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/*
* Copyright (C) 2015 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS 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 APPLE INC. OR ITS 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.
*/
#ifndef DFABytecode_h
#define DFABytecode_h
#if ENABLE(CONTENT_EXTENSIONS)
namespace WebCore {
namespace ContentExtensions {
typedef uint8_t DFABytecode;
// Increment UserContentExtensionStore::CurrentContentExtensionFileVersion
// when making any non-backwards-compatible changes to the bytecode.
// FIXME: Changes here should not require changes in WebKit2. Move all versioning to WebCore.
enum class DFABytecodeInstruction : uint8_t {
// CheckValue has two arguments:
// The value to check (1 byte),
// The distance to jump if the values are equal (1-4 bytes, signed).
CheckValueCaseInsensitive = 0x0,
CheckValueCaseSensitive = 0x1,
// Jump table if the input value is within a certain range.
// The lower value (1 byte).
// The higher value (1 byte).
// The distance to jump if the value is in the range
// for every character in the range (1-4 bytes, signed).
JumpTableCaseInsensitive = 0x2,
JumpTableCaseSensitive = 0x3,
// Jump to an offset if the input value is within a certain range.
// The lower value (1 byte).
// The higher value (1 byte).
// The distance to jump if the value is in the range (1-4 bytes, signed).
CheckValueRangeCaseInsensitive = 0x4,
CheckValueRangeCaseSensitive = 0x5,
// AppendAction has one argument:
// The action to append (4 bytes).
AppendAction = 0x6,
AppendActionWithIfDomain = 0x7,
// TestFlagsAndAppendAction has two arguments:
// The flags to check before appending (2 bytes).
// The action to append (4 bytes).
TestFlagsAndAppendAction = 0x8,
TestFlagsAndAppendActionWithIfDomain = 0x9,
// Terminate has no arguments.
Terminate = 0xA,
// Jump has one argument:
// The distance to jump (1-4 bytes, signed).
Jump = 0xB,
};
// The last four bits contain the instruction type.
const uint8_t DFABytecodeInstructionMask = 0x0F;
const uint8_t DFABytecodeJumpSizeMask = 0xF0;
// DFA bytecode starts with a 4 byte header which contains the size of this DFA.
typedef uint32_t DFAHeader;
// A DFABytecodeJumpSize is stored in the top four bits of the DFABytecodeInstructions that have a jump.
enum DFABytecodeJumpSize {
Int8 = 0x10,
Int16 = 0x20,
Int24 = 0x30,
Int32 = 0x40,
};
const int32_t Int24Max = (1 << 23) - 1;
const int32_t Int24Min = -(1 << 23);
static inline DFABytecodeJumpSize smallestPossibleJumpSize(int32_t longestPossibleJump)
{
if (longestPossibleJump <= std::numeric_limits<int8_t>::max() && longestPossibleJump >= std::numeric_limits<int8_t>::min())
return Int8;
if (longestPossibleJump <= std::numeric_limits<int16_t>::max() && longestPossibleJump >= std::numeric_limits<int16_t>::min())
return Int16;
if (longestPossibleJump <= Int24Max && longestPossibleJump >= Int24Min)
return Int24;
return Int32;
}
static inline size_t instructionSizeWithArguments(DFABytecodeInstruction instruction)
{
switch (instruction) {
case DFABytecodeInstruction::CheckValueCaseSensitive:
case DFABytecodeInstruction::CheckValueCaseInsensitive:
case DFABytecodeInstruction::JumpTableCaseInsensitive:
case DFABytecodeInstruction::JumpTableCaseSensitive:
case DFABytecodeInstruction::CheckValueRangeCaseSensitive:
case DFABytecodeInstruction::CheckValueRangeCaseInsensitive:
case DFABytecodeInstruction::Jump:
RELEASE_ASSERT_NOT_REACHED(); // Variable instruction size.
case DFABytecodeInstruction::AppendAction:
case DFABytecodeInstruction::AppendActionWithIfDomain:
return sizeof(DFABytecodeInstruction) + sizeof(uint32_t);
case DFABytecodeInstruction::TestFlagsAndAppendAction:
case DFABytecodeInstruction::TestFlagsAndAppendActionWithIfDomain:
return sizeof(DFABytecodeInstruction) + sizeof(uint16_t) + sizeof(uint32_t);
case DFABytecodeInstruction::Terminate:
return sizeof(DFABytecodeInstruction);
}
}
} // namespace ContentExtensions
} // namespace WebCore
#endif // ENABLE(CONTENT_EXTENSIONS)
#endif // DFABytecode_h
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