class RegExpLookahead: public RegExpTree {
public:
- RegExpLookahead(RegExpTree* body, bool is_positive)
+ RegExpLookahead(RegExpTree* body,
+ bool is_positive,
+ int capture_count,
+ int capture_from)
: body_(body),
- is_positive_(is_positive) { }
+ is_positive_(is_positive),
+ capture_count_(capture_count),
+ capture_from_(capture_from) { }
+
virtual void* Accept(RegExpVisitor* visitor, void* data);
virtual RegExpNode* ToNode(RegExpCompiler* compiler,
RegExpNode* on_success);
virtual int max_match() { return 0; }
RegExpTree* body() { return body_; }
bool is_positive() { return is_positive_; }
+ int capture_count() { return capture_count_; }
+ int capture_from() { return capture_from_; }
private:
RegExpTree* body_;
bool is_positive_;
+ int capture_count_;
+ int capture_from_;
};
}
-void Trace::PushAffectedRegisters(RegExpMacroAssembler* assembler,
- int max_register,
- OutSet& affected_registers) {
- // Stay safe and check every half times the limit.
- // (Round up in case the limit is 1).
- int push_limit = (assembler->stack_limit_slack() + 1) / 2;
- for (int reg = 0, pushes = 0; reg <= max_register; reg++) {
- if (affected_registers.Get(reg)) {
- pushes++;
- RegExpMacroAssembler::StackCheckFlag check_stack_limit =
- (pushes % push_limit) == 0 ?
- RegExpMacroAssembler::kCheckStackLimit :
- RegExpMacroAssembler::kNoStackLimitCheck;
- assembler->PushRegister(reg, check_stack_limit);
- }
- }
-}
-
-
void Trace::RestoreAffectedRegisters(RegExpMacroAssembler* assembler,
int max_register,
- OutSet& affected_registers) {
+ OutSet& registers_to_pop,
+ OutSet& registers_to_clear) {
for (int reg = max_register; reg >= 0; reg--) {
- if (affected_registers.Get(reg)) assembler->PopRegister(reg);
+ if (registers_to_pop.Get(reg)) assembler->PopRegister(reg);
+ else if (registers_to_clear.Get(reg)) {
+ int clear_to = reg;
+ while (reg > 0 && registers_to_pop.Get(reg - 1)) {
+ reg--;
+ }
+ assembler->ClearRegisters(reg, clear_to);
+ }
}
}
void Trace::PerformDeferredActions(RegExpMacroAssembler* assembler,
int max_register,
- OutSet& affected_registers) {
+ OutSet& affected_registers,
+ OutSet* registers_to_pop,
+ OutSet* registers_to_clear) {
+ // The "+1" is to avoid a push_limit of zero if stack_limit_slack() is 1.
+ const int push_limit = (assembler->stack_limit_slack() + 1) / 2;
+
for (int reg = 0; reg <= max_register; reg++) {
if (!affected_registers.Get(reg)) {
continue;
}
+ // Count pushes performed to force a stack limit check occasionally.
+ int pushes = 0;
+
+ // The chronologically first deferred action in the trace
+ // is used to infer the action needed to restore a register
+ // to its previous state (or not, if it's safe to ignore it).
+ enum DeferredActionUndoType { IGNORE, RESTORE, CLEAR };
+ DeferredActionUndoType undo_action = IGNORE;
+
int value = 0;
bool absolute = false;
bool clear = false;
case ActionNode::SET_REGISTER: {
Trace::DeferredSetRegister* psr =
static_cast<Trace::DeferredSetRegister*>(action);
- value += psr->value();
- absolute = true;
+ if (!absolute) {
+ value += psr->value();
+ absolute = true;
+ }
+ // SET_REGISTER is currently only used for newly introduced loop
+ // counters. They can have a significant previous value if they
+ // occour in a loop. TODO(lrn): Propagate this information, so
+ // we can set undo_action to IGNORE if we know there is no value to
+ // restore.
