// Copyright 2014 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/runtime/runtime-utils.h"
#include "src/arguments.h"
#include "src/regexp/jsregexp-inl.h"
#include "src/string-builder.h"
#include "src/string-search.h"
namespace v8 {
namespace internal {
// This may return an empty MaybeHandle if an exception is thrown or
// we abort due to reaching the recursion limit.
MaybeHandle<String> StringReplaceOneCharWithString(
Isolate* isolate, Handle<String> subject, Handle<String> search,
Handle<String> replace, bool* found, int recursion_limit) {
StackLimitCheck stackLimitCheck(isolate);
if (stackLimitCheck.HasOverflowed() || (recursion_limit == 0)) {
return MaybeHandle<String>();
}
recursion_limit--;
if (subject->IsConsString()) {
ConsString* cons = ConsString::cast(*subject);
Handle<String> first = Handle<String>(cons->first());
Handle<String> second = Handle<String>(cons->second());
Handle<String> new_first;
if (!StringReplaceOneCharWithString(isolate, first, search, replace, found,
recursion_limit).ToHandle(&new_first)) {
return MaybeHandle<String>();
}
if (*found) return isolate->factory()->NewConsString(new_first, second);
Handle<String> new_second;
if (!StringReplaceOneCharWithString(isolate, second, search, replace, found,
recursion_limit)
.ToHandle(&new_second)) {
return MaybeHandle<String>();
}
if (*found) return isolate->factory()->NewConsString(first, new_second);
return subject;
} else {
int index = String::IndexOf(isolate, subject, search, 0);
if (index == -1) return subject;
*found = true;
Handle<String> first = isolate->factory()->NewSubString(subject, 0, index);
Handle<String> cons1;
ASSIGN_RETURN_ON_EXCEPTION(
isolate, cons1, isolate->factory()->NewConsString(first, replace),
String);
Handle<String> second =
isolate->factory()->NewSubString(subject, index + 1, subject->length());
return isolate->factory()->NewConsString(cons1, second);
}
}
RUNTIME_FUNCTION(Runtime_StringReplaceOneCharWithString) {
HandleScope scope(isolate);
DCHECK(args.length() == 3);
CONVERT_ARG_HANDLE_CHECKED(String, subject, 0);
CONVERT_ARG_HANDLE_CHECKED(String, search, 1);
CONVERT_ARG_HANDLE_CHECKED(String, replace, 2);
// If the cons string tree is too deep, we simply abort the recursion and
// retry with a flattened subject string.
const int kRecursionLimit = 0x1000;
bool found = false;
Handle<String> result;
if (StringReplaceOneCharWithString(isolate, subject, search, replace, &found,
kRecursionLimit).ToHandle(&result)) {
return *result;
}
if (isolate->has_pending_exception()) return isolate->heap()->exception();
subject = String::Flatten(subject);
if (StringReplaceOneCharWithString(isolate, subject, search, replace, &found,
kRecursionLimit).ToHandle(&result)) {
return *result;
}
if (isolate->has_pending_exception()) return isolate->heap()->exception();
// In case of empty handle and no pending exception we have stack overflow.
return isolate->StackOverflow();
}
RUNTIME_FUNCTION(Runtime_StringIndexOf) {
HandleScope scope(isolate);
DCHECK(args.length() == 3);
return String::IndexOf(isolate, args.at<Object>(0), args.at<Object>(1),
args.at<Object>(2));
}
RUNTIME_FUNCTION(Runtime_StringLastIndexOf) {
HandleScope handle_scope(isolate);
return String::LastIndexOf(isolate, args.at<Object>(0), args.at<Object>(1),
isolate->factory()->undefined_value());
}
RUNTIME_FUNCTION(Runtime_SubString) {
HandleScope scope(isolate);
DCHECK(args.length() == 3);
CONVERT_ARG_HANDLE_CHECKED(String, string, 0);
int start, end;
// We have a fast integer-only case here to avoid a conversion to double in
// the common case where from and to are Smis.
if (args[1]->IsSmi() && args[2]->IsSmi()) {
CONVERT_SMI_ARG_CHECKED(from_number, 1);
CONVERT_SMI_ARG_CHECKED(to_number, 2);
start = from_number;
end = to_number;
} else if (args[1]->IsNumber() && args[2]->IsNumber()) {
CONVERT_DOUBLE_ARG_CHECKED(from_number, 1);
CONVERT_DOUBLE_ARG_CHECKED(to_number, 2);
start = FastD2IChecked(from_number);
end = FastD2IChecked(to_number);
} else {
return isolate->ThrowIllegalOperation();
}
// The following condition is intentionally robust because the SubStringStub
// delegates here and we test this in cctest/test-strings/RobustSubStringStub.
