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// Copyright (c) 2010 The Chromium 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 PDF_CHUNK_STREAM_H_
#define PDF_CHUNK_STREAM_H_
#include <stddef.h>
#include <string.h>
#include <algorithm>
#include <array>
#include <memory>
#include <utility>
#include <vector>
#include "pdf/range_set.h"
namespace chrome_pdf {
// This class collects a chunks of data into one data stream. Client can check
// if data in certain range is available, and get missing chunks of data.
template <uint32_t N>
class ChunkStream {
public:
static constexpr uint32_t kChunkSize = N;
using ChunkData = typename std::array<unsigned char, N>;
ChunkStream() {}
~ChunkStream() {}
void SetChunkData(uint32_t chunk_index, std::unique_ptr<ChunkData> data) {
if (!data)
return;
if (chunk_index >= data_.size())
data_.resize(chunk_index + 1);
if (!data_[chunk_index])
++filled_chunks_count_;
data_[chunk_index] = std::move(data);
filled_chunks_.Union(gfx::Range(chunk_index, chunk_index + 1));
}
bool ReadData(const gfx::Range& range, void* buffer) const {
if (!IsRangeAvailable(range))
return false;
unsigned char* data_buffer = static_cast<unsigned char*>(buffer);
uint32_t start = range.start();
while (start != range.end()) {
const uint32_t chunk_index = GetChunkIndex(start);
const uint32_t chunk_start = start % kChunkSize;
const uint32_t len =
std::min(kChunkSize - chunk_start, range.end() - start);
memcpy(data_buffer, data_[chunk_index]->data() + chunk_start, len);
data_buffer += len;
start += len;
}
return true;
}
uint32_t GetChunkIndex(uint32_t offset) const { return offset / kChunkSize; }
gfx::Range GetChunksRange(uint32_t offset, uint32_t size) const {
return gfx::Range(GetChunkIndex(offset), GetChunkEnd(offset + size));
}
bool IsRangeAvailable(const gfx::Range& range) const {
if (!range.IsValid() || range.is_reversed() ||
(eof_pos_ > 0 && eof_pos_ < range.end())) {
return false;
}
if (range.is_empty())
return true;
const gfx::Range chunks_range(GetChunkIndex(range.start()),
GetChunkEnd(range.end()));
return filled_chunks_.Contains(chunks_range);
}
bool IsChunkAvailable(uint32_t chunk_index) const {
return filled_chunks_.Contains(chunk_index);
}
void set_eof_pos(uint32_t eof_pos) { eof_pos_ = eof_pos; }
uint32_t eof_pos() const { return eof_pos_; }
const RangeSet& filled_chunks() const { return filled_chunks_; }
bool IsComplete() const {
return eof_pos_ > 0 && IsRangeAvailable(gfx::Range(0, eof_pos_));
}
bool IsValidChunkIndex(uint32_t chunk_index) const {
return !eof_pos_ || (chunk_index <= GetChunkIndex(eof_pos_ - 1));
}
void Clear() {
data_.clear();
eof_pos_ = 0;
filled_chunks_.Clear();
filled_chunks_count_ = 0;
}
uint32_t filled_chunks_count() const { return filled_chunks_count_; }
uint32_t total_chunks_count() const { return GetChunkEnd(eof_pos_); }
private:
uint32_t GetChunkEnd(uint32_t offset) const {
return (offset + kChunkSize - 1) / kChunkSize;
}
std::vector<std::unique_ptr<ChunkData>> data_;
uint32_t eof_pos_ = 0;
RangeSet filled_chunks_;
uint32_t filled_chunks_count_ = 0;
};
}; // namespace chrome_pdf
#endif // PDF_CHUNK_STREAM_H_
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