Synchronize safe-write with safe-read.

diff --git a/lib/ChangeLog b/lib/ChangeLog
index 6048d06..2187838 100644 (file)
--- a/lib/ChangeLog
+++ b/lib/ChangeLog
@@ -1,6 +1,19 @@
+2002-12-02  Bruno Haible  <bruno@clisp.org>
+
+       * safe-write.c (CHAR_BIT, TYPE_SIGNED, TYPE_MINIMUM, TYPE_MAXIMUM):
+       Define, taken from safe-read.c.
+       (INT_MAX): Provide fallback.
+       (safe_write): Rewrite to iterate IFF the write fails with EINTR.
+       * safe-write.h (SAFE_WRITE_ERROR): Define.
+
+       * safe-read.c (EINTR): Remove definition.
+       (safe_read): Don't use EINTR if it is absent.
+
 2002-12-02  Jim Meyering  <jim@meyering.net>
 
        * safe-read.c (EINTR): Define.
+       (CHAR_BIT, TYPE_SIGNED, TYPE_MINIMUM, TYPE_MAXIMUM): Define.
+       (INT_MAX): Provide fallback.
        (safe_read): Rewrite to iterate IFF the read fails with EINTR.
 
        * safe-read.h (SAFE_READ_ERROR): Define.

diff --git a/lib/safe-read.c b/lib/safe-read.c
index 527653c..0d0f29d 100644 (file)
--- a/lib/safe-read.c
+++ b/lib/safe-read.c
@@ -57,12 +57,6 @@ extern int errno;
    Tru64 5.1.  */
 #define MAX_BYTES_TO_READ INT_MAX
 
-#ifndef EINTR
-/* If a system doesn't have support for EINTR, define it
-   to be a value to which errno will never be set.  */
-# define EINTR (INT_MAX - 10)
-#endif
-
 /* Read up to COUNT bytes at BUF from descriptor FD, retrying if interrupted.
    Return the actual number of bytes read, zero for EOF, or SAFE_READ_ERROR
    upon error.  */
@@ -72,9 +66,10 @@ safe_read (int fd, void *buf, size_t count)
   size_t nbytes_to_read = count;
   ssize_t result;
 
-  /* Limit the number of bytes to read, to avoid running
-     into unspecified behaviour.  But keep the file pointer block
-     aligned when doing so.  */
+  /* Limit the number of bytes to read, to avoid running into unspecified
+     behaviour.  But keep the file pointer block aligned when doing so.
+     Note that in this case we don't need to call read() multiple times here,
+     because the caller is prepared to partial results.  */
   if (nbytes_to_read > MAX_BYTES_TO_READ)
     nbytes_to_read = MAX_BYTES_TO_READ & ~8191;
 
@@ -82,7 +77,11 @@ safe_read (int fd, void *buf, size_t count)
     {
       result = read (fd, buf, nbytes_to_read);
     }
+#ifdef EINTR
   while (result < 0 && errno == EINTR);
+#else
+  while (0);
+#endif
 
   return (size_t) result;
 }

diff --git a/lib/safe-write.c b/lib/safe-write.c
index 5596203..8c60bba 100644 (file)
--- a/lib/safe-write.c
+++ b/lib/safe-write.c
@@ -35,6 +35,22 @@ extern int errno;
 
 #include <limits.h>
 
+#ifndef CHAR_BIT
+# define CHAR_BIT 8
+#endif
+
+/* The extra casts work around common compiler bugs.  */
+#define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
+/* The outer cast is needed to work around a bug in Cray C 5.0.3.0.
+   It is necessary at least when t == time_t.  */
+#define TYPE_MINIMUM(t) ((t) (TYPE_SIGNED (t) \
+                             ? ~ (t) 0 << (sizeof (t) * CHAR_BIT - 1) : (t) 0))
+#define TYPE_MAXIMUM(t) ((t) (~ (t) 0 - TYPE_MINIMUM (t)))
+
+#ifndef INT_MAX
+# define INT_MAX TYPE_MAXIMUM (int)
+#endif
+
 /* We don't pass an nbytes count > SSIZE_MAX to write() - POSIX says the
    effect would be implementation-defined.  Also we don't pass an nbytes
    count > INT_MAX but <= SSIZE_MAX to write() - this triggers a bug in
@@ -47,37 +63,25 @@ extern int errno;
 size_t
 safe_write (int fd, const void *buf, size_t count)
 {
-  size_t total_written = 0;
+  size_t nbytes_to_write = count;
+  ssize_t result;
+
+  /* Limit the number of bytes to write, to avoid running into unspecified
+     behaviour.  But keep the file pointer block aligned when doing so.
+     Note that in this case we don't need to call write() multiple times here,
+     because the caller is prepared to partial results.  */
+  if (nbytes_to_write > MAX_BYTES_TO_READ)
+    nbytes_to_write = MAX_BYTES_TO_READ & ~8191;
 
-  if (count > 0)
+  do
     {
-      const char *ptr = (const char *) buf;
-      do
-       {
-         size_t nbytes_to_write = count;
-         ssize_t result;
-
-         /* Limit the number of bytes to write in one round, to avoid running
-            into unspecified behaviour.  But keep the file pointer block
-            aligned when doing so.  */
-         if (nbytes_to_write > MAX_BYTES_TO_READ)
-           nbytes_to_write = MAX_BYTES_TO_READ & ~8191;
-
-         result = write (fd, ptr, nbytes_to_write);
-         if (result < 0)
-           {
+      result = write (fd, buf, nbytes_to_write);
+    }
 #ifdef EINTR
-             if (errno == EINTR)
-               continue;
+  while (result < 0 && errno == EINTR);
+#else
+  while (0);
 #endif
-             return result;
-           }
-         total_written += result;
-         ptr += result;
-         count -= result;
-       }
-      while (count > 0);
-    }
 
-  return total_written;
+  return (size_t) result;
 }

diff --git a/lib/safe-write.h b/lib/safe-write.h
index 25d1a4d..ab1f45b 100644 (file)
--- a/lib/safe-write.h
+++ b/lib/safe-write.h
@@ -17,7 +17,9 @@
 
 #include <stddef.h>
 
+#define SAFE_WRITE_ERROR ((size_t) -1)
+
 /* Write up to COUNT bytes at BUF to descriptor FD, retrying if interrupted.
-   Return the actual number of bytes written, zero for EOF, or (size_t) -1
-   for an error.  */
+   Return the actual number of bytes written, zero for EOF, or SAFE_WRITE_ERROR
+   upon error.  */
 extern size_t safe_write (int fd, const void *buf, size_t count);