simpler and shorter read_TZ_file() helper

    text           data     bss     dec     hex filename
-   1109              8      76    1193     4a9 libc/misc/time/tzset.o
+   1095              8      76    1179     49b libc/misc/time/tzset.o

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

diff --git a/libc/misc/time/time.c b/libc/misc/time/time.c
index 45ec131..168655b 100644 (file)
--- a/libc/misc/time/time.c
+++ b/libc/misc/time/time.c
@@ -1835,30 +1835,43 @@ static smallint TZ_file_read;           /* Let BSS initialization set this to 0. */
 static char *read_TZ_file(char *buf)
 {
        int fd;
-       ssize_t r;
-       size_t todo;
        char *p = NULL;
 
-       if ((fd = open(__UCLIBC_TZ_FILE_PATH__, O_RDONLY)) >= 0) {
-               todo = TZ_BUFLEN;
+       fd = open(__UCLIBC_TZ_FILE_PATH__, O_RDONLY);
+       if (fd >= 0) {
+               ssize_t r;
+#if 0
+               /* TZ are small *files*. On files, short reads
+                * only occur on EOF (unlike, say, pipes).
+                * The code below is pedanticallly more correct,
+                * but this way we always read at least twice:
+                * 1st read is short, 2nd one is zero bytes.
+                */
+               size_t todo = TZ_BUFLEN;
                p = buf;
                do {
-                       if ((r = read(fd, p, todo)) < 0) {
+                       r = read(fd, p, todo);
+                       if (r < 0)
                                goto ERROR;
-                       }
-                       if (r == 0) {
+                       if (r == 0)
                                break;
-                       }
                        p += r;
                        todo -= r;
                } while (todo);
+#else
+               /* Shorter, and does one less read syscall */
+               r = read(fd, buf, TZ_BUFLEN);
+               if (r < 0)
+                       goto ERROR;
+               p = buf + r;
+#endif
 
-               if ((p > buf) && (p[-1] == '\n')) {     /* Must end with newline. */
+               if ((p > buf) && (p[-1] == '\n')) { /* Must end with newline */
                        p[-1] = 0;
                        p = buf;
 #ifndef __UCLIBC_HAS_TZ_FILE_READ_MANY__
                        TZ_file_read = 1;
-#endif /* __UCLIBC_HAS_TZ_FILE_READ_MANY__ */
+#endif
                } else {
 ERROR:
                        p = NULL;