1 // © 2016 and later: Unicode, Inc. and others.
2 // License & terms of use: http://www.unicode.org/copyright.html
3 /*
4 **********************************************************************
5 * Copyright (c) 2001-2016, International Business Machines
6 * Corporation and others. All Rights Reserved.
7 **********************************************************************
8 * Date Name Description
9 * 11/19/2001 aliu Creation.
10 **********************************************************************
11 */
12
13 #include "unicode/uchar.h"
14 #include "unicode/utf16.h"
15 #include "patternprops.h"
16 #include "util.h"
17
18 U_NAMESPACE_BEGIN
19
20 /**
21 * Parse an integer at pos, either of the form \d+ or of the form
22 * 0x[0-9A-Fa-f]+ or 0[0-7]+, that is, in standard decimal, hex,
23 * or octal format.
24 * @param pos INPUT-OUTPUT parameter. On input, the first
25 * character to parse. On output, the character after the last
26 * parsed character.
27 */
parseInteger(const UnicodeString & rule,int32_t & pos,int32_t limit)28 int32_t ICU_Utility::parseInteger(const UnicodeString& rule, int32_t& pos, int32_t limit) {
29 int32_t count = 0;
30 int32_t value = 0;
31 int32_t p = pos;
32 int8_t radix = 10;
33
34 if (p < limit && rule.charAt(p) == 48 /*0*/) {
35 if (p+1 < limit && (rule.charAt(p+1) == 0x78 /*x*/ || rule.charAt(p+1) == 0x58 /*X*/)) {
36 p += 2;
37 radix = 16;
38 }
39 else {
40 p++;
41 count = 1;
42 radix = 8;
43 }
44 }
45
46 while (p < limit) {
47 int32_t d = u_digit(rule.charAt(p++), radix);
48 if (d < 0) {
49 --p;
50 break;
51 }
52 ++count;
53 int32_t v = (value * radix) + d;
54 if (v <= value) {
55 // If there are too many input digits, at some point
56 // the value will go negative, e.g., if we have seen
57 // "0x8000000" already and there is another '0', when
58 // we parse the next 0 the value will go negative.
59 return 0;
60 }
61 value = v;
62 }
63 if (count > 0) {
64 pos = p;
65 }
66 return value;
67 }
68
69 /**
70 * Parse a pattern string starting at offset pos. Keywords are
71 * matched case-insensitively. Spaces may be skipped and may be
72 * optional or required. Integer values may be parsed, and if
73 * they are, they will be returned in the given array. If
74 * successful, the offset of the next non-space character is
75 * returned. On failure, -1 is returned.
76 * @param pattern must only contain lowercase characters, which
77 * will match their uppercase equivalents as well. A space
78 * character matches one or more required spaces. A '~' character
79 * matches zero or more optional spaces. A '#' character matches
80 * an integer and stores it in parsedInts, which the caller must
81 * ensure has enough capacity.
82 * @param parsedInts array to receive parsed integers. Caller
83 * must ensure that parsedInts.length is >= the number of '#'
84 * signs in 'pattern'.
