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#ifndef ICU_UTIL_H
12#define ICU_UTIL_H
13
14#include "unicode/utypes.h"
15#include "unicode/uobject.h"
16#include "unicode/unistr.h"
17
18//--------------------------------------------------------------------
19// class ICU_Utility
20// i18n utility functions, scoped into the class ICU_Utility.
21//--------------------------------------------------------------------
22
23U_NAMESPACE_BEGIN
24
25class UnicodeMatcher;
26
27class U_COMMON_API ICU_Utility /* not : public UObject because all methods are static */ {
28 public:
29
30    /**
31     * Append a number to the given UnicodeString in the given radix.
32     * Standard digits '0'-'9' are used and letters 'A'-'Z' for
33     * radices 11 through 36.
34     * @param result the digits of the number are appended here
35     * @param n the number to be converted to digits; may be negative.
36     * If negative, a '-' is prepended to the digits.
37     * @param radix a radix from 2 to 36 inclusive.
38     * @param minDigits the minimum number of digits, not including
39     * any '-', to produce.  Values less than 2 have no effect.  One
40     * digit is always emitted regardless of this parameter.
41     * @return a reference to result
42     */
43    static UnicodeString& appendNumber(UnicodeString& result, int32_t n,
44                                       int32_t radix = 10,
45                                       int32_t minDigits = 1);
46
47    /**
48     * Return true if the character is NOT printable ASCII.
49     *
50     * This method should really be in UnicodeString (or similar).  For
51     * now, we implement it here and share it with friend classes.
52     */
53    static UBool isUnprintable(UChar32 c);
54
55    /**
56     * Escape unprintable characters using \uxxxx notation for U+0000 to
57     * U+FFFF and \Uxxxxxxxx for U+10000 and above.  If the character is
58     * printable ASCII, then do nothing and return FALSE.  Otherwise,
59     * append the escaped notation and return TRUE.
60     */
61    static UBool escapeUnprintable(UnicodeString& result, UChar32 c);
62
63    /**
64     * Returns the index of a character, ignoring quoted text.
65     * For example, in the string "abc'hide'h", the 'h' in "hide" will not be
66     * found by a search for 'h'.
67     * @param text text to be searched
68     * @param start the beginning index, inclusive; <code>0 <= start
69     * <= limit</code>.
70     * @param limit the ending index, exclusive; <code>start <= limit
71     * <= text.length()</code>.
72     * @param c character to search for
73     * @return Offset of the first instance of c, or -1 if not found.
74     */
75//?FOR FUTURE USE.  DISABLE FOR NOW for coverage reasons.
76//    static int32_t quotedIndexOf(const UnicodeString& text,
77//                                 int32_t start, int32_t limit,
78//                                 UChar c);
79
80    /**
81     * Skip over a sequence of zero or more white space characters at pos.
82     * @param advance if true, advance pos to the first non-white-space
83     * character at or after pos, or str.length(), if there is none.
84     * Otherwise leave pos unchanged.
85     * @return the index of the first non-white-space character at or
86     * after pos, or str.length(), if there is none.
87     */
88    static int32_t skipWhitespace(const UnicodeString& str, int32_t& pos,
89                                  UBool advance = FALSE);
90
91    /**
92     * Skip over Pattern_White_Space in a Replaceable.
93     * Skipping may be done in the forward or
94     * reverse direction.  In either case, the leftmost index will be
95     * inclusive, and the rightmost index will be exclusive.  That is,
96     * given a range defined as [start, limit), the call
97     * skipWhitespace(text, start, limit) will advance start past leading
98     * whitespace, whereas the call skipWhitespace(text, limit, start),
99     * will back up limit past trailing whitespace.
100     * @param text the text to be analyzed
101     * @param pos either the start or limit of a range of 'text', to skip
102     * leading or trailing whitespace, respectively
103     * @param stop either the limit or start of a range of 'text', to skip
104     * leading or trailing whitespace, respectively
105     * @return the new start or limit, depending on what was passed in to
106     * 'pos'
107     */
108//?FOR FUTURE USE.  DISABLE FOR NOW for coverage reasons.
109//?    static int32_t skipWhitespace(const Replaceable& text,
110//?                                  int32_t pos, int32_t stop);
111
112    /**
113     * Parse a single non-whitespace character 'ch', optionally
114     * preceded by whitespace.
115     * @param id the string to be parsed
116     * @param pos INPUT-OUTPUT parameter.  On input, pos[0] is the
117     * offset of the first character to be parsed.  On output, pos[0]
118     * is the index after the last parsed character.  If the parse
119     * fails, pos[0] will be unchanged.
120     * @param ch the non-whitespace character to be parsed.
121     * @return true if 'ch' is seen preceded by zero or more
122     * whitespace characters.
