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Allocate libusb buffers in C (#11)

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* add alloc/free_transfer_and_buffer. Manages the buffer memory on the C
side.

* switch libusb.go to use the new alloc/free_transfer_and_buffer. Add
a new buffer() call to get access to the allocated buffer as a Go slice.

* Fake USB transfer uses the new alloc/free/buffer interface.

* Switch to the new libusb.alloc signature, where libusb owns the buffer.

* newUSBTransfer now allocates a separate buffer, do a copy on
endpoint.transfer.

* newUSBTransfer will now allocate it's own buffer.

* Enable autodetach in rawread.
This commit is contained in:
zagrodzki
2017-08-29 12:11:04 +02:00
committed by GitHub
parent bc91dd3f2c
commit 1aaa100bdb
8 changed files with 82 additions and 28 deletions
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26
transfer.c
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@@ -15,6 +15,7 @@
#include <libusb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
void print_xfer(struct libusb_transfer *xfer);
@@ -53,7 +54,7 @@ void print_xfer(struct libusb_transfer *xfer) {
// compact the data in an isochronous transfer. The contents of individual
// 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 gousb_compact_iso_data(struct libusb_transfer *xfer, unsigned char *status) {
int i;
int sum = 0;
unsigned char *in = xfer->buffer;
@@ -74,3 +75,26 @@ int compact_iso_data(struct libusb_transfer *xfer, unsigned char *status) {
}
return sum;
}
// allocates a libusb transfer and a buffer for packet data.
struct libusb_transfer *gousb_alloc_transfer_and_buffer(int bufLen, int isoPackets) {
struct libusb_transfer *xfer = libusb_alloc_transfer(isoPackets);
if (xfer == NULL) {
return NULL;
}
xfer->buffer = (unsigned char*)malloc(bufLen);
if (xfer->buffer == NULL) {
libusb_free_transfer(xfer);
return NULL;
}
xfer->length = bufLen;
return xfer;
}
// frees a libusb transfer and its buffer. The buffer of the given
// libusb_transfer must have been allocated with alloc_transfer_and_buffer.
void gousb_free_transfer_and_buffer(struct libusb_transfer *xfer) {
free(xfer->buffer);
xfer->length = 0;
libusb_free_transfer(xfer);
}