icuSources/common/util_props.cpp

   1 /*
   2 **********************************************************************
   3 *   Copyright (c) 2001-2006, International Business Machines
   4 *   Corporation and others.  All Rights Reserved.
   5 **********************************************************************
   6 *   Date        Name        Description
   7 *   11/19/2001  aliu        Creation.
   8 **********************************************************************
   9 */
  10
  11 #include "util.h"
  12 #include "unicode/uchar.h"
  13
  14 U_NAMESPACE_BEGIN
  15
  16 /**
  17  * Parse an integer at pos, either of the form \d+ or of the form
  18  * 0x[0-9A-Fa-f]+ or 0[0-7]+, that is, in standard decimal, hex,
  19  * or octal format.
  20  * @param pos INPUT-OUTPUT parameter.  On input, the first
  21  * character to parse.  On output, the character after the last
  22  * parsed character.
  23  */
  24 int32_t ICU_Utility::parseInteger(const UnicodeString& rule, int32_t& pos, int32_t limit) {
  25     int32_t count = 0;
  26     int32_t value = 0;
  27     int32_t p = pos;
  28     int8_t radix = 10;
  29
  30     if (p < limit && rule.charAt(p) == 48 /*0*/) {
  31         if (p+1 < limit && (rule.charAt(p+1) == 0x78 /*x*/ || rule.charAt(p+1) == 0x58 /*X*/)) {
  32             p += 2;
  33             radix = 16;
  34         }
  35         else {
  36             p++;
  37             count = 1;
  38             radix = 8;
  39         }
  40     }
  41
  42     while (p < limit) {
  43         int32_t d = u_digit(rule.charAt(p++), radix);
  44         if (d < 0) {
  45             --p;
  46             break;
  47         }
  48         ++count;
  49         int32_t v = (value * radix) + d;
  50         if (v <= value) {
  51             // If there are too many input digits, at some point
  52             // the value will go negative, e.g., if we have seen
  53             // "0x8000000" already and there is another '0', when
  54             // we parse the next 0 the value will go negative.
  55             return 0;
  56         }
  57         value = v;
  58     }
  59     if (count > 0) {
  60         pos = p;
  61     }
  62     return value;
  63 }
  64
  65 /**
  66  * Parse a pattern string starting at offset pos.  Keywords are
  67  * matched case-insensitively.  Spaces may be skipped and may be
  68  * optional or required.  Integer values may be parsed, and if
  69  * they are, they will be returned in the given array.  If
  70  * successful, the offset of the next non-space character is
  71  * returned.  On failure, -1 is returned.
  72  * @param pattern must only contain lowercase characters, which
  73  * will match their uppercase equivalents as well.  A space
  74  * character matches one or more required spaces.  A '~' character
  75  * matches zero or more optional spaces.  A '#' character matches
  76  * an integer and stores it in parsedInts, which the caller must
  77  * ensure has enough capacity.
  78  * @param parsedInts array to receive parsed integers.  Caller
  79  * must ensure that parsedInts.length is >= the number of '#'
  80  * signs in 'pattern'.
  81  * @return the position after the last character parsed, or -1 if
  82  * the parse failed
  83  */
  84 int32_t ICU_Utility::parsePattern(const UnicodeString& rule, int32_t pos, int32_t limit,
  85                               const UnicodeString& pattern, int32_t* parsedInts) {
  86     // TODO Update this to handle surrogates
  87     int32_t p;
  88     int32_t intCount = 0; // number of integers parsed
  89     for (int32_t i=0; i<pattern.length(); ++i) {
  90         UChar cpat = pattern.charAt(i);
  91         UChar c;
  92         switch (cpat) {
  93         case 32 /*' '*/:
  94             if (pos >= limit) {
  95                 return -1;
  96             }
  97             c = rule.charAt(pos++);
  98             if (!uprv_isRuleWhiteSpace(c)) {
  99                 return -1;
 100             }
 101             // FALL THROUGH to skipWhitespace
 102         case 126 /*'~'*/:
 103             pos = skipWhitespace(rule, pos);
 104             break;
 105         case 35 /*'#'*/:
 106             p = pos;
 107             parsedInts[intCount++] = parseInteger(rule, p, limit);
 108             if (p == pos) {
 109                 // Syntax error; failed to parse integer
 110                 return -1;
 111             }
 112             pos = p;
 113             break;
 114         default:
 115             if (pos >= limit) {
 116                 return -1;
 117             }
 118             c = (UChar) u_tolower(rule.charAt(pos++));
 119             if (c != cpat) {
 120                 return -1;
 121             }
 122             break;
 123         }
 124     }
 125     return pos;
 126 }
 127
 128 /**
 129  * Parse a Unicode identifier from the given string at the given
 130  * position.  Return the identifier, or an empty string if there
 131  * is no identifier.
