icuSources/i18n/number_affixutils.h

   1 // © 2017 and later: Unicode, Inc. and others.
   2 // License & terms of use: http://www.unicode.org/copyright.html
   3
   4 #include "unicode/utypes.h"
   5
   6 #if !UCONFIG_NO_FORMATTING
   7 #ifndef __NUMBER_AFFIXUTILS_H__
   8 #define __NUMBER_AFFIXUTILS_H__
   9
  10 #include <cstdint>
  11 #include "number_types.h"
  12 #include "unicode/stringpiece.h"
  13 #include "unicode/unistr.h"
  14 #include "number_stringbuilder.h"
  15 #include "unicode/uniset.h"
  16
  17 U_NAMESPACE_BEGIN namespace number {
  18 namespace impl {
  19
  20 enum AffixPatternState {
  21     STATE_BASE = 0,
  22     STATE_FIRST_QUOTE = 1,
  23     STATE_INSIDE_QUOTE = 2,
  24     STATE_AFTER_QUOTE = 3,
  25     STATE_FIRST_CURR = 4,
  26     STATE_SECOND_CURR = 5,
  27     STATE_THIRD_CURR = 6,
  28     STATE_FOURTH_CURR = 7,
  29     STATE_FIFTH_CURR = 8,
  30     STATE_OVERFLOW_CURR = 9
  31 };
  32
  33 // enum AffixPatternType defined in internals.h
  34
  35 struct AffixTag {
  36     int32_t offset;
  37     UChar32 codePoint;
  38     AffixPatternState state;
  39     AffixPatternType type;
  40
  41     AffixTag()
  42             : offset(0), state(STATE_BASE) {}
  43
  44     AffixTag(int32_t offset)
  45             : offset(offset) {}
  46
  47     AffixTag(int32_t offset, UChar32 codePoint, AffixPatternState state, AffixPatternType type)
  48             : offset(offset), codePoint(codePoint), state(state), type(type) {}
  49 };
  50
  51 class TokenConsumer {
  52   public:
  53     virtual ~TokenConsumer();
  54
  55     virtual void consumeToken(AffixPatternType type, UChar32 cp, UErrorCode& status) = 0;
  56 };
  57
  58 // Exported as U_I18N_API because it is a base class for other exported types
  59 class U_I18N_API SymbolProvider {
  60   public:
  61     virtual ~SymbolProvider();
  62
  63     // TODO: Could this be more efficient if it returned by reference?
  64     virtual UnicodeString getSymbol(AffixPatternType type) const = 0;
  65 };
  66
  67 /**
  68  * Performs manipulations on affix patterns: the prefix and suffix strings associated with a decimal
  69  * format pattern. For example:
  70  *
  71  * <table>
  72  * <tr><th>Affix Pattern</th><th>Example Unescaped (Formatted) String</th></tr>
  73  * <tr><td>abc</td><td>abc</td></tr>
  74  * <tr><td>ab-</td><td>ab−</td></tr>
  75  * <tr><td>ab'-'</td><td>ab-</td></tr>
  76  * <tr><td>ab''</td><td>ab'</td></tr>
  77  * </table>
  78  *
  79  * To manually iterate over tokens in a literal string, use the following pattern, which is designed
  80  * to be efficient.
  81  *
  82  * <pre>
  83  * long tag = 0L;
  84  * while (AffixPatternUtils.hasNext(tag, patternString)) {
  85  *   tag = AffixPatternUtils.nextToken(tag, patternString);
  86  *   int typeOrCp = AffixPatternUtils.getTypeOrCp(tag);
  87  *   switch (typeOrCp) {
  88  *     case AffixPatternUtils.TYPE_MINUS_SIGN:
  89  *       // Current token is a minus sign.
  90  *       break;
  91  *     case AffixPatternUtils.TYPE_PLUS_SIGN:
  92  *       // Current token is a plus sign.
  93  *       break;
  94  *     case AffixPatternUtils.TYPE_PERCENT:
  95  *       // Current token is a percent sign.
  96  *       break;
  97  *     // ... other types ...
  98  *     default:
  99  *       // Current token is an arbitrary code point.
 100  *       // The variable typeOrCp is the code point.
 101  *       break;
 102  *   }
 103  * }
 104  * </pre>
 105  */
 106 class U_I18N_API AffixUtils {
 107
 108   public:
 109
 110     /**
 111      * Estimates the number of code points present in an unescaped version of the affix pattern string
 112      * (one that would be returned by {@link #unescape}), assuming that all interpolated symbols
 113      * consume one code point and that currencies consume as many code points as their symbol width.
 114      * Used for computing padding width.
 115      *
 116      * @param patternString The original string whose width will be estimated.
 117      * @return The length of the unescaped string.
 118      */
 119     static int32_t estimateLength(const UnicodeString& patternString, UErrorCode& status);
 120
 121     /**
 122      * Takes a string and escapes (quotes) characters that have special meaning in the affix pattern
 123      * syntax. This function does not reverse-lookup symbols.
 124      *
 125      * <p>Example input: "-$x"; example output: "'-'$x"
 126      *
 127      * @param input The string to be escaped.
