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hid-libusb.c
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hid-libusb.c
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/*******************************************************
HIDAPI - Multi-Platform library for
communication with HID devices.
Alan Ott
Signal 11 Software
8/22/2009
Linux Version - 6/2/2010
Libusb Version - 8/13/2010
Copyright 2009, All Rights Reserved.
At the discretion of the user of this library,
this software may be licensed under the terms of the
GNU Public License v3, a BSD-Style license, or the
original HIDAPI license as outlined in the LICENSE.txt,
LICENSE-gpl3.txt, LICENSE-bsd.txt, and LICENSE-orig.txt
files located at the root of the source distribution.
These files may also be found in the public source
code repository located at:
http://github.com/signal11/hidapi .
********************************************************/
#define _GNU_SOURCE // needed for wcsdup() before glibc 2.10
/* C */
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include <locale.h>
#include <errno.h>
/* Unix */
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/utsname.h>
#include <fcntl.h>
#include <pthread.h>
#include <wchar.h>
/* GNU / LibUSB */
//#include "libusb.h"
#include <libusb-1.0/libusb.h>
//#include "iconv.h"
#include <iconv.h>
#include "hidapi.h"
#ifdef __cplusplus
extern "C" {
#endif
#ifdef DEBUG_PRINTF
#define LOG(...) fprintf(stderr, __VA_ARGS__)
#else
#define LOG(...) do {} while (0)
#endif
/* Uncomment to enable the retrieval of Usage and Usage Page in
hid_enumerate(). Warning, this is very invasive as it requires the detach
and re-attach of the kernel driver. See comments inside hid_enumerate().
Linux/libusb HIDAPI programs are encouraged to use the interface number
instead to differentiate between interfaces on a composite HID device. */
/*#define INVASIVE_GET_USAGE*/
/* Linked List of input reports received from the device. */
struct input_report {
uint8_t *data;
size_t len;
struct input_report *next;
};
struct hid_device_ {
/* Handle to the actual device. */
libusb_device_handle *device_handle;
/* Endpoint information */
int input_endpoint;
int output_endpoint;
int input_ep_max_packet_size;
/* The interface number of the HID */
int interface;
/* Indexes of Strings */
int manufacturer_index;
int product_index;
int serial_index;
/* Whether blocking reads are used */
int blocking; /* boolean */
/* Read thread objects */
pthread_t thread;
pthread_mutex_t mutex; /* Protects input_reports */
pthread_cond_t condition;
pthread_barrier_t barrier; /* Ensures correct startup sequence */
int shutdown_thread;
struct libusb_transfer *transfer;
/* List of received input reports. */
struct input_report *input_reports;
};
static int initialized = 0;
uint16_t get_usb_code_for_current_locale(void);
static int return_data(hid_device *dev, unsigned char *data, size_t length);
static hid_device *new_hid_device(void)
{
hid_device *dev = calloc(1, sizeof(hid_device));
dev->device_handle = NULL;
dev->input_endpoint = 0;
dev->output_endpoint = 0;
dev->input_ep_max_packet_size = 0;
dev->interface = 0;
dev->manufacturer_index = 0;
dev->product_index = 0;
dev->serial_index = 0;
dev->blocking = 1;
dev->shutdown_thread = 0;
dev->transfer = NULL;
dev->input_reports = NULL;
pthread_mutex_init(&dev->mutex, NULL);
pthread_cond_init(&dev->condition, NULL);
pthread_barrier_init(&dev->barrier, NULL, 2);
return dev;
}
static void free_hid_device(hid_device *dev)
{
/* Clean up the thread objects */
pthread_barrier_destroy(&dev->barrier);
pthread_cond_destroy(&dev->condition);
pthread_mutex_destroy(&dev->mutex);
/* Free the device itself */
free(dev);
}
#if 0
//TODO: Implement this funciton on Linux.
static void register_error(hid_device *device, const char *op)
{
}
#endif
#ifdef INVASIVE_GET_USAGE
/* Get bytes from a HID Report Descriptor.
