ui/base/text/bytes_formatting.cc

   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