if (end < start || start < 0 || end > string->length()) {
return isolate->ThrowIllegalOperation();
}
isolate->counters()->sub_string_runtime()->Increment();
return *isolate->factory()->NewSubString(string, start, end);
}
RUNTIME_FUNCTION(Runtime_StringAdd) {
HandleScope scope(isolate);
DCHECK(args.length() == 2);
CONVERT_ARG_HANDLE_CHECKED(Object, obj1, 0);
CONVERT_ARG_HANDLE_CHECKED(Object, obj2, 1);
isolate->counters()->string_add_runtime()->Increment();
MaybeHandle<String> maybe_str1(Object::ToString(isolate, obj1));
MaybeHandle<String> maybe_str2(Object::ToString(isolate, obj2));
Handle<String> str1;
Handle<String> str2;
maybe_str1.ToHandle(&str1);
maybe_str2.ToHandle(&str2);
RETURN_RESULT_OR_FAILURE(isolate,
isolate->factory()->NewConsString(str1, str2));
}
RUNTIME_FUNCTION(Runtime_InternalizeString) {
HandleScope handles(isolate);
DCHECK(args.length() == 1);
CONVERT_ARG_HANDLE_CHECKED(String, string, 0);
return *isolate->factory()->InternalizeString(string);
}
RUNTIME_FUNCTION(Runtime_StringCharCodeAtRT) {
HandleScope handle_scope(isolate);
DCHECK(args.length() == 2);
CONVERT_ARG_HANDLE_CHECKED(String, subject, 0);
CONVERT_NUMBER_CHECKED(uint32_t, i, Uint32, args[1]);
// Flatten the string. If someone wants to get a char at an index
// in a cons string, it is likely that more indices will be
// accessed.
subject = String::Flatten(subject);
if (i >= static_cast<uint32_t>(subject->length())) {
return isolate->heap()->nan_value();
}
return Smi::FromInt(subject->Get(i));
}
RUNTIME_FUNCTION(Runtime_StringCompare) {
HandleScope handle_scope(isolate);
DCHECK_EQ(2, args.length());
CONVERT_ARG_HANDLE_CHECKED(String, x, 0);
CONVERT_ARG_HANDLE_CHECKED(String, y, 1);
isolate->counters()->string_compare_runtime()->Increment();
switch (String::Compare(x, y)) {
case ComparisonResult::kLessThan:
return Smi::FromInt(LESS);
case ComparisonResult::kEqual:
return Smi::FromInt(EQUAL);
case ComparisonResult::kGreaterThan:
return Smi::FromInt(GREATER);
case ComparisonResult::kUndefined:
break;
}
UNREACHABLE();
return Smi::kZero;
}
RUNTIME_FUNCTION(Runtime_StringBuilderConcat) {
HandleScope scope(isolate);
DCHECK(args.length() == 3);
CONVERT_ARG_HANDLE_CHECKED(JSArray, array, 0);
int32_t array_length;
if (!args[1]->ToInt32(&array_length)) {
THROW_NEW_ERROR_RETURN_FAILURE(isolate, NewInvalidStringLengthError());
}
CONVERT_ARG_HANDLE_CHECKED(String, special, 2);
size_t actual_array_length = 0;
CHECK(TryNumberToSize(array->length(), &actual_array_length));
CHECK(array_length >= 0);
CHECK(static_cast<size_t>(array_length) <= actual_array_length);
// This assumption is used by the slice encoding in one or two smis.
