[git commit] ed: code shrink
Denys Vlasenko
vda.linux at googlemail.com
Thu Jul 27 09:58:25 UTC 2017
commit: https://git.busybox.net/busybox/commit/?id=7d2f33dc1f6dcd44671d88360bc598ad82c37a60
branch: https://git.busybox.net/busybox/commit/?id=refs/heads/master
function old new delta
findString 117 115 -2
skip_blank 16 - -16
getNum 369 345 -24
doCommands 2448 2183 -265
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 0/3 up/down: 0/-307) Total: -307 bytes
Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
---
editors/ed.c | 94 +++++++++++++++++++++++++++---------------------------------
1 file changed, 43 insertions(+), 51 deletions(-)
diff --git a/editors/ed.c b/editors/ed.c
index a2a389c..b13c3ed 100644
--- a/editors/ed.c
+++ b/editors/ed.c
@@ -78,13 +78,6 @@ static int bad_nums(int num1, int num2, const char *for_what)
return 0;
}
-static char *skip_blank(const char *cp)
-{
- while (isblank(*cp))
- cp++;
- return (char *)cp;
-}
-
/*
* Return a pointer to the specified line number.
*/
@@ -138,15 +131,13 @@ static int findString(const LINE *lp, const char *str, int len, int offset)
const char *cp, *ncp;
cp = &lp->data[offset];
- left = lp->len - offset;
+ left = lp->len - offset - len;
- while (left >= len) {
- ncp = memchr(cp, *str, left);
+ while (left >= 0) {
+ ncp = memchr(cp, str[0], left + 1);
if (ncp == NULL)
return -1;
left -= (ncp - cp);
- if (left < len)
- return -1;
cp = ncp;
if (memcmp(cp, str, len) == 0)
return (cp - lp->data);
@@ -203,25 +194,23 @@ static NOINLINE int searchLines(const char *str, int num1, int num2)
/*
* Parse a line number argument if it is present. This is a sum
* or difference of numbers, '.', '$', 'x, or a search string.
- * Returns TRUE if successful (whether or not there was a number).
- * Returns FALSE if there was a parsing error, with a message output.
+ * Returns pointer which stopped the scan if successful (whether or not
+ * there was a number).
+ * Returns NULL if there was a parsing error, with a message output.
* Whether there was a number is returned indirectly, as is the number.
- * The character pointer which stopped the scan is also returned.
*/
-static int getNum(const char **retcp, smallint *retHaveNum, int *retNum)
+static const char* getNum(const char *cp, smallint *retHaveNum, int *retNum)
{
- const char *cp;
char *endStr, str[USERSIZE];
int value, num;
smallint haveNum, minus;
- cp = *retcp;
value = 0;
haveNum = FALSE;
minus = 0;
while (TRUE) {
- cp = skip_blank(cp);
+ cp = skip_whitespace(cp);
switch (*cp) {
case '.':
@@ -240,7 +229,7 @@ static int getNum(const char **retcp, smallint *retHaveNum, int *retNum)
cp++;
if ((*cp < 'a') || (*cp > 'z')) {
bb_error_msg("bad mark name");
- return FALSE;
+ return NULL;
}
haveNum = TRUE;
num = marks[*cp++ - 'a'];
@@ -256,16 +245,15 @@ static int getNum(const char **retcp, smallint *retHaveNum, int *retNum)
cp = "";
num = searchLines(str, curNum, lastNum);
if (num == 0)
- return FALSE;
+ return NULL;
haveNum = TRUE;
break;
default:
if (!isdigit(*cp)) {
- *retcp = cp;
*retHaveNum = haveNum;
*retNum = value;
- return TRUE;
+ return cp;
}
num = 0;
while (isdigit(*cp))
@@ -276,7 +264,7 @@ static int getNum(const char **retcp, smallint *retHaveNum, int *retNum)
value += (minus ? -num : num);
- cp = skip_blank(cp);
+ cp = skip_whitespace(cp);
switch (*cp) {
case '-':
@@ -290,10 +278,9 @@ static int getNum(const char **retcp, smallint *retHaveNum, int *retNum)
break;
default:
- *retcp = cp;
*retHaveNum = haveNum;
*retNum = value;
- return TRUE;
+ return cp;
}
}
}
@@ -789,12 +776,13 @@ static void subCommand(const char *cmd, int num1, int num2)
*/
static void doCommands(void)
{
- const char *cp;
- char *endbuf, buf[USERSIZE];
- int len, num1, num2;
- smallint have1, have2;
-
while (TRUE) {
+ char buf[USERSIZE];
+ const char *cp;
+ int len;
+ int n, num1, num2;
+ smallint h, have1, have2;
+
/* Returns:
* -1 on read errors or EOF, or on bare Ctrl-D.
