icuSources/common/util_props.cpp

   1 /*
   2 **********************************************************************
   3 *   Copyright (c) 2001-2011, 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 "unicode/uchar.h"
  12 #include "unicode/utf16.h"
  13 #include "patternprops.h"
  14 #include "util.h"
  15
  16 U_NAMESPACE_BEGIN
  17
  18 /**
  19  * Parse an integer at pos, either of the form \d+ or of the form
  20  * 0x[0-9A-Fa-f]+ or 0[0-7]+, that is, in standard decimal, hex,
  21  * or octal format.
  22  * @param pos INPUT-OUTPUT parameter.  On input, the first
  23  * character to parse.  On output, the character after the last
  24  * parsed character.
  25  */
  26 int32_t ICU_Utility::parseInteger(const UnicodeString& rule, int32_t& pos, int32_t limit) {
  27     int32_t count = 0;
  28     int32_t value = 0;
  29     int32_t p = pos;
  30     int8_t radix = 10;
  31
  32     if (p < limit && rule.charAt(p) == 48 /*0*/) {
  33         if (p+1 < limit && (rule.charAt(p+1) == 0x78 /*x*/ || rule.charAt(p+1) == 0x58 /*X*/)) {
  34             p += 2;
  35             radix = 16;
  36         }
  37         else {
  38             p++;
  39             count = 1;
  40             radix = 8;
  41         }
  42     }
  43
  44     while (p < limit) {
  45         int32_t d = u_digit(rule.charAt(p++), radix);
  46         if (d < 0) {
  47             --p;
  48             break;
  49         }
  50         ++count;
  51         int32_t v = (value * radix) + d;
  52         if (v <= value) {
  53             // If there are too many input digits, at some point
  54             // the value will go negative, e.g., if we have seen
  55             // "0x8000000" already and there is another '0', when
  56             // we parse the next 0 the value will go negative.
  57             return 0;
  58         }
  59         value = v;
  60     }
  61     if (count > 0) {
  62         pos = p;
  63     }
  64     return value;
  65 }
  66
  67 /**
  68  * Parse a pattern string starting at offset pos.  Keywords are
  69  * matched case-insensitively.  Spaces may be skipped and may be
  70  * optional or required.  Integer values may be parsed, and if
  71  * they are, they will be returned in the given array.  If
  72  * successful, the offset of the next non-space character is
  73  * returned.  On failure, -1 is returned.
  74  * @param pattern must only contain lowercase characters, which
  75  * will match their uppercase equivalents as well.  A space
  76  * character matches one or more required spaces.  A '~' character
  77  * matches zero or more optional spaces.  A '#' character matches
  78  * an integer and stores it in parsedInts, which the caller must
  79  * ensure has enough capacity.
  80  * @param parsedInts array to receive parsed integers.  Caller
  81  * must ensure that parsedInts.length is >= the number of '#'
  82  * signs in 'pattern'.
  83  * @return the position after the last character parsed, or -1 if
  84  * the parse failed
  85  */
  86 int32_t ICU_Utility::parsePattern(const UnicodeString& rule, int32_t pos, int32_t limit,
  87                               const UnicodeString& pattern, int32_t* parsedInts) {
  88     // TODO Update this to handle surrogates
  89     int32_t p;
  90     int32_t intCount = 0; // number of integers parsed
  91     for (int32_t i=0; i<pattern.length(); ++i) {
  92         UChar cpat = pattern.charAt(i);
  93         UChar c;
  94         switch (cpat) {
  95         case 32 /*' '*/:
  96             if (pos >= limit) {
  97                 return -1;
  98             }
  99             c = rule.charAt(pos++);
 100             if (!PatternProps::isWhiteSpace(c)) {
 101                 return -1;
 102             }
 103             // FALL THROUGH to skipWhitespace
 104         case 126 /*'~'*/:
 105             pos = skipWhitespace(rule, pos);
 106             break;
 107         case 35 /*'#'*/:
 108             p = pos;
 109             parsedInts[intCount++] = parseInteger(rule, p, limit);
 110             if (p == pos) {
 111                 // Syntax error; failed to parse integer
 112                 return -1;
 113             }
 114             pos = p;
 115             break;
 116         default:
 117             if (pos >= limit) {
 118                 return -1;
 119             }
 120             c = (UChar) u_tolower(rule.charAt(pos++));
 121             if (c != cpat) {
 122                 return -1;
 123             }
 124             break;
 125         }
 126     }
 127     return pos;
 128 }
 129
 130 /**
 131  * Parse a Unicode identifier from the given string at the given
 132  * position.  Return the identifier, or an empty string if there
 133  * is no identifier.
 134  * @param str the string to parse
 135  * @param pos INPUT-OUPUT parameter.  On INPUT, pos is the
 136  * first character to examine.  It must be less than str.length(),
 137  * and it must not point to a whitespace character.  That is, must
 138  * have pos < str.length().  On
 139  * OUTPUT, the position after the last parsed character.
 140  * @return the Unicode identifier, or an empty string if there is
 141  * no valid identifier at pos.
 142  */
 143 UnicodeString ICU_Utility::parseUnicodeIdentifier(const UnicodeString& str, int32_t& pos) {
 144     // assert(pos < str.length());
 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 += U16_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