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 */
parseInteger(const UnicodeString & rule,int32_t & pos,int32_t limit)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 */
parsePattern(const UnicodeString & rule,int32_t pos,int32_t limit,const UnicodeString & pattern,int32_t * parsedInts)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 */
parseUnicodeIdentifier(const UnicodeString & str,int32_t & pos)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 */
parseNumber(const UnicodeString & text,int32_t & pos,int8_t radix)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
215