icuSources/common/util.cpp

   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 #include "unicode/unimatch.h"
  14 #include "unicode/utf16.h"
  15 #include "patternprops.h"
  16 #include "util.h"
  17
  18 // Define UChar constants using hex for EBCDIC compatibility
  19
  20 static const UChar BACKSLASH  = 0x005C; /*\*/
  21 static const UChar UPPER_U    = 0x0055; /*U*/
  22 static const UChar LOWER_U    = 0x0075; /*u*/
  23 static const UChar APOSTROPHE = 0x0027; // '\''
  24 static const UChar SPACE      = 0x0020; // ' '
  25
  26 // "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
  27 static const UChar DIGITS[] = {
  28     48,49,50,51,52,53,54,55,56,57,
  29     65,66,67,68,69,70,71,72,73,74,
  30     75,76,77,78,79,80,81,82,83,84,
  31     85,86,87,88,89,90
  32 };
  33
  34 U_NAMESPACE_BEGIN
  35
  36 UnicodeString& ICU_Utility::appendNumber(UnicodeString& result, int32_t n,
  37                                      int32_t radix, int32_t minDigits) {
  38     if (radix < 2 || radix > 36) {
  39         // Bogus radix
  40         return result.append((UChar)63/*?*/);
  41     }
  42     // Handle negatives
  43     if (n < 0) {
  44         n = -n;
  45         result.append((UChar)45/*-*/);
  46     }
  47     // First determine the number of digits
  48     int32_t nn = n;
  49     int32_t r = 1;
  50     while (nn >= radix) {
  51         nn /= radix;
  52         r *= radix;
  53         --minDigits;
  54     }
  55     // Now generate the digits
  56     while (--minDigits > 0) {
  57         result.append(DIGITS[0]);
  58     }
  59     while (r > 0) {
  60         int32_t digit = n / r;
  61         result.append(DIGITS[digit]);
  62         n -= digit * r;
  63         r /= radix;
  64     }
  65     return result;
  66 }
  67
  68 /**
  69  * Return true if the character is NOT printable ASCII.
  70  */
  71 UBool ICU_Utility::isUnprintable(UChar32 c) {
  72     return !(c >= 0x20 && c <= 0x7E);
  73 }
  74
  75 /**
  76  * Escape unprintable characters using \uxxxx notation for U+0000 to
  77  * U+FFFF and \Uxxxxxxxx for U+10000 and above.  If the character is
  78  * printable ASCII, then do nothing and return FALSE.  Otherwise,
  79  * append the escaped notation and return TRUE.
  80  */
  81 UBool ICU_Utility::escapeUnprintable(UnicodeString& result, UChar32 c) {
  82     if (isUnprintable(c)) {
  83         result.append(BACKSLASH);
  84         if (c & ~0xFFFF) {
  85             result.append(UPPER_U);
  86             result.append(DIGITS[0xF&(c>>28)]);
  87             result.append(DIGITS[0xF&(c>>24)]);
  88             result.append(DIGITS[0xF&(c>>20)]);
  89             result.append(DIGITS[0xF&(c>>16)]);
  90         } else {
  91             result.append(LOWER_U);
  92         }
  93         result.append(DIGITS[0xF&(c>>12)]);
  94         result.append(DIGITS[0xF&(c>>8)]);
  95         result.append(DIGITS[0xF&(c>>4)]);
  96         result.append(DIGITS[0xF&c]);
  97         return TRUE;
  98     }
  99     return FALSE;
 100 }
 101
 102 /**
 103  * Returns the index of a character, ignoring quoted text.
 104  * For example, in the string "abc'hide'h", the 'h' in "hide" will not be
 105  * found by a search for 'h'.
 106  */
 107 // FOR FUTURE USE.  DISABLE FOR NOW for coverage reasons.
 108 /*
 109 int32_t ICU_Utility::quotedIndexOf(const UnicodeString& text,
 110                                int32_t start, int32_t limit,
 111                                UChar charToFind) {
 112     for (int32_t i=start; i<limit; ++i) {
 113         UChar c = text.charAt(i);
 114         if (c == BACKSLASH) {
 115             ++i;
 116         } else if (c == APOSTROPHE) {
 117             while (++i < limit
 118                    && text.charAt(i) != APOSTROPHE) {}
 119         } else if (c == charToFind) {
 120             return i;
 121         }
 122     }
 123     return -1;
 124 }
 125 */
 126
 127 /**
 128  * Skip over a sequence of zero or more white space characters at pos.
