code.delx.au - gnu-emacs/blob - lisp/battery.el

   1 ;;; battery.el --- display battery status information  -*- coding: iso-8859-1 -*-
   2
   3 ;; Copyright (C) 1997-1998, 2000-2012 Free Software Foundation, Inc.
   4
   5 ;; Author: Ralph Schleicher <rs@nunatak.allgaeu.org>
   6 ;; Keywords: hardware
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software: you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation, either version 3 of the License, or
  13 ;; (at your option) any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  22
  23 ;;; Commentary:
  24
  25 ;; There is at present support for GNU/Linux, OS X and Windows.  This
  26 ;; library supports both the `/proc/apm' file format of Linux version
  27 ;; 1.3.58 or newer and the `/proc/acpi/' directory structure of Linux
  28 ;; 2.4.20 and 2.6.  Darwin (OS X) is supported by using the `pmset'
  29 ;; program.  Windows is supported by the GetSystemPowerStatus API call.
  30
  31 ;;; Code:
  32
  33 (require 'timer)
  34 (eval-when-compile (require 'cl))
  35
  36 \f
  37 (defgroup battery nil
  38   "Display battery status information."
  39   :prefix "battery-"
  40   :group 'hardware)
  41
  42 ;; Either BATn or yeeloong-bat, basically.
  43 (defconst battery--linux-sysfs-regexp "[bB][aA][tT][0-9]?$")
  44
  45 (defcustom battery-status-function
  46   (cond ((and (eq system-type 'gnu/linux)
  47               (file-readable-p "/proc/apm"))
  48          'battery-linux-proc-apm)
  49         ((and (eq system-type 'gnu/linux)
  50               (file-directory-p "/proc/acpi/battery"))
  51          'battery-linux-proc-acpi)
  52         ((and (eq system-type 'gnu/linux)
  53               (file-directory-p "/sys/class/power_supply/")
  54               (directory-files "/sys/class/power_supply/" nil
  55                                battery--linux-sysfs-regexp))
  56          'battery-linux-sysfs)
  57         ((and (eq system-type 'darwin)
  58               (condition-case nil
  59                   (with-temp-buffer
  60                     (and (eq (call-process "pmset" nil t nil "-g" "ps") 0)
  61                          (> (buffer-size) 0)))
  62                 (error nil)))
  63          'battery-pmset)
  64         ((eq system-type 'windows-nt)
  65          'w32-battery-status))
  66   "Function for getting battery status information.
  67 The function has to return an alist of conversion definitions.
  68 Its cons cells are of the form
  69
  70     (CONVERSION . REPLACEMENT-TEXT)
  71
  72 CONVERSION is the character code of a \"conversion specification\"
  73 introduced by a `%' character in a control string."
  74   :type '(choice (const nil) function)
  75   :group 'battery)
  76
  77 (defcustom battery-echo-area-format
  78   (cond ((eq battery-status-function 'battery-linux-proc-acpi)
  79          "Power %L, battery %B at %r (%p%% load, remaining time %t)")
  80         ((eq battery-status-function 'battery-linux-sysfs)
  81          "Power %L, battery %B (%p%% load, remaining time %t)")
  82         ((eq battery-status-function 'battery-pmset)
  83          "%L power, battery %B (%p%% load, remaining time %t)")
  84         (battery-status-function
  85          "Power %L, battery %B (%p%% load, remaining time %t)"))
  86   "Control string formatting the string to display in the echo area.
  87 Ordinary characters in the control string are printed as-is, while
  88 conversion specifications introduced by a `%' character in the control
  89 string are substituted as defined by the current value of the variable
  90 `battery-status-function'.  Here are the ones generally available:
  91 %c Current capacity (mAh or mWh)
  92 %r Current rate of charge or discharge
  93 %B Battery status (verbose)
  94 %b Battery status: empty means high, `-' means low,
  95    `!' means critical, and `+' means charging
  96 %d Temperature (in degrees Celsius)
  97 %L AC line status (verbose)
  98 %p Battery load percentage
  99 %m Remaining time (to charge or discharge) in minutes
 100 %h Remaining time (to charge or discharge) in hours
 101 %t Remaining time (to charge or discharge) in the form `h:min'"
 102   :type '(choice string (const nil))
 103   :group 'battery)
 104
 105 (defvar battery-mode-line-string nil
 106   "String to display in the mode line.")
