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