+ undo_action = RESTORE;
ASSERT_EQ(store_position, -1);
ASSERT(!clear);
break;
}
ASSERT_EQ(store_position, -1);
ASSERT(!clear);
+ undo_action = RESTORE;
break;
case ActionNode::STORE_POSITION: {
Trace::DeferredCapture* pc =
if (!clear && store_position == -1) {
store_position = pc->cp_offset();
}
+
+ // For captures we know that stores and clears alternate.
+ // Other register, are never cleared, and if the occur
+ // inside a loop, they might be assigned more than once.
+ if (reg <= 1) {
+ // Registers zero and one, aka "capture zero", is
+ // always set correctly if we succeed. There is no
+ // need to undo a setting on backtrack, because we
+ // will set it again or fail.
+ undo_action = IGNORE;
+ } else {
+ undo_action = pc->is_capture() ? CLEAR : RESTORE;
+ }
ASSERT(!absolute);
ASSERT_EQ(value, 0);
break;
// Since we're scanning in reverse order, if we've already
// set the position we have to ignore historically earlier
// clearing operations.
- if (store_position == -1)
+ if (store_position == -1) {
clear = true;
+ }
+ undo_action = RESTORE;
ASSERT(!absolute);
ASSERT_EQ(value, 0);
break;
}
}
}
+ // Prepare for the undo-action (e.g., push if it's going to be popped).
+ if (undo_action == RESTORE) {
+ pushes++;
+ RegExpMacroAssembler::StackCheckFlag stack_check =
+ RegExpMacroAssembler::kNoStackLimitCheck;
+ if (pushes == push_limit) {
+ stack_check = RegExpMacroAssembler::kCheckStackLimit;
+ pushes = 0;
+ }
+
+ assembler->PushRegister(reg, stack_check);
+ registers_to_pop->Set(reg);
+ } else if (undo_action == CLEAR) {
+ registers_to_clear->Set(reg);
+ }
+ // Perform the chronologically last action (or accumulated increment)
+ // for the register.
if (store_position != -1) {
assembler->WriteCurrentPositionToRegister(reg, store_position);
} else if (clear) {
- assembler->ClearRegister(reg);
+ assembler->ClearRegisters(reg, reg);
} else if (absolute) {
assembler->SetRegister(reg, value);
} else if (value != 0) {
// Generate deferred actions here along with code to undo them again.
OutSet affected_registers;
+
int max_register = FindAffectedRegisters(&affected_registers);
- PushAffectedRegisters(assembler, max_register, affected_registers);
- PerformDeferredActions(assembler, max_register, affected_registers);
+ OutSet registers_to_pop;
+ OutSet registers_to_clear;
+ PerformDeferredActions(assembler,
+ max_register,
+ affected_registers,
+ ®isters_to_pop,
+ ®isters_to_clear);
if (backtrack() != NULL) {
// Here we have a concrete backtrack location. These are set up by choice
// nodes and so they indicate that we have a deferred save of the current
if (backtrack() != NULL) {
assembler->PopCurrentPosition();
}
- RestoreAffectedRegisters(assembler, max_register, affected_registers);
+ RestoreAffectedRegisters(assembler,
+ max_register,
+ registers_to_pop,
+ registers_to_clear);
if (backtrack() == NULL) {
assembler->Backtrack();
} else {
bool NegativeSubmatchSuccess::Emit(RegExpCompiler* compiler, Trace* trace) {
- if (!trace->is_trivial()) {
- return trace->Flush(compiler, this);
- }
RegExpMacroAssembler* assembler = compiler->macro_assembler();
+
+ // Omit flushing the trace. We discard the entire stack frame anyway.
+
if (!label()->is_bound()) {
+ // We are completely independent of the trace, since we ignore it,
+ // so this code can be used as the generic version.
assembler->Bind(label());
}
+
+ // Throw away everything on the backtrack stack since the start
+ // of the negative submatch and restore the character position.
assembler->ReadCurrentPositionFromRegister(current_position_register_);
assembler->ReadStackPointerFromRegister(stack_pointer_register_);
+ if (clear_capture_count_ > 0) {
+ // Clear any captures that might have been performed during the success
+ // of the body of the negative look-ahead.
