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d5fa1a0f4

Denys Vlasenko
Denys Vlasenko
2010-06-13
FAILED Duration: 31s

Subject

xargs: code shrink -15 bytes

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Architecture & Compiler Flags

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

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Commit Diff GitHub →

findutils/xargs.c +74 -80testsuite/xargs.tests +5 -0
findutils/xargs.c+74 -80
@@ -122,53 +122,49 @@ typedef struct xlist_t {
char xstr[1];
} xlist_t;
-static smallint eof_stdin_detected;
-
-#define ISBLANK(c) ((c) == ' ' || (c) == '\t')
-#define ISSPACE(c) (ISBLANK(c) || (c) == '\n' || (c) == '\r' \
- || (c) == '\f' || (c) == '\v')
+/* In POSIX/C locale isspace is only these chars: "\t\n\v\f\r" and space.
+ * "\t\n\v\f\r" happen to have ASCII codes 9,10,11,12,13.
+ */
+#define ISSPACE(a) ({ unsigned char xargs__isspace = (a) - 9; xargs__isspace == (' ' - 9) || xargs__isspace <= (13 - 9); })
#if ENABLE_FEATURE_XARGS_SUPPORT_QUOTES
-static xlist_t *process_stdin(xlist_t *list_arg,
+static xlist_t* process_stdin(xlist_t *list_arg,
const char *eof_str, size_t mc, char *buf)
{
#define NORM 0
#define QUOTE 1
#define BACKSLASH 2
#define SPACE 4
-
- char *s = NULL; /* start word */
- char *p = NULL; /* pointer to end word */
+ char *s = NULL; /* start of the word */
+ char *p = NULL; /* pointer to end of the word */
char q = '\0'; /* quote char */
char state = NORM;
char eof_str_detected = 0;
- size_t line_l = 0; /* size loaded args line */
- int c; /* current char */
+ size_t line_l = 0; /* size of loaded args */
xlist_t *cur;
xlist_t *prev;
prev = cur = list_arg;
- while (1) {
- if (!cur) break;
+ while (cur) {
prev = cur;
line_l += cur->length;
cur = cur->link;
}
- while (!eof_stdin_detected) {
- c = getchar();
+ while (1) {
+ int c = getchar();
if (c == EOF) {
- eof_stdin_detected = 1;
if (s)
goto unexpected_eof;
break;
}
- if (eof_str_detected)
+ if (eof_str_detected) /* skip till EOF */
continue;
if (state == BACKSLASH) {
state = NORM;
goto set;
- } else if (state == QUOTE) {
+ }
+ if (state == QUOTE) {
if (c != q)
goto set;
q = '\0';
@@ -202,7 +198,7 @@ static xlist_t *process_stdin(xlist_t *list_arg,
bb_error_msg_and_die("unmatched %s quote",
q == '\'' ? "single" : "double");
}
- /* word loaded */
+ /* A full word is loaded */
if (eof_str) {
eof_str_detected = (strcmp(s, eof_str) == 0);
}
@@ -220,10 +216,8 @@ static xlist_t *process_stdin(xlist_t *list_arg,
}
prev = cur;
line_l += length;
- if (line_l > mc) {
- /* stop memory usage :-) */
+ if (line_l > mc) /* limit stop memory usage */
break;
- }
}
s = NULL;
state = NORM;
@@ -233,33 +227,32 @@ static xlist_t *process_stdin(xlist_t *list_arg,
}
#else
/* The variant does not support single quotes, double quotes or backslash */
-static xlist_t *process_stdin(xlist_t *list_arg,
+static xlist_t* process_stdin(xlist_t *list_arg,
const char *eof_str, size_t mc, char *buf)
{
-
- int c; /* current char */
char eof_str_detected = 0;
- char *s = NULL; /* start word */
- char *p = NULL; /* pointer to end word */
- size_t line_l = 0; /* size loaded args line */
+ char *s = NULL; /* start of the word */
+ char *p = NULL; /* pointer to end of the word */
+ size_t line_l = 0; /* size of loaded args */