 107 ;;;###autoload (put 'battery-mode-line-string 'risky-local-variable t)
 108
 109 (defcustom battery-mode-line-limit 100
 110   "Percentage of full battery load below which display battery status"
 111   :version "24.1"
 112   :type 'integer
 113   :group 'battery)
 114
 115 (defcustom battery-mode-line-format
 116   (cond ((eq battery-status-function 'battery-linux-proc-acpi)
 117          "[%b%p%%,%d°C]")
 118         (battery-status-function
 119          "[%b%p%%]"))
 120   "Control string formatting the string to display in the mode line.
 121 Ordinary characters in the control string are printed as-is, while
 122 conversion specifications introduced by a `%' character in the control
 123 string are substituted as defined by the current value of the variable
 124 `battery-status-function'.  Here are the ones generally available:
 125 %c Current capacity (mAh or mWh)
 126 %r Current rate of charge or discharge
 127 %B Battery status (verbose)
 128 %b Battery status: empty means high, `-' means low,
 129    `!' means critical, and `+' means charging
 130 %d Temperature (in degrees Celsius)
 131 %L AC line status (verbose)
 132 %p Battery load percentage
 133 %m Remaining time (to charge or discharge) in minutes
 134 %h Remaining time (to charge or discharge) in hours
 135 %t Remaining time (to charge or discharge) in the form `h:min'"
 136   :type '(choice string (const nil))
 137   :group 'battery)
 138
 139 (defcustom battery-update-interval 60
 140   "Seconds after which the battery status will be updated."
 141   :type 'integer
 142   :group 'battery)
 143
 144 (defcustom battery-load-low 25
 145   "Upper bound of low battery load percentage.
 146 A battery load percentage below this number is considered low."
 147   :type 'integer
 148   :group 'battery)
 149
 150 (defcustom battery-load-critical 10
 151   "Upper bound of critical battery load percentage.
 152 A battery load percentage below this number is considered critical."
 153   :type 'integer
 154   :group 'battery)
 155
 156 (defvar battery-update-timer nil
 157   "Interval timer object.")
 158
 159 ;;;###autoload
 160 (defun battery ()
 161   "Display battery status information in the echo area.
 162 The text being displayed in the echo area is controlled by the variables
 163 `battery-echo-area-format' and `battery-status-function'."
 164   (interactive)
 165   (message "%s" (if (and battery-echo-area-format battery-status-function)
 166                     (battery-format battery-echo-area-format
 167                                     (funcall battery-status-function))
 168                   "Battery status not available")))
 169
 170 ;;;###autoload
 171 (define-minor-mode display-battery-mode
 172   "Toggle battery status display in mode line (Display Battery mode).
 173 With a prefix argument ARG, enable Display Battery mode if ARG is
 174 positive, and disable it otherwise.  If called from Lisp, enable
 175 the mode if ARG is omitted or nil.
 176
 177 The text displayed in the mode line is controlled by
 178 `battery-mode-line-format' and `battery-status-function'.
 179 The mode line is be updated every `battery-update-interval'
 180 seconds."
 181   :global t :group 'battery
 182   (setq battery-mode-line-string "")
 183   (or global-mode-string (setq global-mode-string '("")))
 184   (and battery-update-timer (cancel-timer battery-update-timer))
 185   (if (and battery-status-function battery-mode-line-format)
 186       (if (not display-battery-mode)
 187           (setq global-mode-string
 188                 (delq 'battery-mode-line-string global-mode-string))
 189         (add-to-list 'global-mode-string 'battery-mode-line-string t)
 190         (setq battery-update-timer (run-at-time nil battery-update-interval
 191                                                 'battery-update-handler))
 192         (battery-update))
 193     (message "Battery status not available")
 194     (setq display-battery-mode nil)))
 195
 196 (defun battery-update-handler ()
 197   (battery-update)
 198   (sit-for 0))
 199
 200 (defun battery-update ()
 201   "Update battery status information in the mode line."