123     */
124    static UBool parseChar(const UnicodeString& id, int32_t& pos, UChar ch);
125
126    /**
127     * Parse a pattern string starting at offset pos.  Keywords are
128     * matched case-insensitively.  Spaces may be skipped and may be
129     * optional or required.  Integer values may be parsed, and if
130     * they are, they will be returned in the given array.  If
131     * successful, the offset of the next non-space character is
132     * returned.  On failure, -1 is returned.
133     * @param pattern must only contain lowercase characters, which
134     * will match their uppercase equivalents as well.  A space
135     * character matches one or more required spaces.  A '~' character
136     * matches zero or more optional spaces.  A '#' character matches
137     * an integer and stores it in parsedInts, which the caller must
138     * ensure has enough capacity.
139     * @param parsedInts array to receive parsed integers.  Caller
140     * must ensure that parsedInts.length is >= the number of '#'
141     * signs in 'pattern'.
142     * @return the position after the last character parsed, or -1 if
143     * the parse failed
144     */
145    static int32_t parsePattern(const UnicodeString& rule, int32_t pos, int32_t limit,
146                                const UnicodeString& pattern, int32_t* parsedInts);
147
148    /**
149     * Parse a pattern string within the given Replaceable and a parsing
150     * pattern.  Characters are matched literally and case-sensitively
151     * except for the following special characters:
152     *
153     * ~  zero or more Pattern_White_Space chars
154     *
155     * If end of pattern is reached with all matches along the way,
156     * pos is advanced to the first unparsed index and returned.
157     * Otherwise -1 is returned.
158     * @param pat pattern that controls parsing
159     * @param text text to be parsed, starting at index
160     * @param index offset to first character to parse
161     * @param limit offset after last character to parse
162     * @return index after last parsed character, or -1 on parse failure.
163     */
164    static int32_t parsePattern(const UnicodeString& pat,
165                                const Replaceable& text,
166                                int32_t index,
167                                int32_t limit);
168
169    /**
170     * Parse an integer at pos, either of the form \d+ or of the form
171     * 0x[0-9A-Fa-f]+ or 0[0-7]+, that is, in standard decimal, hex,
172     * or octal format.
173     * @param pos INPUT-OUTPUT parameter.  On input, the first
174     * character to parse.  On output, the character after the last
175     * parsed character.
176     */
177    static int32_t parseInteger(const UnicodeString& rule, int32_t& pos, int32_t limit);
178
179    /**
180     * Parse a Unicode identifier from the given string at the given
181     * position.  Return the identifier, or an empty string if there
182     * is no identifier.
183     * @param str the string to parse
184     * @param pos INPUT-OUPUT parameter.  On INPUT, pos is the
185     * first character to examine.  It must be less than str.length(),
186     * and it must not point to a whitespace character.  That is, must
187     * have pos < str.length() and
188     * !UCharacter::isWhitespace(str.char32At(pos)).  On
189     * OUTPUT, the position after the last parsed character.
190     * @return the Unicode identifier, or an empty string if there is
191     * no valid identifier at pos.
192     */
193    static UnicodeString parseUnicodeIdentifier(const UnicodeString& str, int32_t& pos);
194
195    /**
196     * Parse an unsigned 31-bit integer at the given offset.  Use
197     * UCharacter.digit() to parse individual characters into digits.
198     * @param text the text to be parsed
199     * @param pos INPUT-OUTPUT parameter.  On entry, pos is the
200     * offset within text at which to start parsing; it should point
201     * to a valid digit.  On exit, pos is the offset after the last
202     * parsed character.  If the parse failed, it will be unchanged on
203     * exit.  Must be >= 0 on entry.
204     * @param radix the radix in which to parse; must be >= 2 and <=
205     * 36.
206     * @return a non-negative parsed number, or -1 upon parse failure.
207     * Parse fails if there are no digits, that is, if pos does not
208     * point to a valid digit on entry, or if the number to be parsed
209     * does not fit into a 31-bit unsigned integer.
210     */
211    static int32_t parseNumber(const UnicodeString& text,
212                               int32_t& pos, int8_t radix);
213
214    static void appendToRule(UnicodeString& rule,
215                             UChar32 c,
216                             UBool isLiteral,
217                             UBool escapeUnprintable,
218                             UnicodeString& quoteBuf);
219
220    static void appendToRule(UnicodeString& rule,
221                             const UnicodeString& text,
222                             UBool isLiteral,
223                             UBool escapeUnprintable,
224                             UnicodeString& quoteBuf);
225
226    static void appendToRule(UnicodeString& rule,
227                             const UnicodeMatcher* matcher,
228                             UBool escapeUnprintable,
229                             UnicodeString& quoteBuf);
230
231private:
232    // do not instantiate
233    ICU_Utility();
234};
235
236U_NAMESPACE_END
237
238#endif
239//eof
240