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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 SkToInt(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 SkToInt(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 
    115 /** \class SkString
    116 
    117     Light weight class for managing strings. Uses reference
    118     counting to make string assignments and copies very fast
    119     with no extra RAM cost. Assumes UTF8 encoding.
    120 */
    121 class SK_API SkString {
    122 public:
    123                 SkString();
    124     explicit    SkString(size_t len);
    125     explicit    SkString(const char text[]);
    126                 SkString(const char text[], size_t len);
    127                 SkString(const SkString&);
    128                 SkString(SkString&&);
    129                 ~SkString();
    130 
    131     bool        isEmpty() const { return 0 == fRec->fLength; }
    132     size_t      size() const { return (size_t) fRec->fLength; }
    133     const char* c_str() const { return fRec->data(); }
    134     char operator[](size_t n) const { return this->c_str()[n]; }
    135 
    136     bool equals(const SkString&) const;
    137     bool equals(const char text[]) const;
    138     bool equals(const char text[], size_t len) const;
    139 
    140     bool startsWith(const char prefixStr[]) const {
    141         return SkStrStartsWith(fRec->data(), prefixStr);
    142     }
    143     bool startsWith(const char prefixChar) const {
    144         return SkStrStartsWith(fRec->data(), prefixChar);
    145     }
    146     bool endsWith(const char suffixStr[]) const {
    147         return SkStrEndsWith(fRec->data(), suffixStr);
    148     }
    149     bool endsWith(const char suffixChar) const {
    150         return SkStrEndsWith(fRec->data(), suffixChar);
    151     }
    152     bool contains(const char substring[]) const {
    153         return SkStrContains(fRec->data(), substring);
    154     }
    155     bool contains(const char subchar) const {
    156         return SkStrContains(fRec->data(), subchar);
    157     }
    158     int find(const char substring[]) const {
    159         return SkStrFind(fRec->data(), substring);
    160     }
    161     int findLastOf(const char subchar) const {
    162         return SkStrFindLastOf(fRec->data(), subchar);
    163     }
    164 
    165     friend bool operator==(const SkString& a, const SkString& b) {
    166         return a.equals(b);
    167     }
    168     friend bool operator!=(const SkString& a, const SkString& b) {
    169         return !a.equals(b);
    170     }
    171 
    172     // these methods edit the string
    173 
    174     SkString& operator=(const SkString&);
    175     SkString& operator=(SkString&&);
    176     SkString& operator=(const char text[]);
    177 
    178     char* writable_str();
    179     char& operator[](size_t n) { return this->writable_str()[n]; }
    180 
    181     void reset();
    182     /** Destructive resize, does not preserve contents. */
    183     void resize(size_t len) { this->set(NULL, len); }
    184     void set(const SkString& src) { *this = src; }
    185     void set(const char text[]);
    186     void set(const char text[], size_t len);
    187     void setUTF16(const uint16_t[]);
    188     void setUTF16(const uint16_t[], size_t len);
    189 
    190     void insert(size_t offset, const SkString& src) { this->insert(offset, src.c_str(), src.size()); }
    191     void insert(size_t offset, const char text[]);
    192     void insert(size_t offset, const char text[], size_t len);
    193     void insertUnichar(size_t offset, SkUnichar);
    194     void insertS32(size_t offset, int32_t value);
    195     void insertS64(size_t offset, int64_t value, int minDigits = 0);
    196     void insertU32(size_t offset, uint32_t value);
    197     void insertU64(size_t offset, uint64_t value, int minDigits = 0);
    198     void insertHex(size_t offset, uint32_t value, int minDigits = 0);
    199     void insertScalar(size_t offset, SkScalar);
    200 
    201     void append(const SkString& str) { this->insert((size_t)-1, str); }
    202     void append(const char text[]) { this->insert((size_t)-1, text); }
    203     void append(const char text[], size_t len) { this->insert((size_t)-1, text, len); }
