blob: 543079ba8b538566c127f635225827063f437ede [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.
*/
#include "include/core/SkString.h"
#include "include/private/SkTPin.h"
#include "include/private/SkTo.h"
#include "src/core/SkSafeMath.h"
#include "src/core/SkUtils.h"
#include "src/utils/SkUTF.h"
#include <cstdio>
#include <new>
#include <string_view>
#include <utility>
#include <vector>
// number of bytes (on the stack) to receive the printf result
static const size_t kBufferSize = 1024;
struct StringBuffer {
char* fText;
int fLength;
};
template <int SIZE>
static StringBuffer apply_format_string(const char* format, va_list args, char (&stackBuffer)[SIZE],
SkString* heapBuffer) SK_PRINTF_LIKE(1, 0);
template <int SIZE>
static StringBuffer apply_format_string(const char* format, va_list args, char (&stackBuffer)[SIZE],
SkString* heapBuffer) {
// First, attempt to print directly to the stack buffer.
va_list argsCopy;
va_copy(argsCopy, args);
int outLength = std::vsnprintf(stackBuffer, SIZE, format, args);
if (outLength < 0) {
SkDebugf("SkString: vsnprintf reported error.");
va_end(argsCopy);
return {stackBuffer, 0};
}
if (outLength < SIZE) {
va_end(argsCopy);
return {stackBuffer, outLength};
}
// Our text was too long to fit on the stack! However, we now know how much space we need to
// format it. Format the string into our heap buffer. `set` automatically reserves an extra
// byte at the end of the buffer for a null terminator, so we don't need to add one here.
heapBuffer->set(nullptr, outLength);
char* heapBufferDest = heapBuffer->writable_str();
SkDEBUGCODE(int checkLength =) std::vsnprintf(heapBufferDest, outLength + 1, format, argsCopy);
SkASSERT(checkLength == outLength);
va_end(argsCopy);
return {heapBufferDest, outLength};
}
///////////////////////////////////////////////////////////////////////////////
bool SkStrEndsWith(const char string[], const char suffixStr[]) {
SkASSERT(string);
SkASSERT(suffixStr);
size_t strLen = strlen(string);
size_t suffixLen = strlen(suffixStr);
return strLen >= suffixLen &&
!strncmp(string + strLen - suffixLen, suffixStr, suffixLen);
}
bool SkStrEndsWith(const char string[], const char suffixChar) {
SkASSERT(string);
size_t strLen = strlen(string);
if (0 == strLen) {
return false;
} else {
return (suffixChar == string[strLen-1]);
}
}
int SkStrStartsWithOneOf(const char string[], const char prefixes[]) {
int index = 0;
do {
const char* limit = strchr(prefixes, '\0');
if (!strncmp(string, prefixes, limit - prefixes)) {
return index;
}
prefixes = limit + 1;
index++;
} while (prefixes[0]);
return -1;
}
char* SkStrAppendU32(char string[], uint32_t dec) {
SkDEBUGCODE(char* start = string;)
char buffer[kSkStrAppendU32_MaxSize];
char* p = buffer + sizeof(buffer);
do {
*--p = SkToU8('0' + dec % 10);
dec /= 10;
} while (dec != 0);
SkASSERT(p >= buffer);
char* stop = buffer + sizeof(buffer);
while (p < stop) {
*string++ = *p++;
}
SkASSERT(string - start <= kSkStrAppendU32_MaxSize);
return string;
}
char* SkStrAppendS32(char string[], int32_t dec) {
uint32_t udec = dec;
if (dec < 0) {
*string++ = '-';
udec = ~udec + 1; // udec = -udec, but silences some warnings that are trying to be helpful
}
return SkStrAppendU32(string, udec);
}
char* SkStrAppendU64(char string[], uint64_t dec, int minDigits) {
SkDEBUGCODE(char* start = string;)
char buffer[kSkStrAppendU64_MaxSize];
char* p = buffer + sizeof(buffer);
do {
*--p = SkToU8('0' + (int32_t) (dec % 10));
dec /= 10;
minDigits--;
} while (dec != 0);
while (minDigits > 0) {
*--p = '0';
minDigits--;
}
SkASSERT(p >= buffer);
size_t cp_len = buffer + sizeof(buffer) - p;
memcpy(string, p, cp_len);
string += cp_len;
SkASSERT(string - start <= kSkStrAppendU64_MaxSize);
return string;
}
char* SkStrAppendS64(char string[], int64_t dec, int minDigits) {
uint64_t udec = dec;
if (dec < 0) {
*string++ = '-';
udec = ~udec + 1; // udec = -udec, but silences some warnings that are trying to be helpful
}
return SkStrAppendU64(string, udec, minDigits);
}
char* SkStrAppendScalar(char string[], SkScalar value) {
// Handle infinity and NaN ourselves to ensure consistent cross-platform results.
