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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.
//
// Implementation of ChunkRange class.
#include <algorithm>
#include "chrome/browser/safe_browsing/chunk_range.h"
#include "base/logging.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_split.h"
#include "base/strings/string_util.h"
ChunkRange::ChunkRange(int start) : start_(start), stop_(start) {
}
ChunkRange::ChunkRange(int start, int stop) : start_(start), stop_(stop) {
}
ChunkRange::ChunkRange(const ChunkRange& rhs)
: start_(rhs.start()), stop_(rhs.stop()) {
}
// Helper functions -----------------------------------------------------------
void ChunksToRangeString(const std::vector<int>& chunks, std::string* result) {
// The following code requires the range to be sorted.
std::vector<int> sorted_chunks(chunks);
std::sort(sorted_chunks.begin(), sorted_chunks.end());
DCHECK(result);
result->clear();
std::vector<int>::const_iterator iter = sorted_chunks.begin();
while (iter != sorted_chunks.end()) {
const int range_begin = *iter;
int range_end = *iter;
// Extend the range forward across duplicates and increments.
for (; iter != sorted_chunks.end() && *iter <= range_end + 1; ++iter) {
range_end = *iter;
}
if (!result->empty())
result->append(",");
result->append(base::IntToString(range_begin));
if (range_end > range_begin) {
result->append("-");
result->append(base::IntToString(range_end));
}
}
}
void RangesToChunks(const std::vector<ChunkRange>& ranges,
std::vector<int>* chunks) {
DCHECK(chunks);
for (size_t i = 0; i < ranges.size(); ++i) {
const ChunkRange& range = ranges[i];
for (int chunk = range.start(); chunk <= range.stop(); ++chunk) {
chunks->push_back(chunk);
}
}
}
bool StringToRanges(const std::string& input,
std::vector<ChunkRange>* ranges) {
DCHECK(ranges);
// Crack the string into chunk parts, then crack each part looking for a
// range.
std::vector<std::string> chunk_parts;
base::SplitString(input, ',', &chunk_parts);
for (size_t i = 0; i < chunk_parts.size(); ++i) {
std::vector<std::string> chunk_ranges;
base::SplitString(chunk_parts[i], '-', &chunk_ranges);
int start = atoi(chunk_ranges[0].c_str());
int stop = start;
if (chunk_ranges.size() == 2)
stop = atoi(chunk_ranges[1].c_str());
if (start == 0 || stop == 0) {
// atoi error, since chunk numbers are guaranteed to never be 0.
ranges->clear();
return false;
}
ranges->push_back(ChunkRange(start, stop));
}
return true;
}
// Binary search over a series of ChunkRanges.
bool IsChunkInRange(int chunk_number, const std::vector<ChunkRange>& ranges) {
if (ranges.empty())
return false;
int low = 0;
int high = ranges.size() - 1;
while (low <= high) {
// http://googleresearch.blogspot.com/2006/06/extra-extra-read-all-about-it-nearly.html
int mid = ((unsigned int)low + (unsigned int)high) >> 1;
const ChunkRange& chunk = ranges[mid];
if ((chunk.stop() >= chunk_number) && (chunk.start() <= chunk_number))
return true; // chunk_number is in range.
// Adjust our mid point.
if (chunk.stop() < chunk_number)
low = mid + 1;
else
high = mid - 1;
}
return false;
}
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