diff options
Diffstat (limited to 'ql')
| -rw-r--r-- | ql/ql.go | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/ql/ql.go b/ql/ql.go new file mode 100644 index 0000000..9f507da --- /dev/null +++ b/ql/ql.go @@ -0,0 +1,218 @@ +// Package ql is a Linux driver for Brother QL-series printers. +package ql + +// Resources: +// http://www.undocprint.org/formats/page_description_languages/brother_p-touch + +import ( + "errors" + "io" + "os" + "path/filepath" + "regexp" + "strings" + "syscall" + "time" + "unsafe" +) + +// #include <linux/ioctl.h> +import "C" + +// ----------------------------------------------------------------------------- + +func _IOC(dir, typ, nr, size int) uintptr { + return (uintptr(dir) << C._IOC_DIRSHIFT) | + (uintptr(typ) << C._IOC_TYPESHIFT) | + (uintptr(nr) << C._IOC_NRSHIFT) | + (uintptr(size) << C._IOC_SIZESHIFT) +} + +const ( + iocnrGetDeviceID = 1 +) + +// lpiocGetDeviceID reads the IEEE-1284 Device ID string of a printer. +func lpiocGetDeviceID(fd uintptr) ([]byte, error) { + var buf [1024]byte + if _, _, err := syscall.Syscall(syscall.SYS_IOCTL, fd, + _IOC(C._IOC_READ, 'P', iocnrGetDeviceID, len(buf)), + uintptr(unsafe.Pointer(&buf))); err != 0 { + return nil, err + } + + // In theory it might get trimmed along the way. + length := int(buf[0])<<8 | int(buf[1]) + if 2+length > len(buf) { + return buf[2:], errors.New("the device ID string got trimmed") + } + + return buf[2 : 2+length], nil +} + +// ----------------------------------------------------------------------------- + +var deviceIDRegexp = regexp.MustCompile( + `(?s:\s*([^:,;]+?)\s*:\s*([^:;]*)\s*(?:;|$))`) + +type deviceID map[string][]string + +// parseIEEE1284DeviceID leniently parses an IEEE 1284 Device ID string +// and returns a map containing a slice of values for each key. +// +// See e.g. http://www.undocprint.org/formats/communication_protocols/ieee_1284 +func parseIEEE1284DeviceID(id []byte) deviceID { + m := make(deviceID) + for _, kv := range deviceIDRegexp.FindAllStringSubmatch(string(id), -1) { + var values []string + for _, v := range strings.Split(kv[2], ",") { + values = append(values, strings.Trim(v, "\t\n\v\f\r ")) + } + m[kv[1]] = values + } + return m +} + +func (id deviceID) Find(key, abbreviation string) []string { + if values, ok := id[key]; ok { + return values + } + if values, ok := id[abbreviation]; ok { + return values + } + return nil +} + +// ----------------------------------------------------------------------------- + +type Printer struct { + File *os.File +} + +func compatible(id deviceID) bool { + for _, commandSet := range id.Find("COMMAND SET", "CMD") { + if commandSet == "PT-CBP" { + return true + } + } + return false +} + +// Open finds and initializes the first USB printer found supporting +// the appropriate protocol. Returns nil if no printer could be found. +func Open() (*Printer, error) { + // Linux usblp module, located in /drivers/usb/class/usblp.c + paths, err := filepath.Glob("/dev/usb/lp[0-9]*") + if err != nil { + return nil, err + } + for _, candidate := range paths { + f, err := os.OpenFile(candidate, os.O_RDWR, 0) + if err != nil { + continue + } + // Filter out obvious non-printers. + deviceID, err := lpiocGetDeviceID(f.Fd()) + if err != nil { + f.Close() + continue + } + // Filter out printers that wouldn't understand the protocol. + if !compatible(parseIEEE1284DeviceID(deviceID)) { + f.Close() + continue + } + return &Printer{File: f}, nil + } + return nil, nil +} + +// Initialize initializes the printer for further operations. +func (p *Printer) Initialize() error { + // Clear the print buffer. + invalidate := make([]byte, 400) + if _, err := p.File.Write(invalidate); err != nil { + return err + } + + // Initialize. + if _, err := p.File.WriteString("\x1b\x40"); err != nil { + return err + } + + // Flush any former responses in the printer's queue. + // + // I'm not sure if this is necessary, or rather whether the kernel driver + // does any buffering that could cause data to be returned at this point. + /* + for { + dummy := make([]byte, 32) + if _, err := f.Read(dummy); err == io.EOF { + break + } + } + */ + + return nil +} + +// GetStatus retrieves the printer's status as raw data. The printer must be +// in an appropriate mode, i.e. on-line and not currently printing. +func (p *Printer) GetStatus() ([]byte, error) { + // Request status information. + if _, err := p.File.WriteString("\x1b\x69\x53"); err != nil { + return nil, err + } + + // We need to poll the device a bit. + status := make([]byte, 32) + start := time.Now() + for { + if n, err := p.File.Read(status); err == io.EOF { + time.Sleep(10 * time.Millisecond) + } else if err != nil { + return nil, err + } else if n < 32 { + return nil, errors.New("invalid read") + } else { + return status, nil + } + if time.Now().Sub(start) > time.Second { + return nil, errors.New("timeout") + } + } +} + +// Close closes the underlying file. +func (p *Printer) Close() error { + return p.File.Close() +} + +// ----------------------------------------------------------------------------- + +type Status struct { + errors []string +} + +func decodeBitfieldErrors(b byte, errors [8]string) []string { + var result []string + for i := uint(0); i < 8; i++ { + if b&(1<<i) != 0 { + result = append(result, errors[i]) + } + } + return result +} + +// TODO: What exactly do we need? Probably extend as needed. +func decodeStatusInformation(d []byte) Status { + var status Status + status.errors = append(status.errors, decodeBitfieldErrors(d[8], [8]string{ + "no media", "end of media", "cutter jam", "?", "printer in use", + "printer turned off", "high-voltage adapter", "fan motor error"})...) + status.errors = append(status.errors, decodeBitfieldErrors(d[9], [8]string{ + "replace media", "expansion buffer full", "communication error", + "communication buffer full", "cover open", "cancel key", + "media cannot be fed", "system error"})...) + return status +} |