DCHECK(Smi::kMaxValue >= String::kMaxLength);
CHECK(array->HasFastElements());
JSObject::EnsureCanContainHeapObjectElements(array);
int special_length = special->length();
if (!array->HasFastObjectElements()) {
return isolate->Throw(isolate->heap()->illegal_argument_string());
}
int length;
bool one_byte = special->HasOnlyOneByteChars();
{
DisallowHeapAllocation no_gc;
FixedArray* fixed_array = FixedArray::cast(array->elements());
if (fixed_array->length() < array_length) {
array_length = fixed_array->length();
}
if (array_length == 0) {
return isolate->heap()->empty_string();
} else if (array_length == 1) {
Object* first = fixed_array->get(0);
if (first->IsString()) return first;
}
length = StringBuilderConcatLength(special_length, fixed_array,
array_length, &one_byte);
}
if (length == -1) {
return isolate->Throw(isolate->heap()->illegal_argument_string());
}
if (one_byte) {
Handle<SeqOneByteString> answer;
ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
isolate, answer, isolate->factory()->NewRawOneByteString(length));
StringBuilderConcatHelper(*special, answer->GetChars(),
FixedArray::cast(array->elements()),
array_length);
return *answer;
} else {
Handle<SeqTwoByteString> answer;
ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
isolate, answer, isolate->factory()->NewRawTwoByteString(length));
StringBuilderConcatHelper(*special, answer->GetChars(),
FixedArray::cast(array->elements()),
array_length);
return *answer;
}
}
RUNTIME_FUNCTION(Runtime_StringBuilderJoin) {
HandleScope scope(isolate);
DCHECK(args.length() == 3);
CONVERT_ARG_HANDLE_CHECKED(JSArray, array, 0);
int32_t array_length;
if (!args[1]->ToInt32(&array_length)) {
THROW_NEW_ERROR_RETURN_FAILURE(isolate, NewInvalidStringLengthError());
}
CONVERT_ARG_HANDLE_CHECKED(String, separator, 2);
CHECK(array->HasFastObjectElements());
CHECK(array_length >= 0);
Handle<FixedArray> fixed_array(FixedArray::cast(array->elements()));
if (fixed_array->length() < array_length) {
array_length = fixed_array->length();
}
if (array_length == 0) {
return isolate->heap()->empty_string();
} else if (array_length == 1) {
Object* first = fixed_array->get(0);
CHECK(first->IsString());
return first;
}
int separator_length = separator->length();
CHECK(separator_length > 0);
int max_nof_separators =
(String::kMaxLength + separator_length - 1) / separator_length;
if (max_nof_separators < (array_length - 1)) {
THROW_NEW_ERROR_RETURN_FAILURE(isolate, NewInvalidStringLengthError());
}
int length = (array_length - 1) * separator_length;
for (int i = 0; i < array_length; i++) {
Object* element_obj = fixed_array->get(i);
CHECK(element_obj->IsString());
String* element = String::cast(element_obj);
int increment = element->length();
if (increment > String::kMaxLength - length) {
STATIC_ASSERT(String::kMaxLength < kMaxInt);
length = kMaxInt; // Provoke exception;
break;
}
length += increment;
}
Handle<SeqTwoByteString> answer;
ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
isolate, answer, isolate->factory()->NewRawTwoByteString(length));
DisallowHeapAllocation no_gc;
uc16* sink = answer->GetChars();
#ifdef DEBUG
uc16* end = sink + length;
#endif
CHECK(fixed_array->get(0)->IsString());
String* first = String::cast(fixed_array->get(0));
String* separator_raw = *separator;
int first_length = first->length();
String::WriteToFlat(first, sink, 0, first_length);
sink += first_length;
for (int i = 1; i < array_length; i++) {
DCHECK(sink + separator_length <= end);
String::WriteToFlat(separator_raw, sink, 0, separator_length);
sink += separator_length;
CHECK(fixed_array->get(i)->IsString());
String* element = String::cast(fixed_array->get(i));
int element_length = element->length();
DCHECK(sink + element_length <= end);
String::WriteToFlat(element, sink, 0, element_length);
sink += element_length;
}
DCHECK(sink == end);
// Use %_FastOneByteArrayJoin instead.
DCHECK(!answer->IsOneByteRepresentation());
return *answer;
}
template <typename sinkchar>
static void WriteRepeatToFlat(String* src, Vector<sinkchar> buffer, int cursor,
int repeat, int length) {
if (repeat == 0) return;
sinkchar* start = &buffer[cursor];
String::WriteToFlat<sinkchar>(src, start, 0, length);
int done = 1;
sinkchar* next = start + length;
while (done < repeat) {
int block = Min(done, repeat - done);
int block_chars = block * length;
CopyChars(next, start, block_chars);
next += block_chars;
done += block;
}
}
template <typename Char>
static void JoinSparseArrayWithSeparator(FixedArray* elements,
int elements_length,
uint32_t array_length,
String* separator,
Vector<Char> buffer) {
DisallowHeapAllocation no_gc;
int previous_separator_position = 0;
int separator_length = separator->length();
DCHECK_LT(0, separator_length);
int cursor = 0;
for (int i = 0; i < elements_length; i += 2) {
int position = NumberToInt32(elements->get(i));
String* string = String::cast(elements->get(i + 1));
int string_length = string->length();
if (string->length() > 0) {
int repeat = position - previous_separator_position;
WriteRepeatToFlat<Char>(separator, buffer, cursor, repeat,
separator_length);
cursor += repeat * separator_length;
previous_separator_position = position;
String::WriteToFlat<Char>(string, &buffer[cursor], 0, string_length);
cursor += string->length();
}
}
int last_array_index = static_cast<int>(array_length - 1);
// Array length must be representable as a signed 32-bit number,
// otherwise the total string length would have been too large.
