String library

C string utils library (STB style, header-only). Features:

• String expression evaluator (streval)
• String formatters (to heap buffers) (strcpyf*, strcatf*)
• String formatters (to temporary buffers) (strf*)
• String fuzzy search (strscore, strfuzzy)
• String regular expression (strregex [c?^$*])
• String 64-bit hashing (both compile-time and runtime) (strhash)
• String interning (quarks) (strput, strget)
• String matching (strsub, strfindl, strfindr, strbegin, strend, strmatch, streq, streqi)
• String splitting (with and without allocations) (strsplit, strchop, strjoin)
• String options parsing (stropt, stropti, stroptf)
• String trim utils (strdel, strtrimws, strtrimblf/bff, strtrimrlfe/ffe)
• String transform utils (strrepl, strremap, strlower, strupper, strrev)
• String normalization utils (strnorm)
• String conversion utils (strint, strhuman, strrobot)
• String unicode utils (strutf8, strutf32, strwiden, strshorten)
• Documentation.

Homepage

• https://github.com/r-lyeh/stdstring.h

Changelog

• 2018.1 (v1.0.4): Fix API() macro; Add new transform utils; Rename a few functions.
• 2018.1 (v1.0.3): Add strnorm(), strjoin(). Fix strcpyf().
• 2018.1 (v1.0.2): Add stropt*() options parser.
• 2018.1 (v1.0.1): Fix wrong version of strcatf() in first commit. Cosmetics.
• 2018.1 (v1.0.0): Initial release.

Credits

• Using Rob Pike's regular expression (apparently public domain).
• Using Sam Hocevar's preprocessor trick (apparently public domain).
• Using Bob Stout's transform utils (public domain).
• Using Sean Barrett and Jeff Roberts' string formatters (unlicensed).
• Using Werner Stoop's expression evaluator (unlicensed).
• Using Dimitri Diakopoulos' & Sean Barrett's unicode stuff (unlicensed).

License

• rlyeh, unlicensed (~public domain).

API

String expression evaluator

• Evaluates a mathematical expression. Returns number value, or NaN if error.
• Note: To check for NaN use isnan(ret) or bool error = (ret != ret);

ABI      double        streval(const char *expression);

String fuzzy completion

• Compares two strings. Returns string matching score (higher is better).
• Fuzzy search a word into a list of given words. Returns best match or empty string (if none).

ABI      int           strscore(const char *string1, const char *string2);
ABI      const char *  strfuzzy(const char *string, int num, const char *words[]);

String regular expression

• Regular expression matching. returns non-zero if found.
  • c matches any literal character c.
  • ? matches any single character.
  • ^ matches the beginning of the input string.
  • $ matches the end of the input string.
  • * matches zero or more occurrences of the previous character.
• Return true if string matches wildcard pattern expression (?*).

ABI      int           strregex(const char *string, const char *regex);
ABI      bool          strmatch(const char *string, const char *substring);

String hashing

• Runtime string hash. Returns 64-bit hash of given string.
• Compile-time string hash macro. Returns 64-bit hash of given string.
• Note: Macro requires code optimizations enabled (-O3 for gcc, /O2 for MSVC).

ABI      uint64_t      strhash(const char *string);
ABI      uint64_t      STRHASH(const char *string);

String interning dictionary (quarks)

• Insert string into dictionary (if not exists). Returns quark ID, or 0 if empty string.
• Retrieve previously interned string. ID#0 returns empty string always.

ABI      int           strput(const char *string);
ABI      const char *  strget(int quark);

String matching

• Extract substring from position. Negative positions are relative to end of string.
• Search substring from beginning (left). Returns end-of-string if not found.
• Search substring from end (right). Returns end-of-string if not found.
• Return true if string starts with substring.
• Return true if string ends with substring.
• Return true if strings are equal.
• Return true if strings are equal (case insensitive).

ABI      const char*   strsub  (const char *string, int position);
ABI      const char*   strfindl(const char *string, const char *substring);
ABI      const char*   strfindr(const char *string, const char *substring);
ABI      bool          strbegin(const char *string, const char *substring);
ABI      bool          strend  (const char *string, const char *substring);
ABI      bool          streq   (const char *string, const char *substring);
ABI      bool          streqi  (const char *string, const char *substring);

String normalization

• Normalize resource identificator. Normalized uris have deterministic string hashes.