// (e.g.: `inf` versus `1.#INF00`, `nan` versus `-nan` for high-bit-set NaNs)
if (SkScalarIsNaN(value)) {
strcpy(string, "nan");
return string + 3;
}
if (!SkScalarIsFinite(value)) {
if (value > 0) {
strcpy(string, "inf");
return string + 3;
} else {
strcpy(string, "-inf");
return string + 4;
}
}
// since floats have at most 8 significant digits, we limit our %g to that.
static const char gFormat[] = "%.8g";
// make it 1 larger for the terminating 0
char buffer[kSkStrAppendScalar_MaxSize + 1];
int len = snprintf(buffer, sizeof(buffer), gFormat, value);
memcpy(string, buffer, len);
SkASSERT(len <= kSkStrAppendScalar_MaxSize);
return string + len;
}
///////////////////////////////////////////////////////////////////////////////
const SkString::Rec SkString::gEmptyRec(0, 0);
#define SizeOfRec() (gEmptyRec.data() - (const char*)&gEmptyRec)
static uint32_t trim_size_t_to_u32(size_t value) {
if (sizeof(size_t) > sizeof(uint32_t)) {
if (value > UINT32_MAX) {
value = UINT32_MAX;
}
}
return (uint32_t)value;
}
static size_t check_add32(size_t base, size_t extra) {
SkASSERT(base <= UINT32_MAX);
if (sizeof(size_t) > sizeof(uint32_t)) {
if (base + extra > UINT32_MAX) {
extra = UINT32_MAX - base;
}
}
return extra;
}
sk_sp<SkString::Rec> SkString::Rec::Make(const char text[], size_t len) {
if (0 == len) {
return sk_sp<SkString::Rec>(const_cast<Rec*>(&gEmptyRec));
}
SkSafeMath safe;
// We store a 32bit version of the length
uint32_t stringLen = safe.castTo<uint32_t>(len);
// Add SizeOfRec() for our overhead and 1 for null-termination
size_t allocationSize = safe.add(len, SizeOfRec() + sizeof(char));
// Align up to a multiple of 4
allocationSize = safe.alignUp(allocationSize, 4);
SkASSERT_RELEASE(safe.ok());
void* storage = ::operator new (allocationSize);
sk_sp<Rec> rec(new (storage) Rec(stringLen, 1));
if (text) {
memcpy(rec->data(), text, len);
}
rec->data()[len] = 0;
return rec;
}
void SkString::Rec::ref() const {
if (this == &SkString::gEmptyRec) {
return;
}
SkAssertResult(this->fRefCnt.fetch_add(+1, std::memory_order_relaxed));
}
void SkString::Rec::unref() const {
if (this == &SkString::gEmptyRec) {
return;
}
int32_t oldRefCnt = this->fRefCnt.fetch_add(-1, std::memory_order_acq_rel);
SkASSERT(oldRefCnt);
if (1 == oldRefCnt) {
delete this;
}
}
bool SkString::Rec::unique() const {
return fRefCnt.load(std::memory_order_acquire) == 1;
}
#ifdef SK_DEBUG
int32_t SkString::Rec::getRefCnt() const {
return fRefCnt.load(std::memory_order_relaxed);
}
const SkString& SkString::validate() const {
// make sure no one has written over our global
SkASSERT(0 == gEmptyRec.fLength);
SkASSERT(0 == gEmptyRec.getRefCnt());
SkASSERT(0 == gEmptyRec.data()[0]);
if (fRec.get() != &gEmptyRec) {
SkASSERT(fRec->fLength > 0);
SkASSERT(fRec->getRefCnt() > 0);
SkASSERT(0 == fRec->data()[fRec->fLength]);
}
return *this;
}
#endif
///////////////////////////////////////////////////////////////////////////////
SkString::SkString() : fRec(const_cast<Rec*>(&gEmptyRec)) {
}
SkString::SkString(size_t len) {
fRec = Rec::Make(nullptr, len);
}
SkString::SkString(const char text[]) {
size_t len = text ? strlen(text) : 0;
fRec = Rec::Make(text, len);
}
SkString::SkString(const char text[], size_t len) {
fRec = Rec::Make(text, len);
}
SkString::SkString(const SkString& src) : fRec(src.validate().fRec) {}
SkString::SkString(SkString&& src) : fRec(std::move(src.validate().fRec)) {
src.fRec.reset(const_cast<Rec*>(&gEmptyRec));
}
SkString::SkString(const std::string& src) {
fRec = Rec::Make(src.c_str(), src.size());
}
SkString::SkString(std::string_view src) {
fRec = Rec::Make(src.data(), src.length());
}
SkString::~SkString() {
this->validate();
}
bool SkString::equals(const SkString& src) const {
return fRec == src.fRec || this->equals(src.c_str(), src.size());
}
bool SkString::equals(const char text[]) const {
return this->equals(text, text ? strlen(text) : 0);
}
bool SkString::equals(const char text[], size_t len) const {
SkASSERT(len == 0 || text != nullptr);
return fRec->fLength == len && !sk_careful_memcmp(fRec->data(), text, len);
}
SkString& SkString::operator=(const SkString& src) {
this->validate();
fRec = src.fRec; // sk_sp<Rec>::operator=(const sk_sp<Ref>&) checks for self-assignment.
