add pwgen from mazzoo

firmware/l0dable/pwgen.c

@@ -0,0 +1,55 @@
+#include "basic/basic.h"
+
+#include "usetable.h"
+
+#define PW_LEN 8
+
+void ram(void)
+{
+	char pw[PW_LEN+1];
+	uint16_t k[8];
+	int button;
+	memset(k, 0, 16);
+	while(1){
+		lcdClear();
+		lcdNl();
+		lcdPrintln(" password");
+		lcdPrintln("    generator");
+		lcdNl();
+		lcdNl();
+		pw_set(pw,&k);
+		pw_cleanup(pw);
+		lcdPrint("   ");
+		lcdPrintln(pw);
+		lcdRefresh();
+		delayms(23);
+		while((button=getInputRaw())==BTN_NONE)
+			delayms(23);
+		if(button==BTN_LEFT) return;
+	}
+}
+
+void pw_cleanup(char * pw)
+{
+	int i;
+	for(i=0;i<PW_LEN;i++)
+	{
+		/* strip unwanted ascii chars */
+		pw[i]&=0x7f;
+		if(pw[i]<0x30)pw[i]+=0x30;
+		if(pw[i]>0x7a)pw[i]-=0x10;
+		if((pw[i]>'Z')&&(pw[i]<'a'))
+			pw[i]-=0x10;
+	}
+}
+
+void pw_set(char * pw, uint16_t * k)
+{
+	int i;
+	memset(pw,0,PW_LEN); /* wipe old PW */
+	for(i=0;i<4;i++)
+		k[1]=getRandom();
+	xxtea_encode_words(pw,PW_LEN/4,k);
+	pw[PW_LEN]=0;
+}
+