Only call with a num_bytes of 0, 1, 2, or 4. */
static uint32_t get_bytes(uint8_t *rpt, size_t len, size_t num_bytes, size_t cur)
{
/* Return if there aren't enough bytes. */
if (cur + num_bytes >= len)
return 0;
if (num_bytes == 0)
return 0;
else if (num_bytes == 1) {
return rpt[cur+1];
}
else if (num_bytes == 2) {
return (rpt[cur+2] * 256 + rpt[cur+1]);
}
else if (num_bytes == 4) {
return (rpt[cur+4] * 0x01000000 +
rpt[cur+3] * 0x00010000 +
rpt[cur+2] * 0x00000100 +
rpt[cur+1] * 0x00000001);
}
else
return 0;
}
/* Retrieves the device's Usage Page and Usage from the report
descriptor. The algorithm is simple, as it just returns the first
Usage and Usage Page that it finds in the descriptor.
The return value is 0 on success and -1 on failure. */
static int get_usage(uint8_t *report_descriptor, size_t size,
unsigned short *usage_page, unsigned short *usage)
{
int i = 0;
int size_code;
int data_len, key_size;
int usage_found = 0, usage_page_found = 0;
while (i < size) {
int key = report_descriptor[i];
int key_cmd = key & 0xfc;
//printf("key: %02hhx\n", key);
if ((key & 0xf0) == 0xf0) {
/* This is a Long Item. The next byte contains the
length of the data section (value) for this key.
See the HID specification, version 1.11, section
6.2.2.3, titled "Long Items." */
if (i+1 < size)
data_len = report_descriptor[i+1];
else
data_len = 0; /* malformed report */
key_size = 3;
}
else {
/* This is a Short Item. The bottom two bits of the
key contain the size code for the data section
(value) for this key. Refer to the HID
specification, version 1.11, section 6.2.2.2,
titled "Short Items." */
size_code = key & 0x3;
switch (size_code) {
case 0:
case 1:
case 2:
data_len = size_code;
break;
case 3:
data_len = 4;
break;
default:
/* Can't ever happen since size_code is & 0x3 */
data_len = 0;
break;
};
key_size = 1;
}
if (key_cmd == 0x4) {
*usage_page = get_bytes(report_descriptor, size, data_len, i);
usage_page_found = 1;
//printf("Usage Page: %x\n", (uint32_t)*usage_page);
}
if (key_cmd == 0x8) {
*usage = get_bytes(report_descriptor, size, data_len, i);
usage_found = 1;
//printf("Usage: %x\n", (uint32_t)*usage);
}
if (usage_page_found && usage_found)
return 0; /* success */
/* Skip over this key and it's associated data */
i += data_len + key_size;
}
return -1; /* failure */
}
#endif // INVASIVE_GET_USAGE
/* Get the first language the device says it reports. This comes from
USB string #0. */
static uint16_t get_first_language(libusb_device_handle *dev)
{
uint16_t buf[32];
int len;
/* Get the string from libusb. */
len = libusb_get_string_descriptor(dev,
0x0, /* String ID */
0x0, /* Language */
(unsigned char*)buf,
sizeof(buf));
if (len < 4)
return 0x0;
return buf[1]; // First two bytes are len and descriptor type.