DCHECK(array_length <= 0x7fffffff); // Is int32_t.
int repeat = last_array_index - previous_separator_position;
WriteRepeatToFlat<Char>(separator, buffer, cursor, repeat, separator_length);
cursor += repeat * separator_length;
DCHECK(cursor <= buffer.length());
}
RUNTIME_FUNCTION(Runtime_SparseJoinWithSeparator) {
HandleScope scope(isolate);
DCHECK(args.length() == 3);
CONVERT_ARG_HANDLE_CHECKED(JSArray, elements_array, 0);
CONVERT_NUMBER_CHECKED(uint32_t, array_length, Uint32, args[1]);
CONVERT_ARG_HANDLE_CHECKED(String, separator, 2);
// elements_array is fast-mode JSarray of alternating positions
// (increasing order) and strings.
CHECK(elements_array->HasFastSmiOrObjectElements());
// array_length is length of original array (used to add separators);
// separator is string to put between elements. Assumed to be non-empty.
CHECK(array_length > 0);
// Find total length of join result.
int string_length = 0;
bool is_one_byte = separator->IsOneByteRepresentation();
bool overflow = false;
CONVERT_NUMBER_CHECKED(int, elements_length, Int32, elements_array->length());
CHECK(elements_length <= elements_array->elements()->length());
CHECK((elements_length & 1) == 0); // Even length.
FixedArray* elements = FixedArray::cast(elements_array->elements());
{
DisallowHeapAllocation no_gc;
for (int i = 0; i < elements_length; i += 2) {
String* string = String::cast(elements->get(i + 1));
int length = string->length();
if (is_one_byte && !string->IsOneByteRepresentation()) {
is_one_byte = false;
}
if (length > String::kMaxLength ||
String::kMaxLength - length < string_length) {
overflow = true;
break;
}
string_length += length;
}
}
int separator_length = separator->length();
if (!overflow && separator_length > 0) {
if (array_length <= 0x7fffffffu) {
int separator_count = static_cast<int>(array_length) - 1;
int remaining_length = String::kMaxLength - string_length;
if ((remaining_length / separator_length) >= separator_count) {
string_length += separator_length * (array_length - 1);
} else {
// Not room for the separators within the maximal string length.
overflow = true;
}
} else {
// Nonempty separator and at least 2^31-1 separators necessary
// means that the string is too large to create.
STATIC_ASSERT(String::kMaxLength < 0x7fffffff);
overflow = true;
}
}
if (overflow) {
// Throw an exception if the resulting string is too large. See
// https://code.google.com/p/chromium/issues/detail?id=336820
// for details.
THROW_NEW_ERROR_RETURN_FAILURE(isolate, NewInvalidStringLengthError());
}
if (is_one_byte) {
Handle<SeqOneByteString> result = isolate->factory()
->NewRawOneByteString(string_length)
.ToHandleChecked();
JoinSparseArrayWithSeparator<uint8_t>(
FixedArray::cast(elements_array->elements()), elements_length,
array_length, *separator,
Vector<uint8_t>(result->GetChars(), string_length));
return *result;
} else {
Handle<SeqTwoByteString> result = isolate->factory()
->NewRawTwoByteString(string_length)
.ToHandleChecked();
JoinSparseArrayWithSeparator<uc16>(
FixedArray::cast(elements_array->elements()), elements_length,
array_length, *separator,
Vector<uc16>(result->GetChars(), string_length));
return *result;
}
}
// Copies Latin1 characters to the given fixed array looking up
// one-char strings in the cache. Gives up on the first char that is
// not in the cache and fills the remainder with smi zeros. Returns
// the length of the successfully copied prefix.
static int CopyCachedOneByteCharsToArray(Heap* heap, const uint8_t* chars,
FixedArray* elements, int length) {
DisallowHeapAllocation no_gc;
FixedArray* one_byte_cache = heap->single_character_string_cache();
Object* undefined = heap->undefined_value();
int i;
WriteBarrierMode mode = elements->GetWriteBarrierMode(no_gc);
for (i = 0; i < length; ++i) {
Object* value = one_byte_cache->get(chars[i]);
if (value == undefined) break;
elements->set(i, value, mode);
}
if (i < length) {
DCHECK(Smi::kZero == 0);
memset(elements->data_start() + i, 0, kPointerSize * (length - i));
}
#ifdef DEBUG
for (int j = 0; j < length; ++j) {
Object* element = elements->get(j);
DCHECK(element == Smi::kZero ||
(element->IsString() && String::cast(element)->LooksValid()));
}
#endif
return i;
}
// Converts a String to JSArray.