+ int clear_capture_end = clear_capture_start_ + clear_capture_count_ - 1;
+ assembler->ClearRegisters(clear_capture_start_, clear_capture_end);
+ }
// Now that we have unwound the stack we find at the top of the stack the
// backtrack that the BeginSubmatch node got.
assembler->Backtrack();
}
-ActionNode* ActionNode::StorePosition(int reg, RegExpNode* on_success) {
+ActionNode* ActionNode::StorePosition(int reg,
+ bool is_capture,
+ RegExpNode* on_success) {
ActionNode* result = new ActionNode(STORE_POSITION, on_success);
result->data_.u_position_register.reg = reg;
+ result->data_.u_position_register.is_capture = is_capture;
return result;
}
ActionNode* ActionNode::PositiveSubmatchSuccess(int stack_reg,
int position_reg,
+ int clear_register_count,
+ int clear_register_from,
RegExpNode* on_success) {
ActionNode* result = new ActionNode(POSITIVE_SUBMATCH_SUCCESS, on_success);
result->data_.u_submatch.stack_pointer_register = stack_reg;
result->data_.u_submatch.current_position_register = position_reg;
+ result->data_.u_submatch.clear_register_count = clear_register_count;
+ result->data_.u_submatch.clear_register_from = clear_register_from;
return result;
}
switch (type_) {
case STORE_POSITION: {
Trace::DeferredCapture
- new_capture(data_.u_position_register.reg, trace);
+ new_capture(data_.u_position_register.reg,
+ data_.u_position_register.is_capture,
+ trace);
Trace new_trace = *trace;
new_trace.add_action(&new_capture);
return on_success()->Emit(compiler, &new_trace);
assembler->Bind(&skip_empty_check);
return on_success()->Emit(compiler, trace);
}
- case POSITIVE_SUBMATCH_SUCCESS:
+ case POSITIVE_SUBMATCH_SUCCESS: {
if (!trace->is_trivial()) return trace->Flush(compiler, this);
assembler->ReadCurrentPositionFromRegister(
data_.u_submatch.current_position_register);
assembler->ReadStackPointerFromRegister(
data_.u_submatch.stack_pointer_register);
- return on_success()->Emit(compiler, trace);
+ int clear_register_count = data_.u_submatch.clear_register_count;
+ if (clear_register_count == 0) {
+ return on_success()->Emit(compiler, trace);
+ }
+ int clear_registers_from = data_.u_submatch.clear_register_from;
+ Label clear_registers_backtrack;
+ Trace new_trace = *trace;
+ new_trace.set_backtrack(&clear_registers_backtrack);
+ bool ok = on_success()->Emit(compiler, &new_trace);
+ if (!ok) { return false; }
+
+ assembler->Bind(&clear_registers_backtrack);
+ int clear_registers_to = clear_registers_from + clear_register_count - 1;
+ assembler->ClearRegisters(clear_registers_from, clear_registers_to);
+
+ ASSERT(trace->backtrack() == NULL);
+ assembler->Backtrack();
+ return true;
+ }
default:
UNREACHABLE();
return false;
if (body_can_be_empty) {
// If the body can be empty we need to store the start position
// so we can bail out if it was empty.
- body_node = ActionNode::StorePosition(body_start_reg, body_node);
+ body_node = ActionNode::StorePosition(body_start_reg, false, body_node);
}
if (needs_capture_clearing) {
// Before entering the body of this loop we need to clear captures.
newline_atom,
ActionNode::PositiveSubmatchSuccess(stack_pointer_register,
position_register,
+ 0, // No captures inside.
+ -1, // Ignored if no captures.
on_success));
// Create an end-of-input matcher.