}
static int is_language_supported(libusb_device_handle *dev, uint16_t lang)
{
uint16_t buf[32];
int len;
int i;
/* Get the string from libusb. */
len = libusb_get_string_descriptor(dev,
0x0, /* String ID */
0x0, /* Language */
(unsigned char*)buf,
sizeof(buf));
if (len < 4)
return 0x0;
len /= 2; /* language IDs are two-bytes each. */
/* Start at index 1 because there are two bytes of protocol data. */
for (i = 1; i < len; i++) {
if (buf[i] == lang)
return 1;
}
return 0;
}
/* This function returns a newly allocated wide string containing the USB
device string numbered by the index. The returned string must be freed
by using free(). */
static wchar_t *get_usb_string(libusb_device_handle *dev, uint8_t idx)
{
char buf[512];
int len;
wchar_t *str = NULL;
wchar_t wbuf[256];
/* iconv variables */
iconv_t ic;
size_t inbytes;
size_t outbytes;
size_t res;
char *inptr;
char *outptr;
/* Determine which language to use. */
uint16_t lang;
lang = get_usb_code_for_current_locale();
if (!is_language_supported(dev, lang))
lang = get_first_language(dev);
/* Get the string from libusb. */
len = libusb_get_string_descriptor(dev,
idx,
lang,
(unsigned char*)buf,
sizeof(buf));
if (len < 0)
return NULL;
buf[sizeof(buf)-1] = '\0';
if (len+1 < sizeof(buf))
buf[len+1] = '\0';
/* Initialize iconv. */
ic = iconv_open("UTF-32", "UTF-16");
if (ic == (iconv_t)-1)
return NULL;
/* Convert to UTF-32 (wchar_t on glibc systems).
Skip the first character (2-bytes). */
inptr = buf+2;
inbytes = len-2;
outptr = (char*) wbuf;
outbytes = sizeof(wbuf);
res = iconv(ic, &inptr, &inbytes, &outptr, &outbytes);
if (res == (size_t)-1)
goto err;
/* Write the terminating NULL. */
wbuf[sizeof(wbuf)/sizeof(wbuf[0])-1] = 0x00000000;
if (outbytes >= sizeof(wbuf[0]))
*((wchar_t*)outptr) = 0x00000000;
/* Allocate and copy the string. */
str = wcsdup(wbuf+1);
err:
iconv_close(ic);
return str;
}
static char *make_path(libusb_device *dev, int interface_number)
{
char str[64];
snprintf(str, sizeof(str), "%04x:%04x:%02x",
libusb_get_bus_number(dev),
libusb_get_device_address(dev),
interface_number);
str[sizeof(str)-1] = '\0';
return strdup(str);
}
int HID_API_EXPORT hid_init(void)
{
if (!initialized) {
if (libusb_init(NULL))
return -1;
initialized = 1;
}
return 0;
}
int HID_API_EXPORT hid_exit(void)
{
if (initialized) {
libusb_exit(NULL);
initialized = 0;
}
return 0;
}
struct hid_device_info HID_API_EXPORT *hid_enumerate(unsigned short vendor_id, unsigned short product_id)
{
libusb_device **devs;
libusb_device *dev;
libusb_device_handle *handle;
ssize_t num_devs;
int i = 0;
struct hid_device_info *root = NULL; // return object
struct hid_device_info *cur_dev = NULL;
setlocale(LC_ALL,"");
if (!initialized)
hid_init();
num_devs = libusb_get_device_list(NULL, &devs);
if (num_devs < 0)
return NULL;
while ((dev = devs[i++]) != NULL) {
struct libusb_device_descriptor desc;
struct libusb_config_descriptor *conf_desc = NULL;
int j, k;
int interface_num = 0;
int res = libusb_get_device_descriptor(dev, &desc);
unsigned short dev_vid = desc.idVendor;
unsigned short dev_pid = desc.idProduct;
/* HID's are defined at the interface level. */
if (desc.bDeviceClass != LIBUSB_CLASS_PER_INTERFACE)
continue;
res = libusb_get_active_config_descriptor(dev, &conf_desc);
if (res < 0)