xlist_t *cur;
xlist_t *prev;
prev = cur = list_arg;
- while (1) {
- if (!cur) break;
+ while (cur) {
prev = cur;
line_l += cur->length;
cur = cur->link;
}
- while (!eof_stdin_detected) {
- c = getchar();
+ while (1) {
+ int c = getchar();
if (c == EOF) {
- eof_stdin_detected = 1;
+ if (s == NULL)
+ break;
}
- if (eof_str_detected)
+ if (eof_str_detected) { /* skip till EOF */
continue;
+ }
if (c == EOF || ISSPACE(c)) {
if (s == NULL)
continue;
@@ -271,7 +264,7 @@ static xlist_t *process_stdin(xlist_t *list_arg,
bb_error_msg_and_die("argument line too long");
*p++ = (c == EOF ? '\0' : c);
if (c == EOF) { /* word's delimiter or EOF detected */
- /* word loaded */
+ /* A full word is loaded */
if (eof_str) {
eof_str_detected = (strcmp(s, eof_str) == 0);
}
@@ -289,12 +282,10 @@ static xlist_t *process_stdin(xlist_t *list_arg,
}
prev = cur;
line_l += length;
- if (line_l > mc) {
- /* stop memory usage :-) */
+ if (line_l > mc) /* limit stop memory usage */
break;
- }
- s = NULL;
}
+ s = NULL;
}
}
return list_arg;
@@ -325,28 +316,25 @@ static int xargs_ask_confirmation(void)
#endif /* FEATURE_XARGS_SUPPORT_CONFIRMATION */
#if ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM
-static xlist_t *process0_stdin(xlist_t *list_arg,
+static xlist_t* process0_stdin(xlist_t *list_arg,
const char *eof_str UNUSED_PARAM, size_t mc, char *buf)
{
- int c; /* current char */
- char *s = NULL; /* start word */
- char *p = NULL; /* pointer to end word */
- size_t line_l = 0; /* size loaded args line */
+ char *s = NULL; /* start of the word */
+ char *p = NULL; /* pointer to end of the word */
+ size_t line_l = 0; /* size of loaded args */
xlist_t *cur;
xlist_t *prev;
prev = cur = list_arg;
- while (1) {
- if (!cur) break;
+ while (cur) {
prev = cur;
line_l += cur->length;
cur = cur->link;
}
- while (!eof_stdin_detected) {
- c = getchar();
+ while (1) {
+ int c = getchar();
if (c == EOF) {
- eof_stdin_detected = 1;
if (s == NULL)
break;
c = '\0';
@@ -357,7 +345,7 @@ static xlist_t *process0_stdin(xlist_t *list_arg,
bb_error_msg_and_die("argument line too long");
*p++ = c;
if (c == '\0') { /* word's delimiter or EOF detected */
- /* word loaded */
+ /* A full word is loaded */
size_t length = (p - buf);
/* Dont xzalloc - it can be quite big */
cur = xmalloc(offsetof(xlist_t, xstr) + length);
@@ -371,10 +359,8 @@ static xlist_t *process0_stdin(xlist_t *list_arg,
}
prev = cur;
line_l += length;
- if (line_l > mc) {
- /* stop memory usage :-) */
+ if (line_l > mc) /* limit stop memory usage */
break;
- }
s = NULL;
}
}
@@ -412,12 +398,11 @@ enum {
int xargs_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int xargs_main(int argc, char **argv)
{
- char **args;
- int i, n;
xlist_t *list = NULL;
- xlist_t *cur;
int child_error = 0;
- char *max_args, *max_chars;
+ char *max_args;
+ char *max_chars;
+ char *buf;
int n_max_arg;
const char *eof_str = NULL;
unsigned opt;
@@ -441,15 +426,12 @@ int xargs_main(int argc, char **argv)
argv += optind;
argc -= optind;
- if (!argc) {
+ if (!argv[0]) {
/* default behavior is to echo all the filenames */
- *argv = (char*)"echo";
+ *--argv = (char*)"echo";
argc++;
}
- n_max_chars = ARG_MAX; /* might be calling sysconf(_SC_ARG_MAX) */
- if (n_max_chars < 4*1024); /* paranoia */
- n_max_chars = LONG_MAX;
