1 /* 2 ****************************************************************************** 3 * Copyright (C) 2014, International Business Machines 4 * Corporation and others. All Rights Reserved. 5 ****************************************************************************** 6 * simplepatternformatter.h 7 */ 8 9 #ifndef __SIMPLEPATTERNFORMATTER_H__ 10 #define __SIMPLEPATTERNFORMATTER_H__ 11 12 #define EXPECTED_PLACEHOLDER_COUNT 3 13 14 #include "unicode/utypes.h" 15 #include "unicode/unistr.h" 16 17 U_NAMESPACE_BEGIN 18 19 /** 20 * Compiled version of a pattern string such as "{1} was born in {0}". 21 * <p> 22 * Using SimplePatternFormatter is both faster and safer than adhoc replacement. 23 * They are faster because they are precompiled; they are safer because they 24 * account for curly braces escaped by apostrophe ('). 25 * 26 * Placeholders are of the form \{[0-9]+\}. If a curly brace is preceded 27 * by a single quote, it becomes a curly brace instead of the start of a 28 * placeholder. Two single quotes resolve to one single quote. 29 * <p> 30 * Example: 31 * <pre> 32 * SimplePatternFormatter fmt("{1} '{born} in {0}"); 33 * UnicodeString result; 34 * UErrorCode status = U_ZERO_ERROR; 35 * // Evaluates to: "paul {born} in england" 36 * fmt.format("englad", "paul", result, status); 37 * </pre> 38 */ 39 class U_COMMON_API SimplePatternFormatter : public UMemory { 40 public: 41 /** 42 * Default constructor 43 */ 44 SimplePatternFormatter(); 45 46 /** 47 * Construct from a pattern. Will never fail if pattern has three or 48 * fewer placeholders in it. 49 */ 50 explicit SimplePatternFormatter(const UnicodeString& pattern); 51 52 /** 53 * Copy constructor. 54 */ 55 SimplePatternFormatter(const SimplePatternFormatter& other); 56 57 /** 58 * Assignment operator 59 */ 60 SimplePatternFormatter &operator=(const SimplePatternFormatter& other); 61 62 /** 63 * Destructor. 64 */ 65 ~SimplePatternFormatter(); 66 67 /** 68 * Compiles pattern and makes this object represent pattern. 69 * 70 * Returns TRUE on success; FALSE on failure. Will not fail if 71 * there are three or fewer placeholders in pattern. May fail with 72 * U_MEMORY_ALLOCATION_ERROR if there are more than three placeholders. 73 */ 74 UBool compile(const UnicodeString &pattern, UErrorCode &status); 75 76 /** 77 * Returns (maxPlaceholderId + 1). For example 78 * <code>SimplePatternFormatter("{0} {2}").getPlaceholderCount() 79 * evaluates to 3. 80 * Callers use this function to find out how many values this object 81 * expects when formatting. 82 */ getPlaceholderCount()83 int32_t getPlaceholderCount() const { 84 return placeholderCount; 85 } 86 87 /** 88 * Formats given value. 89 */ 90 UnicodeString &format( 91 const UnicodeString &args0, 92 UnicodeString &appendTo, 93 UErrorCode &status) const; 94 95 /** 96 * Formats given values. 97 */ 98 UnicodeString &format( 99 const UnicodeString &args0, 100 const UnicodeString &args1, 101 UnicodeString &appendTo, 102 UErrorCode &status) const; 103 104 /** 105 * Formats given values. 106 */ 107 UnicodeString &format( 108 const UnicodeString &args0, 109 const UnicodeString &args1, 110 const UnicodeString &args2, 111 UnicodeString &appendTo, 112 UErrorCode &status) const; 113 114 /** 115 * Formats given values. 116 * 117 * The caller retains ownership of all pointers. 118 * @param placeholderValues 1st one corresponds to {0}; 2nd to {1}; 119 * 3rd to {2} etc. 120 * @param placeholderValueCount the number of placeholder values 121 * must be at least large enough to provide values for all placeholders 122 * in this object. Otherwise status set to U_ILLEGAL_ARGUMENT_ERROR. 123 * @param appendTo resulting string appended here. 124 * @param offsetArray The offset of each placeholder value in appendTo 125 * stored here. The first value gets the offset of the value for {0}; 126 * the 2nd for {1}; the 3rd for {2} etc. -1 means that the corresponding 127 * placeholder does not exist in this object. If caller is not 128 * interested in offsets, it may pass NULL and 0 for the length. 129 * @param offsetArrayLength the size of offsetArray may be less than 130 * placeholderValueCount. 131 * @param status any error stored here. 132 */ 133 UnicodeString &format( 134 const UnicodeString * const *placeholderValues, 135 int32_t placeholderValueCount, 136 UnicodeString &appendTo, 137 int32_t *offsetArray, 138 int32_t offsetArrayLength, 139 UErrorCode &status) const; 140 private: 141 UnicodeString noPlaceholders; 142 int32_t placeholderBuffer[EXPECTED_PLACEHOLDER_COUNT * 2]; 143 int32_t *placeholdersByOffset; 144 int32_t placeholderSize; 145 int32_t placeholderCapacity; 146 int32_t placeholderCount; 147 int32_t ensureCapacity(int32_t size); 148 UBool addPlaceholder(int32_t id, int32_t offset); 149 }; 150 151 U_NAMESPACE_END 152 153 #endif 154