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// Copyright (c) 2006-2008 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 "chrome/browser/safe_browsing/chunk_range.h"
#include "base/logging.h"
#include "base/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 -----------------------------------------------------------
// Traverse the chunks vector looking for contiguous integers.
void ChunksToRanges(const std::vector<int>& chunks,
std::vector<ChunkRange>* ranges) {
DCHECK(ranges);
for (size_t i = 0; i < chunks.size(); ++i) {
int start = static_cast<int>(i);
int next = start + 1;
while (next < static_cast<int>(chunks.size()) &&
(chunks[start] == chunks[next] - 1 ||
chunks[start] == chunks[next])) {
++start;
++next;
}
ranges->push_back(ChunkRange(chunks[i], chunks[start]));
if (next >= static_cast<int>(chunks.size()))
break;
i = start;
}
}
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);
}
}
}
void RangesToString(const std::vector<ChunkRange>& ranges,
std::string* result) {
DCHECK(result);
result->clear();
std::vector<ChunkRange>::const_iterator it = ranges.begin();
for (; it != ranges.end(); ++it) {
if (!result->empty())
result->append(",");
if (it->start() == it->stop()) {
std::string num_buf = IntToString(it->start());
result->append(num_buf);
} else {
result->append(StringPrintf("%d-%d", it->start(), it->stop()));
}
}
}
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;
SplitString(input, ',', &chunk_parts);
for (size_t i = 0; i < chunk_parts.size(); ++i) {
std::vector<std::string> chunk_ranges;
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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