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// Copyright 2012 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.
#ifndef V8_SNAPSHOT_SOURCE_SINK_H_
#define V8_SNAPSHOT_SOURCE_SINK_H_
#include "src/base/logging.h"
#include "src/utils.h"
namespace v8 {
namespace internal {
/**
* Source to read snapshot and builtins files from.
*
* Note: Memory ownership remains with callee.
*/
class SnapshotByteSource FINAL {
public:
SnapshotByteSource(const byte* array, int length);
~SnapshotByteSource();
bool HasMore() { return position_ < length_; }
int Get() {
DCHECK(position_ < length_);
return data_[position_++];
}
int32_t GetUnalignedInt();
void Advance(int by) { position_ += by; }
void CopyRaw(byte* to, int number_of_bytes);
inline int GetInt() {
// This way of variable-length encoding integers does not suffer from branch
// mispredictions.
uint32_t answer = GetUnalignedInt();
int bytes = (answer & 3) + 1;
Advance(bytes);
uint32_t mask = 0xffffffffu;
mask >>= 32 - (bytes << 3);
answer &= mask;
answer >>= 2;
return answer;
}
bool GetBlob(const byte** data, int* number_of_bytes);
bool AtEOF();
int position() { return position_; }
private:
const byte* data_;
int length_;
int position_;
DISALLOW_COPY_AND_ASSIGN(SnapshotByteSource);
};
/**
* Sink to write snapshot files to.
*
* Subclasses must implement actual storage or i/o.
*/
class SnapshotByteSink {
public:
virtual ~SnapshotByteSink() { }
virtual void Put(byte b, const char* description) = 0;
virtual void PutSection(int b, const char* description) {
DCHECK_LE(b, kMaxUInt8);
Put(static_cast<byte>(b), description);
}
void PutInt(uintptr_t integer, const char* description);
void PutRaw(byte* data, int number_of_bytes, const char* description);
void PutBlob(byte* data, int number_of_bytes, const char* description);
virtual int Position() = 0;
};
class DummySnapshotSink : public SnapshotByteSink {
public:
DummySnapshotSink() : length_(0) {}
virtual ~DummySnapshotSink() {}
virtual void Put(byte b, const char* description) { length_++; }
virtual int Position() { return length_; }
private:
int length_;
};
// Wrap a SnapshotByteSink into a DebugSnapshotSink to get debugging output.
class DebugSnapshotSink : public SnapshotByteSink {
public:
explicit DebugSnapshotSink(SnapshotByteSink* chained) : sink_(chained) {}
virtual void Put(byte b, const char* description) OVERRIDE;
virtual int Position() OVERRIDE { return sink_->Position(); }
private:
SnapshotByteSink* sink_;
};
class ListSnapshotSink : public i::SnapshotByteSink {
public:
explicit ListSnapshotSink(i::List<byte>* data) : data_(data) {}
virtual void Put(byte b, const char* description) OVERRIDE {
data_->Add(b);
}
virtual int Position() OVERRIDE { return data_->length(); }
private:
i::List<byte>* data_;
};
} // namespace v8::internal
} // namespace v8
#endif // V8_SNAPSHOT_SOURCE_SINK_H_
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