RegExpNode* end_of_line = ActionNode::BeginSubmatch(
RegExpNode* on_success) {
int stack_pointer_register = compiler->AllocateRegister();
int position_register = compiler->AllocateRegister();
+
+ const int registers_per_capture = 2;
+ const int register_of_first_capture = 2;
+ int register_count = capture_count_ * registers_per_capture;
+ int register_start =
+ register_of_first_capture + capture_from_ * registers_per_capture;
+
RegExpNode* success;
if (is_positive()) {
- return ActionNode::BeginSubmatch(
+ RegExpNode* node = ActionNode::BeginSubmatch(
stack_pointer_register,
position_register,
body()->ToNode(
compiler,
ActionNode::PositiveSubmatchSuccess(stack_pointer_register,
position_register,
+ register_count,
+ register_start,
on_success)));
+ return node;
} else {
// We use a ChoiceNode for a negative lookahead because it has most of
// the characteristics we need. It has the body of the lookahead as its
body()->ToNode(
compiler,
success = new NegativeSubmatchSuccess(stack_pointer_register,
- position_register)));
+ position_register,
+ register_count,
+ register_start)));
ChoiceNode* choice_node =
new NegativeLookaheadChoiceNode(body_alt,
GuardedAlternative(on_success));
RegExpNode* on_success) {
int start_reg = RegExpCapture::StartRegister(index);
int end_reg = RegExpCapture::EndRegister(index);
- RegExpNode* store_end = ActionNode::StorePosition(end_reg, on_success);
+ RegExpNode* store_end = ActionNode::StorePosition(end_reg, true, on_success);
RegExpNode* body_node = body->ToNode(compiler, store_end);
- return ActionNode::StorePosition(start_reg, body_node);
+ return ActionNode::StorePosition(start_reg, true, body_node);
}
};
static ActionNode* SetRegister(int reg, int val, RegExpNode* on_success);
static ActionNode* IncrementRegister(int reg, RegExpNode* on_success);
- static ActionNode* StorePosition(int reg, RegExpNode* on_success);
+ static ActionNode* StorePosition(int reg,
+ bool is_capture,
+ RegExpNode* on_success);
static ActionNode* ClearCaptures(Interval range, RegExpNode* on_success);
static ActionNode* BeginSubmatch(int stack_pointer_reg,
int position_reg,
RegExpNode* on_success);
static ActionNode* PositiveSubmatchSuccess(int stack_pointer_reg,
int restore_reg,
+ int clear_capture_count,
+ int clear_capture_from,
RegExpNode* on_success);
static ActionNode* EmptyMatchCheck(int start_register,
int repetition_register,
} u_increment_register;
struct {
int reg;
+ bool is_capture;
} u_position_register;
struct {
int stack_pointer_register;
int current_position_register;
+ int clear_register_count;
+ int clear_register_from;
} u_submatch;
struct {
int start_register;
class NegativeSubmatchSuccess: public EndNode {
public:
- NegativeSubmatchSuccess(int stack_pointer_reg, int position_reg)
+ NegativeSubmatchSuccess(int stack_pointer_reg,
+ int position_reg,
+ int clear_capture_count,
+ int clear_capture_start)
: EndNode(NEGATIVE_SUBMATCH_SUCCESS),
stack_pointer_register_(stack_pointer_reg),
- current_position_register_(position_reg) { }
+ current_position_register_(position_reg),
+ clear_capture_count_(clear_capture_count),
+ clear_capture_start_(clear_capture_start) { }
virtual bool Emit(RegExpCompiler* compiler, Trace* trace);
private:
int stack_pointer_register_;
int current_position_register_;
+ int clear_capture_count_;
+ int clear_capture_start_;
};
friend class Trace;
};
- class DeferredCapture: public DeferredAction {
+ class DeferredCapture : public DeferredAction {
public:
- DeferredCapture(int reg, Trace* trace)
+ DeferredCapture(int reg, bool is_capture, Trace* trace)
: DeferredAction(ActionNode::STORE_POSITION, reg),
cp_offset_(trace->cp_offset()) { }
int cp_offset() { return cp_offset_; }
