[git commit] stty: code shrink

[Denys Vlasenko]

commit: http://git.busybox.net/busybox/commit/?id=e9581b673cb731490dac0db597296047acf9b828
branch: http://git.busybox.net/busybox/commit/?id=refs/heads/master

function                                             old     new   delta
set_mode                                             759     725     -34

Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
---
 coreutils/stty.c |   59 ++++++++++++++++++++++++++---------------------------
 1 files changed, 29 insertions(+), 30 deletions(-)

diff --git a/coreutils/stty.c b/coreutils/stty.c
index 96754dd..c522968 100644
--- a/coreutils/stty.c
+++ b/coreutils/stty.c
@@ -246,10 +246,21 @@ enum speed_setting {
 
 /* Which member(s) of 'struct termios' a mode uses */
 enum {
-	/* Do NOT change the order or values, as mode_type_flag()
-	 * depends on them */
 	control, input, output, local, combination
 };
+static tcflag_t *get_ptr_to_tcflag(unsigned type, const struct termios *mode)
+{
+	static const uint8_t tcflag_offsets[] ALIGN1 = {
+		offsetof(struct termios, c_cflag), /* control */
+		offsetof(struct termios, c_iflag), /* input */
+		offsetof(struct termios, c_oflag), /* output */
+		offsetof(struct termios, c_lflag)  /* local */
+	};
+	if (type <= local) {
+		return (tcflag_t*) (((char*)mode) + tcflag_offsets[type]);
+	}
+	return NULL;
+}
 
 /* Flags for 'struct mode_info' */
 #define SANE_SET 1              /* Set in 'sane' mode                  */
@@ -800,21 +811,6 @@ static const char *visible(unsigned ch)
 	return G.buf;
 }
 
-static tcflag_t *mode_type_flag(unsigned type, const struct termios *mode)
-{
-	static const uint8_t tcflag_offsets[] ALIGN1 = {
-		offsetof(struct termios, c_cflag), /* control */
-		offsetof(struct termios, c_iflag), /* input */
-		offsetof(struct termios, c_oflag), /* output */
-		offsetof(struct termios, c_lflag)  /* local */
-	};
-
-	if (type <= local) {
-		return (tcflag_t*) (((char*)mode) + tcflag_offsets[type]);
-	}
-	return NULL;
-}
-
 static void set_speed_or_die(enum speed_setting type, const char *arg,
 					struct termios *mode)
 {
@@ -1072,7 +1068,7 @@ static void do_display(const struct termios *mode, int all)
 			prev_type = mode_info[i].type;
 		}
 
-		bitsp = mode_type_flag(mode_info[i].type, mode);
+		bitsp = get_ptr_to_tcflag(mode_info[i].type, mode);
 		mask = mode_info[i].mask ? mode_info[i].mask : mode_info[i].bits;
 		if ((*bitsp & mask) == mode_info[i].bits) {
 			if (all || (mode_info[i].flags & SANE_UNSET))
@@ -1091,7 +1087,6 @@ static void do_display(const struct termios *mode, int all)
 static void sane_mode(struct termios *mode)
 {
 	int i;
-	tcflag_t *bitsp;
 
 	for (i = 0; i < NUM_control_info; ++i) {
 #if VMIN == VEOF
@@ -1102,14 +1097,17 @@ static void sane_mode(struct termios *mode)
 	}
 
 	for (i = 0; i < NUM_mode_info; ++i) {
+		tcflag_t val;
+		tcflag_t *bitsp = get_ptr_to_tcflag(mode_info[i].type, mode);
+
+		if (!bitsp)
+			continue;
+		val = *bitsp & ~((unsigned long)mode_info[i].mask);
 		if (mode_info[i].flags & SANE_SET) {
-			bitsp = mode_type_flag(mode_info[i].type, mode);
-			*bitsp = (*bitsp & ~((unsigned long)mode_info[i].mask))
-				| mode_info[i].bits;
-		} else if (mode_info[i].flags & SANE_UNSET) {
-			bitsp = mode_type_flag(mode_info[i].type, mode);
-			*bitsp = *bitsp & ~((unsigned long)mode_info[i].mask)
-				& ~mode_info[i].bits;
+			*bitsp = val | mode_info[i].bits;
+		} else
+		if (mode_info[i].flags & SANE_UNSET) {
+			*bitsp = val & ~mode_info[i].bits;
 		}
 	}
 }
@@ -1119,17 +1117,18 @@ static void set_mode(const struct mode_info *info, int reversed,
 {
 	tcflag_t *bitsp;
 
-	bitsp = mode_type_flag(info->type, mode);
+	bitsp = get_ptr_to_tcflag(info->type, mode);
 
 	if (bitsp) {
+		tcflag_t val = *bitsp & ~info->mask;
 		if (reversed)
-			*bitsp = *bitsp & ~info->mask & ~info->bits;
+			*bitsp = val & ~info->bits;
 		else
-			*bitsp = (*bitsp & ~info->mask) | info->bits;
+			*bitsp = val | info->bits;
 		return;
 	}
 
-	/* Combination mode */
+	/* !bitsp - it's a "combination" mode */
 	if (info == &mode_info[IDX_evenp] || info == &mode_info[IDX_parity]) {
 		if (reversed)
 			mode->c_cflag = (mode->c_cflag & ~PARENB & ~CSIZE) | CS8;