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Simplify the C part even more - the buffer that xfer uses for

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transferring data is the same as the one that was created in
newUSBTransfer.
This commit is contained in:
Sebastian Zagrodzki
2017-02-13 02:50:47 +01:00
parent 83a4778988
commit a47809fda8
2 changed files with 20 additions and 47 deletions
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53
usb/transfer.c
View File

@@ -54,54 +54,27 @@ void print_xfer(struct libusb_transfer *xfer) {
} }
} }
// extract data from a non-isochronous transfer. // compact the data in an isochronous transfer. The contents of individual
int extract_data(struct libusb_transfer *xfer, void *raw, int max, unsigned char *status) { // iso packets are shifted left, so that no gaps are left between them.
// Status is set to the first non-zero status of an iso packet.
int compact_iso_data(struct libusb_transfer *xfer, unsigned char *status) {
int i; int i;
int sum = 0;
unsigned char *in = xfer->buffer; unsigned char *in = xfer->buffer;
unsigned char *out = raw; unsigned char *out = xfer->buffer;
int len = xfer->actual_length;
if (len > max) {
len = max;
}
memcpy(out, in, len);
if (xfer->status != 0 && *status == 0) {
*status = xfer->status;
}
return len;
}
// extract data from an isochronous transfer. Very similar to extract_data, but
// acquires data from xfer->iso_packet_desc array instead of xfer attributes.
int extract_iso_data(struct libusb_transfer *xfer, void *raw, int max, unsigned char *status) {
int i;
int copied = 0;
unsigned char *in = xfer->buffer;
unsigned char *out = raw;
for (i = 0; i < xfer->num_iso_packets; i++) { for (i = 0; i < xfer->num_iso_packets; i++) {
struct libusb_iso_packet_descriptor pkt = xfer->iso_packet_desc[i]; struct libusb_iso_packet_descriptor pkt = xfer->iso_packet_desc[i];
if (pkt.status != 0) {
*status = pkt.status;
break;
}
// Copy the data // Copy the data
int len = pkt.actual_length; int len = pkt.actual_length;
if (copied + len > max) { memmove(out, in, len);
len = max - copied;
}
memcpy(out, in, len);
copied += len;
// Increment offsets // Increment offsets
sum += len;
in += pkt.length; in += pkt.length;
out += len; out += len;
if (copied == max) {
break;
}
// Extract first error
if (pkt.status == 0 || *status != 0) {
continue;
}
*status = pkt.status;
} }
return copied; return sum;
} }

14
usb/transfer.go
View File

@@ -17,8 +17,7 @@ package usb
/* /*
#include <libusb-1.0/libusb.h> #include <libusb-1.0/libusb.h>
int extract_data(struct libusb_transfer *xfer, void *data, int max, unsigned char *status); int compact_iso_data(struct libusb_transfer *xfer, unsigned char *status);
int extract_iso_data(struct libusb_transfer *xfer, void *data, int max, unsigned char *status);
int submit(struct libusb_transfer *xfer); int submit(struct libusb_transfer *xfer);
*/ */
import "C" import "C"
@@ -56,15 +55,16 @@ func (t *usbTransfer) wait() (n int, err error) {
return 0, fmt.Errorf("wait timed out after 10s") return 0, fmt.Errorf("wait timed out after 10s")
case <-t.done: case <-t.done:
} }
var status uint8 var status TransferStatus
switch TransferType(t.xfer._type) { switch TransferType(t.xfer._type) {
case TRANSFER_TYPE_ISOCHRONOUS: case TRANSFER_TYPE_ISOCHRONOUS:
n = int(C.extract_iso_data(t.xfer, unsafe.Pointer(&t.buf[0]), C.int(len(t.buf)), (*C.uchar)(unsafe.Pointer(&status)))) n = int(C.compact_iso_data(t.xfer, (*C.uchar)(unsafe.Pointer(&status))))
default: default:
n = int(C.extract_data(t.xfer, unsafe.Pointer(&t.buf[0]), C.int(len(t.buf)), (*C.uchar)(unsafe.Pointer(&status)))) n = int(t.xfer.length)
status = TransferStatus(t.xfer.status)
} }
if status != 0 { if status != LIBUSB_TRANSFER_COMPLETED {
err = TransferStatus(status) return 0, status
} }
return n, err return n, err
} }