blob: 819e14d8581eb99e3e1fcee9497210f77b5a25cc [file] [log] [blame]
* Copyright 2006 The Android Open Source Project
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
#ifndef SkString_DEFINED
#define SkString_DEFINED
#include "include/core/SkRefCnt.h"
#include "include/core/SkScalar.h"
#include "include/core/SkTypes.h"
#include "include/private/base/SkTo.h"
#include "include/private/base/SkTypeTraits.h"
#include <atomic>
#include <cstdarg>
#include <cstdint>
#include <cstring>
#include <string>
#include <string_view>
#include <type_traits>
/* Some helper functions for C strings */
static inline bool SkStrStartsWith(const char string[], const char prefixStr[]) {
return !strncmp(string, prefixStr, strlen(prefixStr));
static inline bool SkStrStartsWith(const char string[], const char prefixChar) {
return (prefixChar == *string);
bool SkStrEndsWith(const char string[], const char suffixStr[]);
bool SkStrEndsWith(const char string[], const char suffixChar);
int SkStrStartsWithOneOf(const char string[], const char prefixes[]);
static inline int SkStrFind(const char string[], const char substring[]) {
const char *first = strstr(string, substring);
if (nullptr == first) return -1;
return SkToInt(first - &string[0]);
static inline int SkStrFindLastOf(const char string[], const char subchar) {
const char* last = strrchr(string, subchar);
if (nullptr == last) return -1;
return SkToInt(last - &string[0]);
static inline bool SkStrContains(const char string[], const char substring[]) {
return (-1 != SkStrFind(string, substring));
static inline bool SkStrContains(const char string[], const char subchar) {
char tmp[2];
tmp[0] = subchar;
tmp[1] = '\0';
return (-1 != SkStrFind(string, tmp));
* The SkStrAppend... methods will write into the provided buffer, assuming it is large enough.
* Each method has an associated const (e.g. kSkStrAppendU32_MaxSize) which will be the largest
* value needed for that method's buffer.
* char storage[kSkStrAppendU32_MaxSize];
* SkStrAppendU32(storage, value);
* Note : none of the SkStrAppend... methods write a terminating 0 to their buffers. Instead,
* the methods return the ptr to the end of the written part of the buffer. This can be used
* to compute the length, and/or know where to write a 0 if that is desired.
* char storage[kSkStrAppendU32_MaxSize + 1];
* char* stop = SkStrAppendU32(storage, value);
* size_t len = stop - storage;
* *stop = 0; // valid, since storage was 1 byte larger than the max.
static constexpr int kSkStrAppendU32_MaxSize = 10;
char* SkStrAppendU32(char buffer[], uint32_t);
static constexpr int kSkStrAppendU64_MaxSize = 20;
char* SkStrAppendU64(char buffer[], uint64_t, int minDigits);
static constexpr int kSkStrAppendS32_MaxSize = kSkStrAppendU32_MaxSize + 1;
char* SkStrAppendS32(char buffer[], int32_t);
static constexpr int kSkStrAppendS64_MaxSize = kSkStrAppendU64_MaxSize + 1;
char* SkStrAppendS64(char buffer[], int64_t, int minDigits);
* Floats have at most 8 significant digits, so we limit our %g to that.
* However, the total string could be 15 characters: -1.2345678e-005
* In theory we should only expect up to 2 digits for the exponent, but on
* some platforms we have seen 3 (as in the example above).
static constexpr int kSkStrAppendScalar_MaxSize = 15;
* Write the scalar in decimal format into buffer, and return a pointer to
* the next char after the last one written. Note: a terminating 0 is not
* written into buffer, which must be at least kSkStrAppendScalar_MaxSize.
* Thus if the caller wants to add a 0 at the end, buffer must be at least
* kSkStrAppendScalar_MaxSize + 1 bytes large.
char* SkStrAppendScalar(char buffer[], SkScalar);
/** \class SkString
Light weight class for managing strings. Uses reference
counting to make string assignments and copies very fast
with no extra RAM cost. Assumes UTF8 encoding.
class SK_API SkString {
explicit SkString(size_t len);
explicit SkString(const char text[]);
SkString(const char text[], size_t len);
SkString(const SkString&);
explicit SkString(const std::string&);
explicit SkString(std::string_view);
bool isEmpty() const { return 0 == fRec->fLength; }
size_t size() const { return (size_t) fRec->fLength; }
const char* data() const { return fRec->data(); }
const char* c_str() const { return fRec->data(); }
char operator[](size_t n) const { return this->c_str()[n]; }
bool equals(const SkString&) const;
bool equals(const char text[]) const;
bool equals(const char text[], size_t len) const;
bool startsWith(const char prefixStr[]) const {
return SkStrStartsWith(fRec->data(), prefixStr);
bool startsWith(const char prefixChar) const {
return SkStrStartsWith(fRec->data(), prefixChar);
bool endsWith(const char suffixStr[]) const {
return SkStrEndsWith(fRec->data(), suffixStr);
bool endsWith(const char suffixChar) const {
return SkStrEndsWith(fRec->data(), suffixChar);
bool contains(const char substring[]) const {
return SkStrContains(fRec->data(), substring);
bool contains(const char subchar) const {
return SkStrContains(fRec->data(), subchar);
int find(const char substring[]) const {
return SkStrFind(fRec->data(), substring);
int findLastOf(const char subchar) const {
return SkStrFindLastOf(fRec->data(), subchar);
friend bool operator==(const SkString& a, const SkString& b) {
return a.equals(b);
friend bool operator!=(const SkString& a, const SkString& b) {
return !a.equals(b);
// these methods edit the string
SkString& operator=(const SkString&);
SkString& operator=(SkString&&);
SkString& operator=(const char text[]);
char* data();
char& operator[](size_t n) { return this->data()[n]; }
void reset();
/** String contents are preserved on resize. (For destructive resize, `set(nullptr, length)`.)