return *this;
}
SkString& SkString::operator=(SkString&& src) {
this->validate();
if (fRec != src.fRec) {
this->swap(src);
}
return *this;
}
SkString& SkString::operator=(const char text[]) {
this->validate();
return *this = SkString(text);
}
void SkString::reset() {
this->validate();
fRec.reset(const_cast<Rec*>(&gEmptyRec));
}
char* SkString::writable_str() {
this->validate();
if (fRec->fLength) {
if (!fRec->unique()) {
fRec = Rec::Make(fRec->data(), fRec->fLength);
}
}
return fRec->data();
}
void SkString::resize(size_t len) {
len = trim_size_t_to_u32(len);
if (0 == len) {
this->reset();
} else if (fRec->unique() && ((len >> 2) <= (fRec->fLength >> 2))) {
// Use less of the buffer we have without allocating a smaller one.
char* p = this->writable_str();
p[len] = '\0';
fRec->fLength = SkToU32(len);
} else {
SkString newString(len);
char* dest = newString.writable_str();
int copyLen = std::min<uint32_t>(len, this->size());
memcpy(dest, this->c_str(), copyLen);
dest[copyLen] = '\0';
this->swap(newString);
}
}
void SkString::set(const char text[]) {
this->set(text, text ? strlen(text) : 0);
}
void SkString::set(const char text[], size_t len) {
len = trim_size_t_to_u32(len);
if (0 == len) {
this->reset();
} else if (fRec->unique() && ((len >> 2) <= (fRec->fLength >> 2))) {
// Use less of the buffer we have without allocating a smaller one.
char* p = this->writable_str();
if (text) {
memcpy(p, text, len);
}
p[len] = '\0';
fRec->fLength = SkToU32(len);
} else {
SkString tmp(text, len);
this->swap(tmp);
}
}
void SkString::insert(size_t offset, const char text[]) {
this->insert(offset, text, text ? strlen(text) : 0);
}
void SkString::insert(size_t offset, const char text[], size_t len) {
if (len) {
size_t length = fRec->fLength;
if (offset > length) {
offset = length;
}
// Check if length + len exceeds 32bits, we trim len
len = check_add32(length, len);
if (0 == len) {
return;
}
/* If we're the only owner, and we have room in our allocation for the insert,
do it in place, rather than allocating a new buffer.
To know we have room, compare the allocated sizes
beforeAlloc = SkAlign4(length + 1)
afterAlloc = SkAligh4(length + 1 + len)
but SkAlign4(x) is (x + 3) >> 2 << 2
which is equivalent for testing to (length + 1 + 3) >> 2 == (length + 1 + 3 + len) >> 2
and we can then eliminate the +1+3 since that doesn't affec the answer
*/
if (fRec->unique() && (length >> 2) == ((length + len) >> 2)) {
char* dst = this->writable_str();
if (offset < length) {
memmove(dst + offset + len, dst + offset, length - offset);
}
memcpy(dst + offset, text, len);
dst[length + len] = 0;
fRec->fLength = SkToU32(length + len);
} else {
/* Seems we should use realloc here, since that is safe if it fails
(we have the original data), and might be faster than alloc/copy/free.
