text: /*
   * Side-channel API definitions for CUPS.
   *
   * Copyright 2007-2012 by Apple Inc.
   * Copyright 2006 by Easy Software Products.
   *
   * These coded instructions, statements, and computer programs are the
   * property of Apple Inc. and are protected by Federal copyright
   * law.  Distribution and use rights are outlined in the file "LICENSE.txt"
   * which should have been included with this file.  If this file is
   * missing or damaged, see the license at "http://www.cups.org/".
   *
   * This file is subject to the Apple OS-Developed Software exception.
   */
  
  #ifndef _CUPS_SIDECHANNEL_H_
  #  define _CUPS_SIDECHANNEL_H_
  
  /*
   * Include necessary headers...
   */
  
  #  include "versioning.h"
  
  
  /*
   * C++ magic...
   */
  
  #  ifdef __cplusplus
  extern "C" {
  #  endif /* __cplusplus */
  
  
  /*
   * Constants...
   */
  
  #define CUPS_SC_FD	4		/* File descriptor for select/poll */
  
  
  /*
   * Enumerations...
   */
  
  enum cups_sc_bidi_e			/**** Bidirectional capability values ****/
  {
    CUPS_SC_BIDI_NOT_SUPPORTED = 0,	/* Bidirectional I/O is not supported */
    CUPS_SC_BIDI_SUPPORTED = 1		/* Bidirectional I/O is supported */
  };
  typedef enum cups_sc_bidi_e cups_sc_bidi_t;
  					/**** Bidirectional capabilities ****/
  
  enum cups_sc_command_e			/**** Request command codes ****/
  {
    CUPS_SC_CMD_NONE = 0,			/* No command @private@ */
    CUPS_SC_CMD_SOFT_RESET = 1,		/* Do a soft reset */
    CUPS_SC_CMD_DRAIN_OUTPUT = 2,		/* Drain all pending output */
    CUPS_SC_CMD_GET_BIDI = 3,		/* Return bidirectional capabilities */
    CUPS_SC_CMD_GET_DEVICE_ID = 4,	/* Return the IEEE-1284 device ID */
    CUPS_SC_CMD_GET_STATE = 5,		/* Return the device state */
    CUPS_SC_CMD_SNMP_GET = 6,		/* Query an SNMP OID @since CUPS 1.4/macOS 10.6@ */
    CUPS_SC_CMD_SNMP_GET_NEXT = 7,	/* Query the next SNMP OID @since CUPS 1.4/macOS 10.6@ */
    CUPS_SC_CMD_GET_CONNECTED = 8,	/* Return whether the backend is "connected" to the printer @since CUPS 1.5/macOS 10.7@ */
    CUPS_SC_CMD_MAX			/* End of valid values @private@ */
  };
  typedef enum cups_sc_command_e cups_sc_command_t;
  					/**** Request command codes ****/
  
  enum cups_sc_connected_e		/**** Connectivity values ****/
  {
    CUPS_SC_NOT_CONNECTED = 0,		/* Backend is not "connected" to printer */
    CUPS_SC_CONNECTED = 1			/* Backend is "connected" to printer */
  };
  typedef enum cups_sc_connected_e cups_sc_connected_t;
  					/**** Connectivity values ****/
  
  
  enum cups_sc_state_e			/**** Printer state bits ****/
  {
    CUPS_SC_STATE_OFFLINE = 0,		/* Device is offline */
    CUPS_SC_STATE_ONLINE = 1,		/* Device is online */
    CUPS_SC_STATE_BUSY = 2,		/* Device is busy */
    CUPS_SC_STATE_ERROR = 4,		/* Other error condition */
    CUPS_SC_STATE_MEDIA_LOW = 16,		/* Paper low condition */
    CUPS_SC_STATE_MEDIA_EMPTY = 32,	/* Paper out condition */
    CUPS_SC_STATE_MARKER_LOW = 64,	/* Toner/ink low condition */
    CUPS_SC_STATE_MARKER_EMPTY = 128	/* Toner/ink out condition */
  };
  typedef enum cups_sc_state_e cups_sc_state_t;
  					/**** Printer state bits ****/
  
  enum cups_sc_status_e			/**** Response status codes ****/
  {
    CUPS_SC_STATUS_NONE,			/* No status */
    CUPS_SC_STATUS_OK,			/* Operation succeeded */
    CUPS_SC_STATUS_IO_ERROR,		/* An I/O error occurred */
    CUPS_SC_STATUS_TIMEOUT,		/* The backend did not respond */
    CUPS_SC_STATUS_NO_RESPONSE,		/* The device did not respond */
    CUPS_SC_STATUS_BAD_MESSAGE,		/* The command/response message was invalid */
    CUPS_SC_STATUS_TOO_BIG,		/* Response too big */
    CUPS_SC_STATUS_NOT_IMPLEMENTED	/* Command not implemented */
  };
  typedef enum cups_sc_status_e cups_sc_status_t;
  					/**** Response status codes ****/
  
  typedef void (*cups_sc_walk_func_t)(const char *oid, const char *data,
                                      int datalen, void *context);
  					/**** SNMP walk callback ****/
  
  
  /*
   * Prototypes...
   */
  
  extern cups_sc_status_t	cupsSideChannelDoRequest(cups_sc_command_t command,
  			                         char *data, int *datalen,
  						 double timeout) _CUPS_API_1_3;
  extern int		cupsSideChannelRead(cups_sc_command_t *command,
  			                    cups_sc_status_t *status,
  					    char *data, int *datalen,
  					    double timeout) _CUPS_API_1_3;
  extern int		cupsSideChannelWrite(cups_sc_command_t command,
  			                     cups_sc_status_t status,
  					     const char *data, int datalen,
  					     double timeout) _CUPS_API_1_3;
  
  /**** New in CUPS 1.4 ****/
  extern cups_sc_status_t	cupsSideChannelSNMPGet(const char *oid, char *data,
  			                       int *datalen, double timeout)
  					       _CUPS_API_1_4;
  extern cups_sc_status_t	cupsSideChannelSNMPWalk(const char *oid, double timeout,
  						cups_sc_walk_func_t cb,
  						void *context) _CUPS_API_1_4;
  
  
  #  ifdef __cplusplus
  }
  #  endif /* __cplusplus */
  
  #endif /* !_CUPS_SIDECHANNEL_H_ */
  