icuSources/common/util_props.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) 2001-2016, 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/uchar.h"
  14 #include "unicode/utf16.h"
  15 #include "patternprops.h"
  16 #include "util.h"
  17
  18 U_NAMESPACE_BEGIN
  19
  20 /**
  21  * Parse an integer at pos, either of the form \d+ or of the form
  22  * 0x[0-9A-Fa-f]+ or 0[0-7]+, that is, in standard decimal, hex,
  23  * or octal format.
  24  * @param pos INPUT-OUTPUT parameter.  On input, the first
  25  * character to parse.  On output, the character after the last
  26  * parsed character.
  27  */
  28 int32_t ICU_Utility::parseInteger(const UnicodeString& rule, int32_t& pos, int32_t limit) {
  29     int32_t count = 0;
  30     int32_t value = 0;
  31     int32_t p = pos;
  32     int8_t radix = 10;
  33
  34     if (p < limit && rule.charAt(p) == 48 /*0*/) {
  35         if (p+1 < limit && (rule.charAt(p+1) == 0x78 /*x*/ || rule.charAt(p+1) == 0x58 /*X*/)) {
  36             p += 2;
  37             radix = 16;
  38         }
  39         else {
  40             p++;
  41             count = 1;
  42             radix = 8;
  43         }
  44     }
  45
  46     while (p < limit) {
  47         int32_t d = u_digit(rule.charAt(p++), radix);
  48         if (d < 0) {
  49             --p;
  50             break;
  51         }
  52         ++count;
  53         int32_t v = (value * radix) + d;
  54         if (v <= value) {
  55             // If there are too many input digits, at some point
  56             // the value will go negative, e.g., if we have seen
  57             // "0x8000000" already and there is another '0', when
  58             // we parse the next 0 the value will go negative.
  59             return 0;
  60         }
  61         value = v;
  62     }
  63     if (count > 0) {
  64         pos = p;
  65     }
  66     return value;
  67 }
  68
  69 /**
  70  * Parse a pattern string starting at offset pos.  Keywords are
  71  * matched case-insensitively.  Spaces may be skipped and may be
  72  * optional or required.  Integer values may be parsed, and if
  73  * they are, they will be returned in the given array.  If
  74  * successful, the offset of the next non-space character is
  75  * returned.  On failure, -1 is returned.
  76  * @param pattern must only contain lowercase characters, which
  77  * will match their uppercase equivalents as well.  A space
  78  * character matches one or more required spaces.  A '~' character
  79  * matches zero or more optional spaces.  A '#' character matches
  80  * an integer and stores it in parsedInts, which the caller must
  81  * ensure has enough capacity.
  82  * @param parsedInts array to receive parsed integers.  Caller
  83  * must ensure that parsedInts.length is >= the number of '#'
  84  * signs in 'pattern'.
  85  * @return the position after the last character parsed, or -1 if
  86  * the parse failed
  87  */
  88 int32_t ICU_Utility::parsePattern(const UnicodeString& rule, int32_t pos, int32_t limit,
  89                               const UnicodeString& pattern, int32_t* parsedInts) {
  90     // TODO Update this to handle surrogates
  91     int32_t p;
  92     int32_t intCount = 0; // number of integers parsed
  93     for (int32_t i=0; i<pattern.length(); ++i) {
  94         UChar cpat = pattern.charAt(i);
  95         UChar c;
  96         switch (cpat) {
  97         case 32 /*' '*/:
  98             if (pos >= limit) {
  99                 return -1;
 100             }
 101             c = rule.charAt(pos++);
 102             if (!PatternProps::isWhiteSpace(c)) {
 103                 return -1;
 104             }
 105             // FALL THROUGH to skipWhitespace
 106             U_FALLTHROUGH;
 107         case 126 /*'~'*/:
 108             pos = skipWhitespace(rule, pos);
 109             break;
 110         case 35 /*'#'*/:
 111             p = pos;
 112             parsedInts[intCount++] = parseInteger(rule, p, limit);
 113             if (p == pos) {
 114                 // Syntax error; failed to parse integer
 115                 return -1;
 116             }
 117             pos = p;
 118             break;
 119         default:
 120             if (pos >= limit) {
 121                 return -1;
 122             }
 123             c = (UChar) u_tolower(rule.charAt(pos++));
 124             if (c != cpat) {
 125                 return -1;
 126             }
 127             break;
 128         }
 129     }
 130     return pos;
 131 }
 132
 133 /**
 134  * Parse a Unicode identifier from the given string at the given
 135  * position.  Return the identifier, or an empty string if there
 136  * is no identifier.
 137  * @param str the string to parse
 138  * @param pos INPUT-OUPUT parameter.  On INPUT, pos is the
 139  * first character to examine.  It must be less than str.length(),
 140  * and it must not point to a whitespace character.  That is, must
 141  * have pos < str.length().  On
 142  * OUTPUT, the position after the last parsed character.
 143  * @return the Unicode identifier, or an empty string if there is
 144  * no valid identifier at pos.
 145  */
 146 UnicodeString ICU_Utility::parseUnicodeIdentifier(const UnicodeString& str, int32_t& pos) {
 147     // assert(pos < str.length());
 148     UnicodeString buf;
 149     int p = pos;
 150     while (p < str.length()) {
 151         UChar32 ch = str.char32At(p);
 152         if (buf.length() == 0) {
 153             if (u_isIDStart(ch)) {
 154                 buf.append(ch);
 155             } else {
 156                 buf.truncate(0);
 157                 return buf;
 158             }
 159         } else {
 160             if (u_isIDPart(ch)) {
 161                 buf.append(ch);
 162             } else {
 163                 break;
 164             }
 165         }
 166         p += U16_LENGTH(ch);
 167     }
 168     pos = p;
 169     return buf;
 170 }
 171
 172 /**
 173  * Parse an unsigned 31-bit integer at the given offset.  Use
 174  * UCharacter.digit() to parse individual characters into digits.
 175  * @param text the text to be parsed
 176  * @param pos INPUT-OUTPUT parameter.  On entry, pos[0] is the
 177  * offset within text at which to start parsing; it should point
 178  * to a valid digit.  On exit, pos[0] is the offset after the last
 179  * parsed character.  If the parse failed, it will be unchanged on
 180  * exit.  Must be >= 0 on entry.
 181  * @param radix the radix in which to parse; must be >= 2 and <=
 182  * 36.
 183  * @return a non-negative parsed number, or -1 upon parse failure.
 184  * Parse fails if there are no digits, that is, if pos[0] does not
 185  * point to a valid digit on entry, or if the number to be parsed
 186  * does not fit into a 31-bit unsigned integer.
 187  */
 188 int32_t ICU_Utility::parseNumber(const UnicodeString& text,
 189                                  int32_t& pos, int8_t radix) {
 190     // assert(pos[0] >= 0);
 191     // assert(radix >= 2);
 192     // assert(radix <= 36);
 193     int32_t n = 0;
 194     int32_t p = pos;
 195     while (p < text.length()) {
 196         UChar32 ch = text.char32At(p);
 197         int32_t d = u_digit(ch, radix);
 198         if (d < 0) {
 199             break;
 200         }
 201         n = radix*n + d;
 202         // ASSUME that when a 32-bit integer overflows it becomes
 203         // negative.  E.g., 214748364 * 10 + 8 => negative value.
 204         if (n < 0) {
 205             return -1;
 206         }
 207         ++p;
 208     }
 209     if (p == pos) {
 210         return -1;
 211     }
 212     pos = p;
 213     return n;
 214 }
 215
 216 U_NAMESPACE_END
 217