* `resize` automatically reserves an extra byte at the end of the buffer for a null terminator.
void resize(size_t len);
void set(const SkString& src) { *this = src; }
void set(const char text[]);
void set(const char text[], size_t len);
void set(std::string_view str) { this->set(, str.size()); }
void insert(size_t offset, const char text[]);
void insert(size_t offset, const char text[], size_t len);
void insert(size_t offset, const SkString& str) { this->insert(offset, str.c_str(), str.size()); }
void insert(size_t offset, std::string_view str) { this->insert(offset,, str.size()); }
void insertUnichar(size_t offset, SkUnichar);
void insertS32(size_t offset, int32_t value);
void insertS64(size_t offset, int64_t value, int minDigits = 0);
void insertU32(size_t offset, uint32_t value);
void insertU64(size_t offset, uint64_t value, int minDigits = 0);
void insertHex(size_t offset, uint32_t value, int minDigits = 0);
void insertScalar(size_t offset, SkScalar);
void append(const char text[]) { this->insert((size_t)-1, text); }
void append(const char text[], size_t len) { this->insert((size_t)-1, text, len); }
void append(const SkString& str) { this->insert((size_t)-1, str.c_str(), str.size()); }
void append(std::string_view str) { this->insert((size_t)-1,, str.size()); }
void appendUnichar(SkUnichar uni) { this->insertUnichar((size_t)-1, uni); }
void appendS32(int32_t value) { this->insertS32((size_t)-1, value); }
void appendS64(int64_t value, int minDigits = 0) { this->insertS64((size_t)-1, value, minDigits); }
void appendU32(uint32_t value) { this->insertU32((size_t)-1, value); }
void appendU64(uint64_t value, int minDigits = 0) { this->insertU64((size_t)-1, value, minDigits); }
void appendHex(uint32_t value, int minDigits = 0) { this->insertHex((size_t)-1, value, minDigits); }
void appendScalar(SkScalar value) { this->insertScalar((size_t)-1, value); }
void prepend(const char text[]) { this->insert(0, text); }
void prepend(const char text[], size_t len) { this->insert(0, text, len); }
void prepend(const SkString& str) { this->insert(0, str.c_str(), str.size()); }
void prepend(std::string_view str) { this->insert(0,, str.size()); }
void prependUnichar(SkUnichar uni) { this->insertUnichar(0, uni); }
void prependS32(int32_t value) { this->insertS32(0, value); }
void prependS64(int32_t value, int minDigits = 0) { this->insertS64(0, value, minDigits); }
void prependHex(uint32_t value, int minDigits = 0) { this->insertHex(0, value, minDigits); }
void prependScalar(SkScalar value) { this->insertScalar((size_t)-1, value); }
void printf(const char format[], ...) SK_PRINTF_LIKE(2, 3);
void printVAList(const char format[], va_list) SK_PRINTF_LIKE(2, 0);
void appendf(const char format[], ...) SK_PRINTF_LIKE(2, 3);
void appendVAList(const char format[], va_list) SK_PRINTF_LIKE(2, 0);
void prependf(const char format[], ...) SK_PRINTF_LIKE(2, 3);
void prependVAList(const char format[], va_list) SK_PRINTF_LIKE(2, 0);
void remove(size_t offset, size_t length);
SkString& operator+=(const SkString& s) { this->append(s); return *this; }
SkString& operator+=(const char text[]) { this->append(text); return *this; }
SkString& operator+=(const char c) { this->append(&c, 1); return *this; }
* Swap contents between this and other. This function is guaranteed
* to never fail or throw.
void swap(SkString& other);
using sk_is_trivially_relocatable = std::true_type;
struct Rec {
constexpr Rec(uint32_t len, int32_t refCnt) : fLength(len), fRefCnt(refCnt) {}
static sk_sp<Rec> Make(const char text[], size_t len);
char* data() { return fBeginningOfData; }
const char* data() const { return fBeginningOfData; }
void ref() const;
void unref() const;
bool unique() const;
#ifdef SK_DEBUG
int32_t getRefCnt() const;
uint32_t fLength; // logically size_t, but we want it to stay 32 bits
mutable std::atomic<int32_t> fRefCnt;
char fBeginningOfData[1] = {'\0'};
// Ensure the unsized delete is called.
void operator delete(void* p) { ::operator delete(p); }
sk_sp<Rec> fRec;
#ifdef SK_DEBUG
SkString& validate();
const SkString& validate() const;
SkString& validate() { return *this; }
const SkString& validate() const { return *this; }
static const Rec gEmptyRec;
/// Creates a new string and writes into it using a printf()-style format.
SK_API SkString SkStringPrintf(const char* format, ...) SK_PRINTF_LIKE(1, 2);
/// This makes it easier to write a caller as a VAR_ARGS function where the format string is
/// optional.
static inline SkString SkStringPrintf() { return SkString(); }
static inline void swap(SkString& a, SkString& b) {