Save memory

Store the device string in 8 bit and in program memory. Also
reduce the size of a few variables.

main.c

@@ -55,6 +55,7 @@
 #include "dataHidReport.c"
 
 #define MAX_READ_ERRORS	30
+static uint8_t error_count[MAX_PLAYERS] = { };
 
 struct cfg0 {
 	struct usb_configuration_descriptor configdesc;
@@ -434,12 +435,11 @@ int main(void)
 {
 	Gamepad *pads[MAX_PLAYERS] = { };
 	gamepad_data pad_data;
-	unsigned char gamepad_vibrate = 0;
-	unsigned char state = STATE_WAIT_POLLTIME;
-	int error_count[MAX_PLAYERS] = { };
-	int i;
-	int channel;
-	int num_players = 1;
+	uint8_t gamepad_vibrate = 0;
+	uint8_t state = STATE_WAIT_POLLTIME;
+	uint8_t channel;
+	uint8_t num_players = 1;
+	uint8_t i;
 
 	hwinit();
 	usart1_init();
@@ -451,20 +451,21 @@ int main(void)
 	{
 		default:
 		case CFG_MODE_STANDARD:
+			usbstrings_changeProductString_P(PSTR("GC/N64 to USB v"VERSIONSTR_SHORT));
 			break;
 
 		case CFG_MODE_N64_ONLY:
-			usbstrings_changeProductString(L"N64 to USB v"VERSIONSTR_SHORT);
+			usbstrings_changeProductString_P(PSTR("N64 to USB v"VERSIONSTR_SHORT));
 			device_descriptor.idProduct = N64_USB_PID;
 			break;
 
 		case CFG_MODE_GC_ONLY:
-			usbstrings_changeProductString(L"Gamecube to USB v"VERSIONSTR_SHORT);
+			usbstrings_changeProductString_P(PSTR("Gamecube to USB v"VERSIONSTR_SHORT));
 			device_descriptor.idProduct = GC_USB_PID;
 			break;
 
 		case CFG_MODE_2P_STANDARD:
-			usbstrings_changeProductString(L"Dual GC/N64 to USB v"VERSIONSTR_SHORT);
+			usbstrings_changeProductString_P(PSTR("Dual GC/N64 to USB v"VERSIONSTR_SHORT));
 			device_descriptor.idProduct = DUAL_GCN64_USB_PID;
 			usb_params.configdesc = (PGM_VOID_P)&cfg0_2p;
 			usb_params.configdesc_ttllen = sizeof(cfg0_2p);
@@ -473,7 +474,7 @@ int main(void)
 			break;
 
 		case CFG_MODE_2P_N64_ONLY:
-			usbstrings_changeProductString(L"Dual N64 to USB v"VERSIONSTR_SHORT);
+			usbstrings_changeProductString_P(PSTR("Dual N64 to USB v"VERSIONSTR_SHORT));
 			device_descriptor.idProduct = DUAL_N64_USB_PID;
 			usb_params.configdesc = (PGM_VOID_P)&cfg0_2p;
 			usb_params.configdesc_ttllen = sizeof(cfg0_2p);
@@ -482,7 +483,7 @@ int main(void)
 			break;
 
 		case CFG_MODE_2P_GC_ONLY:
-			usbstrings_changeProductString(L"Dual Gamecube to USB v"VERSIONSTR_SHORT);
+			usbstrings_changeProductString_P(PSTR("Dual Gamecube to USB v"VERSIONSTR_SHORT));
 			device_descriptor.idProduct = DUAL_GC_USB_PID;
 			usb_params.configdesc = (PGM_VOID_P)&cfg0_2p;
 			usb_params.configdesc_ttllen = sizeof(cfg0_2p);

usbstrings.c

@@ -17,13 +17,32 @@
 #include <stdlib.h> // for wchar_t
 #include "usbstrings.h"
 
+static wchar_t product_string[PRODUCT_STRING_MAXCHARS]; // = L"GC/N64 to USB v"VERSIONSTR_SHORT;
+
 const wchar_t *g_usb_strings[] = {
 	[0] = L"raphnet technologies", 	// 1 : Vendor
-	[1] = L"GC/N64 to USB v"VERSIONSTR_SHORT,	// 2: Product
+	[1] = product_string,	// 2: Product
 	[2] = L"123456",				// 3 : Serial
 };
 
-void usbstrings_changeProductString(const wchar_t *str)
+void usbstrings_changeProductString_P(const char *str)
 {
-	g_usb_strings[1] = str;
+	const char *s = str;
+	wchar_t *d = product_string;
+	uint8_t c;
+	int n = 0;
+
+	do {
+		/* Make sure target is always NUL terminated. */
+		n++;
+		if (n == PRODUCT_STRING_MAXCHARS) {
+			*d = 0;
+			break;
+		}
+
+		c = pgm_read_byte(s);
+
+		*d = c;
+		s++; d++;
+	} while (c);
 }

usbstrings.h

@@ -1,13 +1,21 @@
 #ifndef _usbstrings_h__
 #define _usbstrings_h__
 
+#include <avr/pgmspace.h>
+
 extern const wchar_t *g_usb_strings[];
 
+/* Sample: "Dual Gamecube to USB v3.4" (25) */
+#define PRODUCT_STRING_MAXCHARS	32
+
 #define NUM_USB_STRINGS	3
 
 /* Array indexes (i.e. zero-based0 */
 #define USB_STRING_SERIAL_IDX	2
 
-void usbstrings_changeProductString(const wchar_t *str);
+/**
+ * \param str Must be in PROGMEM
+ */
+void usbstrings_changeProductString_P(const char *str);
 
 #endif