<commit_before>// Copyright 2013 Google Inc.  All rights reserved.
// Copyright 2016 the gousb Authors.  All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package usb

/*
#include <libusb-1.0/libusb.h>

int submit(struct libusb_transfer *xfer);
void print_xfer(struct libusb_transfer *xfer);
int extract_data(struct libusb_transfer *xfer, void *data, int max, unsigned char *status);
*/
import "C"

import (
	"fmt"
	"log"
	"time"
	"unsafe"
)

//export iso_callback
func iso_callback(cptr unsafe.Pointer) {
	ch := *(*chan struct{})(cptr)
	close(ch)
}

func (end *endpoint) allocTransfer() *Transfer {
	const (
		iso_packets = 8 // 128 // 242
	)

	xfer := C.libusb_alloc_transfer(C.int(iso_packets))
	if xfer == nil {
		log.Printf("usb: transfer allocation failed?!")
		return nil
	}

	buf := make([]byte, iso_packets*end.EndpointInfo.MaxIsoPacket)
	done := make(chan struct{}, 1)

	xfer.dev_handle = end.Device.handle
	xfer.endpoint = C.uchar(end.Address)
	xfer._type = C.LIBUSB_TRANSFER_TYPE_ISOCHRONOUS

	xfer.buffer = (*C.uchar)((unsafe.Pointer)(&buf[0]))
	xfer.length = C.int(len(buf))
	xfer.num_iso_packets = iso_packets

	C.libusb_set_iso_packet_lengths(xfer, C.uint(end.EndpointInfo.MaxIsoPacket))
	/*
		pkts := *(*[]C.struct_libusb_packet_descriptor)(unsafe.Pointer(&reflect.SliceHeader{
			Data: uintptr(unsafe.Pointer(&xfer.iso_packet_desc)),
			Len:  iso_packets,
			Cap:  iso_packets,
		}))
	*/

	t := &Transfer{
		xfer: xfer,
		done: done,
		buf:  buf,
	}
	xfer.user_data = (unsafe.Pointer)(&t.done)

	return t
}

type Transfer struct {
	xfer *C.struct_libusb_transfer
	pkts []*C.struct_libusb_packet_descriptor
	done chan struct{}
	buf  []byte
}

func (t *Transfer) Submit(timeout time.Duration) error {
	//log.Printf("iso: submitting %#v", t.xfer)
	t.xfer.timeout = C.uint(timeout / time.Millisecond)
	if errno := C.submit(t.xfer); errno < 0 {
		return usbError(errno)
	}
	return nil
}

func (t *Transfer) Wait(b []byte) (n int, err error) {
	select {
	case <-time.After(10 * time.Second):
		return 0, fmt.Errorf("wait timed out after 10s")
	case <-t.done:
	}
	// Non-iso transfers:
	//n = int(t.xfer.actual_length)
	//copy(b, ((*[1 << 16]byte)(unsafe.Pointer(t.xfer.buffer)))[:n])

	//C.print_xfer(t.xfer)
	/*
		buf, offset := ((*[1 << 16]byte)(unsafe.Pointer(t.xfer.buffer))), 0
		for i, pkt := range *t.pkts {
			log.Printf("Type is %T", t.pkts)
			n += copy(b[n:], buf[offset:][:pkt.actual_length])
			offset += pkt.Length
			if pkt.status != 0 && err == nil {
				err = error(TransferStatus(pkt.status))
			}
		}
	*/
	var status uint8
	n = int(C.extract_data(t.xfer, unsafe.Pointer(&b[0]), C.int(len(b)), (*C.uchar)(unsafe.Pointer(&status))))
	if status != 0 {
		err = TransferStatus(status)
	}
	return n, err
}

func (t *Transfer) Close() error {
	C.libusb_free_transfer(t.xfer)
	return nil
}

func isochronous_xfer(e *endpoint, buf []byte, timeout time.Duration) (int, error) {
	t := e.allocTransfer()
	defer t.Close()

	if err := t.Submit(timeout); err != nil {
		log.Printf("iso: xfer failed to submit: %s", err)
		return 0, err
	}

	n, err := t.Wait(buf)
	if err != nil {
		log.Printf("iso: xfer failed: %s", err)
		return 0, err
	}
	return n, err
}<commit_msg>Pass the max buffer size down to the alloc_transfer. Use the number of iso packets matching the buffer size. This guarantees that the transfer size is smaller or equal to the buffer. Device will transfer less data if iso transfer response does not utilize the maximum available number of iso packets per microframe or doesn't fill the packets entirely.<commit_after>// Copyright 2013 Google Inc.  All rights reserved.
// Copyright 2016 the gousb Authors.  All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package usb