 202   (let ((data (and battery-status-function (funcall battery-status-function))))
 203     (setq battery-mode-line-string
 204           (propertize (if (and battery-mode-line-format
 205                                (<= (car (read-from-string (cdr (assq ?p data))))
 206                                    battery-mode-line-limit))
 207                           (battery-format
 208                            battery-mode-line-format
 209                            data)
 210                         "")
 211                       'face
 212                       (and (<= (car (read-from-string (cdr (assq ?p data))))
 213                                    battery-load-critical)
 214                            'error)
 215                       'help-echo "Battery status information")))
 216   (force-mode-line-update))
 217 \f
 218 ;;; `/proc/apm' interface for Linux.
 219
 220 (defconst battery-linux-proc-apm-regexp
 221   (concat "^\\([^ ]+\\)"                ; Driver version.
 222           " \\([^ ]+\\)"                ; APM BIOS version.
 223           " 0x\\([0-9a-f]+\\)"          ; APM BIOS flags.
 224           " 0x\\([0-9a-f]+\\)"          ; AC line status.
 225           " 0x\\([0-9a-f]+\\)"          ; Battery status.
 226           " 0x\\([0-9a-f]+\\)"          ; Battery flags.
 227           " \\(-?[0-9]+\\)%"            ; Load percentage.
 228           " \\(-?[0-9]+\\)"             ; Remaining time.
 229           " \\(.*\\)"                   ; Time unit.
 230           "$")
 231   "Regular expression matching contents of `/proc/apm'.")
 232
 233 (defun battery-linux-proc-apm ()
 234   "Get APM status information from Linux (the kernel).
 235 This function works only with the new `/proc/apm' format introduced
 236 in Linux version 1.3.58.
 237
 238 The following %-sequences are provided:
 239 %v Linux driver version
 240 %V APM BIOS version
 241 %I APM BIOS status (verbose)
 242 %L AC line status (verbose)
 243 %B Battery status (verbose)
 244 %b Battery status, empty means high, `-' means low,
 245    `!' means critical, and `+' means charging
 246 %p Battery load percentage
 247 %s Remaining time (to charge or discharge) in seconds
 248 %m Remaining time (to charge or discharge) in minutes
 249 %h Remaining time (to charge or discharge) in hours
 250 %t Remaining time (to charge or discharge) in the form `h:min'"
 251   (let (driver-version bios-version bios-interface line-status
 252         battery-status battery-status-symbol load-percentage
 253         seconds minutes hours remaining-time tem)
 254     (with-temp-buffer
 255       (ignore-errors (insert-file-contents "/proc/apm"))
 256       (when (re-search-forward battery-linux-proc-apm-regexp)
 257         (setq driver-version (match-string 1))
 258         (setq bios-version (match-string 2))
 259         (setq tem (string-to-number (match-string 3) 16))
 260         (if (not (logand tem 2))
 261             (setq bios-interface "not supported")
 262           (setq bios-interface "enabled")
 263           (cond ((logand tem 16) (setq bios-interface "disabled"))
 264                 ((logand tem 32) (setq bios-interface "disengaged")))
 265           (setq tem (string-to-number (match-string 4) 16))
 266           (cond ((= tem 0) (setq line-status "off-line"))
 267                 ((= tem 1) (setq line-status "on-line"))
 268                 ((= tem 2) (setq line-status "on backup")))
 269           (setq tem (string-to-number (match-string 6) 16))
 270           (if (= tem 255)
 271               (setq battery-status "N/A")
 272             (setq tem (string-to-number (match-string 5) 16))
 273             (cond ((= tem 0) (setq battery-status "high"
 274                                    battery-status-symbol ""))
 275                   ((= tem 1) (setq battery-status "low"
 276                                    battery-status-symbol "-"))
 277                   ((= tem 2) (setq battery-status "critical"
 278                                    battery-status-symbol "!"))
