1 files changed, 106 insertions, 0 deletions
diff --git a/libvoltronic/voltronic_dev_usb_hidapi.c b/libvoltronic/voltronic_dev_usb_hidapi.c
new file mode 100644
index 0000000..05d9a83
--- /dev/null
+++ b/libvoltronic/voltronic_dev_usb_hidapi.c
@@ -0,0 +1,106 @@
+/**
+ * Copyright (C) 2019  Johan van der Vyver
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <string.h>
+#include <stdlib.h>
+#include "voltronic_dev_impl.h"
+#include "voltronic_dev_usb.h"
+#include "hidapi.h"
+
+#define HID_REPORT_SIZE 8
+
+#define VOLTRONIC_DEV_USB(_impl_ptr_) \
+  ((hid_device*) (_impl_ptr_))
+
+#define GET_REPORT_SIZE(_val_) \
+  (((_val_) > HID_REPORT_SIZE) ? HID_REPORT_SIZE : (_val_))
+
+static inline void voltronic_usb_init_hidapi(void);
+
+voltronic_dev_t voltronic_usb_create(
+  const unsigned int vendor_id,
+  const unsigned int product_id) {
+
+  voltronic_usb_init_hidapi();
+
+  SET_LAST_ERROR(0);
+  hid_device* dev = hid_open(
+    (unsigned short) vendor_id,
+    (unsigned short) product_id,
+    (const wchar_t*) 0);
+
+  if (dev != 0) {
+    SET_LAST_ERROR(0);
+    return voltronic_dev_internal_create((void*) dev);
+  }
+
+  return 0;
+}
+
+inline int voltronic_dev_impl_read(
+  void* impl_ptr,
+  char* buffer,
+  const size_t buffer_size,
+  const unsigned int timeout_milliseconds) {
+
+  SET_LAST_ERROR(0);
+  return hid_read_timeout(
+    VOLTRONIC_DEV_USB(impl_ptr),
+    (unsigned char*) buffer,
+    GET_REPORT_SIZE(buffer_size),
+    (int) timeout_milliseconds);
+}
+
+inline int voltronic_dev_impl_write(
+  void* impl_ptr,
+  const char* buffer,
+  const size_t buffer_size,
+  unsigned int timeout_milliseconds) {
+
+  ++timeout_milliseconds; // stop unused warnings
+  const int write_size = GET_REPORT_SIZE(buffer_size);
+  unsigned char write_buffer[HID_REPORT_SIZE + 1] = { 0 };
+  COPY_MEMORY(&write_buffer[1], buffer, write_size);
+
+  SET_LAST_ERROR(0);
+  const int bytes_written = hid_write(
+    VOLTRONIC_DEV_USB(impl_ptr),
+    (const unsigned char*) write_buffer,
+    (size_t) (HID_REPORT_SIZE + 1));
+
+  return GET_REPORT_SIZE(bytes_written);
+}
+
+inline int voltronic_dev_impl_close(void* impl_ptr) {
+  hid_close(VOLTRONIC_DEV_USB(impl_ptr));
+  return 1;
+}
+
+static inline void voltronic_usb_exit_hidapi(void) {
+  hid_exit();
+}
+
+static inline void voltronic_usb_init_hidapi(void) {
+  static int hidapi_init_complete = 0;
+
+  if (hidapi_init_complete == 0) {
+    if (hid_init() == 0) {
+      atexit(voltronic_usb_exit_hidapi);
+      hidapi_init_complete = 1;
+    }
+  }
+}