 129  * @param advance if true, advance pos to the first non-white-space
 130  * character at or after pos, or str.length(), if there is none.
 131  * Otherwise leave pos unchanged.
 132  * @return the index of the first non-white-space character at or
 133  * after pos, or str.length(), if there is none.
 134  */
 135 int32_t ICU_Utility::skipWhitespace(const UnicodeString& str, int32_t& pos,
 136                                     UBool advance) {
 137     int32_t p = pos;
 138     const UChar* s = str.getBuffer();
 139     p = (int32_t)(PatternProps::skipWhiteSpace(s + p, str.length() - p) - s);
 140     if (advance) {
 141         pos = p;
 142     }
 143     return p;
 144 }
 145
 146 /**
 147  * Skip over Pattern_White_Space in a Replaceable.
 148  * Skipping may be done in the forward or
 149  * reverse direction.  In either case, the leftmost index will be
 150  * inclusive, and the rightmost index will be exclusive.  That is,
 151  * given a range defined as [start, limit), the call
 152  * skipWhitespace(text, start, limit) will advance start past leading
 153  * whitespace, whereas the call skipWhitespace(text, limit, start),
 154  * will back up limit past trailing whitespace.
 155  * @param text the text to be analyzed
 156  * @param pos either the start or limit of a range of 'text', to skip
 157  * leading or trailing whitespace, respectively
 158  * @param stop either the limit or start of a range of 'text', to skip
 159  * leading or trailing whitespace, respectively
 160  * @return the new start or limit, depending on what was passed in to
 161  * 'pos'
 162  */
 163 //?FOR FUTURE USE.  DISABLE FOR NOW for coverage reasons.
 164 //?int32_t ICU_Utility::skipWhitespace(const Replaceable& text,
 165 //?                                    int32_t pos, int32_t stop) {
 166 //?    UChar32 c;
 167 //?    UBool isForward = (stop >= pos);
 168 //?
 169 //?    if (!isForward) {
 170 //?        --pos; // pos is a limit, so back up by one
 171 //?    }
 172 //?
 173 //?    while (pos != stop &&
 174 //?           PatternProps::isWhiteSpace(c = text.char32At(pos))) {
 175 //?        if (isForward) {
 176 //?            pos += U16_LENGTH(c);
 177 //?        } else {
 178 //?            pos -= U16_LENGTH(c);
 179 //?        }
 180 //?    }
 181 //?
 182 //?    if (!isForward) {
 183 //?        ++pos; // make pos back into a limit
 184 //?    }
 185 //?
 186 //?    return pos;
 187 //?}
 188
 189 /**
 190  * Parse a single non-whitespace character 'ch', optionally
 191  * preceded by whitespace.
 192  * @param id the string to be parsed
 193  * @param pos INPUT-OUTPUT parameter.  On input, pos[0] is the
 194  * offset of the first character to be parsed.  On output, pos[0]
 195  * is the index after the last parsed character.  If the parse
 196  * fails, pos[0] will be unchanged.
 197  * @param ch the non-whitespace character to be parsed.
 198  * @return true if 'ch' is seen preceded by zero or more
 199  * whitespace characters.
 200  */
 201 UBool ICU_Utility::parseChar(const UnicodeString& id, int32_t& pos, UChar ch) {
 202     int32_t start = pos;
 203     skipWhitespace(id, pos, TRUE);
 204     if (pos == id.length() ||
 205         id.charAt(pos) != ch) {
 206         pos = start;
 207         return FALSE;
 208     }
 209     ++pos;
 210     return TRUE;
 211 }
 212
 213 /**
 214  * Parse a pattern string within the given Replaceable and a parsing
 215  * pattern.  Characters are matched literally and case-sensitively
 216  * except for the following special characters:
 217  *
 218  * ~  zero or more Pattern_White_Space chars
 219  *
 220  * If end of pattern is reached with all matches along the way,
 221  * pos is advanced to the first unparsed index and returned.