// For example, "foo" => ["f", "o", "o"].
RUNTIME_FUNCTION(Runtime_StringToArray) {
HandleScope scope(isolate);
DCHECK(args.length() == 2);
CONVERT_ARG_HANDLE_CHECKED(String, s, 0);
CONVERT_NUMBER_CHECKED(uint32_t, limit, Uint32, args[1]);
s = String::Flatten(s);
const int length = static_cast<int>(Min<uint32_t>(s->length(), limit));
Handle<FixedArray> elements;
int position = 0;
if (s->IsFlat() && s->IsOneByteRepresentation()) {
// Try using cached chars where possible.
elements = isolate->factory()->NewUninitializedFixedArray(length);
DisallowHeapAllocation no_gc;
String::FlatContent content = s->GetFlatContent();
if (content.IsOneByte()) {
Vector<const uint8_t> chars = content.ToOneByteVector();
// Note, this will initialize all elements (not only the prefix)
// to prevent GC from seeing partially initialized array.
position = CopyCachedOneByteCharsToArray(isolate->heap(), chars.start(),
*elements, length);
} else {
MemsetPointer(elements->data_start(), isolate->heap()->undefined_value(),
length);
}
} else {
elements = isolate->factory()->NewFixedArray(length);
}
for (int i = position; i < length; ++i) {
Handle<Object> str =
isolate->factory()->LookupSingleCharacterStringFromCode(s->Get(i));
elements->set(i, *str);
}
#ifdef DEBUG
for (int i = 0; i < length; ++i) {
DCHECK(String::cast(elements->get(i))->length() == 1);
}
#endif
return *isolate->factory()->NewJSArrayWithElements(elements);
}
static inline bool ToUpperOverflows(uc32 character) {
// y with umlauts and the micro sign are the only characters that stop
// fitting into one-byte when converting to uppercase.
static const uc32 yuml_code = 0xff;
static const uc32 micro_code = 0xb5;
return (character == yuml_code || character == micro_code);
}
template <class Converter>
MUST_USE_RESULT static Object* ConvertCaseHelper(
Isolate* isolate, String* string, SeqString* result, int result_length,
unibrow::Mapping<Converter, 128>* mapping) {
DisallowHeapAllocation no_gc;
// We try this twice, once with the assumption that the result is no longer
// than the input and, if that assumption breaks, again with the exact
// length. This may not be pretty, but it is nicer than what was here before
// and I hereby claim my vaffel-is.
//
// NOTE: This assumes that the upper/lower case of an ASCII
// character is also ASCII. This is currently the case, but it
// might break in the future if we implement more context and locale
// dependent upper/lower conversions.
bool has_changed_character = false;
// Convert all characters to upper case, assuming that they will fit
// in the buffer
StringCharacterStream stream(string);
unibrow::uchar chars[Converter::kMaxWidth];
// We can assume that the string is not empty
uc32 current = stream.GetNext();
bool ignore_overflow = Converter::kIsToLower || result->IsSeqTwoByteString();
for (int i = 0; i < result_length;) {
bool has_next = stream.HasMore();
uc32 next = has_next ? stream.GetNext() : 0;
int char_length = mapping->get(current, next, chars);
if (char_length == 0) {
// The case conversion of this character is the character itself.
result->Set(i, current);
i++;
} else if (char_length == 1 &&
(ignore_overflow || !ToUpperOverflows(current))) {
// Common case: converting the letter resulted in one character.
DCHECK(static_cast<uc32>(chars[0]) != current);
result->Set(i, chars[0]);
has_changed_character = true;
i++;
} else if (result_length == string->length()) {
bool overflows = ToUpperOverflows(current);
// We've assumed that the result would be as long as the
// input but here is a character that converts to several
// characters. No matter, we calculate the exact length
// of the result and try the whole thing again.