/* The Open Group Base Specifications Issue 6:
* "The xargs utility shall limit the command line length such that
* when the command line is invoked, the combined argument
@@ -457,27 +439,32 @@ int xargs_main(int argc, char **argv)
* in the System Interfaces volume of IEEE Std 1003.1-2001)
* shall not exceed {ARG_MAX}-2048 bytes".
*/
+ n_max_chars = ARG_MAX; /* might be calling sysconf(_SC_ARG_MAX) */
+ if (n_max_chars < 4*1024); /* paranoia */
+ n_max_chars = 4*1024;
n_max_chars -= 2048;
/* Sanity check for systems with huge ARG_MAX defines (e.g., Suns which
- * have it at 1 meg). Things will work fine with a large ARG_MAX but it
- * will probably hurt the system more than it needs to; an array of this
- * size is allocated.
+ * have it at 1 meg). Things will work fine with a large ARG_MAX
+ * but it will probably hurt the system more than it needs to;
+ * an array of this size is allocated.
*/
if (n_max_chars > 20 * 1024)
n_max_chars = 20 * 1024;
if (opt & OPT_UPTO_SIZE) {
+ int i;
size_t n_chars = 0;
n_max_chars = xatoul_range(max_chars, 1, n_max_chars);
- for (i = 0; i < argc; i++) {
- n_chars += strlen(*argv) + 1;
+ for (i = 0; argv[i]; i++) {
+ n_chars += strlen(argv[i]) + 1;
}
- if (n_max_chars <= n_chars) {
+ n_max_chars -= n_chars;
+ if ((ssize_t)n_max_chars <= 0) {
bb_error_msg_and_die("can't fit single argument within argument list size limit");
}
- n_max_chars -= n_chars;
}
- max_chars = xmalloc(n_max_chars);
+
+ buf = xmalloc(n_max_chars);
if (opt & OPT_UPTO_NUMBER) {
n_max_arg = xatoul_range(max_args, 1, INT_MAX);
@@ -485,10 +472,14 @@ int xargs_main(int argc, char **argv)
n_max_arg = n_max_chars;
}
- while ((list = read_args(list, eof_str, n_max_chars, max_chars)) != NULL ||
- !(opt & OPT_NO_EMPTY))
- {
+ while ((list = read_args(list, eof_str, n_max_chars, buf)) != NULL
+ || !(opt & OPT_NO_EMPTY)
+ ) {
+ char **args;
+ xlist_t *cur;
+ int i, n;
size_t n_chars = 0;
+
opt |= OPT_NO_EMPTY;
n = 0;
#if ENABLE_FEATURE_XARGS_SUPPORT_TERMOPT
@@ -510,15 +501,14 @@ int xargs_main(int argc, char **argv)
break;
}
}
-#endif /* FEATURE_XARGS_SUPPORT_TERMOPT */
+#endif
- /* allocate pointers for execvp:
- argc*arg, n*arg from stdin, NULL */
- args = xzalloc((n + argc + 1) * sizeof(char *));
+ /* allocate pointers for execvp */
+ args = xzalloc(sizeof(args[0]) * (argc + n + 1));
/* store the command to be executed
- (taken from the command line) */
- for (i = 0; i < argc; i++)
+ * (taken from the command line) */
+ for (i = 0; argv[i]; i++)
args[i] = argv[i];
/* (taken from stdin) */
for (cur = list; n; cur = cur->link) {
@@ -535,6 +525,7 @@ int xargs_main(int argc, char **argv)
if (!(opt & OPT_INTERACTIVE))
bb_putchar_stderr('\n');
}
+
if (!(opt & OPT_INTERACTIVE) || xargs_ask_confirmation()) {
child_error = xargs_exec(args);
}
@@ -546,12 +537,15 @@ int xargs_main(int argc, char **argv)
free(cur);
}
free(args);
+
if (child_error > 0 && child_error != 123) {
break;
}
} /* while */
+
if (ENABLE_FEATURE_CLEAN_UP)
- free(max_chars);
+ free(buf);
+
return child_error;
}
testsuite/xargs.tests+5 -0
@@ -26,4 +26,9 @@ testing "xargs does not stop on underscore ('new' GNU behavior)" \
"a _ b\n" \
"" "a\n_\nb\n"
+testing "xargs -s7 can take one-char input" \
+ "xargs -s7" \
+ "a\n" \
+ "" "a\n"
+
exit $FAILCOUNT