print_buffer: optimize & shrink

Applying a little creative format string allows us to shrink the initial
data read & display loop by only calling printf once.  Re-using the local
data buffer to generate the string we want to display then allows us to
output everything with just one printf call instead of multiple calls to
the putc function.

The local stack buffer needs increasing by 1 byte, but the resulting code
shrink and speed up is worth it I think.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>

lib/display_options.c

@@ -101,7 +101,7 @@ void print_size(unsigned long long size, const char *s)
 #define DEFAULT_LINE_LENGTH_BYTES (16)
 int print_buffer (ulong addr, void* data, uint width, uint count, uint linelen)
 {
-	uint8_t linebuf[MAX_LINE_LENGTH_BYTES];
+	uint8_t linebuf[MAX_LINE_LENGTH_BYTES + 1];
 	uint32_t *uip = (void*)linebuf;
 	uint16_t *usp = (void*)linebuf;
 	uint8_t *ucp = (void*)linebuf;
@@ -121,24 +121,23 @@ int print_buffer (ulong addr, void* data, uint width, uint count, uint linelen)
 
 		/* Copy from memory into linebuf and print hex values */
 		for (i = 0; i < linelen; i++) {
-			if (width == 4) {
-				uip[i] = *(volatile uint32_t *)data;
-				printf(" %08x", uip[i]);
-			} else if (width == 2) {
-				usp[i] = *(volatile uint16_t *)data;
-				printf(" %04x", usp[i]);
-			} else {
-				ucp[i] = *(volatile uint8_t *)data;
-				printf(" %02x", ucp[i]);
-			}
+			uint32_t x;
+			if (width == 4)
+				x = uip[i] = *(volatile uint32_t *)data;
+			else if (width == 2)
+				x = usp[i] = *(volatile uint16_t *)data;
+			else
+				x = ucp[i] = *(volatile uint8_t *)data;
+			printf(" %0*x", width * 2, x);
 			data += width;
 		}
 
 		/* Print data in ASCII characters */
-		puts("    ");
 		for (i = 0; i < linelen * width; i++)
-			putc(isprint(ucp[i]) && (ucp[i] < 0x80) ? ucp[i] : '.');
-		putc ('\n');
+			if (!isprint(ucp[i]) || ucp[i] >= 0x80)
+				ucp[i] = '.';
+		ucp[i] = '\0';
+		printf("    %s\n", ucp);
 
 		/* update references */
 		addr += linelen * width;