*/
SkString tmp(fRec->fLength + len);
char* dst = tmp.writable_str();
if (offset > 0) {
memcpy(dst, fRec->data(), offset);
}
memcpy(dst + offset, text, len);
if (offset < fRec->fLength) {
memcpy(dst + offset + len, fRec->data() + offset,
fRec->fLength - offset);
}
this->swap(tmp);
}
}
}
void SkString::insertUnichar(size_t offset, SkUnichar uni) {
char buffer[SkUTF::kMaxBytesInUTF8Sequence];
size_t len = SkUTF::ToUTF8(uni, buffer);
if (len) {
this->insert(offset, buffer, len);
}
}
void SkString::insertS32(size_t offset, int32_t dec) {
char buffer[kSkStrAppendS32_MaxSize];
char* stop = SkStrAppendS32(buffer, dec);
this->insert(offset, buffer, stop - buffer);
}
void SkString::insertS64(size_t offset, int64_t dec, int minDigits) {
char buffer[kSkStrAppendS64_MaxSize];
char* stop = SkStrAppendS64(buffer, dec, minDigits);
this->insert(offset, buffer, stop - buffer);
}
void SkString::insertU32(size_t offset, uint32_t dec) {
char buffer[kSkStrAppendU32_MaxSize];
char* stop = SkStrAppendU32(buffer, dec);
this->insert(offset, buffer, stop - buffer);
}
void SkString::insertU64(size_t offset, uint64_t dec, int minDigits) {
char buffer[kSkStrAppendU64_MaxSize];
char* stop = SkStrAppendU64(buffer, dec, minDigits);
this->insert(offset, buffer, stop - buffer);
}
void SkString::insertHex(size_t offset, uint32_t hex, int minDigits) {
minDigits = SkTPin(minDigits, 0, 8);
char buffer[8];
char* p = buffer + sizeof(buffer);
do {
*--p = SkHexadecimalDigits::gUpper[hex & 0xF];
hex >>= 4;
minDigits -= 1;
} while (hex != 0);
while (--minDigits >= 0) {
*--p = '0';
}
SkASSERT(p >= buffer);
this->insert(offset, p, buffer + sizeof(buffer) - p);
}
void SkString::insertScalar(size_t offset, SkScalar value) {
char buffer[kSkStrAppendScalar_MaxSize];
char* stop = SkStrAppendScalar(buffer, value);
this->insert(offset, buffer, stop - buffer);
}
///////////////////////////////////////////////////////////////////////////////
void SkString::printf(const char format[], ...) {
va_list args;
va_start(args, format);
this->printVAList(format, args);
va_end(args);
}
void SkString::printVAList(const char format[], va_list args) {
char stackBuffer[kBufferSize];
StringBuffer result = apply_format_string(format, args, stackBuffer, this);
if (result.fText == stackBuffer) {
this->set(result.fText, result.fLength);
}
}
void SkString::appendf(const char format[], ...) {
va_list args;
va_start(args, format);
this->appendVAList(format, args);
va_end(args);
}
void SkString::appendVAList(const char format[], va_list args) {
if (this->isEmpty()) {
this->printVAList(format, args);
return;
}
SkString overflow;
char stackBuffer[kBufferSize];
StringBuffer result = apply_format_string(format, args, stackBuffer, &overflow);
this->append(result.fText, result.fLength);
}
void SkString::prependf(const char format[], ...) {
va_list args;
va_start(args, format);
this->prependVAList(format, args);
va_end(args);
}
void SkString::prependVAList(const char format[], va_list args) {
if (this->isEmpty()) {
this->printVAList(format, args);
return;
}
SkString overflow;
char stackBuffer[kBufferSize];
StringBuffer result = apply_format_string(format, args, stackBuffer, &overflow);
this->prepend(result.fText, result.fLength);
}
///////////////////////////////////////////////////////////////////////////////
void SkString::remove(size_t offset, size_t length) {
size_t size = this->size();
if (offset < size) {
if (length > size - offset) {
length = size - offset;
}
SkASSERT(length <= size);
SkASSERT(offset <= size - length);
if (length > 0) {
SkString tmp(size - length);
char* dst = tmp.writable_str();
const char* src = this->c_str();
if (offset) {
memcpy(dst, src, offset);
}
size_t tail = size - (offset + length);
if (tail) {
memcpy(dst + offset, src + (offset + length), tail);
}
SkASSERT(dst[tmp.size()] == 0);
this->swap(tmp);
}
}
}
void SkString::swap(SkString& other) {
this->validate();
other.validate();
using std::swap;
swap(fRec, other.fRec);
}
///////////////////////////////////////////////////////////////////////////////
SkString SkStringPrintf(const char* format, ...) {
SkString formattedOutput;
va_list args;
va_start(args, format);
formattedOutput.printVAList(format, args);
va_end(args);
return formattedOutput;
}
void SkStrSplit(const char* str, const char* delimiters, SkStrSplitMode splitMode,
SkTArray<SkString>* out) {
if (splitMode == kCoalesce_SkStrSplitMode) {
// Skip any delimiters.
str += strspn(str, delimiters);
}
if (!*str) {
return;
}
while (true) {
// Find a token.
const size_t len = strcspn(str, delimiters);
if (splitMode == kStrict_SkStrSplitMode || len > 0) {
out->push_back().set(str, len);
str += len;
}
if (!*str) {
return;
}
if (splitMode == kCoalesce_SkStrSplitMode) {
// Skip any delimiters.
str += strspn(str, delimiters);
} else {
// Skip one delimiter.
str += 1;
}
}
}