[PERLIO] In line-buffered mode, flush on the *last* newline,

not on every newline.

p4raw-id: //depot/perl@22478

diff --git a/perlio.c b/perlio.c
index 87ac75f..da4a182 100644 (file)
--- a/perlio.c
+++ b/perlio.c
@@ -3691,6 +3691,7 @@ PerlIOBuf_write(pTHX_ PerlIO *f, const void *vbuf, Size_t count)
 {
     PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
     const STDCHAR *buf = (const STDCHAR *) vbuf;
+    const STDCHAR *flushptr = buf;
     Size_t written = 0;
     if (!b->buf)
        PerlIO_get_base(f);
@@ -3701,32 +3702,26 @@ PerlIOBuf_write(pTHX_ PerlIO *f, const void *vbuf, Size_t count)
            return 0;
        }
     }  
+    if (PerlIOBase(f)->flags & PERLIO_F_LINEBUF) {
+       flushptr = buf + count;
+       while (flushptr > buf && *(flushptr - 1) != '\n')
+           --flushptr;
+    }
     while (count > 0) {
        SSize_t avail = b->bufsiz - (b->ptr - b->buf);
        if ((SSize_t) count < avail)
            avail = count;
+       if (flushptr > buf && flushptr <= buf + avail)
+           avail = flushptr - buf;
        PerlIOBase(f)->flags |= PERLIO_F_WRBUF;
-       if (PerlIOBase(f)->flags & PERLIO_F_LINEBUF) {
-           while (avail > 0) {
-               int ch = *buf++;
-               *(b->ptr)++ = ch;
-               count--;
-               avail--;
-               written++;
-               if (ch == '\n') {
-                   PerlIO_flush(f);
-                   break;
-               }
-           }
-       }
-       else {
-           if (avail) {
-               Copy(buf, b->ptr, avail, STDCHAR);
-               count -= avail;
-               buf += avail;
-               written += avail;
-               b->ptr += avail;
-           }
+       if (avail) {
+           Copy(buf, b->ptr, avail, STDCHAR);
+           count -= avail;
+           buf += avail;
+           written += avail;
+           b->ptr += avail;
+           if (buf == flushptr)
+               PerlIO_flush(f);
        }
        if (b->ptr >= (b->buf + b->bufsiz))
            PerlIO_flush(f);