 279                   ((= tem 3) (setq battery-status "charging"
 280                                    battery-status-symbol "+")))
 281             (setq load-percentage (match-string 7))
 282             (setq seconds (string-to-number (match-string 8)))
 283             (and (string-equal (match-string 9) "min")
 284                  (setq seconds (* 60 seconds)))
 285             (setq minutes (/ seconds 60)
 286                   hours (/ seconds 3600))
 287             (setq remaining-time
 288                   (format "%d:%02d" hours (- minutes (* 60 hours))))))))
 289     (list (cons ?v (or driver-version "N/A"))
 290           (cons ?V (or bios-version "N/A"))
 291           (cons ?I (or bios-interface "N/A"))
 292           (cons ?L (or line-status "N/A"))
 293           (cons ?B (or battery-status "N/A"))
 294           (cons ?b (or battery-status-symbol ""))
 295           (cons ?p (or load-percentage "N/A"))
 296           (cons ?s (or (and seconds (number-to-string seconds)) "N/A"))
 297           (cons ?m (or (and minutes (number-to-string minutes)) "N/A"))
 298           (cons ?h (or (and hours (number-to-string hours)) "N/A"))
 299           (cons ?t (or remaining-time "N/A")))))
 300
 301 \f
 302 ;;; `/proc/acpi/' interface for Linux.
 303
 304 (defun battery-linux-proc-acpi ()
 305   "Get ACPI status information from Linux (the kernel).
 306 This function works only with the `/proc/acpi/' format introduced
 307 in Linux version 2.4.20 and 2.6.0.
 308
 309 The following %-sequences are provided:
 310 %c Current capacity (mAh)
 311 %r Current rate
 312 %B Battery status (verbose)
 313 %b Battery status, empty means high, `-' means low,
 314    `!' means critical, and `+' means charging
 315 %d Temperature (in degrees Celsius)
 316 %L AC line status (verbose)
 317 %p Battery load percentage
 318 %m Remaining time (to charge or discharge) in minutes
 319 %h Remaining time (to charge or discharge) in hours
 320 %t Remaining time (to charge or discharge) in the form `h:min'"
 321   (let ((design-capacity 0)
 322         (last-full-capacity 0)
 323         full-capacity
 324         (warn 0)
 325         (low 0)
 326         capacity rate rate-type charging-state minutes hours)
 327     ;; ACPI provides information about each battery present in the system in
 328     ;; a separate subdirectory.  We are going to merge the available
 329     ;; information together since displaying for a variable amount of
 330     ;; batteries seems overkill for format-strings.
 331     (with-temp-buffer
 332       (dolist (dir (ignore-errors (directory-files "/proc/acpi/battery/"
 333                                                    t "\\`[^.]")))
 334         (erase-buffer)
 335         (ignore-errors (insert-file-contents (expand-file-name "state" dir)))
 336         (when (re-search-forward "present: +yes$" nil t)
 337           (and (re-search-forward "charging state: +\\(.*\\)$" nil t)
 338                (member charging-state '("unknown" "charged" nil))
 339                ;; On most multi-battery systems, most of the time only one
 340                ;; battery is "charging"/"discharging", the others are
 341                ;; "unknown".
