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      1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "ui/base/text/bytes_formatting.h"
      6 
      7 #include "base/i18n/number_formatting.h"
      8 #include "base/logging.h"
      9 #include "base/strings/string_util.h"
     10 #include "base/strings/utf_string_conversions.h"
     11 #include "grit/ui_strings.h"
     12 #include "ui/base/l10n/l10n_util.h"
     13 
     14 namespace ui {
     15 
     16 namespace {
     17 
     18 // Byte suffix string constants. These both must match the DataUnits enum.
     19 const int kByteStrings[] = {
     20   IDS_APP_BYTES,
     21   IDS_APP_KIBIBYTES,
     22   IDS_APP_MEBIBYTES,
     23   IDS_APP_GIBIBYTES,
     24   IDS_APP_TEBIBYTES,
     25   IDS_APP_PEBIBYTES
     26 };
     27 
     28 const int kSpeedStrings[] = {
     29   IDS_APP_BYTES_PER_SECOND,
     30   IDS_APP_KIBIBYTES_PER_SECOND,
     31   IDS_APP_MEBIBYTES_PER_SECOND,
     32   IDS_APP_GIBIBYTES_PER_SECOND,
     33   IDS_APP_TEBIBYTES_PER_SECOND,
     34   IDS_APP_PEBIBYTES_PER_SECOND
     35 };
     36 
     37 base::string16 FormatBytesInternal(int64 bytes,
     38                                    DataUnits units,
     39                                    bool show_units,
     40                                    const int* const suffix) {
     41   DCHECK(units >= DATA_UNITS_BYTE && units <= DATA_UNITS_PEBIBYTE);
     42   if (bytes < 0) {
     43     NOTREACHED() << "Negative bytes value";
     44     return base::string16();
     45   }
     46 
     47   // Put the quantity in the right units.
     48   double unit_amount = static_cast<double>(bytes);
     49   for (int i = 0; i < units; ++i)
     50     unit_amount /= 1024.0;
     51 
     52   int fractional_digits = 0;
     53   if (bytes != 0 && units != DATA_UNITS_BYTE && unit_amount < 100)
     54     fractional_digits = 1;
     55 
     56   base::string16 result = base::FormatDouble(unit_amount, fractional_digits);
     57 
     58   if (show_units)
     59     result = l10n_util::GetStringFUTF16(suffix[units], result);
     60 
     61   return result;
     62 }
     63 
     64 }  // namespace
     65 
     66 DataUnits GetByteDisplayUnits(int64 bytes) {
     67   // The byte thresholds at which we display amounts. A byte count is displayed
     68   // in unit U when kUnitThresholds[U] <= bytes < kUnitThresholds[U+1].
     69   // This must match the DataUnits enum.
     70   static const int64 kUnitThresholds[] = {
     71     0,                // DATA_UNITS_BYTE,
     72     3 * (1LL << 10),  // DATA_UNITS_KIBIBYTE,
     73     2 * (1LL << 20),  // DATA_UNITS_MEBIBYTE,
     74     1LL << 30,        // DATA_UNITS_GIBIBYTE,
     75     1LL << 40,        // DATA_UNITS_TEBIBYTE,
     76     1LL << 50         // DATA_UNITS_PEBIBYTE,
     77   };
     78 
     79   if (bytes < 0) {
     80     NOTREACHED() << "Negative bytes value";
     81     return DATA_UNITS_BYTE;
     82   }
     83 
     84   int unit_index = arraysize(kUnitThresholds);
     85   while (--unit_index > 0) {
     86     if (bytes >= kUnitThresholds[unit_index])
     87       break;
     88   }
     89 
     90   DCHECK(unit_index >= DATA_UNITS_BYTE && unit_index <= DATA_UNITS_PEBIBYTE);
     91   return DataUnits(unit_index);
     92 }
     93 
     94 base::string16 FormatBytesWithUnits(int64 bytes,
     95                                     DataUnits units,
     96                                     bool show_units) {
     97   return FormatBytesInternal(bytes, units, show_units, kByteStrings);
     98 }
     99 
    100 base::string16 FormatSpeedWithUnits(int64 bytes,
    101                                     DataUnits units,
    102                                     bool show_units) {
    103   return FormatBytesInternal(bytes, units, show_units, kSpeedStrings);
    104 }
    105 
    106 base::string16 FormatBytes(int64 bytes) {
    107   return FormatBytesWithUnits(bytes, GetByteDisplayUnits(bytes), true);
    108 }
    109 
    110 base::string16 FormatSpeed(int64 bytes) {
    111   return FormatSpeedWithUnits(bytes, GetByteDisplayUnits(bytes), true);
    112 }
    113 
    114 }  // namespace ui
    115