* 0 on ctrl-C,
@@ -803,32 +791,36 @@ static void doCommands(void)
len = read_line_input(NULL, ": ", buf, sizeof(buf), /*timeout*/ -1);
if (len <= 0)
return;
- endbuf = &buf[len - 1];
- while ((endbuf > buf) && isblank(endbuf[-1]))
- endbuf--;
- *endbuf = '\0';
-
- cp = skip_blank(buf);
- have1 = FALSE;
- have2 = FALSE;
+ while (len && isblank(buf[--len]))
+ buf[len] = '\0';
if ((curNum == 0) && (lastNum > 0)) {
curNum = 1;
curLine = lines.next;
}
- if (!getNum(&cp, &have1, &num1))
+ have1 = FALSE;
+ have2 = FALSE;
+ /* Don't pass &have1, &num1 to getNum() since this forces
+ * compiler to keep them on stack, not in registers,
+ * which is usually quite suboptimal.
+ * Using intermediate variables shrinks code by ~150 bytes.
+ */
+ cp = getNum(skip_whitespace(buf), &h, &n);
+ if (!cp)
continue;
+ have1 = h;
+ num1 = n;
- cp = skip_blank(cp);
-
+ cp = skip_whitespace(cp);
if (*cp == ',') {
- cp++;
- if (!getNum(&cp, &have2, &num2))
+ cp = getNum(cp + 1, &h, &n);
+ if (!cp)
continue;
+ num2 = n;
if (!have1)
num1 = 1;
- if (!have2)
+ if (!h)
num2 = lastNum;
have1 = TRUE;
have2 = TRUE;
@@ -857,7 +849,7 @@ static void doCommands(void)
bb_error_msg("bad file command");
break;
}
- cp = skip_blank(cp);
+ cp = skip_whitespace(cp);
if (*cp == '\0') {
if (fileName)
printf("\"%s\"\n", fileName);
@@ -874,7 +866,7 @@ static void doCommands(void)
break;
case 'k':
- cp = skip_blank(cp);
+ cp = skip_whitespace(cp);
if ((*cp < 'a') || (*cp > 'z') || cp[1]) {
bb_error_msg("bad mark name");
break;
@@ -891,7 +883,7 @@ static void doCommands(void)
break;
case 'q':
- cp = skip_blank(cp);
+ cp = skip_whitespace(cp);
if (have1 || *cp) {
bb_error_msg("bad quit command");
break;
@@ -902,7 +894,7 @@ static void doCommands(void)
/* read error/EOF - no way to continue */
if (len < 0)
return;
- cp = skip_blank(buf);
+ cp = skip_whitespace(buf);
if ((*cp | 0x20) == 'y') /* Y or y */
return;
break;
@@ -912,7 +904,7 @@ static void doCommands(void)
bb_error_msg("bad read command");
break;
}
- cp = skip_blank(cp);
+ cp = skip_whitespace(cp);
if (*cp == '\0') {
bb_error_msg("no file name");
break;
@@ -934,7 +926,7 @@ static void doCommands(void)
bb_error_msg("bad write command");
break;
}
- cp = skip_blank(cp);
+ cp = skip_whitespace(cp);
if (!have1) {
num1 = 1;
num2 = lastNum;
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