awk: code shrink: avoid duplicate NUL checks and strlen()

function                                             old     new   delta
awk_printf                                           665     652     -13

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 33 insertions, 21 deletions

diff --git a/editors/awk.c b/editors/awk.c
index 3594717b1..46bda93b2 100644
--- a/editors/awk.c
+++ b/editors/awk.c
@@ -2345,38 +2345,49 @@ static char *awk_printf(node *n, size_t *len)
                 var *arg;
                 size_t slen;
 
+                /* Find end of the next format spec, or end of line */
                 s = f;
-                while (*f && *f != '%')
+                while (1) {
+                        c = *f;
+                        if (!c) /* no percent chars found at all */
+                                goto nul;
+                        if (c == '%') {
+                                c = *++f;
+                                if (!c) /* we are past % in "....%" */
+                                        goto nul;
+                                break;
+                        }
+                        f++;
+                }
+                /* we are past % in "....%...", c == char after % */
+                if (c == '%') { /* double % */
+                        slen = f - s;
+                        s = xstrndup(s, slen);
                         f++;
-                if (*f) {
+                        goto tail; /* print "....%" part verbatim */
+                }
+                while (1) {
+                        if (isalpha(c))
+                                break;
+                        if (c == '*')
+                                syntax_error("%*x formats are not supported");
                         c = *++f;
-                        if (c == '%') { /* double % */
+                        if (!c) { /* "....%...." and no letter found after % */
+                                /* Example: awk 'BEGIN { printf "^^^%^^^\n"; }' */
+ nul:
                                 slen = f - s;
-                                s = xstrndup(s, slen);
-                                f++;
-                                goto tail;
-                        }
-                        while (*f && !isalpha(*f)) {
-                                if (*f == '*')
-                                        syntax_error("%*x formats are not supported");
-                                f++;
+                                goto tail; /* print remaining string, exit loop */
                         }
                 }
-                c = *f;
-                if (!c) {
-                        /* Tail of fmt with no percent chars,
-                         * or "....%" (percent seen, but no format specifier char found)
-                         */
-                        slen = strlen(s);
-                        goto tail;
-                }
-                sv = *++f;
-                *f = '\0';
+                /* we are at A in "....%...A..." */
+
                 arg = evaluate(nextarg(&n), TMPVAR);
 
                 /* Result can be arbitrarily long. Example:
                  *  printf "%99999s", "BOOM"
                  */
+                sv = *++f;
+                *f = '\0';
                 if (c == 'c') {
                         char cc = is_numeric(arg) ? getvar_i(arg) : *getvar_s(arg);
                         char *r = xasprintf(s, cc ? cc : '^' /* else strlen will be wrong */);
@@ -2395,6 +2406,7 @@ static char *awk_printf(node *n, size_t *len)
                                 } else if (strchr("eEfFgGaA", c)) {
                                         s = xasprintf(s, d);
                                 } else {
+//TODO: GNU Awk 5.0.1: printf "%W" prints "%W", does not error out
                                         syntax_error(EMSG_INV_FMT);
                                 }
                         }