libusb_get_config_descriptor(dev, 0, &conf_desc);
if (conf_desc) {
for (j = 0; j < conf_desc->bNumInterfaces; j++) {
const struct libusb_interface *intf = &conf_desc->interface[j];
for (k = 0; k < intf->num_altsetting; k++) {
const struct libusb_interface_descriptor *intf_desc;
intf_desc = &intf->altsetting[k];
if (intf_desc->bInterfaceClass == LIBUSB_CLASS_HID) {
interface_num = intf_desc->bInterfaceNumber;
/* Check the VID/PID against the arguments */
if ((vendor_id == 0x0 && product_id == 0x0) ||
(vendor_id == dev_vid && product_id == dev_pid)) {
struct hid_device_info *tmp;
/* VID/PID match. Create the record. */
tmp = calloc(1, sizeof(struct hid_device_info));
if (cur_dev) {
cur_dev->next = tmp;
}
else {
root = tmp;
}
cur_dev = tmp;
/* Fill out the record */
cur_dev->next = NULL;
cur_dev->path = make_path(dev, interface_num);
res = libusb_open(dev, &handle);
if (res >= 0) {
/* Serial Number */
if (desc.iSerialNumber > 0)
cur_dev->serial_number =
get_usb_string(handle, desc.iSerialNumber);
/* Manufacturer and Product strings */
if (desc.iManufacturer > 0)
cur_dev->manufacturer_string =
get_usb_string(handle, desc.iManufacturer);
if (desc.iProduct > 0)
cur_dev->product_string =
get_usb_string(handle, desc.iProduct);
#ifdef INVASIVE_GET_USAGE
/*
This section is removed because it is too
invasive on the system. Getting a Usage Page
and Usage requires parsing the HID Report
descriptor. Getting a HID Report descriptor
involves claiming the interface. Claiming the
interface involves detaching the kernel driver.
Detaching the kernel driver is hard on the system
because it will unclaim interfaces (if another
app has them claimed) and the re-attachment of
the driver will sometimes change /dev entry names.
It is for these reasons that this section is
#if 0. For composite devices, use the interface
field in the hid_device_info struct to distinguish
between interfaces. */
int detached = 0;
unsigned char data[256];
/* Usage Page and Usage */
res = libusb_kernel_driver_active(handle, interface_num);
if (res == 1) {
res = libusb_detach_kernel_driver(handle, interface_num);
if (res < 0)
LOG("Couldn't detach kernel driver, even though a kernel driver was attached.");
else
detached = 1;
}
res = libusb_claim_interface(handle, interface_num);
if (res >= 0) {
/* Get the HID Report Descriptor. */
res = libusb_control_transfer(handle, LIBUSB_ENDPOINT_IN|LIBUSB_RECIPIENT_INTERFACE, LIBUSB_REQUEST_GET_DESCRIPTOR, (LIBUSB_DT_REPORT << 8)|interface_num, 0, data, sizeof(data), 5000);
if (res >= 0) {
unsigned short page=0, usage=0;
/* Parse the usage and usage page
out of the report descriptor. */
get_usage(data, res, &page, &usage);
cur_dev->usage_page = page;
cur_dev->usage = usage;
}
else
LOG("libusb_control_transfer() for getting the HID report failed with %d\n", res);
/* Release the interface */
res = libusb_release_interface(handle, interface_num);
if (res < 0)
LOG("Can't release the interface.\n");
}
else
LOG("Can't claim interface %d\n", res);
/* Re-attach kernel driver if necessary. */
if (detached) {
res = libusb_attach_kernel_driver(handle, interface_num);
if (res < 0)
LOG("Couldn't re-attach kernel driver.\n");
}
#endif /*******************/
libusb_close(handle);
}
/* VID/PID */
cur_dev->vendor_id = dev_vid;