 132  * @param str the string to parse
 133  * @param pos INPUT-OUPUT parameter.  On INPUT, pos is the
 134  * first character to examine.  It must be less than str.length(),
 135  * and it must not point to a whitespace character.  That is, must
 136  * have pos < str.length() and
 137  * !uprv_isRuleWhiteSpace(str.char32At(pos)).  On
 138  * OUTPUT, the position after the last parsed character.
 139  * @return the Unicode identifier, or an empty string if there is
 140  * no valid identifier at pos.
 141  */
 142 UnicodeString ICU_Utility::parseUnicodeIdentifier(const UnicodeString& str, int32_t& pos) {
 143     // assert(pos < str.length());
 144     // assert(!uprv_isRuleWhiteSpace(str.char32At(pos)));
 145     UnicodeString buf;
 146     int p = pos;
 147     while (p < str.length()) {
 148         UChar32 ch = str.char32At(p);
 149         if (buf.length() == 0) {
 150             if (u_isIDStart(ch)) {
 151                 buf.append(ch);
 152             } else {
 153                 buf.truncate(0);
 154                 return buf;
 155             }
 156         } else {
 157             if (u_isIDPart(ch)) {
 158                 buf.append(ch);
 159             } else {
 160                 break;
 161             }
 162         }
 163         p += UTF_CHAR_LENGTH(ch);
 164     }
 165     pos = p;
 166     return buf;
 167 }
 168
 169 /**
 170  * Parse an unsigned 31-bit integer at the given offset.  Use
 171  * UCharacter.digit() to parse individual characters into digits.
 172  * @param text the text to be parsed
 173  * @param pos INPUT-OUTPUT parameter.  On entry, pos[0] is the
 174  * offset within text at which to start parsing; it should point
 175  * to a valid digit.  On exit, pos[0] is the offset after the last
 176  * parsed character.  If the parse failed, it will be unchanged on
 177  * exit.  Must be >= 0 on entry.
 178  * @param radix the radix in which to parse; must be >= 2 and <=
 179  * 36.
 180  * @return a non-negative parsed number, or -1 upon parse failure.
 181  * Parse fails if there are no digits, that is, if pos[0] does not
 182  * point to a valid digit on entry, or if the number to be parsed
 183  * does not fit into a 31-bit unsigned integer.
 184  */
 185 int32_t ICU_Utility::parseNumber(const UnicodeString& text,
 186                                  int32_t& pos, int8_t radix) {
 187     // assert(pos[0] >= 0);
 188     // assert(radix >= 2);
 189     // assert(radix <= 36);
 190     int32_t n = 0;
 191     int32_t p = pos;
 192     while (p < text.length()) {
 193         UChar32 ch = text.char32At(p);
 194         int32_t d = u_digit(ch, radix);
 195         if (d < 0) {
 196             break;
 197         }
 198         n = radix*n + d;
 199         // ASSUME that when a 32-bit integer overflows it becomes
 200         // negative.  E.g., 214748364 * 10 + 8 => negative value.
 201         if (n < 0) {
 202             return -1;
 203         }
 204         ++p;
 205     }
 206     if (p == pos) {
 207         return -1;
 208     }
 209     pos = p;
 210     return n;
 211 }
 212
 213 U_NAMESPACE_END
 214