text: // Copyright (c) 2012 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.
  
  #include "base/version.h"
  
  #include <stddef.h>
  
  #include <algorithm>
  
  #include "base/logging.h"
  #include "base/strings/string_number_conversions.h"
  #include "base/strings/string_split.h"
  #include "base/strings/string_util.h"
  
  namespace base {
  
  namespace {
  
  // Parses the |numbers| vector representing the different numbers
  // inside the version string and constructs a vector of valid integers. It stops
  // when it reaches an invalid item (including the wildcard character). |parsed|
  // is the resulting integer vector. Function returns true if all numbers were
  // parsed successfully, false otherwise.
  bool ParseVersionNumbers(const std::string& version_str,
                           std::vector<uint16>* parsed) {
    std::vector<std::string> numbers;
    SplitString(version_str, '.', &numbers);
    if (numbers.empty())
      return false;
  
    for (std::vector<std::string>::const_iterator it = numbers.begin();
         it != numbers.end(); ++it) {
      if (StartsWithASCII(*it, "+", false))
        return false;
      int num;
      if (!StringToInt(*it, &num))
        return false;
  
      if (num < 0)
        return false;
  
      const uint16 max = 0xFFFF;
      if (num > max)
        return false;
  
      // This throws out leading zeros for the first item only.
      if (it == numbers.begin() && IntToString(num) != *it)
        return false;
  
      parsed->push_back(static_cast<uint16>(num));
    }
    return true;
  }
  
  // Compares version components in |components1| with components in
  // |components2|. Returns -1, 0 or 1 if |components1| is less than, equal to,
  // or greater than |components2|, respectively.
  int CompareVersionComponents(const std::vector<uint16>& components1,
                               const std::vector<uint16>& components2) {
    const size_t count = std::min(components1.size(), components2.size());
    for (size_t i = 0; i < count; ++i) {
      if (components1[i] > components2[i])
        return 1;
      if (components1[i] < components2[i])
        return -1;
    }
    if (components1.size() > components2.size()) {
      for (size_t i = count; i < components1.size(); ++i) {
        if (components1[i] > 0)
          return 1;
      }
    } else if (components1.size() < components2.size()) {
      for (size_t i = count; i < components2.size(); ++i) {
        if (components2[i] > 0)
          return -1;
      }
    }
    return 0;
  }
  
  }  // namespace
  
  Version::Version() {
  }
  
  Version::~Version() {
  }
  
  Version::Version(const std::string& version_str) {
    std::vector<uint16> parsed;
    if (!ParseVersionNumbers(version_str, &parsed))
      return;
  
    components_.swap(parsed);
  }
  
  bool Version::IsValid() const {
    return (!components_.empty());
  }
  
  // static
  bool Version::IsValidWildcardString(const std::string& wildcard_string) {
    std::string version_string = wildcard_string;
    if (EndsWith(wildcard_string.c_str(), ".*", false))
      version_string = wildcard_string.substr(0, wildcard_string.size() - 2);
  
    Version version(version_string);
    return version.IsValid();
  }
  
  bool Version::IsOlderThan(const std::string& version_str) const {
    Version proposed_ver(version_str);
    if (!proposed_ver.IsValid())
      return false;
    return (CompareTo(proposed_ver) < 0);
  }
  
  int Version::CompareToWildcardString(const std::string& wildcard_string) const {
    DCHECK(IsValid());
    DCHECK(Version::IsValidWildcardString(wildcard_string));
  
    // Default behavior if the string doesn't end with a wildcard.
    if (!EndsWith(wildcard_string.c_str(), ".*", false)) {
      Version version(wildcard_string);
      DCHECK(version.IsValid());
      return CompareTo(version);
    }
  
    std::vector<uint16> parsed;
    const bool success = ParseVersionNumbers(
        wildcard_string.substr(0, wildcard_string.length() - 2), &parsed);
    DCHECK(success);
    const int comparison = CompareVersionComponents(components_, parsed);
    // If the version is smaller than the wildcard version's |parsed| vector,
    // then the wildcard has no effect (e.g. comparing 1.2.3 and 1.3.*) and the
    // version is still smaller. Same logic for equality (e.g. comparing 1.2.2 to
    // 1.2.2.* is 0 regardless of the wildcard). Under this logic,
    // 1.2.0.0.0.0 compared to 1.2.* is 0.
    if (comparison == -1 || comparison == 0)
      return comparison;
  
    // Catch the case where the digits of |parsed| are found in |components_|,
    // which means that the two are equal since |parsed| has a trailing "*".
    // (e.g. 1.2.3 vs. 1.2.* will return 0). All other cases return 1 since
    // components is greater (e.g. 3.2.3 vs 1.*).
    DCHECK_GT(parsed.size(), 0UL);
    const size_t min_num_comp = std::min(components_.size(), parsed.size());
    for (size_t i = 0; i < min_num_comp; ++i) {
      if (components_[i] != parsed[i])
        return 1;
    }
    return 0;
  }
  
  bool Version::Equals(const Version& that) const {
    DCHECK(IsValid());
    DCHECK(that.IsValid());
    return (CompareTo(that) == 0);
  }
  
  int Version::CompareTo(const Version& other) const {
    DCHECK(IsValid());
    DCHECK(other.IsValid());
    return CompareVersionComponents(components_, other.components_);
  }
  
  const std::string Version::GetString() const {
    DCHECK(IsValid());
    std::string version_str;
    size_t count = components_.size();
    for (size_t i = 0; i < count - 1; ++i) {
      version_str.append(IntToString(components_[i]));
      version_str.append(".");
    }
    version_str.append(IntToString(components_[count - 1]));
    return version_str;
  }
  
  }  // namespace base
  