 342                (setq charging-state (match-string 1)))
 343           (when (re-search-forward "present rate: +\\([0-9]+\\) \\(m[AW]\\)$"
 344                                    nil t)
 345             (setq rate (+ (or rate 0) (string-to-number (match-string 1))))
 346             (when (> rate 0)
 347               (setq rate-type (or (and rate-type
 348                                      (if (string= rate-type (match-string 2))
 349                                          rate-type
 350                                        (error
 351                                         "Inconsistent rate types (%s vs. %s)"
 352                                         rate-type (match-string 2))))
 353                                   (match-string 2)))))
 354           (when (re-search-forward "remaining capacity: +\\([0-9]+\\) m[AW]h$"
 355                                    nil t)
 356             (setq capacity
 357                   (+ (or capacity 0) (string-to-number (match-string 1))))))
 358         (goto-char (point-max))
 359         (ignore-errors (insert-file-contents (expand-file-name "info" dir)))
 360         (when (re-search-forward "present: +yes$" nil t)
 361           (when (re-search-forward "design capacity: +\\([0-9]+\\) m[AW]h$"
 362                                    nil t)
 363             (incf design-capacity (string-to-number (match-string 1))))
 364           (when (re-search-forward "last full capacity: +\\([0-9]+\\) m[AW]h$"
 365                                    nil t)
 366             (incf last-full-capacity (string-to-number (match-string 1))))
 367           (when (re-search-forward
 368                  "design capacity warning: +\\([0-9]+\\) m[AW]h$" nil t)
 369             (incf warn (string-to-number (match-string 1))))
 370           (when (re-search-forward "design capacity low: +\\([0-9]+\\) m[AW]h$"
 371                                    nil t)
 372             (incf low (string-to-number (match-string 1)))))))
 373     (setq full-capacity (if (> last-full-capacity 0)
 374                             last-full-capacity design-capacity))
 375     (and capacity rate
 376          (setq minutes (if (zerop rate) 0
 377                          (floor (* (/ (float (if (string= charging-state
 378                                                           "charging")
 379                                                  (- full-capacity capacity)
 380                                                capacity))
 381                                       rate)
 382                                    60)))
 383                hours (/ minutes 60)))
 384     (list (cons ?c (or (and capacity (number-to-string capacity)) "N/A"))
 385           (cons ?L (or (battery-search-for-one-match-in-files
 386                         (mapcar (lambda (e) (concat e "/state"))
 387                                 (ignore-errors
 388                                   (directory-files "/proc/acpi/ac_adapter/"
 389                                                    t "\\`[^.]")))
 390                         "state: +\\(.*\\)$" 1)
 391
 392                        "N/A"))
 393           (cons ?d (or (battery-search-for-one-match-in-files
 394                         (mapcar (lambda (e) (concat e "/temperature"))
 395                                 (ignore-errors
 396                                   (directory-files "/proc/acpi/thermal_zone/"
 397                                                    t "\\`[^.]")))
 398                         "temperature: +\\([0-9]+\\) C$" 1)
 399
 400                        "N/A"))
 401           (cons ?r (or (and rate (concat (number-to-string rate) " "
 402                                          rate-type)) "N/A"))
 403           (cons ?B (or charging-state "N/A"))
 404           (cons ?b (or (and (string= charging-state "charging") "+")
 405                        (and capacity (< capacity low) "!")
 406                        (and capacity (< capacity warn) "-")
 407                        ""))
 408           (cons ?h (or (and hours (number-to-string hours)) "N/A"))
 409           (cons ?m (or (and minutes (number-to-string minutes)) "N/A"))
 410           (cons ?t (or (and minutes
 411                             (format "%d:%02d" hours (- minutes (* 60 hours))))
 412                        "N/A"))
 413           (cons ?p (or (and full-capacity capacity
 414                             (> full-capacity 0)
 415                             (number-to-string
 416                              (floor (/ capacity
 417                                        (/ (float full-capacity) 100)))))
 418                        "N/A")))))
 419
 420 \f
 421 ;;; `/sys/class/power_supply/BATN' interface for Linux.
 422
 423 (defun battery-linux-sysfs ()
 424   "Get ACPI status information from Linux kernel.
 425 This function works only with the new `/sys/class/power_supply/'
 426 format introduced in Linux version 2.4.25.
 427
 428 The following %-sequences are provided:
 429 %c Current capacity (mAh or mWh)
 430 %r Current rate
 431 %B Battery status (verbose)
 432 %d Temperature (in degrees Celsius)
 433 %p Battery load percentage
 434 %L AC line status (verbose)
 435 %m Remaining time (to charge or discharge) in minutes
 436 %h Remaining time (to charge or discharge) in hours
 437 %t Remaining time (to charge or discharge) in the form `h:min'"
 438   (let (charging-state rate temperature hours
 439         (charge-full 0.0)
 440         (charge-now 0.0)
 441         (energy-full 0.0)
 442         (energy-now 0.0))
 443     ;; SysFS provides information about each battery present in the
 444     ;; system in a separate subdirectory.  We are going to merge the
 445     ;; available information together.
