libbb: code shrink fgets_str

Use a NULL value of maxsz_p to indicate to xmalloc_fgets_internal()
that the caller doesn't care about the maximum size of the buffer.
This allows the default maximum size to be set once in
xmalloc_fgets_internal() instead of separately in each caller.

function                                             old     new   delta
xmalloc_fgets_internal                               273     287     +14
xmalloc_fgets_str                                     30       9     -21
xmalloc_fgetline_str                                  33      12     -21
xmalloc_fgets_str_len                                 38      10     -28
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/3 up/down: 14/-70)            Total: -56 bytes

Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 5 insertions, 12 deletions

diff --git a/libbb/fgets_str.c b/libbb/fgets_str.c
index 1a7f2e9e0..c884ef8af 100644
--- a/libbb/fgets_str.c
+++ b/libbb/fgets_str.c
@@ -17,7 +17,7 @@ static char *xmalloc_fgets_internal(FILE *file, const char *terminating_string,
         int linebufsz = 0;
         int idx = 0;
         int ch;
-        size_t maxsz = *maxsz_p;
+        size_t maxsz = maxsz_p ? *maxsz_p : INT_MAX - 4095;
 
         while (1) {
                 ch = fgetc(file);
@@ -53,7 +53,8 @@ static char *xmalloc_fgets_internal(FILE *file, const char *terminating_string,
         /* Grow/shrink *first*, then store NUL */
         linebuf = xrealloc(linebuf, idx + 1);
         linebuf[idx] = '\0';
-        *maxsz_p = idx;
+        if (maxsz_p)
+                *maxsz_p = idx;
         return linebuf;
 }
 
@@ -63,23 +64,15 @@ static char *xmalloc_fgets_internal(FILE *file, const char *terminating_string,
  * Return NULL if EOF is reached immediately.  */
 char* FAST_FUNC xmalloc_fgets_str(FILE *file, const char *terminating_string)
 {
-        size_t maxsz = INT_MAX - 4095;
-        return xmalloc_fgets_internal(file, terminating_string, 0, &maxsz);
+        return xmalloc_fgets_internal(file, terminating_string, 0, NULL);
 }
 
 char* FAST_FUNC xmalloc_fgets_str_len(FILE *file, const char *terminating_string, size_t *maxsz_p)
 {
-        size_t maxsz;
-
-        if (!maxsz_p) {
-                maxsz = INT_MAX - 4095;
-                maxsz_p = &maxsz;
-        }
         return xmalloc_fgets_internal(file, terminating_string, 0, maxsz_p);
 }
 
 char* FAST_FUNC xmalloc_fgetline_str(FILE *file, const char *terminating_string)
 {
-        size_t maxsz = INT_MAX - 4095;
-        return xmalloc_fgets_internal(file, terminating_string, 1, &maxsz);
+        return xmalloc_fgets_internal(file, terminating_string, 1, NULL);
 }