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/*
* Copyright (C) 2017 The Android Open Source Project
*
* Licensed 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
*
* http://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.
*/
#pragma once
#include <stddef.h>
#include <string>
#include <vector>
#include <android-base/logging.h>
#include <android-base/parseint.h>
#include <android-base/strings.h>
struct RangeSet {
size_t count; // Limit is INT_MAX.
size_t size; // The number of blocks in the RangeSet.
std::vector<size_t> pos; // Actual limit is INT_MAX.
static RangeSet Parse(const std::string& range_text) {
std::vector<std::string> pieces = android::base::Split(range_text, ",");
CHECK_GE(pieces.size(), static_cast<size_t>(3)) << "Invalid range text: " << range_text;
size_t num;
CHECK(android::base::ParseUint(pieces[0], &num, static_cast<size_t>(INT_MAX)))
<< "Failed to parse the number of tokens: " << range_text;
CHECK_NE(num, static_cast<size_t>(0)) << "Invalid number of tokens: " << range_text;
CHECK_EQ(num % 2, static_cast<size_t>(0)) << "Number of tokens must be even: " << range_text;
CHECK_EQ(num, pieces.size() - 1) << "Mismatching number of tokens: " << range_text;
std::vector<size_t> pairs(num);
size_t size = 0;
for (size_t i = 0; i < num; i += 2) {
CHECK(android::base::ParseUint(pieces[i + 1], &pairs[i], static_cast<size_t>(INT_MAX)));
CHECK(android::base::ParseUint(pieces[i + 2], &pairs[i + 1], static_cast<size_t>(INT_MAX)));
CHECK_LT(pairs[i], pairs[i + 1])
<< "Empty or negative range: " << pairs[i] << ", " << pairs[i + 1];
size_t sz = pairs[i + 1] - pairs[i];
CHECK_LE(size, SIZE_MAX - sz) << "RangeSet size overflow";
size += sz;
}
return RangeSet{ num / 2, size, std::move(pairs) };
}
// Get the block number for the i-th (starting from 0) block in the RangeSet.
size_t GetBlockNumber(size_t idx) const {
CHECK_LT(idx, size) << "Index " << idx << " is greater than RangeSet size " << size;
for (size_t i = 0; i < pos.size(); i += 2) {
if (idx < pos[i + 1] - pos[i]) {
return pos[i] + idx;
}
idx -= (pos[i + 1] - pos[i]);
}
CHECK(false);
return 0; // Unreachable, but to make compiler happy.
}
// RangeSet has half-closed half-open bounds. For example, "3,5" contains blocks 3 and 4. So "3,5"
// and "5,7" are not overlapped.
bool Overlaps(const RangeSet& other) const {
for (size_t i = 0; i < count; ++i) {
size_t start = pos[i * 2];
size_t end = pos[i * 2 + 1];
for (size_t j = 0; j < other.count; ++j) {
size_t other_start = other.pos[j * 2];
size_t other_end = other.pos[j * 2 + 1];
// [start, end) vs [other_start, other_end)
if (!(other_start >= end || start >= other_end)) {
return true;
}
}
}
return false;
}
bool operator==(const RangeSet& other) const {
return (count == other.count && size == other.size && pos == other.pos);
}
};
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