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// Copyright 2014, ARM Limited
// 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 ARM Limited 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 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.
#ifndef VIXL_CODE_BUFFER_H
#define VIXL_CODE_BUFFER_H
#include <string.h>
#include "vixl/globals.h"
namespace vixl {
class CodeBuffer {
public:
explicit CodeBuffer(size_t capacity = 4 * KBytes);
CodeBuffer(void* buffer, size_t capacity);
~CodeBuffer();
void Reset();
ptrdiff_t OffsetFrom(ptrdiff_t offset) const {
ptrdiff_t cursor_offset = cursor_ - buffer_;
VIXL_ASSERT((offset >= 0) && (offset <= cursor_offset));
return cursor_offset - offset;
}
ptrdiff_t CursorOffset() const {
return OffsetFrom(0);
}
template <typename T>
T GetOffsetAddress(ptrdiff_t offset) const {
VIXL_ASSERT((offset >= 0) && (offset <= (cursor_ - buffer_)));
return reinterpret_cast<T>(buffer_ + offset);
}
size_t RemainingBytes() const {
VIXL_ASSERT((cursor_ >= buffer_) && (cursor_ <= (buffer_ + capacity_)));
return (buffer_ + capacity_) - cursor_;
}
// A code buffer can emit:
// * 32-bit data: instruction and constant.
// * 64-bit data: constant.
// * string: debug info.
void Emit32(uint32_t data) { Emit(data); }
void Emit64(uint64_t data) { Emit(data); }
void EmitString(const char* string);
// Align to kInstructionSize.
void Align();
size_t capacity() const { return capacity_; }
bool IsManaged() const { return managed_; }
void Grow(size_t new_capacity);
bool IsDirty() const { return dirty_; }
void SetClean() { dirty_ = false; }
private:
template <typename T>
void Emit(T value) {
VIXL_ASSERT(RemainingBytes() >= sizeof(value));
dirty_ = true;
memcpy(cursor_, &value, sizeof(value));
cursor_ += sizeof(value);
}
// Backing store of the buffer.
byte* buffer_;
// If true the backing store is allocated and deallocated by the buffer. The
// backing store can then grow on demand. If false the backing store is
// provided by the user and cannot be resized internally.
bool managed_;
// Pointer to the next location to be written.
byte* cursor_;
// True if there has been any write since the buffer was created or cleaned.
bool dirty_;
// Capacity in bytes of the backing store.
size_t capacity_;
};
} // namespace vixl
#endif // VIXL_CODE_BUFFER_H
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