cur_dev->product_id = dev_pid;
/* Release Number */
cur_dev->release_number = desc.bcdDevice;
/* Interface Number */
cur_dev->interface_number = interface_num;
}
}
} /* altsettings */
} /* interfaces */
libusb_free_config_descriptor(conf_desc);
}
}
libusb_free_device_list(devs, 1);
return root;
}
void HID_API_EXPORT hid_free_enumeration(struct hid_device_info *devs)
{
struct hid_device_info *d = devs;
while (d) {
struct hid_device_info *next = d->next;
free(d->path);
free(d->serial_number);
free(d->manufacturer_string);
free(d->product_string);
free(d);
d = next;
}
}
hid_device * hid_open(unsigned short vendor_id, unsigned short product_id, wchar_t *serial_number)
{
struct hid_device_info *devs, *cur_dev;
const char *path_to_open = NULL;
hid_device *handle = NULL;
devs = hid_enumerate(vendor_id, product_id);
cur_dev = devs;
while (cur_dev) {
if (cur_dev->vendor_id == vendor_id &&
cur_dev->product_id == product_id) {
if (serial_number) {
if (wcscmp(serial_number, cur_dev->serial_number) == 0) {
path_to_open = cur_dev->path;
break;
}
}
else {
path_to_open = cur_dev->path;
break;
}
}
cur_dev = cur_dev->next;
}
if (path_to_open) {
/* Open the device */
handle = hid_open_path(path_to_open);
}
hid_free_enumeration(devs);
return handle;
}
static void read_callback(struct libusb_transfer *transfer)
{
hid_device *dev = transfer->user_data;
if (transfer->status == LIBUSB_TRANSFER_COMPLETED) {
struct input_report *rpt = malloc(sizeof(*rpt));
rpt->data = malloc(transfer->actual_length);
memcpy(rpt->data, transfer->buffer, transfer->actual_length);
rpt->len = transfer->actual_length;
rpt->next = NULL;
pthread_mutex_lock(&dev->mutex);
/* Attach the new report object to the end of the list. */
if (dev->input_reports == NULL) {
/* The list is empty. Put it at the root. */
dev->input_reports = rpt;
pthread_cond_signal(&dev->condition);
}
else {
/* Find the end of the list and attach. */
struct input_report *cur = dev->input_reports;
int num_queued = 0;
while (cur->next != NULL) {
cur = cur->next;
num_queued++;
}
cur->next = rpt;
/* Pop one off if we've reached 30 in the queue. This
way we don't grow forever if the user never reads
anything from the device. */
if (num_queued > 30) {
return_data(dev, NULL, 0);
}
}
pthread_mutex_unlock(&dev->mutex);
}
else if (transfer->status == LIBUSB_TRANSFER_CANCELLED) {
dev->shutdown_thread = 1;
return;
}
else if (transfer->status == LIBUSB_TRANSFER_NO_DEVICE) {
dev->shutdown_thread = 1;
return;
}
else if (transfer->status == LIBUSB_TRANSFER_TIMED_OUT) {
//LOG("Timeout (normal)\n");
}
else {
LOG("Unknown transfer code: %d\n", transfer->status);
}
/* Re-submit the transfer object. */
libusb_submit_transfer(transfer);
}
static void *read_thread(void *param)
{
hid_device *dev = param;
unsigned char *buf;
const size_t length = dev->input_ep_max_packet_size;
/* Set up the transfer object. */
buf = malloc(length);
dev->transfer = libusb_alloc_transfer(0);
libusb_fill_interrupt_transfer(dev->transfer,
dev->device_handle,
dev->input_endpoint,
buf,
length,
read_callback,
dev,
5000/*timeout*/);
/* Make the first submission. Further submissions are made
from inside read_callback() */
libusb_submit_transfer(dev->transfer);
// Notify the main thread that the read thread is up and running.
