/** * Parse an integer at pos, either of the form \d+ or of the form * 0x[0-9A-Fa-f]+ or 0[0-7]+, that is, in standard decimal, hex, * or octal format. * @param pos INPUT-OUTPUT parameter. On input, the first * character to parse. On output, the character after the last * parsed character.
*/
int32_t ICU_Utility::parseInteger(const UnicodeString& rule, int32_t& pos, int32_t limit) {
int32_t count = 0;
int32_t value = 0;
int32_t p = pos;
int8_t radix = 10;
while (p < limit) {
int32_t d = u_digit(rule.charAt(p++), radix); if (d < 0) {
--p; break;
}
++count;
int32_t v = (value * radix) + d; if (v <= value) { // If there are too many input digits, at some point // the value will go negative, e.g., if we have seen // "0x8000000" already and there is another '0', when // we parse the next 0 the value will go negative. return 0;
}
value = v;
} if (count > 0) {
pos = p;
} return value;
}
/** * Parse a pattern string starting at offset pos. Keywords are * matched case-insensitively. Spaces may be skipped and may be * optional or required. Integer values may be parsed, and if * they are, they will be returned in the given array. If * successful, the offset of the next non-space character is * returned. On failure, -1 is returned. * @param pattern must only contain lowercase characters, which * will match their uppercase equivalents as well. A space * character matches one or more required spaces. A '~' character * matches zero or more optional spaces. A '#' character matches * an integer and stores it in parsedInts, which the caller must * ensure has enough capacity. * @param parsedInts array to receive parsed integers. Caller * must ensure that parsedInts.length is >= the number of '#' * signs in 'pattern'. * @return the position after the last character parsed, or -1 if * the parse failed
*/
int32_t ICU_Utility::parsePattern(const UnicodeString& rule, int32_t pos, int32_t limit, const UnicodeString& pattern, int32_t* parsedInts) { // TODO Update this to handle surrogates
int32_t p;
int32_t intCount = 0; // number of integers parsed for (int32_t i=0; i<pattern.length(); ++i) {
char16_t cpat = pattern.charAt(i);
char16_t c; switch (cpat) { case 32 /*' '*/: if (pos >= limit) { return -1;
}
c = rule.charAt(pos++); if (!PatternProps::isWhiteSpace(c)) { return -1;
} // FALL THROUGH to skipWhitespace
U_FALLTHROUGH; case 126 /*'~'*/:
pos = skipWhitespace(rule, pos); break; case 35 /*'#'*/:
p = pos;
parsedInts[intCount++] = parseInteger(rule, p, limit); if (p == pos) { // Syntax error; failed to parse integer return -1;
}
pos = p; break; default: if (pos >= limit) { return -1;
}
c = static_cast<char16_t>(u_tolower(rule.charAt(pos++))); if (c != cpat) { return -1;
} break;
}
} return pos;
}
/** * Parse a Unicode identifier from the given string at the given * position. Return the identifier, or an empty string if there * is no identifier. * @param str the string to parse * @param pos INPUT-OUTPUT parameter. On INPUT, pos is the * first character to examine. It must be less than str.length(), * and it must not point to a whitespace character. That is, must * have pos < str.length(). On * OUTPUT, the position after the last parsed character. * @return the Unicode identifier, or an empty string if there is * no valid identifier at pos.
*/
UnicodeString ICU_Utility::parseUnicodeIdentifier(const UnicodeString& str, int32_t& pos) { // assert(pos < str.length());
UnicodeString buf; int p = pos; while (p < str.length()) {
UChar32 ch = str.char32At(p); if (buf.length() == 0) { if (u_isIDStart(ch)) {
buf.append(ch);
} else {
buf.truncate(0); return buf;
}
} else { if (u_isIDPart(ch)) {
buf.append(ch);
} else { break;
}
}
p += U16_LENGTH(ch);
}
pos = p; return buf;
}
/** * Parse an unsigned 31-bit integer at the given offset. Use * UCharacter.digit() to parse individual characters into digits. * @param text the text to be parsed * @param pos INPUT-OUTPUT parameter. On entry, pos[0] is the * offset within text at which to start parsing; it should point * to a valid digit. On exit, pos[0] is the offset after the last * parsed character. If the parse failed, it will be unchanged on * exit. Must be >= 0 on entry. * @param radix the radix in which to parse; must be >= 2 and <= * 36. * @return a non-negative parsed number, or -1 upon parse failure. * Parse fails if there are no digits, that is, if pos[0] does not * point to a valid digit on entry, or if the number to be parsed * does not fit into a 31-bit unsigned integer.
*/
int32_t ICU_Utility::parseNumber(const UnicodeString& text,
int32_t& pos, int8_t radix) { // assert(pos[0] >= 0); // assert(radix >= 2); // assert(radix <= 36);
int32_t n = 0;
int32_t p = pos; while (p < text.length()) {
UChar32 ch = text.char32At(p);
int32_t d = u_digit(ch, radix); if (d < 0) { break;
}
int64_t update = radix*static_cast<int64_t>(n) + d; if (update > INT32_MAX) { return -1;
}
n = static_cast<int32_t>(update);
++p;
} if (p == pos) { return -1;
}
pos = p; return n;
}
U_NAMESPACE_END
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