215 lines
6.8 KiB
C++
215 lines
6.8 KiB
C++
/*
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**********************************************************************
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* Copyright (c) 2001-2006, International Business Machines
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* Corporation and others. All Rights Reserved.
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**********************************************************************
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* Date Name Description
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* 11/19/2001 aliu Creation.
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**********************************************************************
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*/
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#include "util.h"
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#include "unicode/uchar.h"
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U_NAMESPACE_BEGIN
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/**
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* Parse an integer at pos, either of the form \d+ or of the form
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* 0x[0-9A-Fa-f]+ or 0[0-7]+, that is, in standard decimal, hex,
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* or octal format.
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* @param pos INPUT-OUTPUT parameter. On input, the first
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* character to parse. On output, the character after the last
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* parsed character.
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*/
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int32_t ICU_Utility::parseInteger(const UnicodeString& rule, int32_t& pos, int32_t limit) {
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int32_t count = 0;
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int32_t value = 0;
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int32_t p = pos;
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int8_t radix = 10;
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if (p < limit && rule.charAt(p) == 48 /*0*/) {
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if (p+1 < limit && (rule.charAt(p+1) == 0x78 /*x*/ || rule.charAt(p+1) == 0x58 /*X*/)) {
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p += 2;
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radix = 16;
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}
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else {
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p++;
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count = 1;
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radix = 8;
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}
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}
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while (p < limit) {
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int32_t d = u_digit(rule.charAt(p++), radix);
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if (d < 0) {
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--p;
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break;
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}
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++count;
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int32_t v = (value * radix) + d;
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if (v <= value) {
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// If there are too many input digits, at some point
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// the value will go negative, e.g., if we have seen
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// "0x8000000" already and there is another '0', when
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// we parse the next 0 the value will go negative.
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return 0;
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}
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value = v;
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}
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if (count > 0) {
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pos = p;
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}
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return value;
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}
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/**
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* Parse a pattern string starting at offset pos. Keywords are
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* matched case-insensitively. Spaces may be skipped and may be
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* optional or required. Integer values may be parsed, and if
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* they are, they will be returned in the given array. If
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* successful, the offset of the next non-space character is
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* returned. On failure, -1 is returned.
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* @param pattern must only contain lowercase characters, which
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* will match their uppercase equivalents as well. A space
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* character matches one or more required spaces. A '~' character
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* matches zero or more optional spaces. A '#' character matches
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* an integer and stores it in parsedInts, which the caller must
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* ensure has enough capacity.
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* @param parsedInts array to receive parsed integers. Caller
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* must ensure that parsedInts.length is >= the number of '#'
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* signs in 'pattern'.
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* @return the position after the last character parsed, or -1 if
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* the parse failed
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*/
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int32_t ICU_Utility::parsePattern(const UnicodeString& rule, int32_t pos, int32_t limit,
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const UnicodeString& pattern, int32_t* parsedInts) {
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// TODO Update this to handle surrogates
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int32_t p;
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int32_t intCount = 0; // number of integers parsed
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for (int32_t i=0; i<pattern.length(); ++i) {
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UChar cpat = pattern.charAt(i);
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UChar c;
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switch (cpat) {
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case 32 /*' '*/:
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if (pos >= limit) {
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return -1;
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}
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c = rule.charAt(pos++);
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if (!uprv_isRuleWhiteSpace(c)) {
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return -1;
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}
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// FALL THROUGH to skipWhitespace
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case 126 /*'~'*/:
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pos = skipWhitespace(rule, pos);
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break;
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case 35 /*'#'*/:
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p = pos;
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parsedInts[intCount++] = parseInteger(rule, p, limit);
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if (p == pos) {
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// Syntax error; failed to parse integer
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return -1;
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}
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pos = p;
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break;
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default:
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if (pos >= limit) {
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return -1;
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}
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c = (UChar) u_tolower(rule.charAt(pos++));
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if (c != cpat) {
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return -1;
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}
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break;
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}
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}
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return pos;
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}
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/**
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* Parse a Unicode identifier from the given string at the given
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* position. Return the identifier, or an empty string if there
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* is no identifier.
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* @param str the string to parse
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* @param pos INPUT-OUPUT parameter. On INPUT, pos is the
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* first character to examine. It must be less than str.length(),
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* and it must not point to a whitespace character. That is, must
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* have pos < str.length() and
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* !uprv_isRuleWhiteSpace(str.char32At(pos)). On
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* OUTPUT, the position after the last parsed character.
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* @return the Unicode identifier, or an empty string if there is
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* no valid identifier at pos.
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*/
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UnicodeString ICU_Utility::parseUnicodeIdentifier(const UnicodeString& str, int32_t& pos) {
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// assert(pos < str.length());
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// assert(!uprv_isRuleWhiteSpace(str.char32At(pos)));
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UnicodeString buf;
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int p = pos;
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while (p < str.length()) {
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UChar32 ch = str.char32At(p);
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if (buf.length() == 0) {
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if (u_isIDStart(ch)) {
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buf.append(ch);
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} else {
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buf.truncate(0);
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return buf;
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}
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} else {
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if (u_isIDPart(ch)) {
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buf.append(ch);
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} else {
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break;
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}
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}
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p += UTF_CHAR_LENGTH(ch);
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}
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pos = p;
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return buf;
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}
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/**
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* Parse an unsigned 31-bit integer at the given offset. Use
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* UCharacter.digit() to parse individual characters into digits.
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* @param text the text to be parsed
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* @param pos INPUT-OUTPUT parameter. On entry, pos[0] is the
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* offset within text at which to start parsing; it should point
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* to a valid digit. On exit, pos[0] is the offset after the last
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* parsed character. If the parse failed, it will be unchanged on
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* exit. Must be >= 0 on entry.
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* @param radix the radix in which to parse; must be >= 2 and <=
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* 36.
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* @return a non-negative parsed number, or -1 upon parse failure.
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* Parse fails if there are no digits, that is, if pos[0] does not
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* point to a valid digit on entry, or if the number to be parsed
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* does not fit into a 31-bit unsigned integer.
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*/
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int32_t ICU_Utility::parseNumber(const UnicodeString& text,
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int32_t& pos, int8_t radix) {
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// assert(pos[0] >= 0);
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// assert(radix >= 2);
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// assert(radix <= 36);
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int32_t n = 0;
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int32_t p = pos;
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while (p < text.length()) {
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UChar32 ch = text.char32At(p);
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int32_t d = u_digit(ch, radix);
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if (d < 0) {
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break;
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}
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n = radix*n + d;
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// ASSUME that when a 32-bit integer overflows it becomes
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// negative. E.g., 214748364 * 10 + 8 => negative value.
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if (n < 0) {
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return -1;
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}
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++p;
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}
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if (p == pos) {
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return -1;
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}
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pos = p;
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return n;
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}
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U_NAMESPACE_END
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