pthread_barrier_wait(&dev->barrier);
/* Handle all the events. */
while (!dev->shutdown_thread) {
int res;
res = libusb_handle_events(NULL);
if (res < 0) {
/* There was an error. Break out of this loop. */
break;
}
}
/* Cancel any transfer that may be pending. This call will fail
if no transfers are pending, but that's OK. */
if (libusb_cancel_transfer(dev->transfer) == 0) {
/* The transfer was cancelled, so wait for its completion. */
libusb_handle_events(NULL);
}
/* Now that the read thread is stopping, Wake any threads which are
waiting on data (in hid_read_timeout()). Do this under a mutex to
make sure that a thread which is about to go to sleep waiting on
the condition acutally will go to sleep before the condition is
signaled. */
pthread_mutex_lock(&dev->mutex);
pthread_cond_broadcast(&dev->condition);
pthread_mutex_unlock(&dev->mutex);
/* The dev->transfer->buffer and dev->transfer objects are cleaned up
in hid_close(). They are not cleaned up here because this thread
could end either due to a disconnect or due to a user
call to hid_close(). In both cases the objects can be safely
cleaned up after the call to pthread_join() (in hid_close()), but
since hid_close() calls libusb_cancel_transfer(), on these objects,
they can not be cleaned up here. */
return NULL;
}
hid_device * HID_API_EXPORT hid_open_path(const char *path)
{
hid_device *dev = NULL;
dev = new_hid_device();
libusb_device **devs;
libusb_device *usb_dev;
ssize_t num_devs;
int res;
int d = 0;
int good_open = 0;
setlocale(LC_ALL,"");
if (!initialized)
hid_init();
num_devs = libusb_get_device_list(NULL, &devs);
while ((usb_dev = devs[d++]) != NULL) {
struct libusb_device_descriptor desc;
struct libusb_config_descriptor *conf_desc = NULL;
int i,j,k;
libusb_get_device_descriptor(usb_dev, &desc);
if (libusb_get_active_config_descriptor(usb_dev, &conf_desc) < 0)
continue;
for (j = 0; j < conf_desc->bNumInterfaces; j++) {
const struct libusb_interface *intf = &conf_desc->interface[j];
for (k = 0; k < intf->num_altsetting; k++) {
const struct libusb_interface_descriptor *intf_desc;
intf_desc = &intf->altsetting[k];
if (intf_desc->bInterfaceClass == LIBUSB_CLASS_HID) {
char *dev_path = make_path(usb_dev, intf_desc->bInterfaceNumber);
if (!strcmp(dev_path, path)) {
/* Matched Paths. Open this device */
// OPEN HERE //
res = libusb_open(usb_dev, &dev->device_handle);
if (res < 0) {
LOG("can't open device\n");
free(dev_path);
break;
}
good_open = 1;
/* Detach the kernel driver, but only if the
device is managed by the kernel */
if (libusb_kernel_driver_active(dev->device_handle, intf_desc->bInterfaceNumber) == 1) {
res = libusb_detach_kernel_driver(dev->device_handle, intf_desc->bInterfaceNumber);
if (res < 0) {
libusb_close(dev->device_handle);
LOG("Unable to detach Kernel Driver\n");
free(dev_path);
good_open = 0;
break;
}
}
res = libusb_claim_interface(dev->device_handle, intf_desc->bInterfaceNumber);
if (res < 0) {
LOG("can't claim interface %d: %d\n", intf_desc->bInterfaceNumber, res);
free(dev_path);
libusb_close(dev->device_handle);
good_open = 0;
break;
}
/* Store off the string descriptor indexes */
dev->manufacturer_index = desc.iManufacturer;
dev->product_index = desc.iProduct;
dev->serial_index = desc.iSerialNumber;
/* Store off the interface number */
dev->interface = intf_desc->bInterfaceNumber;
/* Find the INPUT and OUTPUT endpoints. An
OUTPUT endpoint is not required. */
for (i = 0; i < intf_desc->bNumEndpoints; i++) {
const struct libusb_endpoint_descriptor *ep
= &intf_desc->endpoint[i];
/* Determine the type and direction of this
endpoint. */
int is_interrupt =
(ep->bmAttributes & LIBUSB_TRANSFER_TYPE_MASK)
== LIBUSB_TRANSFER_TYPE_INTERRUPT;
int is_output =
(ep->bEndpointAddress & LIBUSB_ENDPOINT_DIR_MASK)
== LIBUSB_ENDPOINT_OUT;
int is_input =
(ep->bEndpointAddress & LIBUSB_ENDPOINT_DIR_MASK)
== LIBUSB_ENDPOINT_IN;
/* Decide whether to use it for intput or output. */
if (dev->input_endpoint == 0 &&
is_interrupt && is_input) {
/* Use this endpoint for INPUT */
dev->input_endpoint = ep->bEndpointAddress;
dev->input_ep_max_packet_size = ep->wMaxPacketSize;
}
if (dev->output_endpoint == 0 &&
is_interrupt && is_output) {
/* Use this endpoint for OUTPUT */
dev->output_endpoint = ep->bEndpointAddress;
}
}
pthread_create(&dev->thread, NULL, read_thread, dev);
// Wait here for the read thread to be initialized.
