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      1 
      2 /*
      3  * Copyright 2006 The Android Open Source Project
      4  *
      5  * Use of this source code is governed by a BSD-style license that can be
      6  * found in the LICENSE file.
      7  */
      8 
      9 
     10 #ifndef SkString_DEFINED
     11 #define SkString_DEFINED
     12 
     13 #include "../private/SkTArray.h"
     14 #include "SkScalar.h"
     15 
     16 #include <stdarg.h>
     17 
     18 /*  Some helper functions for C strings
     19 */
     20 
     21 static bool SkStrStartsWith(const char string[], const char prefixStr[]) {
     22     SkASSERT(string);
     23     SkASSERT(prefixStr);
     24     return !strncmp(string, prefixStr, strlen(prefixStr));
     25 }
     26 static bool SkStrStartsWith(const char string[], const char prefixChar) {
     27     SkASSERT(string);
     28     return (prefixChar == *string);
     29 }
     30 
     31 bool SkStrEndsWith(const char string[], const char suffixStr[]);
     32 bool SkStrEndsWith(const char string[], const char suffixChar);
     33 
     34 int SkStrStartsWithOneOf(const char string[], const char prefixes[]);
     35 
     36 static int SkStrFind(const char string[], const char substring[]) {
     37     const char *first = strstr(string, substring);
     38     if (NULL == first) return -1;
     39     return SkToS32(first - &string[0]);
     40 }
     41 
     42 static int SkStrFindLastOf(const char string[], const char subchar) {
     43     const char* last = strrchr(string, subchar);
     44     if (NULL == last) return -1;
     45     return SkToS32(last - &string[0]);
     46 }
     47 
     48 static bool SkStrContains(const char string[], const char substring[]) {
     49     SkASSERT(string);
     50     SkASSERT(substring);
     51     return (-1 != SkStrFind(string, substring));
     52 }
     53 static bool SkStrContains(const char string[], const char subchar) {
     54     SkASSERT(string);
     55     char tmp[2];
     56     tmp[0] = subchar;
     57     tmp[1] = '\0';
     58     return (-1 != SkStrFind(string, tmp));
     59 }
     60 
     61 static inline char *SkStrDup(const char string[]) {
     62     char *ret = (char *) sk_malloc_throw(strlen(string)+1);
     63     memcpy(ret,string,strlen(string)+1);
     64     return ret;
     65 }
     66 
     67 /*
     68  *  The SkStrAppend... methods will write into the provided buffer, assuming it is large enough.
     69  *  Each method has an associated const (e.g. SkStrAppendU32_MaxSize) which will be the largest
     70  *  value needed for that method's buffer.
     71  *
     72  *  char storage[SkStrAppendU32_MaxSize];
     73  *  SkStrAppendU32(storage, value);
     74  *
     75  *  Note : none of the SkStrAppend... methods write a terminating 0 to their buffers. Instead,
     76  *  the methods return the ptr to the end of the written part of the buffer. This can be used
     77  *  to compute the length, and/or know where to write a 0 if that is desired.
     78  *
     79  *  char storage[SkStrAppendU32_MaxSize + 1];
     80  *  char* stop = SkStrAppendU32(storage, value);
     81  *  size_t len = stop - storage;
     82  *  *stop = 0;   // valid, since storage was 1 byte larger than the max.
     83  */
     84 
     85 #define SkStrAppendU32_MaxSize  10
     86 char*   SkStrAppendU32(char buffer[], uint32_t);
     87 #define SkStrAppendU64_MaxSize  20
     88 char*   SkStrAppendU64(char buffer[], uint64_t, int minDigits);
     89 
     90 #define SkStrAppendS32_MaxSize  (SkStrAppendU32_MaxSize + 1)
     91 char*   SkStrAppendS32(char buffer[], int32_t);
     92 #define SkStrAppendS64_MaxSize  (SkStrAppendU64_MaxSize + 1)
     93 char*   SkStrAppendS64(char buffer[], int64_t, int minDigits);
     94 
     95 /**
     96  *  Floats have at most 8 significant digits, so we limit our %g to that.
     97  *  However, the total string could be 15 characters: -1.2345678e-005
     98  *
     99  *  In theory we should only expect up to 2 digits for the exponent, but on
    100  *  some platforms we have seen 3 (as in the example above).