 446     (with-temp-buffer
 447       (dolist (dir (ignore-errors
 448                     (directory-files
 449                      "/sys/class/power_supply/" t
 450                      battery--linux-sysfs-regexp)))
 451         (erase-buffer)
 452         (ignore-errors (insert-file-contents
 453                         (expand-file-name "uevent" dir)))
 454         (when (re-search-forward "POWER_SUPPLY_PRESENT=1$" nil t)
 455           (goto-char (point-min))
 456           (and (re-search-forward "POWER_SUPPLY_STATUS=\\(.*\\)$" nil t)
 457                (member charging-state '("Unknown" "Full" nil))
 458                (setq charging-state (match-string 1)))
 459           (when (re-search-forward
 460                  "POWER_SUPPLY_\\(CURRENT\\|POWER\\)_NOW=\\([0-9]*\\)$"
 461                  nil t)
 462             (setq rate (float (string-to-number (match-string 2)))))
 463           (when (re-search-forward "POWER_SUPPLY_TEMP=\\([0-9]*\\)$" nil t)
 464             (setq temperature (match-string 1)))
 465           (let (full-string now-string)
 466             ;; Sysfs may list either charge (mAh) or energy (mWh).
 467             ;; Keep track of both, and choose which to report later.
 468             (cond ((and (re-search-forward
 469                          "POWER_SUPPLY_CHARGE_FULL=\\([0-9]*\\)$" nil t)
 470                         (setq full-string (match-string 1))
 471                         (re-search-forward
 472                          "POWER_SUPPLY_CHARGE_NOW=\\([0-9]*\\)$" nil t)
 473                         (setq now-string (match-string 1)))
 474                    (setq charge-full (+ charge-full
 475                                         (string-to-number full-string))
 476                          charge-now  (+ charge-now
 477                                         (string-to-number now-string))))
 478                   ((and (re-search-forward
 479                          "POWER_SUPPLY_ENERGY_FULL=\\([0-9]*\\)$" nil t)
 480                         (setq full-string (match-string 1))
 481                         (re-search-forward
 482                          "POWER_SUPPLY_ENERGY_NOW=\\([0-9]*\\)$" nil t)
 483                         (setq now-string (match-string 1)))
 484                    (setq energy-full (+ energy-full
 485                                         (string-to-number full-string))
 486                          energy-now  (+ energy-now
 487                                         (string-to-number now-string))))))
 488           (goto-char (point-min))
 489           (when (and energy-now rate (not (zerop rate))
 490                      (re-search-forward
 491                       "POWER_SUPPLY_VOLTAGE_NOW=\\([0-9]*\\)$" nil t))
 492             (let ((remaining (if (string= charging-state "Discharging")
 493                                  energy-now
 494                                (- energy-full energy-now))))
 495               (setq hours (/ (/ (* remaining (string-to-number
 496                                               (match-string 1)))
 497                                 rate)
 498                              10000000.0)))))))
 499     (list (cons ?c (cond ((or (> charge-full 0) (> charge-now 0))
 500                           (number-to-string charge-now))
 501                          ((or (> energy-full 0) (> energy-now 0))
 502                           (number-to-string energy-now))
 503                          (t "N/A")))
 504           (cons ?r (if rate (format "%.1f" (/ rate 1000000.0)) "N/A"))
 505           (cons ?m (if hours (format "%d" (* hours 60)) "N/A"))
 506           (cons ?h (if hours (format "%d" hours) "N/A"))
 507           (cons ?t (if hours
 508                        (format "%d:%02d" hours (* (- hours (floor hours)) 60))
 509                      "N/A"))
 510           (cons ?d (or temperature "N/A"))
 511           (cons ?B (or charging-state "N/A"))
 512           (cons ?p (cond ((and (> charge-full 0) (> charge-now 0))
 513                           (format "%.1f"
 514                                   (/ (* 100 charge-now) charge-full)))
 515                          ((> energy-full 0)
 516                           (format "%.1f"
 517                                   (/ (* 100 energy-now) energy-full)))
 518                          (t "N/A")))
 519           (cons ?L (if (file-readable-p "/sys/class/power_supply/AC/online")
 520                        (if (battery-search-for-one-match-in-files
 521                             (list "/sys/class/power_supply/AC/online"
 522                                   "/sys/class/power_supply/ACAD/online")
 523                             "1" 0)
 524                            "AC"
 525                          "BAT")
 526                      "N/A")))))
 527 \f
 528 ;;; `pmset' interface for Darwin (OS X).