ABI TEMP char *        strnorm (const char *uri);

String conversion utils

• Convert a string to integer.
• Convert number to human readable string (12000000 -> 12M)
• Convert human readable string to number (12M -> 12000000)

ABI      int64_t       strint  (const char *string);
ABI TEMP char*         strhuman(uint64_t number);
ABI      uint64_t      strrobot(const char *string);

String options parsing

• Parse argc/argv looking for comma-separated values. Returns matching string or defaults.
• Parse argc/argv looking for comma-separated values. Returns matching integer or defaults.
• Parse argc/argv looking for comma-separated values. Returns matching floating or defaults.

ABI      const char *  stropt (const char *defaults, const char *options_csv);
ABI      int64_t       stropti(int64_t defaults, const char *options_csv);
ABI      double        stroptf(double defaults, const char *options_csv);

String format (temporary buffers)

• Format a C-style formatted string. Returns temporary buffer (do not free()).
• Format a C-style formatted valist. Returns temporary buffer (do not free()).
• Note: 16 buffers are handled internally so that nested calls are safe within reasonable limits.

ABI TEMP char *        strf (const char *format, ...);
ABI TEMP char *        strfv(const char *format, va_list list);

String format (heap buffers)

• Assign a C-style formatted string. Reallocates input buffer (will create buffer if str is NULL).
• Assign a C-style formatted valist. Reallocates input buffer (will create buffer if str is NULL).
• Concat a C-style formatted string. Reallocates input buffer (will create buffer if str is NULL).
• Concat a C-style formatted valist. Reallocates input buffer (will create buffer if str is NULL).

ABI HEAP char *        strcpyf (INOUT char **string, const char *format, ...);
ABI HEAP char *        strcpyfv(INOUT char **string, const char *format, va_list list);
ABI HEAP char *        strcatf (INOUT char **string, const char *format, ...);
ABI HEAP char *        strcatfv(INOUT char **string, const char *format, va_list list);

String splitting

• Check delimiters and split string into tokens. Function never allocates.
• Check delimiters and split string into tokens. Returns null-terminated list.
• Join tokens into a string.

ABI      int           strchop (const char *string, const char *delimiters, int avail, const char *tokens[]);
ABI HEAP char**        strsplit(const char *string, const char *delimiters);
ABI HEAP char*         strjoin (INOUT char **out, const char *tokens[], const char *separator);

String trimming

• Delete substring from a string.
• Trim characters from begin of string to first-find (b-str-str-e to x-xxx-str-e).
• Trim characters from begin of string to last-find (b-str-str-e to x-xxx-xxx-e).
• Trim characters from first-find to end of string (b-str-str-e to b-xxx-xxx-x).
• Trim characters from last-find to end of string (b-str-str-e to b-str-xxx-x).
• Trim leading, trailing and excess embedded whitespaces.

ABI      char*         strdel    (char *string, const char *substring);
ABI      char*         strtrimbff(char *string, const char *substring);
ABI      char*         strtrimblf(char *string, const char *substring);
ABI      char*         strtrimffe(char *string, const char *substring);
ABI      char*         strtrimlfe(char *string, const char *substring);
ABI      char*         strtrimws (char *string);

String transforms

• Replace a substring in a string.
• Remap specific characters in a string from a given set to another one. Length of both sets must be identical.
• Convert a string to lowercase (ANSI only, not utf8/locale aware!).
• Convert a string to uppercase (ANSI only, not utf8/locale aware!).
• Reverse a string in-place.

ABI HEAP char*         strrepl   (INOUT char **string, const char *target, const char *replace);
ABI      char*         strremap  (INOUT char *string, const char srcs[], const char dsts[]);
ABI      char*         strlower  (char *string);
ABI      char*         strupper  (char *string);
ABI      char*         strrev    (char *string);

String unicode utils

• Extract 32bit codepoint from string. Also advances input string to next codepoint.
• Convert 32bit codepoint to utf8 string.
• Convert utf8 to utf16 string.
• Convert utf16 to utf8 string.

ABI      uint32_t      strutf32(INOUT const char **utf8);
ABI TEMP char *        strutf8(uint32_t codepoint);
ABI TEMP wchar_t*      strwiden(const char *utf8);
ABI TEMP char*         strshorten(const wchar_t *utf16);