    101  */
    102 #define SkStrAppendScalar_MaxSize  15
    103 
    104 /**
    105  *  Write the scaler in decimal format into buffer, and return a pointer to
    106  *  the next char after the last one written. Note: a terminating 0 is not
    107  *  written into buffer, which must be at least SkStrAppendScalar_MaxSize.
    108  *  Thus if the caller wants to add a 0 at the end, buffer must be at least
    109  *  SkStrAppendScalar_MaxSize + 1 bytes large.
    110  */
    111 #define SkStrAppendScalar SkStrAppendFloat
    112 
    113 char* SkStrAppendFloat(char buffer[], float);
    114 char* SkStrAppendFixed(char buffer[], SkFixed);
    115 
    116 /** \class SkString
    117 
    118     Light weight class for managing strings. Uses reference
    119     counting to make string assignments and copies very fast
    120     with no extra RAM cost. Assumes UTF8 encoding.
    121 */
    122 class SK_API SkString {
    123 public:
    124                 SkString();
    125     explicit    SkString(size_t len);
    126     explicit    SkString(const char text[]);
    127                 SkString(const char text[], size_t len);
    128                 SkString(const SkString&);
    129                 SkString(SkString&&);
    130                 ~SkString();
    131 
    132     bool        isEmpty() const { return 0 == fRec->fLength; }
    133     size_t      size() const { return (size_t) fRec->fLength; }
    134     const char* c_str() const { return fRec->data(); }
    135     char operator[](size_t n) const { return this->c_str()[n]; }
    136 
    137     bool equals(const SkString&) const;
    138     bool equals(const char text[]) const;
    139     bool equals(const char text[], size_t len) const;
    140 
    141     bool startsWith(const char prefixStr[]) const {
    142         return SkStrStartsWith(fRec->data(), prefixStr);
    143     }
    144     bool startsWith(const char prefixChar) const {
    145         return SkStrStartsWith(fRec->data(), prefixChar);
    146     }
    147     bool endsWith(const char suffixStr[]) const {
    148         return SkStrEndsWith(fRec->data(), suffixStr);
    149     }
    150     bool endsWith(const char suffixChar) const {
    151         return SkStrEndsWith(fRec->data(), suffixChar);
    152     }
    153     bool contains(const char substring[]) const {
    154         return SkStrContains(fRec->data(), substring);
    155     }
    156     bool contains(const char subchar) const {
    157         return SkStrContains(fRec->data(), subchar);
    158     }
    159     int find(const char substring[]) const {
    160         return SkStrFind(fRec->data(), substring);
    161     }
    162     int findLastOf(const char subchar) const {
    163         return SkStrFindLastOf(fRec->data(), subchar);
    164     }
    165 
    166     friend bool operator==(const SkString& a, const SkString& b) {
    167         return a.equals(b);
    168     }
    169     friend bool operator!=(const SkString& a, const SkString& b) {
    170         return !a.equals(b);
    171     }
    172 
    173     // these methods edit the string
    174 
    175     SkString& operator=(const SkString&);
    176     SkString& operator=(SkString&&);
    177     SkString& operator=(const char text[]);
    178 
    179     char* writable_str();
    180     char& operator[](size_t n) { return this->writable_str()[n]; }
    181 
    182     void reset();
    183     /** Destructive resize, does not preserve contents. */
    184     void resize(size_t len) { this->set(NULL, len); }
    185     void set(const SkString& src) { *this = src; }
    186     void set(const char text[]);
    187     void set(const char text[], size_t len);
    188     void setUTF16(const uint16_t[]);
    189     void setUTF16(const uint16_t[], size_t len);
    190 
    191     void insert(size_t offset, const SkString& src) { this->insert(offset, src.c_str(), src.size()); }
    192     void insert(size_t offset, const char text[]);
    193     void insert(size_t offset, const char text[], size_t len);
    194     void insertUnichar(size_t offset, SkUnichar);
    195     void insertS32(size_t offset, int32_t value);
    196     void insertS64(size_t offset, int64_t value, int minDigits = 0);
    197     void insertU32(size_t offset, uint32_t value);
    198     void insertU64(size_t offset, uint64_t value, int minDigits = 0);
    199     void insertHex(size_t offset, uint32_t value, int minDigits = 0);
    200     void insertScalar(size_t offset, SkScalar);
    201 
    202     void append(const SkString& str) { this->insert((size_t)-1, str); }
