icuSources/common/util.h

   1 // © 2016 and later: Unicode, Inc. and others.
   2 // License & terms of use: http://www.unicode.org/copyright.html
   3 /*
   4  **********************************************************************
   5  *   Copyright (c) 2001-2011, International Business Machines
   6  *   Corporation and others.  All Rights Reserved.
   7  **********************************************************************
   8  *   Date        Name        Description
   9  *   11/19/2001  aliu        Creation.
  10  **********************************************************************
  11  */
  12
  13 #ifndef ICU_UTIL_H
  14 #define ICU_UTIL_H
  15
  16 #include "unicode/utypes.h"
  17 #include "unicode/uobject.h"
  18 #include "unicode/unistr.h"
  19
  20 //--------------------------------------------------------------------
  21 // class ICU_Utility
  22 // i18n utility functions, scoped into the class ICU_Utility.
  23 //--------------------------------------------------------------------
  24
  25 U_NAMESPACE_BEGIN
  26
  27 class UnicodeMatcher;
  28
  29 class U_COMMON_API ICU_Utility /* not : public UObject because all methods are static */ {
  30  public:
  31
  32     /**
  33      * Append a number to the given UnicodeString in the given radix.
  34      * Standard digits '0'-'9' are used and letters 'A'-'Z' for
  35      * radices 11 through 36.
  36      * @param result the digits of the number are appended here
  37      * @param n the number to be converted to digits; may be negative.
  38      * If negative, a '-' is prepended to the digits.
  39      * @param radix a radix from 2 to 36 inclusive.
  40      * @param minDigits the minimum number of digits, not including
  41      * any '-', to produce.  Values less than 2 have no effect.  One
  42      * digit is always emitted regardless of this parameter.
  43      * @return a reference to result
  44      */
  45     static UnicodeString& appendNumber(UnicodeString& result, int32_t n,
  46                                        int32_t radix = 10,
  47                                        int32_t minDigits = 1);
  48
  49     /** Returns a bogus UnicodeString by value. */
  50     static inline UnicodeString makeBogusString() {
  51         UnicodeString result;
  52         result.setToBogus();
  53         return result;
  54     }
  55
  56     /**
  57      * Return true if the character is NOT printable ASCII.
  58      *
  59      * This method should really be in UnicodeString (or similar).  For
  60      * now, we implement it here and share it with friend classes.
  61      */
  62     static UBool isUnprintable(UChar32 c);
  63
  64     /**
  65      * Escape unprintable characters using \uxxxx notation for U+0000 to
  66      * U+FFFF and \Uxxxxxxxx for U+10000 and above.  If the character is
  67      * printable ASCII, then do nothing and return FALSE.  Otherwise,
  68      * append the escaped notation and return TRUE.
  69      */
  70     static UBool escapeUnprintable(UnicodeString& result, UChar32 c);
  71
  72     /**
  73      * Returns the index of a character, ignoring quoted text.
  74      * For example, in the string "abc'hide'h", the 'h' in "hide" will not be
  75      * found by a search for 'h'.
  76      * @param text text to be searched
  77      * @param start the beginning index, inclusive; <code>0 <= start
  78      * <= limit</code>.
  79      * @param limit the ending index, exclusive; <code>start <= limit
  80      * <= text.length()</code>.
  81      * @param c character to search for
  82      * @return Offset of the first instance of c, or -1 if not found.
  83      */
  84 //?FOR FUTURE USE.  DISABLE FOR NOW for coverage reasons.
  85 //    static int32_t quotedIndexOf(const UnicodeString& text,
  86 //                                 int32_t start, int32_t limit,
  87 //                                 UChar c);
  88
  89     /**
  90      * Skip over a sequence of zero or more white space characters at pos.
  91      * @param advance if true, advance pos to the first non-white-space
  92      * character at or after pos, or str.length(), if there is none.
  93      * Otherwise leave pos unchanged.
  94      * @return the index of the first non-white-space character at or
  95      * after pos, or str.length(), if there is none.
  96      */
  97     static int32_t skipWhitespace(const UnicodeString& str, int32_t& pos,
  98                                   UBool advance = FALSE);
  99
 100     /**
 101      * Skip over Pattern_White_Space in a Replaceable.
 102      * Skipping may be done in the forward or
 103      * reverse direction.  In either case, the leftmost index will be
 104      * inclusive, and the rightmost index will be exclusive.  That is,
 105      * given a range defined as [start, limit), the call
 106      * skipWhitespace(text, start, limit) will advance start past leading
 107      * whitespace, whereas the call skipWhitespace(text, limit, start),
 108      * will back up limit past trailing whitespace.
 109      * @param text the text to be analyzed
 110      * @param pos either the start or limit of a range of 'text', to skip
 111      * leading or trailing whitespace, respectively
 112      * @param stop either the limit or start of a range of 'text', to skip
 113      * leading or trailing whitespace, respectively
 114      * @return the new start or limit, depending on what was passed in to
 115      * 'pos'
 116      */
 117 //?FOR FUTURE USE.  DISABLE FOR NOW for coverage reasons.
 118 //?    static int32_t skipWhitespace(const Replaceable& text,
 119 //?                                  int32_t pos, int32_t stop);
 120
 121     /**
 122      * Parse a single non-whitespace character 'ch', optionally
 123      * preceded by whitespace.