//
// Note that this leaves room for optimization. We could just
// memcpy what we already have to the result string. Also,
// the result string is the last object allocated we could
// "realloc" it and probably, in the vast majority of cases,
// extend the existing string to be able to hold the full
// result.
int next_length = 0;
if (has_next) {
next_length = mapping->get(next, 0, chars);
if (next_length == 0) next_length = 1;
}
int current_length = i + char_length + next_length;
while (stream.HasMore()) {
current = stream.GetNext();
overflows |= ToUpperOverflows(current);
// NOTE: we use 0 as the next character here because, while
// the next character may affect what a character converts to,
// it does not in any case affect the length of what it convert
// to.
int char_length = mapping->get(current, 0, chars);
if (char_length == 0) char_length = 1;
current_length += char_length;
if (current_length > String::kMaxLength) {
AllowHeapAllocation allocate_error_and_return;
THROW_NEW_ERROR_RETURN_FAILURE(isolate,
NewInvalidStringLengthError());
}
}
// Try again with the real length. Return signed if we need
// to allocate a two-byte string for to uppercase.
return (overflows && !ignore_overflow) ? Smi::FromInt(-current_length)
: Smi::FromInt(current_length);
} else {
for (int j = 0; j < char_length; j++) {
result->Set(i, chars[j]);
i++;
}
has_changed_character = true;
}
current = next;
}
if (has_changed_character) {
return result;
} else {
// If we didn't actually change anything in doing the conversion
// we simple return the result and let the converted string
// become garbage; there is no reason to keep two identical strings
// alive.
return string;
}
}
static const uintptr_t kOneInEveryByte = kUintptrAllBitsSet / 0xFF;
static const uintptr_t kAsciiMask = kOneInEveryByte << 7;
// Given a word and two range boundaries returns a word with high bit
// set in every byte iff the corresponding input byte was strictly in
// the range (m, n). All the other bits in the result are cleared.
// This function is only useful when it can be inlined and the
// boundaries are statically known.
// Requires: all bytes in the input word and the boundaries must be
// ASCII (less than 0x7F).
static inline uintptr_t AsciiRangeMask(uintptr_t w, char m, char n) {
// Use strict inequalities since in edge cases the function could be
// further simplified.
DCHECK(0 < m && m < n);
// Has high bit set in every w byte less than n.
uintptr_t tmp1 = kOneInEveryByte * (0x7F + n) - w;
// Has high bit set in every w byte greater than m.
uintptr_t tmp2 = w + kOneInEveryByte * (0x7F - m);
return (tmp1 & tmp2 & (kOneInEveryByte * 0x80));
}
#ifdef DEBUG
static bool CheckFastAsciiConvert(char* dst, const char* src, int length,
bool changed, bool is_to_lower) {
bool expected_changed = false;
for (int i = 0; i < length; i++) {
if (dst[i] == src[i]) continue;
expected_changed = true;
if (is_to_lower) {
DCHECK('A' <= src[i] && src[i] <= 'Z');
DCHECK(dst[i] == src[i] + ('a' - 'A'));
} else {
DCHECK('a' <= src[i] && src[i] <= 'z');
DCHECK(dst[i] == src[i] - ('a' - 'A'));
}
}
return (expected_changed == changed);
}
#endif
template <class Converter>
static bool FastAsciiConvert(char* dst, const char* src, int length,
bool* changed_out) {
#ifdef DEBUG
char* saved_dst = dst;
const char* saved_src = src;
#endif
DisallowHeapAllocation no_gc;
// We rely on the distance between upper and lower case letters
// being a known power of 2.
DCHECK('a' - 'A' == (1 << 5));
// Boundaries for the range of input characters than require conversion.
static const char lo = Converter::kIsToLower ? 'A' - 1 : 'a' - 1;
static const char hi = Converter::kIsToLower ? 'Z' + 1 : 'z' + 1;
bool changed = false;
uintptr_t or_acc = 0;
const char* const limit = src + length;
// dst is newly allocated and always aligned.