 128      * @return The resulting UnicodeString.
 129      */
 130     static UnicodeString escape(const UnicodeString& input);
 131
 132     static Field getFieldForType(AffixPatternType type);
 133
 134     /**
 135      * Executes the unescape state machine. Replaces the unquoted characters "-", "+", "%", "‰", and
 136      * "¤" with the corresponding symbols provided by the {@link SymbolProvider}, and inserts the
 137      * result into the NumberStringBuilder at the requested location.
 138      *
 139      * <p>Example input: "'-'¤x"; example output: "-$x"
 140      *
 141      * @param affixPattern The original string to be unescaped.
 142      * @param output The NumberStringBuilder to mutate with the result.
 143      * @param position The index into the NumberStringBuilder to insert the string.
 144      * @param provider An object to generate locale symbols.
 145      */
 146     static int32_t unescape(const UnicodeString& affixPattern, NumberStringBuilder& output,
 147                             int32_t position, const SymbolProvider& provider, UErrorCode& status);
 148
 149     /**
 150    * Sames as {@link #unescape}, but only calculates the code point count.  More efficient than {@link #unescape}
 151    * if you only need the length but not the string itself.
 152      *
 153      * @param affixPattern The original string to be unescaped.
 154      * @param provider An object to generate locale symbols.
 155      * @return The same return value as if you called {@link #unescape}.
 156      */
 157     static int32_t unescapedCodePointCount(const UnicodeString& affixPattern,
 158                                            const SymbolProvider& provider, UErrorCode& status);
 159
 160     /**
 161      * Checks whether the given affix pattern contains at least one token of the given type, which is
 162      * one of the constants "TYPE_" in {@link AffixPatternUtils}.
 163      *
 164      * @param affixPattern The affix pattern to check.
 165      * @param type The token type.
 166      * @return true if the affix pattern contains the given token type; false otherwise.
 167      */
 168     static bool containsType(const UnicodeString& affixPattern, AffixPatternType type, UErrorCode& status);
 169
 170     /**
 171      * Checks whether the specified affix pattern has any unquoted currency symbols ("¤").
 172      *
 173      * @param affixPattern The string to check for currency symbols.
 174      * @return true if the literal has at least one unquoted currency symbol; false otherwise.
 175      */
 176     static bool hasCurrencySymbols(const UnicodeString& affixPattern, UErrorCode& status);
 177
 178     /**
 179      * Replaces all occurrences of tokens with the given type with the given replacement char.
 180      *
 181      * @param affixPattern The source affix pattern (does not get modified).
 182      * @param type The token type.
 183      * @param replacementChar The char to substitute in place of chars of the given token type.
 184      * @return A string containing the new affix pattern.
 185      */
 186     static UnicodeString replaceType(const UnicodeString& affixPattern, AffixPatternType type,
 187                                      char16_t replacementChar, UErrorCode& status);
 188
 189     /**
 190      * Returns whether the given affix pattern contains only symbols and ignorables as defined by the
 191      * given ignorables set.
 192      */
 193     static bool containsOnlySymbolsAndIgnorables(const UnicodeString& affixPattern,
 194                                                  const UnicodeSet& ignorables, UErrorCode& status);
 195
 196     /**
 197      * Iterates over the affix pattern, calling the TokenConsumer for each token.
 198      */
 199     static void iterateWithConsumer(const UnicodeString& affixPattern, TokenConsumer& consumer,
 200                                     UErrorCode& status);
 201
 202     /**
 203      * Returns the next token from the affix pattern.
 204      *
 205      * @param tag A bitmask used for keeping track of state from token to token. The initial value
 206      *     should be 0L.
 207      * @param patternString The affix pattern.
 208      * @return The bitmask tag to pass to the next call of this method to retrieve the following token
 209      *     (never negative), or -1 if there were no more tokens in the affix pattern.
 210      * @see #hasNext
 211      */
 212     static AffixTag nextToken(AffixTag tag, const UnicodeString& patternString, UErrorCode& status);
 213
 214     /**
 215      * Returns whether the affix pattern string has any more tokens to be retrieved from a call to
 216      * {@link #nextToken}.
 217      *
 218      * @param tag The bitmask tag of the previous token, as returned by {@link #nextToken}.
 219      * @param string The affix pattern.
 220      * @return true if there are more tokens to consume; false otherwise.
 221      */
 222     static bool hasNext(const AffixTag& tag, const UnicodeString& string);
 223
 224   private:
 225     /**
 226      * Encodes the given values into a tag struct.
 227      * The order of the arguments is consistent with Java, but the order of the stored
 228      * fields is not necessarily the same.
 229      */
 230     static inline AffixTag makeTag(int32_t offset, AffixPatternType type, AffixPatternState state,
 231                                    UChar32 cp) {
 232         return {offset, cp, state, type};
 233     }
 234 };
 235
 236 } // namespace impl
 237 } // namespace number
 238 U_NAMESPACE_END
 239
 240
 241 #endif //__NUMBER_AFFIXUTILS_H__
 242
 243 #endif /* #if !UCONFIG_NO_FORMATTING */