    204     void appendUnichar(SkUnichar uni) { this->insertUnichar((size_t)-1, uni); }
    205     void appendS32(int32_t value) { this->insertS32((size_t)-1, value); }
    206     void appendS64(int64_t value, int minDigits = 0) { this->insertS64((size_t)-1, value, minDigits); }
    207     void appendU32(uint32_t value) { this->insertU32((size_t)-1, value); }
    208     void appendU64(uint64_t value, int minDigits = 0) { this->insertU64((size_t)-1, value, minDigits); }
    209     void appendHex(uint32_t value, int minDigits = 0) { this->insertHex((size_t)-1, value, minDigits); }
    210     void appendScalar(SkScalar value) { this->insertScalar((size_t)-1, value); }
    211 
    212     void prepend(const SkString& str) { this->insert(0, str); }
    213     void prepend(const char text[]) { this->insert(0, text); }
    214     void prepend(const char text[], size_t len) { this->insert(0, text, len); }
    215     void prependUnichar(SkUnichar uni) { this->insertUnichar(0, uni); }
    216     void prependS32(int32_t value) { this->insertS32(0, value); }
    217     void prependS64(int32_t value, int minDigits = 0) { this->insertS64(0, value, minDigits); }
    218     void prependHex(uint32_t value, int minDigits = 0) { this->insertHex(0, value, minDigits); }
    219     void prependScalar(SkScalar value) { this->insertScalar((size_t)-1, value); }
    220 
    221     void printf(const char format[], ...) SK_PRINTF_LIKE(2, 3);
    222     void appendf(const char format[], ...) SK_PRINTF_LIKE(2, 3);
    223     void appendVAList(const char format[], va_list);
    224     void prependf(const char format[], ...) SK_PRINTF_LIKE(2, 3);
    225     void prependVAList(const char format[], va_list);
    226 
    227     void remove(size_t offset, size_t length);
    228 
    229     SkString& operator+=(const SkString& s) { this->append(s); return *this; }
    230     SkString& operator+=(const char text[]) { this->append(text); return *this; }
    231     SkString& operator+=(const char c) { this->append(&c, 1); return *this; }
    232 
    233     /**
    234      *  Swap contents between this and other. This function is guaranteed
    235      *  to never fail or throw.
    236      */
    237     void swap(SkString& other);
    238 
    239 private:
    240     struct Rec {
    241     public:
    242         uint32_t    fLength; // logically size_t, but we want it to stay 32bits
    243         int32_t     fRefCnt;
    244         char        fBeginningOfData;
    245 
    246         char* data() { return &fBeginningOfData; }
    247         const char* data() const { return &fBeginningOfData; }
    248     };
    249     Rec* fRec;
    250 
    251 #ifdef SK_DEBUG
    252     void validate() const;
    253 #else
    254     void validate() const {}
    255 #endif
    256 
    257     static const Rec gEmptyRec;
    258     static Rec* AllocRec(const char text[], size_t len);
    259     static Rec* RefRec(Rec*);
    260 };
    261 
    262 /// Creates a new string and writes into it using a printf()-style format.
    263 SkString SkStringPrintf(const char* format, ...);
    264 
    265 // Specialized to take advantage of SkString's fast swap path. The unspecialized function is
    266 // declared in SkTypes.h and called by SkTSort.
    267 template <> inline void SkTSwap(SkString& a, SkString& b) {
    268     a.swap(b);
    269 }
    270 
    271 enum SkStrSplitMode {
    272     // Strictly return all results. If the input is ",," and the separator is ',' this will return
    273     // an array of three empty strings.
    274     kStrict_SkStrSplitMode,
    275 
    276     // Only nonempty results will be added to the results. Multiple separators will be
    277     // coalesced. Separators at the beginning and end of the input will be ignored.  If the input is
    278     // ",," and the separator is ',', this will return an empty vector.
    279     kCoalesce_SkStrSplitMode
    280 };
    281 
    282 // Split str on any characters in delimiters into out.  (Think, strtok with a sane API.)
    283 void SkStrSplit(const char* str, const char* delimiters, SkStrSplitMode splitMode,
    284                 SkTArray<SkString>* out);
    285 inline void SkStrSplit(const char* str, const char* delimiters, SkTArray<SkString>* out) {
    286     SkStrSplit(str, delimiters, kCoalesce_SkStrSplitMode, out);
    287 }
    288 
    289 #endif
    290