DCHECK(IsAligned(reinterpret_cast<intptr_t>(dst), sizeof(uintptr_t)));
// Only attempt processing one word at a time if src is also aligned.
if (IsAligned(reinterpret_cast<intptr_t>(src), sizeof(uintptr_t))) {
// Process the prefix of the input that requires no conversion one aligned
// (machine) word at a time.
while (src <= limit - sizeof(uintptr_t)) {
const uintptr_t w = *reinterpret_cast<const uintptr_t*>(src);
or_acc |= w;
if (AsciiRangeMask(w, lo, hi) != 0) {
changed = true;
break;
}
*reinterpret_cast<uintptr_t*>(dst) = w;
src += sizeof(uintptr_t);
dst += sizeof(uintptr_t);
}
// Process the remainder of the input performing conversion when
// required one word at a time.
while (src <= limit - sizeof(uintptr_t)) {
const uintptr_t w = *reinterpret_cast<const uintptr_t*>(src);
or_acc |= w;
uintptr_t m = AsciiRangeMask(w, lo, hi);
// The mask has high (7th) bit set in every byte that needs
// conversion and we know that the distance between cases is
// 1 << 5.
*reinterpret_cast<uintptr_t*>(dst) = w ^ (m >> 2);
src += sizeof(uintptr_t);
dst += sizeof(uintptr_t);
}
}
// Process the last few bytes of the input (or the whole input if
// unaligned access is not supported).
while (src < limit) {
char c = *src;
or_acc |= c;
if (lo < c && c < hi) {
c ^= (1 << 5);
changed = true;
}
*dst = c;
++src;
++dst;
}
if ((or_acc & kAsciiMask) != 0) return false;
DCHECK(CheckFastAsciiConvert(saved_dst, saved_src, length, changed,
Converter::kIsToLower));
*changed_out = changed;
return true;
}
template <class Converter>
MUST_USE_RESULT static Object* ConvertCase(
Handle<String> s, Isolate* isolate,
unibrow::Mapping<Converter, 128>* mapping) {
s = String::Flatten(s);
int length = s->length();
// Assume that the string is not empty; we need this assumption later
if (length == 0) return *s;
// Simpler handling of ASCII strings.
//
// NOTE: This assumes that the upper/lower case of an ASCII
// character is also ASCII. This is currently the case, but it
// might break in the future if we implement more context and locale
// dependent upper/lower conversions.
if (s->IsOneByteRepresentationUnderneath()) {
// Same length as input.
Handle<SeqOneByteString> result =
isolate->factory()->NewRawOneByteString(length).ToHandleChecked();
DisallowHeapAllocation no_gc;
String::FlatContent flat_content = s->GetFlatContent();
DCHECK(flat_content.IsFlat());
bool has_changed_character = false;
bool is_ascii = FastAsciiConvert<Converter>(
reinterpret_cast<char*>(result->GetChars()),
reinterpret_cast<const char*>(flat_content.ToOneByteVector().start()),
length, &has_changed_character);
// If not ASCII, we discard the result and take the 2 byte path.
if (is_ascii) return has_changed_character ? *result : *s;
}
Handle<SeqString> result; // Same length as input.
if (s->IsOneByteRepresentation()) {
result = isolate->factory()->NewRawOneByteString(length).ToHandleChecked();
} else {
result = isolate->factory()->NewRawTwoByteString(length).ToHandleChecked();
}
Object* answer = ConvertCaseHelper(isolate, *s, *result, length, mapping);
if (answer->IsException(isolate) || answer->IsString()) return answer;
DCHECK(answer->IsSmi());
length = Smi::cast(answer)->value();
if (s->IsOneByteRepresentation() && length > 0) {
ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
isolate, result, isolate->factory()->NewRawOneByteString(length));
} else {
if (length < 0) length = -length;
ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
isolate, result, isolate->factory()->NewRawTwoByteString(length));
}
return ConvertCaseHelper(isolate, *s, *result, length, mapping);
}
RUNTIME_FUNCTION(Runtime_StringToLowerCase) {
HandleScope scope(isolate);
DCHECK_EQ(args.length(), 1);
CONVERT_ARG_HANDLE_CHECKED(String, s, 0);
return ConvertCase(s, isolate, isolate->runtime_state()->to_lower_mapping());
}