+ bool is_capture() { return is_capture_; }
private:
int cp_offset_;
+ bool is_capture_;
void set_cp_offset(int cp_offset) { cp_offset_ = cp_offset; }
};
- class DeferredSetRegister :public DeferredAction {
+ class DeferredSetRegister : public DeferredAction {
public:
DeferredSetRegister(int reg, int value)
: DeferredAction(ActionNode::SET_REGISTER, reg),
Interval range_;
};
- class DeferredIncrementRegister: public DeferredAction {
+ class DeferredIncrementRegister : public DeferredAction {
public:
explicit DeferredIncrementRegister(int reg)
: DeferredAction(ActionNode::INCREMENT_REGISTER, reg) { }
int FindAffectedRegisters(OutSet* affected_registers);
void PerformDeferredActions(RegExpMacroAssembler* macro,
int max_register,
- OutSet& affected_registers);
+ OutSet& affected_registers,
+ OutSet* registers_to_pop,
+ OutSet* registers_to_clear);
void RestoreAffectedRegisters(RegExpMacroAssembler* macro,
int max_register,
- OutSet& affected_registers);
- void PushAffectedRegisters(RegExpMacroAssembler* macro,
- int max_register,
- OutSet& affected_registers);
+ OutSet& registers_to_pop,
+ OutSet& registers_to_clear);
int cp_offset_;
DeferredAction* actions_;
Label* backtrack_;
} else {
ASSERT(type == '=' || type == '!');
bool is_positive = (type == '=');
- return new RegExpLookahead(body, is_positive);
+ return new RegExpLookahead(body,
+ is_positive,
+ end_capture_index - capture_index,
+ capture_index);
}
}
__ push(ebx);
const int four_arguments = 4;
FrameAlign(four_arguments, ecx);
- // Put arguments into allocated stack area.
+ // Put arguments into allocated stack area, last argument highest on stack.
+ // Parameters are
+ // UC16** buffer - really the String** of the input string
+ // int byte_offset1 - byte offset from *buffer of start of capture
+ // int byte_offset2 - byte offset from *buffer of current position
+ // size_t byte_length - length of capture in bytes(!)
+
+ // Set byte_length.
__ mov(Operand(esp, 3 * kPointerSize), ebx);
+ // Set byte_offset2.
+ // Found by adding negative string-end offset of current position (edi)
+ // to String** offset of end of string.
__ mov(ecx, Operand(ebp, kInputEndOffset));
__ add(edi, Operand(ecx));
__ mov(Operand(esp, 2 * kPointerSize), edi);
+ // Set byte_offset1.
+ // Start of capture, where eax already holds string-end negative offset.
__ add(eax, Operand(ecx));
__ mov(Operand(esp, 1 * kPointerSize), eax);
+ // Set buffer. Original String** parameter to regexp code.
__ mov(eax, Operand(ebp, kInputBuffer));
__ mov(Operand(esp, 0 * kPointerSize), eax);
+
Address function_address = FUNCTION_ADDR(&CaseInsensitiveCompareUC16);
CallCFunction(function_address, four_arguments);
// Pop original values before reacting on result value.
}
-void RegExpMacroAssemblerIA32::ClearRegister(int reg) {
+void RegExpMacroAssemblerIA32::ClearRegisters(int reg_from, int reg_to) {
+ ASSERT(reg_from <= reg_to);
__ mov(eax, Operand(ebp, kInputStartMinusOne));
- __ mov(register_location(reg), eax);
+ for (int reg = reg_from; reg <= reg_to; reg++) {
+ __ mov(register_location(reg), eax);
+ }
}
stack_top);
if (result < 0 && !Top::has_pending_exception()) {
- // We detected a stack overflow in RegExp code, but haven't created
- // the exception yet.
+ // We detected a stack overflow (on the backtrack stack) in RegExp code,
+ // but haven't created the exception yet.
Top::StackOverflow();
}
return (result < 0) ? EXCEPTION : (result ? SUCCESS : FAILURE);
void RegExpMacroAssemblerIA32::FrameAlign(int num_arguments, Register scratch) {
+ // TODO(lrn): Since we no longer use the system stack arbitrarily, we
+ // know the current stack alignment - esp points to the last regexp register.
