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/** 
 * Licensed to the Apache Software Foundation (ASF) under one 
 * or more contributor license agreements.  See the NOTICE file 
 * distributed with this work for additional information 
 * regarding copyright ownership.  The ASF licenses this file 
 * to you under the Apache License, Version 2.0 (the 
 * "License"); you may not use this file except in compliance 
 * with the License.  You may obtain a copy of the License at 
 * 
 *     https://www.apache.org/licenses/LICENSE-2.0 
 * 
 * Unless required by applicable law or agreed to in writing, software 
 * distributed under the License is distributed on an "AS IS" BASIS, 
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
 * See the License for the specific language governing permissions and 
 * limitations under the License. 
 */ 
 
#include "Stream.hh" 
#include <vector> 
 
namespace avro { 
 
using std::vector; 
 
class MemoryInputStream : public InputStream { 
    const std::vector<uint8_t*>& data_; 
    const size_t chunkSize_; 
    const size_t size_; 
    const size_t available_; 
    size_t cur_; 
    size_t curLen_; 
 
    size_t maxLen() { 
        size_t n = (cur_ == (size_ - 1)) ? available_ : chunkSize_; 
        if (n == curLen_) { 
            if (cur_ == (size_ - 1)) { 
                return 0; 
            } 
            ++cur_; 
            n = (cur_ == (size_ - 1)) ? available_ : chunkSize_; 
            curLen_ = 0; 
        } 
        return n; 
    } 
 
public: 
    MemoryInputStream(const std::vector<uint8_t*>& b, 
        size_t chunkSize, size_t available) : 
            data_(b), chunkSize_(chunkSize), size_(b.size()), 
            available_(available), cur_(0), curLen_(0) { } 
 
    bool next(const uint8_t** data, size_t* len) { 
        if (size_t n = maxLen()) { 
            *data = data_[cur_] + curLen_; 
            *len = n - curLen_; 
            curLen_ = n; 
            return true; 
        } 
        return false; 
    } 
 
    void backup(size_t len) { 
        curLen_ -= len; 
    } 
 
    void skip(size_t len) { 
        while (len > 0) { 
            if (size_t n = maxLen()) { 
                if ((curLen_ + len) < n) { 
                    n = curLen_ + len; 
                } 
                len -= n - curLen_; 
                curLen_ = n; 
            } else { 
                break; 
            } 
        } 
    } 
 
    size_t byteCount() const { 
        return cur_ * chunkSize_ + curLen_; 
    } 
}; 
 
class MemoryInputStream2 : public InputStream { 
    const uint8_t* const data_; 
    const size_t size_; 
    size_t curLen_; 
public: 
    MemoryInputStream2(const uint8_t *data, size_t len) 
        : data_(data), size_(len), curLen_(0) { } 
 
    bool next(const uint8_t** data, size_t* len) { 
        if (curLen_ == size_) { 
            return false; 
        } 
        *data = &data_[curLen_]; 
        *len = size_ - curLen_; 
        curLen_ = size_; 
        return true; 
    } 
 
    void backup(size_t len) { 
        curLen_ -= len; 
    } 
 
    void skip(size_t len) { 
        if (len > (size_ - curLen_)) { 
            len = size_ - curLen_; 
        } 
        curLen_ += len; 
    } 
 
    size_t byteCount() const { 
        return curLen_; 
    } 
}; 
 
class MemoryOutputStream : public OutputStream { 
public: 
    const size_t chunkSize_; 
    std::vector<uint8_t*> data_; 
    size_t available_; 
    size_t byteCount_; 
 
    MemoryOutputStream(size_t chunkSize) : chunkSize_(chunkSize), 
        available_(0), byteCount_(0) { } 
    ~MemoryOutputStream() { 
        for (std::vector<uint8_t*>::const_iterator it = data_.begin(); 
            it != data_.end(); ++it) { 
            delete[] *it; 
        } 
    } 
 
    bool next(uint8_t** data, size_t* len) { 
        if (available_ == 0) { 
            data_.push_back(new uint8_t[chunkSize_]); 
            available_ = chunkSize_; 
        } 
        *data = &data_.back()[chunkSize_ - available_]; 
        *len = available_; 
        byteCount_ += available_; 
        available_ = 0; 
        return true; 
    } 
 
    void backup(size_t len) { 
        available_ += len; 
        byteCount_ -= len; 
    } 
 
    uint64_t byteCount() const { 
        return byteCount_; 
    } 
 
    void flush() { } 
}; 
 
std::unique_ptr<OutputStream> memoryOutputStream(size_t chunkSize) 
{ 
    return std::unique_ptr<OutputStream>(new MemoryOutputStream(chunkSize)); 
} 
 
std::unique_ptr<InputStream> memoryInputStream(const uint8_t* data, size_t len) 
{ 
    return std::unique_ptr<InputStream>(new MemoryInputStream2(data, len)); 
} 
 
std::unique_ptr<InputStream> memoryInputStream(const OutputStream& source) 
{ 
    const MemoryOutputStream& mos = 
        dynamic_cast<const MemoryOutputStream&>(source); 
    return (mos.data_.empty()) ? 
        std::unique_ptr<InputStream>(new MemoryInputStream2(0, 0)) : 
        std::unique_ptr<InputStream>(new MemoryInputStream(mos.data_, 
            mos.chunkSize_, 
            (mos.chunkSize_ - mos.available_))); 
} 
 
std::shared_ptr<std::vector<uint8_t> > snapshot(const OutputStream& source) 
{ 
    const MemoryOutputStream& mos = 
        dynamic_cast<const MemoryOutputStream&>(source); 
    std::shared_ptr<std::vector<uint8_t> > result(new std::vector<uint8_t>()); 
    size_t c = mos.byteCount_; 
    result->reserve(mos.byteCount_); 
    for (vector<uint8_t*>::const_iterator it = mos.data_.begin(); 
        it != mos.data_.end(); ++it) { 
        size_t n = std::min(c, mos.chunkSize_); 
        std::copy(*it, *it + n, std::back_inserter(*result)); 
        c -= n; 
    } 
    return result; 
} 
 
}   // namespace avro