 222  * Otherwise -1 is returned.
 223  * @param pat pattern that controls parsing
 224  * @param text text to be parsed, starting at index
 225  * @param index offset to first character to parse
 226  * @param limit offset after last character to parse
 227  * @return index after last parsed character, or -1 on parse failure.
 228  */
 229 int32_t ICU_Utility::parsePattern(const UnicodeString& pat,
 230                                   const Replaceable& text,
 231                                   int32_t index,
 232                                   int32_t limit) {
 233     int32_t ipat = 0;
 234
 235     // empty pattern matches immediately
 236     if (ipat == pat.length()) {
 237         return index;
 238     }
 239
 240     UChar32 cpat = pat.char32At(ipat);
 241
 242     while (index < limit) {
 243         UChar32 c = text.char32At(index);
 244
 245         // parse \s*
 246         if (cpat == 126 /*~*/) {
 247             if (PatternProps::isWhiteSpace(c)) {
 248                 index += U16_LENGTH(c);
 249                 continue;
 250             } else {
 251                 if (++ipat == pat.length()) {
 252                     return index; // success; c unparsed
 253                 }
 254                 // fall thru; process c again with next cpat
 255             }
 256         }
 257
 258         // parse literal
 259         else if (c == cpat) {
 260             index += U16_LENGTH(c);
 261             ipat += U16_LENGTH(cpat);
 262             if (ipat == pat.length()) {
 263                 return index; // success; c parsed
 264             }
 265             // fall thru; get next cpat
 266         }
 267
 268         // match failure of literal
 269         else {
 270             return -1;
 271         }
 272
 273         cpat = pat.char32At(ipat);
 274     }
 275
 276     return -1; // text ended before end of pat
 277 }
 278
 279 int32_t ICU_Utility::parseAsciiInteger(const UnicodeString& str, int32_t& pos) {
 280     int32_t result = 0;
 281     UChar c;
 282     while (pos < str.length() && (c = str.charAt(pos)) >= u'0' && c <= u'9') {
 283         result = result * 10 + (c - u'0');
 284         pos++;
 285     }
 286     return result;
 287 }
 288
 289 /**
 290  * Append a character to a rule that is being built up.  To flush
 291  * the quoteBuf to rule, make one final call with isLiteral == TRUE.
 292  * If there is no final character, pass in (UChar32)-1 as c.
 293  * @param rule the string to append the character to
 294  * @param c the character to append, or (UChar32)-1 if none.
 295  * @param isLiteral if true, then the given character should not be
 296  * quoted or escaped.  Usually this means it is a syntactic element
 297  * such as > or $
 298  * @param escapeUnprintable if true, then unprintable characters
 299  * should be escaped using \uxxxx or \Uxxxxxxxx.  These escapes will
 300  * appear outside of quotes.
 301  * @param quoteBuf a buffer which is used to build up quoted
 302  * substrings.  The caller should initially supply an empty buffer,
 303  * and thereafter should not modify the buffer.  The buffer should be
 304  * cleared out by, at the end, calling this method with a literal
 305  * character.
 306  */
 307 void ICU_Utility::appendToRule(UnicodeString& rule,
 308                                UChar32 c,
 309                                UBool isLiteral,
 310                                UBool escapeUnprintable,
 311                                UnicodeString& quoteBuf) {
 312     // If we are escaping unprintables, then escape them outside
 313     // quotes.  \u and \U are not recognized within quotes.  The same
 314     // logic applies to literals, but literals are never escaped.
 315     if (isLiteral ||
 316         (escapeUnprintable && ICU_Utility::isUnprintable(c))) {
 317         if (quoteBuf.length() > 0) {
 318             // We prefer backslash APOSTROPHE to double APOSTROPHE
 319             // (more readable, less similar to ") so if there are
 320             // double APOSTROPHEs at the ends, we pull them outside
 321             // of the quote.
 322
 323             // If the first thing in the quoteBuf is APOSTROPHE
 324             // (doubled) then pull it out.