RUNTIME_FUNCTION(Runtime_StringToUpperCase) {
HandleScope scope(isolate);
DCHECK_EQ(args.length(), 1);
CONVERT_ARG_HANDLE_CHECKED(String, s, 0);
return ConvertCase(s, isolate, isolate->runtime_state()->to_upper_mapping());
}
RUNTIME_FUNCTION(Runtime_StringLessThan) {
HandleScope handle_scope(isolate);
DCHECK_EQ(2, args.length());
CONVERT_ARG_HANDLE_CHECKED(String, x, 0);
CONVERT_ARG_HANDLE_CHECKED(String, y, 1);
switch (String::Compare(x, y)) {
case ComparisonResult::kLessThan:
return isolate->heap()->true_value();
case ComparisonResult::kEqual:
case ComparisonResult::kGreaterThan:
return isolate->heap()->false_value();
case ComparisonResult::kUndefined:
break;
}
UNREACHABLE();
return Smi::kZero;
}
RUNTIME_FUNCTION(Runtime_StringLessThanOrEqual) {
HandleScope handle_scope(isolate);
DCHECK_EQ(2, args.length());
CONVERT_ARG_HANDLE_CHECKED(String, x, 0);
CONVERT_ARG_HANDLE_CHECKED(String, y, 1);
switch (String::Compare(x, y)) {
case ComparisonResult::kEqual:
case ComparisonResult::kLessThan:
return isolate->heap()->true_value();
case ComparisonResult::kGreaterThan:
return isolate->heap()->false_value();
case ComparisonResult::kUndefined:
break;
}
UNREACHABLE();
return Smi::kZero;
}
RUNTIME_FUNCTION(Runtime_StringGreaterThan) {
HandleScope handle_scope(isolate);
DCHECK_EQ(2, args.length());
CONVERT_ARG_HANDLE_CHECKED(String, x, 0);
CONVERT_ARG_HANDLE_CHECKED(String, y, 1);
switch (String::Compare(x, y)) {
case ComparisonResult::kGreaterThan:
return isolate->heap()->true_value();
case ComparisonResult::kEqual:
case ComparisonResult::kLessThan:
return isolate->heap()->false_value();
case ComparisonResult::kUndefined:
break;
}
UNREACHABLE();
return Smi::kZero;
}
RUNTIME_FUNCTION(Runtime_StringGreaterThanOrEqual) {
HandleScope handle_scope(isolate);
DCHECK_EQ(2, args.length());
CONVERT_ARG_HANDLE_CHECKED(String, x, 0);
CONVERT_ARG_HANDLE_CHECKED(String, y, 1);
switch (String::Compare(x, y)) {
case ComparisonResult::kEqual:
case ComparisonResult::kGreaterThan:
return isolate->heap()->true_value();
case ComparisonResult::kLessThan:
return isolate->heap()->false_value();
case ComparisonResult::kUndefined:
break;
}
UNREACHABLE();
return Smi::kZero;
}
RUNTIME_FUNCTION(Runtime_StringEqual) {
HandleScope handle_scope(isolate);
DCHECK_EQ(2, args.length());
CONVERT_ARG_HANDLE_CHECKED(String, x, 0);
CONVERT_ARG_HANDLE_CHECKED(String, y, 1);
return isolate->heap()->ToBoolean(String::Equals(x, y));
}
RUNTIME_FUNCTION(Runtime_StringNotEqual) {
HandleScope handle_scope(isolate);
DCHECK_EQ(2, args.length());
CONVERT_ARG_HANDLE_CHECKED(String, x, 0);
CONVERT_ARG_HANDLE_CHECKED(String, y, 1);
return isolate->heap()->ToBoolean(!String::Equals(x, y));
}
RUNTIME_FUNCTION(Runtime_FlattenString) {
HandleScope scope(isolate);
DCHECK(args.length() == 1);
CONVERT_ARG_HANDLE_CHECKED(String, str, 0);
return *String::Flatten(str);
}
RUNTIME_FUNCTION(Runtime_StringCharFromCode) {
HandleScope handlescope(isolate);
DCHECK_EQ(1, args.length());
if (args[0]->IsNumber()) {
CONVERT_NUMBER_CHECKED(uint32_t, code, Uint32, args[0]);
code &= 0xffff;
return *isolate->factory()->LookupSingleCharacterStringFromCode(code);
}
return isolate->heap()->empty_string();
}
RUNTIME_FUNCTION(Runtime_ExternalStringGetChar) {
SealHandleScope shs(isolate);
DCHECK_EQ(2, args.length());
CONVERT_ARG_CHECKED(ExternalString, string, 0);
CONVERT_INT32_ARG_CHECKED(index, 1);
return Smi::FromInt(string->Get(index));
}
RUNTIME_FUNCTION(Runtime_StringCharCodeAt) {
SealHandleScope shs(isolate);
DCHECK(args.length() == 2);
if (!args[0]->IsString()) return isolate->heap()->undefined_value();
if (!args[1]->IsNumber()) return isolate->heap()->undefined_value();
if (std::isinf(args.number_at(1))) return isolate->heap()->nan_value();
return __RT_impl_Runtime_StringCharCodeAtRT(args, isolate);
}
} // namespace internal
} // namespace v8