 124      * @param id the string to be parsed
 125      * @param pos INPUT-OUTPUT parameter.  On input, pos[0] is the
 126      * offset of the first character to be parsed.  On output, pos[0]
 127      * is the index after the last parsed character.  If the parse
 128      * fails, pos[0] will be unchanged.
 129      * @param ch the non-whitespace character to be parsed.
 130      * @return true if 'ch' is seen preceded by zero or more
 131      * whitespace characters.
 132      */
 133     static UBool parseChar(const UnicodeString& id, int32_t& pos, UChar ch);
 134
 135     /**
 136      * Parse a pattern string starting at offset pos.  Keywords are
 137      * matched case-insensitively.  Spaces may be skipped and may be
 138      * optional or required.  Integer values may be parsed, and if
 139      * they are, they will be returned in the given array.  If
 140      * successful, the offset of the next non-space character is
 141      * returned.  On failure, -1 is returned.
 142      * @param pattern must only contain lowercase characters, which
 143      * will match their uppercase equivalents as well.  A space
 144      * character matches one or more required spaces.  A '~' character
 145      * matches zero or more optional spaces.  A '#' character matches
 146      * an integer and stores it in parsedInts, which the caller must
 147      * ensure has enough capacity.
 148      * @param parsedInts array to receive parsed integers.  Caller
 149      * must ensure that parsedInts.length is >= the number of '#'
 150      * signs in 'pattern'.
 151      * @return the position after the last character parsed, or -1 if
 152      * the parse failed
 153      */
 154     static int32_t parsePattern(const UnicodeString& rule, int32_t pos, int32_t limit,
 155                                 const UnicodeString& pattern, int32_t* parsedInts);
 156
 157     /**
 158      * Parse a pattern string within the given Replaceable and a parsing
 159      * pattern.  Characters are matched literally and case-sensitively
 160      * except for the following special characters:
 161      *
 162      * ~  zero or more Pattern_White_Space chars
 163      *
 164      * If end of pattern is reached with all matches along the way,
 165      * pos is advanced to the first unparsed index and returned.
 166      * Otherwise -1 is returned.
 167      * @param pat pattern that controls parsing
 168      * @param text text to be parsed, starting at index
 169      * @param index offset to first character to parse
 170      * @param limit offset after last character to parse
 171      * @return index after last parsed character, or -1 on parse failure.
 172      */
 173     static int32_t parsePattern(const UnicodeString& pat,
 174                                 const Replaceable& text,
 175                                 int32_t index,
 176                                 int32_t limit);
 177
 178     /**
 179      * Parse an integer at pos, either of the form \d+ or of the form
 180      * 0x[0-9A-Fa-f]+ or 0[0-7]+, that is, in standard decimal, hex,
 181      * or octal format.
 182      * @param pos INPUT-OUTPUT parameter.  On input, the first
 183      * character to parse.  On output, the character after the last
 184      * parsed character.
 185      */
 186     static int32_t parseInteger(const UnicodeString& rule, int32_t& pos, int32_t limit);
 187
 188     /**
 189      * Parse a Unicode identifier from the given string at the given
 190      * position.  Return the identifier, or an empty string if there
 191      * is no identifier.
 192      * @param str the string to parse
 193      * @param pos INPUT-OUPUT parameter.  On INPUT, pos is the
 194      * first character to examine.  It must be less than str.length(),
 195      * and it must not point to a whitespace character.  That is, must
 196      * have pos < str.length() and
 197      * !UCharacter::isWhitespace(str.char32At(pos)).  On
 198      * OUTPUT, the position after the last parsed character.
 199      * @return the Unicode identifier, or an empty string if there is
 200      * no valid identifier at pos.
 201      */
 202     static UnicodeString parseUnicodeIdentifier(const UnicodeString& str, int32_t& pos);
 203
 204     /**
 205      * Parse an unsigned 31-bit integer at the given offset.  Use
 206      * UCharacter.digit() to parse individual characters into digits.
 207      * @param text the text to be parsed
 208      * @param pos INPUT-OUTPUT parameter.  On entry, pos is the
 209      * offset within text at which to start parsing; it should point
 210      * to a valid digit.  On exit, pos is the offset after the last
 211      * parsed character.  If the parse failed, it will be unchanged on
 212      * exit.  Must be >= 0 on entry.
 213      * @param radix the radix in which to parse; must be >= 2 and <=
 214      * 36.
 215      * @return a non-negative parsed number, or -1 upon parse failure.
 216      * Parse fails if there are no digits, that is, if pos does not
 217      * point to a valid digit on entry, or if the number to be parsed
 218      * does not fit into a 31-bit unsigned integer.
 219      */
 220     static int32_t parseNumber(const UnicodeString& text,
 221                                int32_t& pos, int8_t radix);
 222
 223     static void appendToRule(UnicodeString& rule,
 224                              UChar32 c,
 225                              UBool isLiteral,
 226                              UBool escapeUnprintable,
 227                              UnicodeString& quoteBuf);
 228
 229     static void appendToRule(UnicodeString& rule,
 230                              const UnicodeString& text,
 231                              UBool isLiteral,
 232                              UBool escapeUnprintable,
 233                              UnicodeString& quoteBuf);
 234
 235     static void appendToRule(UnicodeString& rule,
 236                              const UnicodeMatcher* matcher,
 237                              UBool escapeUnprintable,
 238                              UnicodeString& quoteBuf);
 239
 240 private:
 241     // do not instantiate
 242     ICU_Utility();
 243 };
 244
 245 U_NAMESPACE_END
 246
 247 #endif
 248 //eof