 325             while (quoteBuf.length() >= 2 &&
 326                    quoteBuf.charAt(0) == APOSTROPHE &&
 327                    quoteBuf.charAt(1) == APOSTROPHE) {
 328                 rule.append(BACKSLASH).append(APOSTROPHE);
 329                 quoteBuf.remove(0, 2);
 330             }
 331             // If the last thing in the quoteBuf is APOSTROPHE
 332             // (doubled) then remove and count it and add it after.
 333             int32_t trailingCount = 0;
 334             while (quoteBuf.length() >= 2 &&
 335                    quoteBuf.charAt(quoteBuf.length()-2) == APOSTROPHE &&
 336                    quoteBuf.charAt(quoteBuf.length()-1) == APOSTROPHE) {
 337                 quoteBuf.truncate(quoteBuf.length()-2);
 338                 ++trailingCount;
 339             }
 340             if (quoteBuf.length() > 0) {
 341                 rule.append(APOSTROPHE);
 342                 rule.append(quoteBuf);
 343                 rule.append(APOSTROPHE);
 344                 quoteBuf.truncate(0);
 345             }
 346             while (trailingCount-- > 0) {
 347                 rule.append(BACKSLASH).append(APOSTROPHE);
 348             }
 349         }
 350         if (c != (UChar32)-1) {
 351             /* Since spaces are ignored during parsing, they are
 352              * emitted only for readability.  We emit one here
 353              * only if there isn't already one at the end of the
 354              * rule.
 355              */
 356             if (c == SPACE) {
 357                 int32_t len = rule.length();
 358                 if (len > 0 && rule.charAt(len-1) != c) {
 359                     rule.append(c);
 360                 }
 361             } else if (!escapeUnprintable || !ICU_Utility::escapeUnprintable(rule, c)) {
 362                 rule.append(c);
 363             }
 364         }
 365     }
 366
 367     // Escape ' and '\' and don't begin a quote just for them
 368     else if (quoteBuf.length() == 0 &&
 369              (c == APOSTROPHE || c == BACKSLASH)) {
 370         rule.append(BACKSLASH);
 371         rule.append(c);
 372     }
 373
 374     // Specials (printable ascii that isn't [0-9a-zA-Z]) and
 375     // whitespace need quoting.  Also append stuff to quotes if we are
 376     // building up a quoted substring already.
 377     else if (quoteBuf.length() > 0 ||
 378              (c >= 0x0021 && c <= 0x007E &&
 379               !((c >= 0x0030/*'0'*/ && c <= 0x0039/*'9'*/) ||
 380                 (c >= 0x0041/*'A'*/ && c <= 0x005A/*'Z'*/) ||
 381                 (c >= 0x0061/*'a'*/ && c <= 0x007A/*'z'*/))) ||
 382              PatternProps::isWhiteSpace(c)) {
 383         quoteBuf.append(c);
 384         // Double ' within a quote
 385         if (c == APOSTROPHE) {
 386             quoteBuf.append(c);
 387         }
 388     }
 389
 390     // Otherwise just append
 391     else {
 392         rule.append(c);
 393     }
 394 }
 395
 396 void ICU_Utility::appendToRule(UnicodeString& rule,
 397                                const UnicodeString& text,
 398                                UBool isLiteral,
 399                                UBool escapeUnprintable,
 400                                UnicodeString& quoteBuf) {
 401     for (int32_t i=0; i<text.length(); ++i) {
 402         appendToRule(rule, text[i], isLiteral, escapeUnprintable, quoteBuf);
 403     }
 404 }
 405
 406 /**
 407  * Given a matcher reference, which may be null, append its
 408  * pattern as a literal to the given rule.
 409  */
 410 void ICU_Utility::appendToRule(UnicodeString& rule,
 411                                const UnicodeMatcher* matcher,
 412                                UBool escapeUnprintable,
 413                                UnicodeString& quoteBuf) {
 414     if (matcher != NULL) {
 415         UnicodeString pat;
 416         appendToRule(rule, matcher->toPattern(pat, escapeUnprintable),
 417                      TRUE, escapeUnprintable, quoteBuf);
 418     }
 419 }
 420
 421 U_NAMESPACE_END