85 * @return the position after the last character parsed, or -1 if
86 * the parse failed
87 */
parsePattern(const UnicodeString & rule,int32_t pos,int32_t limit,const UnicodeString & pattern,int32_t * parsedInts)88 int32_t ICU_Utility::parsePattern(const UnicodeString& rule, int32_t pos, int32_t limit,
89 const UnicodeString& pattern, int32_t* parsedInts) {
90 // TODO Update this to handle surrogates
91 int32_t p;
92 int32_t intCount = 0; // number of integers parsed
93 for (int32_t i=0; i<pattern.length(); ++i) {
94 UChar cpat = pattern.charAt(i);
95 UChar c;
96 switch (cpat) {
97 case 32 /*' '*/:
98 if (pos >= limit) {
99 return -1;
100 }
101 c = rule.charAt(pos++);
102 if (!PatternProps::isWhiteSpace(c)) {
103 return -1;
104 }
105 // FALL THROUGH to skipWhitespace
106 U_FALLTHROUGH;
107 case 126 /*'~'*/:
108 pos = skipWhitespace(rule, pos);
109 break;
110 case 35 /*'#'*/:
111 p = pos;
112 parsedInts[intCount++] = parseInteger(rule, p, limit);
113 if (p == pos) {
114 // Syntax error; failed to parse integer
115 return -1;
116 }
117 pos = p;
118 break;
119 default:
120 if (pos >= limit) {
121 return -1;
122 }
123 c = (UChar) u_tolower(rule.charAt(pos++));
124 if (c != cpat) {
125 return -1;
126 }
127 break;
128 }
129 }
130 return pos;
131 }
132
133 /**
134 * Parse a Unicode identifier from the given string at the given
135 * position. Return the identifier, or an empty string if there
136 * is no identifier.
137 * @param str the string to parse
138 * @param pos INPUT-OUTPUT parameter. On INPUT, pos is the
139 * first character to examine. It must be less than str.length(),
140 * and it must not point to a whitespace character. That is, must
141 * have pos < str.length(). On
142 * OUTPUT, the position after the last parsed character.
143 * @return the Unicode identifier, or an empty string if there is
144 * no valid identifier at pos.
145 */
parseUnicodeIdentifier(const UnicodeString & str,int32_t & pos)146 UnicodeString ICU_Utility::parseUnicodeIdentifier(const UnicodeString& str, int32_t& pos) {
147 // assert(pos < str.length());
148 UnicodeString buf;
149 int p = pos;
150 while (p < str.length()) {
151 UChar32 ch = str.char32At(p);
152 if (buf.length() == 0) {
153 if (u_isIDStart(ch)) {
154 buf.append(ch);
155 } else {
156 buf.truncate(0);
157 return buf;
158 }
159 } else {
160 if (u_isIDPart(ch)) {
161 buf.append(ch);
162 } else {
163 break;
164 }
165 }
166 p += U16_LENGTH(ch);
167 }
168 pos = p;
169 return buf;
170 }
171
172 /**
173 * Parse an unsigned 31-bit integer at the given offset. Use
174 * UCharacter.digit() to parse individual characters into digits.
175 * @param text the text to be parsed
176 * @param pos INPUT-OUTPUT parameter. On entry, pos[0] is the
177 * offset within text at which to start parsing; it should point
178 * to a valid digit. On exit, pos[0] is the offset after the last
179 * parsed character. If the parse failed, it will be unchanged on
180 * exit. Must be >= 0 on entry.
181 * @param radix the radix in which to parse; must be >= 2 and <=
182 * 36.
183 * @return a non-negative parsed number, or -1 upon parse failure.
184 * Parse fails if there are no digits, that is, if pos[0] does not
185 * point to a valid digit on entry, or if the number to be parsed
186 * does not fit into a 31-bit unsigned integer.
187 */
parseNumber(const UnicodeString & text,int32_t & pos,int8_t radix)188 int32_t ICU_Utility::parseNumber(const UnicodeString& text,
189 int32_t& pos, int8_t radix) {
190 // assert(pos[0] >= 0);
191 // assert(radix >= 2);
192 // assert(radix <= 36);
193 int32_t n = 0;
194 int32_t p = pos;
195 while (p < text.length()) {
196 UChar32 ch = text.char32At(p);
197 int32_t d = u_digit(ch, radix);
198 if (d < 0) {
199 break;
200 }
201 n = radix*n + d;
202 // ASSUME that when a 32-bit integer overflows it becomes
203 // negative. E.g., 214748364 * 10 + 8 => negative value.
204 if (n < 0) {
205 return -1;
206 }
207 ++p;
208 }
209 if (p == pos) {
210 return -1;
211 }
212 pos = p;
213 return n;
214 }
215
216 U_NAMESPACE_END
217
218