feat: Add methods to copy and reset reports

This change adds functions to copy and reset a report via a library
function.

daemon/io.c

@@ -28,7 +28,7 @@ static void process_report(libx52io_report *report, libx52io_report *prev)
 {
     // TODO: Process changes
     x52d_mouse_report_event(report);
-    memcpy(prev, report, sizeof(*prev));
+    libx52io_copy_report(prev, report);
 }
 
 static void *x52_io_thr(void *param)
@@ -43,7 +43,7 @@ static void *x52_io_thr(void *param)
     PINELOG_INFO(_("Starting X52 I/O thread"));
 
     // Reset the previous report, so that process_report  can handle changes.
-    memset(&prev_report, 0, sizeof(prev_report));
+    libx52io_reset_report(&prev_report);
 
     for (;;) {
         rc = libx52io_read_timeout(io_ctx, &report, IO_READ_TIMEOUT);

daemon/mouse_handler.c

@@ -196,17 +196,14 @@ static void report_sync(void)
     if (rc != VKM_SUCCESS) {
         PINELOG_ERROR(_("Error writing mouse sync event"));
     } else {
-        memcpy((void *)&old_report, (void *)&new_report, sizeof(old_report));
+        libx52io_copy_report(&new_report, &old_report);
     }
 }
 
 static void reset_reports(void)
 {
-    memset((void *)&old_report, 0, sizeof(old_report));
-    /* Set the default thumbstick values to the mid-point */
-    old_report.axis[LIBX52IO_AXIS_THUMBX] = 8;
-    old_report.axis[LIBX52IO_AXIS_THUMBY] = 8;
-    memcpy((void *)&new_report, (void *)&old_report, sizeof(new_report));
+    libx52io_reset_report(&old_report);
+    libx52io_copy_report(&new_report, &old_report);
 }
 
 static void * x52_mouse_thr(void *param)
@@ -273,7 +270,7 @@ void x52d_mouse_report_event(libx52io_report *report)
 {
     bool state_changed;
     if (report) {
-        memcpy((void *)&new_report, report, sizeof(new_report));
+        libx52io_copy_report(&new_report, report);
 
         if (!vkm_is_ready(mouse_context) || !mouse_thr_enabled) {
             return;

include/libx52/libx52io.h

@@ -629,6 +629,29 @@ LIBX52IO_API const char *libx52io_get_serial_number_string(libx52io_context *ctx
  * @returns 64-bit bitmask of which fields changed. See \ref libx52io_report_bitmask
  */
 LIBX52IO_API uint64_t libx52io_compare_reports(const libx52io_report *prev, const libx52io_report *curr);
+
+/**
+ * @brief Copy one report into another
+ *
+ * Copy \c source report to \c target report. If either parameter is NULL, it
+ * does nothing.
+ *
+ * @param[in]   target  Pointer to the target report
+ * @param[in]   source  Pointer to the source report
+ */
+LIBX52IO_API void libx52io_copy_report(libx52io_report *target, const libx52io_report *source);
+
+/**
+ * @brief Reset the report values to defaults.
+ *
+ * Resets all axis values to 0, except for the thumb stick axes, which are
+ * reset to their midpoint of 8. Also, all button states are reset to unpressed
+ * and mode/hat are reset to 0.
+ *
+ * @param[in]   report  Pointer to the report to reset
+ */
+LIBX52IO_API void libx52io_reset_report(libx52io_report *report);
+
 /** @} */
 
 #ifdef __cplusplus

libx52io/meson.build

@@ -8,6 +8,7 @@ libx52io_files = files(
   'device.c',
   'validation.c',
   'compare.c',
+  'report.c',
 )
 
 lib_libx52io = library('x52io', libx52io_files,

libx52io/report.c

@@ -0,0 +1,59 @@
+/*
+ * Saitek X52 IO driver
+ *
+ * Copyright (C) 2012-2026 Nirenjan Krishnan (nirenjan@nirenjan.org)
+ *
+ * SPDX-License-Identifier: GPL-2.0-only WITH Classpath-exception-2.0
+ */
+
+#include "build-config.h"
+#include <stdlib.h>
+#include <string.h>
+#include "common.h"
+#include "usb-ids.h"
+#include "gettext.h"
+
+void libx52io_copy_report(libx52io_report *target, const libx52io_report *source)
+{
+    if (target == NULL || source == NULL) {
+        return;
+    }
+
+    for (int ax = 0; ax < LIBX52IO_AXIS_MAX; ax++) {
+        target->axis[ax] = source->axis[ax];
+    }
+
+    for (int btn = 0; btn < LIBX52IO_BUTTON_MAX; btn++) {
+        target->button[btn] = source->button[btn];
+    }
+
+    target->mode = source->mode;
+    target->hat = source->hat;
+}
+
+void libx52io_reset_report(libx52io_report *report)
+{
+    if (report == NULL) {
+        return;
+    }
+
+    for (int ax = 0; ax < LIBX52IO_AXIS_MAX; ax++) {
+        switch (ax) {
+        case LIBX52IO_AXIS_THUMBX:
+        case LIBX52IO_AXIS_THUMBY:
+            report->axis[ax] = 8;
+            break;
+
+        default:
+            report->axis[ax] = 0;
+            break;
+        }
+    }
+
+    for (int btn = 0; btn < LIBX52IO_BUTTON_MAX; btn++) {
+        report->button[btn] = 0;
+    }
+
+    report->mode = 0;
+    report->hat = 0;
+}