    203     void append(const char text[]) { this->insert((size_t)-1, text); }
    204     void append(const char text[], size_t len) { this->insert((size_t)-1, text, len); }
    205     void appendUnichar(SkUnichar uni) { this->insertUnichar((size_t)-1, uni); }
    206     void appendS32(int32_t value) { this->insertS32((size_t)-1, value); }
    207     void appendS64(int64_t value, int minDigits = 0) { this->insertS64((size_t)-1, value, minDigits); }
    208     void appendU32(uint32_t value) { this->insertU32((size_t)-1, value); }
    209     void appendU64(uint64_t value, int minDigits = 0) { this->insertU64((size_t)-1, value, minDigits); }
    210     void appendHex(uint32_t value, int minDigits = 0) { this->insertHex((size_t)-1, value, minDigits); }
    211     void appendScalar(SkScalar value) { this->insertScalar((size_t)-1, value); }
    212 
    213     void prepend(const SkString& str) { this->insert(0, str); }
    214     void prepend(const char text[]) { this->insert(0, text); }
    215     void prepend(const char text[], size_t len) { this->insert(0, text, len); }
    216     void prependUnichar(SkUnichar uni) { this->insertUnichar(0, uni); }
    217     void prependS32(int32_t value) { this->insertS32(0, value); }
    218     void prependS64(int32_t value, int minDigits = 0) { this->insertS64(0, value, minDigits); }
    219     void prependHex(uint32_t value, int minDigits = 0) { this->insertHex(0, value, minDigits); }
    220     void prependScalar(SkScalar value) { this->insertScalar((size_t)-1, value); }
    221 
    222     void printf(const char format[], ...) SK_PRINTF_LIKE(2, 3);
    223     void appendf(const char format[], ...) SK_PRINTF_LIKE(2, 3);
    224     void appendVAList(const char format[], va_list);
    225     void prependf(const char format[], ...) SK_PRINTF_LIKE(2, 3);
    226     void prependVAList(const char format[], va_list);
    227 
    228     void remove(size_t offset, size_t length);
    229 
    230     SkString& operator+=(const SkString& s) { this->append(s); return *this; }
    231     SkString& operator+=(const char text[]) { this->append(text); return *this; }
    232     SkString& operator+=(const char c) { this->append(&c, 1); return *this; }
    233 
    234     /**
    235      *  Swap contents between this and other. This function is guaranteed
    236      *  to never fail or throw.
    237      */
    238     void swap(SkString& other);
    239 
    240 private:
    241     struct Rec {
    242     public:
    243         uint32_t    fLength; // logically size_t, but we want it to stay 32bits
    244         int32_t     fRefCnt;
    245         char        fBeginningOfData;
    246 
    247         char* data() { return &fBeginningOfData; }
    248         const char* data() const { return &fBeginningOfData; }
    249     };
    250     Rec* fRec;
    251 
    252 #ifdef SK_DEBUG
    253     void validate() const;
    254 #else
    255     void validate() const {}
    256 #endif
    257 
    258     static const Rec gEmptyRec;
    259     static Rec* AllocRec(const char text[], size_t len);
    260     static Rec* RefRec(Rec*);
    261 };
    262 
    263 /// Creates a new string and writes into it using a printf()-style format.
    264 SkString SkStringPrintf(const char* format, ...);
    265 
    266 // Specialized to take advantage of SkString's fast swap path. The unspecialized function is
    267 // declared in SkTypes.h and called by SkTSort.
    268 template <> inline void SkTSwap(SkString& a, SkString& b) {
    269     a.swap(b);
    270 }
    271 
    272 enum SkStrSplitMode {
    273     // Strictly return all results. If the input is ",," and the separator is ',' this will return
    274     // an array of three empty strings.
    275     kStrict_SkStrSplitMode,
    276 
    277     // Only nonempty results will be added to the results. Multiple separators will be
    278     // coalesced. Separators at the beginning and end of the input will be ignored.  If the input is
    279     // ",," and the separator is ',', this will return an empty vector.
    280     kCoalesce_SkStrSplitMode
    281 };
    282 
    283 // Split str on any characters in delimiters into out.  (Think, strtok with a sane API.)
    284 void SkStrSplit(const char* str, const char* delimiters, SkStrSplitMode splitMode,
    285                 SkTArray<SkString>* out);
    286 inline void SkStrSplit(const char* str, const char* delimiters, SkTArray<SkString>* out) {
    287     SkStrSplit(str, delimiters, kCoalesce_SkStrSplitMode, out);
    288 }
    289 
    290 #endif
    291