+ // We can do this simpler then.
int frameAlignment = OS::ActivationFrameAlignment();
if (frameAlignment != 0) {
// Make stack end at alignment and make room for num_arguments words
virtual void SetRegister(int register_index, int to);
virtual void Succeed();
virtual void WriteCurrentPositionToRegister(int reg, int cp_offset);
- virtual void ClearRegister(int reg);
+ virtual void ClearRegisters(int reg_from, int reg_to);
virtual void WriteStackPointerToRegister(int reg);
static Result Execute(Code* code,
}
-void RegExpMacroAssemblerIrregexp::ClearRegister(int reg) {
- SetRegister(reg, -1);
+void RegExpMacroAssemblerIrregexp::ClearRegisters(int reg_from, int reg_to) {
+ ASSERT(reg_from <= reg_to);
+ for (int reg = reg_from; reg <= reg_to; reg++) {
+ SetRegister(reg, -1);
+ }
}
virtual void AdvanceRegister(int reg, int by); // r[reg] += by.
virtual void SetRegister(int register_index, int to);
virtual void WriteCurrentPositionToRegister(int reg, int cp_offset);
- virtual void ClearRegister(int reg);
+ virtual void ClearRegisters(int reg_from, int reg_to);
virtual void ReadCurrentPositionFromRegister(int reg);
virtual void WriteStackPointerToRegister(int reg);
virtual void ReadStackPointerFromRegister(int reg);
}
-void RegExpMacroAssemblerTracer::ClearRegister(int reg) {
- PrintF(" ClearRegister(register=%d);\n", reg);
- assembler_->ClearRegister(reg);
+void RegExpMacroAssemblerTracer::ClearRegisters(int reg_from, int reg_to) {
+ PrintF(" ClearRegister(from=%d, to=%d);\n", reg_from, reg_to);
+ assembler_->ClearRegisters(reg_from, reg_to);
}
virtual void SetRegister(int register_index, int to);
virtual void Succeed();
virtual void WriteCurrentPositionToRegister(int reg, int cp_offset);
- virtual void ClearRegister(int reg);
+ virtual void ClearRegisters(int reg_from, int reg_to);
virtual void WriteStackPointerToRegister(int reg);
private:
RegExpMacroAssembler* assembler_;
virtual void SetRegister(int register_index, int to) = 0;
virtual void Succeed() = 0;
virtual void WriteCurrentPositionToRegister(int reg, int cp_offset) = 0;
- virtual void ClearRegister(int reg) = 0;
+ virtual void ClearRegisters(int reg_from, int reg_to) = 0;
virtual void WriteStackPointerToRegister(int reg) = 0;
private:
--- /dev/null
+// Copyright 2009 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following
+// disclaimer in the documentation and/or other materials provided
+// with the distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived
+// from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Tests captures in positive and negative look-ahead in regular expressions.
+
+function stringEscape(string) {
+ // Converts string to source literal.
+ return '"' + string.replace(/["\\]/g, "\\$1") + '"';
+}
+
+function testRE(re, input, expected_result) {
+ var testName = re + ".test(" + stringEscape(input) +")";
+ if (expected_result) {
+ assertTrue(re.test(input), testName);
+ } else {
+ assertFalse(re.test(input), testName);
+ }
+}
+
+function execRE(re, input, expected_result) {
+ var testName = re + ".exec('" + stringEscape(input) +"')";
+ assertEquals(expected_result, re.exec(input), testName);
+}
+
+// Test of simple positive lookahead.
+
+var re = /^(?=a)/;
+testRE(re, "a", true);
+testRE(re, "b", false);
+execRE(re, "a", [""]);
+
+re = /^(?=\woo)f\w/;
+testRE(re, "foo", true);
+testRE(re, "boo", false);
+testRE(re, "fao", false);
+testRE(re, "foa", false);
+execRE(re, "foo", ["fo"]);
+
+re = /(?=\w).(?=\W)/;
+testRE(re, ".a! ", true);
+testRE(re, ".! ", false);
+testRE(re, ".ab! ", true);
+execRE(re, ".ab! ", ["b"]);
+
+re = /(?=f(?=[^f]o))../;
+testRE(re, ", foo!", true);
+testRE(re, ", fo!", false);
+testRE(re, ", ffo", false);
+execRE(re, ", foo!", ["fo"]);
+
+// Positive lookahead with captures.