 529
 530 (defun battery-pmset ()
 531   "Get battery status information using `pmset'.
 532
 533 The following %-sequences are provided:
 534 %L Power source (verbose)
 535 %B Battery status (verbose)
 536 %b Battery status, empty means high, `-' means low,
 537    `!' means critical, and `+' means charging
 538 %p Battery load percentage
 539 %h Remaining time in hours
 540 %m Remaining time in minutes
 541 %t Remaining time in the form `h:min'"
 542   (let (power-source load-percentage battery-status battery-status-symbol
 543         remaining-time hours minutes)
 544     (with-temp-buffer
 545       (ignore-errors (call-process "pmset" nil t nil "-g" "ps"))
 546       (goto-char (point-min))
 547       (when (re-search-forward "Currentl?y drawing from '\\(AC\\|Battery\\) Power'" nil t)
 548         (setq power-source (match-string 1))
 549         (when (re-search-forward "^ -InternalBattery-0[ \t]+" nil t)
 550           (when (looking-at "\\([0-9]\\{1,3\\}\\)%")
 551             (setq load-percentage (match-string 1))
 552             (goto-char (match-end 0))
 553             (cond ((looking-at "; charging")
 554                    (setq battery-status "charging"
 555                          battery-status-symbol "+"))
 556                   ((< (string-to-number load-percentage) battery-load-low)
 557                    (setq battery-status "low"
 558                          battery-status-symbol "-"))
 559                   ((< (string-to-number load-percentage) battery-load-critical)
 560                    (setq battery-status "critical"
 561                          battery-status-symbol "!"))
 562                   (t
 563                    (setq battery-status "high"
 564                          battery-status-symbol "")))
 565             (when (re-search-forward "\\(\\([0-9]+\\):\\([0-9]+\\)\\) remaining"  nil t)
 566               (setq remaining-time (match-string 1))
 567               (let ((h (string-to-number (match-string 2)))
 568                     (m (string-to-number (match-string 3))))
 569                 (setq hours (number-to-string (+ h (if (< m 30) 0 1)))
 570                       minutes (number-to-string (+ (* h 60) m)))))))))
 571     (list (cons ?L (or power-source "N/A"))
 572           (cons ?p (or load-percentage "N/A"))
 573           (cons ?B (or battery-status "N/A"))
 574           (cons ?b (or battery-status-symbol ""))
 575           (cons ?h (or hours "N/A"))
 576           (cons ?m (or minutes "N/A"))
 577           (cons ?t (or remaining-time "N/A")))))
 578
 579 \f
 580 ;;; Private functions.
 581
 582 (defun battery-format (format alist)
 583   "Substitute %-sequences in FORMAT."
 584   (replace-regexp-in-string
 585    "%."
 586    (lambda (str)
 587      (let ((char (aref str 1)))
 588        (if (eq char ?%) "%"
 589          (or (cdr (assoc char alist)) ""))))
 590    format t t))
 591
 592 (defun battery-search-for-one-match-in-files (files regexp match-num)
 593   "Search REGEXP in the content of the files listed in FILES.
 594 If a match occurred, return the parenthesized expression numbered by
 595 MATCH-NUM in the match.  Otherwise, return nil."
 596   (with-temp-buffer
 597     (catch 'found
 598       (dolist (file files)
 599         (and (ignore-errors (insert-file-contents file nil nil nil 'replace))
 600              (re-search-forward regexp nil t)
 601              (throw 'found (match-string match-num)))))))
 602
 603 \f
 604 (provide 'battery)
 605
 606 ;;; battery.el ends here