shaka-packager/packager/media/formats/webvtt/webvtt_utils.cc

// Copyright 2017 Google Inc. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd

#include "packager/media/formats/webvtt/webvtt_utils.h"

#include <ctype.h>
#include <inttypes.h>

#include "packager/base/logging.h"
#include "packager/base/strings/string_number_conversions.h"
#include "packager/base/strings/stringprintf.h"

namespace shaka {
namespace media {

namespace {

bool GetTotalMilliseconds(uint64_t hours,
                          uint64_t minutes,
                          uint64_t seconds,
                          uint64_t ms,
                          uint64_t* out) {
  DCHECK(out);
  if (minutes > 59 || seconds > 59 || ms > 999) {
    VLOG(1) << "Hours:" << hours << " Minutes:" << minutes
            << " Seconds:" << seconds << " MS:" << ms
            << " shoud have never made it to GetTotalMilliseconds";
    return false;
  }
  *out = 60 * 60 * 1000 * hours + 60 * 1000 * minutes + 1000 * seconds + ms;
  return true;
}
}  // namespace

bool WebVttTimestampToMs(const base::StringPiece& source, uint64_t* out) {
  DCHECK(out);

  if (source.length() < 9) {
    LOG(WARNING) << "Timestamp '" << source << "' is mal-formed";
    return false;
  }

  const size_t minutes_begin = source.length() - 9;
  const size_t seconds_begin = source.length() - 6;
  const size_t milliseconds_begin = source.length() - 3;

  uint64_t hours = 0;
  uint64_t minutes = 0;
  uint64_t seconds = 0;
  uint64_t ms = 0;

  const bool has_hours =
      minutes_begin >= 3 && source[minutes_begin - 1] == ':' &&
      base::StringToUint64(source.substr(0, minutes_begin - 1), &hours);

  if ((minutes_begin == 0 || has_hours) && source[seconds_begin - 1] == ':' &&
      source[milliseconds_begin - 1] == '.' &&
      base::StringToUint64(source.substr(minutes_begin, 2), &minutes) &&
      base::StringToUint64(source.substr(seconds_begin, 2), &seconds) &&
      base::StringToUint64(source.substr(milliseconds_begin, 3), &ms)) {
    return GetTotalMilliseconds(hours, minutes, seconds, ms, out);
  }

  LOG(WARNING) << "Timestamp '" << source << "' is mal-formed";
  return false;
}

std::string MsToWebVttTimestamp(uint64_t ms) {
  uint64_t remaining = ms;

  uint64_t only_ms = remaining % 1000;
  remaining /= 1000;
  uint64_t only_seconds = remaining % 60;
  remaining /= 60;
  uint64_t only_minutes = remaining % 60;
  remaining /= 60;
  uint64_t only_hours = remaining;

  return base::StringPrintf("%02" PRIu64 ":%02" PRIu64 ":%02" PRIu64
                            ".%03" PRIu64,
                            only_hours, only_minutes, only_seconds, only_ms);
}

std::string WebVttSettingsToString(const TextSettings& settings) {
  std::string ret;
  if (!settings.region.empty()) {
    ret += " region:";
    ret += settings.region;
  }
  if (settings.line) {
    switch (settings.line->type) {
      case TextUnitType::kPercent:
        ret += " line:";
        ret += base::DoubleToString(settings.line->value);
        ret += "%";
        break;
      case TextUnitType::kLines:
        ret += " line:";
        ret += base::DoubleToString(settings.line->value);
        break;
      case TextUnitType::kPixels:
        LOG(WARNING) << "WebVTT doesn't support pixel line settings";
        break;
    }
  }
  if (settings.position) {
    if (settings.position->type == TextUnitType::kPercent) {
      ret += " position:";
      ret += base::DoubleToString(settings.position->value);
      ret += "%";
    } else {
      LOG(WARNING) << "WebVTT only supports percent position settings";
    }
  }
  if (settings.size) {
    if (settings.size->type == TextUnitType::kPercent) {
      ret += " size:";
      ret += base::DoubleToString(settings.size->value);
      ret += "%";
    } else {
      LOG(WARNING) << "WebVTT only supports percent size settings";
    }
  }
  if (settings.writing_direction != WritingDirection::kHorizontal) {
    ret += " direction:";
    if (settings.writing_direction == WritingDirection::kVerticalGrowingLeft) {
      ret += "rl";
    } else {
      ret += "lr";
    }
  }
  switch (settings.text_alignment) {
    case TextAlignment::kStart:
      ret += " align:start";
      break;
    case TextAlignment::kEnd:
      ret += " align:end";
      break;
    case TextAlignment::kLeft:
      ret += " align:left";
      break;
    case TextAlignment::kRight:
      ret += " align:right";
      break;
    case TextAlignment::kCenter:
      break;
  }

  if (!ret.empty()) {
    DCHECK_EQ(ret[0], ' ');
    ret.erase(0, 1);
  }
  return ret;
}

std::string WebVttFragmentToString(const TextFragment& fragment) {
  return fragment.body;
}

}  // namespace media
}  // namespace shaka