we encode as a '?' */
 121         return 1;
 122 }
 123
 124
 125 /**
 126  * Return the length of an UTF-8 encoded value based on a single char. This
 127  * char should be the first byte of the UTF-8 encoding. If not, or encoding
 128  * is invalid, return value is 0
 129  * @param c char to query length of
 130  * @return requested size
 131  */
 132 static inline int8 Utf8EncodedCharLen(char c)
 133 {
 134         if (GB(c, 3, 5) == 0x1E) return 4;
 135         if (GB(c, 4, 4) == 0x0E) return 3;
 136         if (GB(c, 5, 3) == 0x06) return 2;
 137         if (GB(c, 7, 1) == 0x00) return 1;
 138
 139         /* Invalid UTF8 start encoding */
 140         return 0;
 141 }
 142
 143
 144 /* Check if the given character is part of a UTF8 sequence */
 145 static inline bool IsUtf8Part(char c)
 146 {
 147         return GB(c, 6, 2) == 2;
 148 }
 149
 150 /**
 151  * Retrieve the previous UNICODE character in an UTF-8 encoded string.
 152  * @param s char pointer pointing to (the first char of) the next character
 153  * @return a pointer in 's' to the previous UNICODE character's first byte
 154  * @note The function should not be used to determine the length of the previous
 155  * encoded char because it might be an invalid/corrupt start-sequence
 156  */
 157 static inline char *Utf8PrevChar(char *s)
 158 {
 159         char *ret = s;
 160         while (IsUtf8Part(*--ret)) {}
 161         return ret;
 162 }
 163
 164 static inline const char *Utf8PrevChar(const char *s)
 165 {
 166         const char *ret = s;
 167         while (IsUtf8Part(*--ret)) {}
 168         return ret;
 169 }
 170
 171 size_t Utf8StringLength(const char *s);
 172 size_t Utf8StringLength(const std::string &str);
 173
 174 /**
 175  * Is the given character a lead surrogate code point?
 176  * @param c The character to test.
 177  * @return True if the character is a lead surrogate code point.
 178  */
 179 static inline bool Utf16IsLeadSurrogate(uint c)
 180 {
 181         return c >= 0xD800 && c <= 0xDBFF;
 182 }
 183
 184 /**
 185  * Is the given character a lead surrogate code point?
 186  * @param c The character to test.
 187  * @return True if the character is a lead surrogate code point.
 188  */
 189 static inline bool Utf16IsTrailSurrogate(uint c)
 190 {
 191         return c >= 0xDC00 && c <= 0xDFFF;
 192 }
 193
 194 /**
 195  * Convert an UTF-16 surrogate pair to the corresponding Unicode character.
 196  * @param lead Lead surrogate code point.
 197  * @param trail Trail surrogate code point.
 198  * @return Decoded Unicode character.
 199  */
 200 static inline WChar Utf16DecodeSurrogate(uint lead, uint trail)
 201 {
 202         return 0x10000 + (((lead - 0xD800) << 10) | (trail - 0xDC00));
 203 }
 204
 205 /**
 206  * Decode an UTF-16 character.
 207  * @param c Pointer to one or two UTF-16 code points.
 208  * @return Decoded Unicode character.
 209  */
 210 static inline WChar Utf16DecodeChar(const uint16 *c)
 211 {
 212         if (Utf16IsLeadSurrogate(c[0])) {
 213                 return Utf16DecodeSurrogate(c[0], c[1]);
 214         } else {
 215                 return *c;
 216         }
 217 }
 218
 219 /**
 220  * Is the given character a text direction character.
 221  * @param c The character to test.
 222  * @return true iff the character is used to influence
 223  *         the text direction.
 224  */
 225 static inline bool IsTextDirectionChar(WChar c)
 226 {
 227         switch (c) {
 228                 case CHAR_TD_LRM:
 229                 case CHAR_TD_RLM:
 230                 case CHAR_TD_LRE:
 231                 case CHAR_TD_RLE:
 232                 case CHAR_TD_LRO:
 233                 case CHAR_TD_RLO:
 234                 case CHAR_TD_PDF:
 235                         return true;
 236
 237                 default:
 238                         return false;
 239         }
 240 }
 241
 242 static inline bool IsPrintable(WChar c)
 243 {
 244         if (c < 0x20)   return false;
 245         if (c < 0xE000) return true;
 246         if (c < 0xE200) return false;
 247         return true;
 248 }
 249
 250 /**
 251  * Check whether UNICODE character is whitespace or not, i.e. whether
 252  * this is a potential line-break character.
 253  * @param c UNICODE character to check
 254  * @return a boolean value whether 'c' is a whitespace character or not
 255  * @see http://www.fileformat.info/info/unicode/category/Zs/list.htm
 256  */
 257 static inline bool IsWhitespace(WChar c)
 258 {
 259         return c == 0x0020 /* SPACE */ || c == 0x3000; /* IDEOGRAPHIC SPACE */
 260 }
 261
 262 /* Needed for NetBSD version (so feature) testing */
 263 #if defined(__NetBSD__) || defined(__FreeBSD__)
 264 #include <sys/param.h>
 265 #endif
 266
 267 /* strcasestr is available for _GNU_SOURCE, BSD and some Apple */
 268 #if defined(_GNU_SOURCE) || (defined(__BSD_VISIBLE) && __BSD_VISIBLE) || (defined(__APPLE__) && (!defined(_POSIX_C_SOURCE) || defined(_DARWIN_C_SOURCE))) || defined(_NETBSD_SOURCE)
 269 #       undef DEFINE_STRCASESTR
 270 #else
 271 #       define DEFINE_STRCASESTR
 272 char *strcasestr(const char *haystack, const char *needle);
 273 #endif /* strcasestr is available */
 274
 275 int strnatcmp(const char *s1, const char *s2, bool ignore_garbage_at_front = false);
 276
 277 #endif /* STRING_FUNC_H */