/*
#include <libusb-1.0/libusb.h>

int submit(struct libusb_transfer *xfer);
void print_xfer(struct libusb_transfer *xfer);
int extract_data(struct libusb_transfer *xfer, void *data, int max, unsigned char *status);
*/
import "C"

import (
	"fmt"
	"log"
	"time"
	"unsafe"
)

//export iso_callback
func iso_callback(cptr unsafe.Pointer) {
	ch := *(*chan struct{})(cptr)
	close(ch)
}

func (end *endpoint) allocTransfer(maxLen int) *Transfer {
	isoPacketSize := end.EndpointInfo.MaxIsoPacket
	// the larget the input buffer, the more packets we use in a single
	// transfer.
	numIsoPackets := maxLen / int(isoPacketSize)
	if numIsoPackets*int(isoPacketSize) < maxLen {
		numIsoPackets++
	}
	// arbitrary limit
	if numIsoPackets > 200 {
		numIsoPackets = 200
	}
	xfer := C.libusb_alloc_transfer(C.int(numIsoPackets))
	if xfer == nil {
		log.Printf("usb: transfer allocation failed?!")
		return nil
	}

	buf := make([]byte, numIsoPackets*int(end.EndpointInfo.MaxIsoPacket))
	done := make(chan struct{}, 1)

	xfer.dev_handle = end.Device.handle
	xfer.endpoint = C.uchar(end.Address)
	xfer._type = C.LIBUSB_TRANSFER_TYPE_ISOCHRONOUS

	xfer.buffer = (*C.uchar)((unsafe.Pointer)(&buf[0]))
	xfer.length = C.int(len(buf))
	xfer.num_iso_packets = C.int(numIsoPackets)

	C.libusb_set_iso_packet_lengths(xfer, C.uint(end.EndpointInfo.MaxIsoPacket))
	/*
		pkts := *(*[]C.struct_libusb_packet_descriptor)(unsafe.Pointer(&reflect.SliceHeader{
			Data: uintptr(unsafe.Pointer(&xfer.iso_packet_desc)),
			Len:  iso_packets,
			Cap:  iso_packets,
		}))
	*/

	t := &Transfer{
		xfer: xfer,
		done: done,
		buf:  buf,
	}
	xfer.user_data = (unsafe.Pointer)(&t.done)

	return t
}

type Transfer struct {
	xfer *C.struct_libusb_transfer
	pkts []*C.struct_libusb_packet_descriptor
	done chan struct{}
	buf  []byte
}

func (t *Transfer) Submit(timeout time.Duration) error {
	//log.Printf("iso: submitting %#v", t.xfer)
	t.xfer.timeout = C.uint(timeout / time.Millisecond)
	if errno := C.submit(t.xfer); errno < 0 {
		return usbError(errno)
	}
	return nil
}

func (t *Transfer) Wait(b []byte) (n int, err error) {
	select {
	case <-time.After(10 * time.Second):
		return 0, fmt.Errorf("wait timed out after 10s")
	case <-t.done:
	}
	// Non-iso transfers:
	//n = int(t.xfer.actual_length)
	//copy(b, ((*[1 << 16]byte)(unsafe.Pointer(t.xfer.buffer)))[:n])

	//C.print_xfer(t.xfer)
	/*
		buf, offset := ((*[1 << 16]byte)(unsafe.Pointer(t.xfer.buffer))), 0
		for i, pkt := range *t.pkts {
			log.Printf("Type is %T", t.pkts)
			n += copy(b[n:], buf[offset:][:pkt.actual_length])
			offset += pkt.Length
			if pkt.status != 0 && err == nil {
				err = error(TransferStatus(pkt.status))
			}
		}
	*/
	var status uint8
	n = int(C.extract_data(t.xfer, unsafe.Pointer(&b[0]), C.int(len(b)), (*C.uchar)(unsafe.Pointer(&status))))
	if status != 0 {
		err = TransferStatus(status)
	}
	return n, err
}

func (t *Transfer) Close() error {
	C.libusb_free_transfer(t.xfer)
	return nil
}

func isochronous_xfer(e *endpoint, buf []byte, timeout time.Duration) (int, error) {
	t := e.allocTransfer(len(buf))
	defer t.Close()

	if err := t.Submit(timeout); err != nil {
		log.Printf("iso: xfer failed to submit: %s", err)
		return 0, err
	}

	n, err := t.Wait(buf)
	if err != nil {
		log.Printf("iso: xfer failed: %s", err)
		return 0, err
	}
	return n, err
}
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{'dir': 'git-commits-cleaned', 'id': '3332994', 'n_tokens_mistral': 3106, 'n_tokens_neox': 2924, 'n_words': 792}