+re = /^[^\'\"]*(?=([\'\"])).*\1(\w+)\1/;
+testRE(re, " 'foo' ", true);
+testRE(re, ' "foo" ', true);
+testRE(re, " \" 'foo' ", false);
+testRE(re, " ' \"foo\" ", false);
+testRE(re, " 'foo\" ", false);
+testRE(re, " \"foo' ", false);
+execRE(re, " 'foo' ", [" 'foo'", "'", "foo"]);
+execRE(re, ' "foo" ', [' "foo"', '"', 'foo']);
+
+// Captures are cleared on backtrack past the look-ahead.
+re = /^(?:(?=(.))a|b)\1$/;
+testRE(re, "aa", true);
+testRE(re, "b", true);
+testRE(re, "bb", false);
+testRE(re, "a", false);
+execRE(re, "aa", ["aa", "a"]);
+execRE(re, "b", ["b", undefined]);
+
+re = /^(?=(.)(?=(.)\1\2)\2\1)\1\2/;
+testRE(re, "abab", true);
+testRE(re, "ababxxxxxxxx", true);
+testRE(re, "aba", false);
+execRE(re, "abab", ["ab", "a", "b"]);
+
+re = /^(?:(?=(.))a|b|c)$/;
+testRE(re, "a", true);
+testRE(re, "b", true);
+testRE(re, "c", true);
+testRE(re, "d", false);
+execRE(re, "a", ["a", "a"]);
+execRE(re, "b", ["b", undefined]);
+execRE(re, "c", ["c", undefined]);
+
+execRE(/^(?=(b))b/, "b", ["b", "b"]);
+execRE(/^(?:(?=(b))|a)b/, "ab", ["ab", undefined]);
+execRE(/^(?:(?=(b)(?:(?=(c))|d))|)bd/, "bd", ["bd", "b", undefined]);
+
+
+
+// Test of Negative Look-Ahead.
+
+re = /(?!x)./;
+testRE(re, "y", true);
+testRE(re, "x", false);
+execRE(re, "y", ["y"]);
+
+re = /(?!(\d))|\d/;
+testRE(re, "4", true);
+execRE(re, "4", ["4", undefined]);
+execRE(re, "x", ["", undefined]);
+
+
+// Test mixed nested look-ahead with captures.
+
+re = /^(?=(x)(?=(y)))/;
+testRE(re, "xy", true);
+testRE(re, "xz", false);
+execRE(re, "xy", ["", "x", "y"]);
+
+re = /^(?!(x)(?!(y)))/;
+testRE(re, "xy", true);
+testRE(re, "xz", false);
+execRE(re, "xy", ["", undefined, undefined]);
+
+re = /^(?=(x)(?!(y)))/;
+testRE(re, "xz", true);
+testRE(re, "xy", false)
+execRE(re, "xz", ["", "x", undefined]);
+
+re = /^(?!(x)(?=(y)))/;
+testRE(re, "xz", true);
+testRE(re, "xy", false);
+execRE(re, "xz", ["", undefined, undefined]);
+
+re = /^(?=(x)(?!(y)(?=(z))))/;
+testRE(re, "xaz", true);
+testRE(re, "xya", true);
+testRE(re, "xyz", false);
+testRE(re, "a", false);
+execRE(re, "xaz", ["", "x", undefined, undefined]);
+execRE(re, "xya", ["", "x", undefined, undefined]);
+
+re = /^(?!(x)(?=(y)(?!(z))))/;
+testRE(re, "a", true);
+testRE(re, "xa", true);
+testRE(re, "xyz", true);
+testRE(re, "xya", false);
+execRE(re, "a", ["", undefined, undefined, undefined]);
+execRE(re, "xa", ["", undefined, undefined, undefined]);
+execRE(re, "xyz", ["", undefined, undefined, undefined]);
projects / platform / upstream / v8.git / commitdiff