pthread_barrier_wait(&dev->barrier);
}
free(dev_path);
}
}
}
libusb_free_config_descriptor(conf_desc);
}
libusb_free_device_list(devs, 1);
// If we have a good handle, return it.
if (good_open) {
return dev;
}
else {
// Unable to open any devices.
free_hid_device(dev);
return NULL;
}
}
int HID_API_EXPORT hid_write(hid_device *dev, const unsigned char *data, size_t length)
{
int res;
int report_number = data[0];
int skipped_report_id = 0;
if (report_number == 0x0) {
data++;
length--;
skipped_report_id = 1;
}
if (dev->output_endpoint <= 0) {
/* No interrput out endpoint. Use the Control Endpoint */
res = libusb_control_transfer(dev->device_handle,
LIBUSB_REQUEST_TYPE_CLASS|LIBUSB_RECIPIENT_INTERFACE|LIBUSB_ENDPOINT_OUT,
0x09/*HID Set_Report*/,
(2/*HID output*/ << 8) | report_number,
dev->interface,
(unsigned char *)data, length,
1000/*timeout millis*/);
if (res < 0)
return -1;
if (skipped_report_id)
length++;
return length;
}
else {
/* Use the interrupt out endpoint */
int actual_length;
res = libusb_interrupt_transfer(dev->device_handle,
dev->output_endpoint,
(unsigned char*)data,
length,
&actual_length, 1000);
if (res < 0)
return -1;
if (skipped_report_id)
actual_length++;
return actual_length;
}
}
/* Helper function, to simplify hid_read().
This should be called with dev->mutex locked. */
static int return_data(hid_device *dev, unsigned char *data, size_t length)
{
/* Copy the data out of the linked list item (rpt) into the
return buffer (data), and delete the liked list item. */
struct input_report *rpt = dev->input_reports;
size_t len = (length < rpt->len)? length: rpt->len;
if (len > 0)
memcpy(data, rpt->data, len);
dev->input_reports = rpt->next;
free(rpt->data);
free(rpt);
return len;
}
static void cleanup_mutex(void *param)
{
hid_device *dev = param;
pthread_mutex_unlock(&dev->mutex);
}
int HID_API_EXPORT hid_read_timeout(hid_device *dev, unsigned char *data, size_t length, int milliseconds)
{
int bytes_read = -1;
#if 0
int transferred;
int res = libusb_interrupt_transfer(dev->device_handle, dev->input_endpoint, data, length, &transferred, 5000);
LOG("transferred: %d\n", transferred);
return transferred;
#endif
pthread_mutex_lock(&dev->mutex);
pthread_cleanup_push(&cleanup_mutex, dev);
/* There's an input report queued up. Return it. */
if (dev->input_reports) {
/* Return the first one */
bytes_read = return_data(dev, data, length);
goto ret;
}
if (dev->shutdown_thread) {
/* This means the device has been disconnected.
An error code of -1 should be returned. */
bytes_read = -1;
goto ret;
}
if (milliseconds == -1) {
/* Blocking */
while (!dev->input_reports && !dev->shutdown_thread) {
pthread_cond_wait(&dev->condition, &dev->mutex);
}
if (dev->input_reports) {
bytes_read = return_data(dev, data, length);
}
}
else if (milliseconds > 0) {
/* Non-blocking, but called with timeout. */
int res;
struct timespec ts;
clock_gettime(CLOCK_REALTIME, &ts);
ts.tv_sec += milliseconds / 1000;
ts.tv_nsec += (milliseconds % 1000) * 1000000;
if (ts.tv_nsec >= 1000000000L) {
ts.tv_sec++;
ts.tv_nsec -= 1000000000L;
}
while (!dev->input_reports && !dev->shutdown_thread) {