diff: use mempcpy

* bootstrap.conf (gnulib_modules): Add mempcpy, stpcpy.
* src/ifdef.c (do_printf_spec):
* src/sdiff.c (expand_name, lf_snarf, temporary_file):
* src/util.c (message5):
Prefer mempcpy to memcpy plus manual size-updating.
Prefer stpcpy to mempcpy plus manual size-spec.

4 files changed, 22 insertions, 23 deletions

diff --git a/bootstrap.conf b/bootstrap.conf
index f2359f6..b3c39e6 100644
--- a/bootstrap.conf
+++ b/bootstrap.conf
@@ -59,6 +59,7 @@ lstat
 maintainer-makefile
 manywarnings
 mbrtowc
+mempcpy
 mkstemp
 mktime
 nstrftime
@@ -73,6 +74,7 @@ stat
 stat-macros
 stat-time
 stdint
+stpcpy
 strcase
 strptime
 strtoimax
diff --git a/src/ifdef.c b/src/ifdef.c
index d82d2d1..b82288f 100644
--- a/src/ifdef.c
+++ b/src/ifdef.c
@@ -362,9 +362,8 @@ do_printf_spec (FILE *out, char const *spec,
             size_t spec_prefix_len = f - spec - 2;
             size_t pI_len = sizeof pI - 1;
             char *format = xmalloca (spec_prefix_len + pI_len + 2);
-            char *p = format + spec_prefix_len + pI_len;
-            memcpy (format, spec, spec_prefix_len);
-            memcpy (format + spec_prefix_len, pI, pI_len);
+            char *p = mempcpy (format, spec, spec_prefix_len);
+            p = stpcpy (p, pI);
             *p++ = c;
             *p = '\0';
             fprintf (out, format, value);
diff --git a/src/sdiff.c b/src/sdiff.c
index ab12987..f6011ce 100644
--- a/src/sdiff.c
+++ b/src/sdiff.c
@@ -337,10 +337,10 @@ expand_name (char *name, bool is_dir, char const *other_name)
       size_t namelen = strlen (name), baselen = base_len (base);
       bool insert_slash = *last_component (name) && name[namelen - 1] != '/';
       char *r = xmalloc (namelen + insert_slash + baselen + 1);
-      memcpy (r, name, namelen);
-      r[namelen] = '/';
-      memcpy (r + namelen + insert_slash, base, baselen);
-      r[namelen + insert_slash + baselen] = '\0';
+      char *p = stpcpy (r, name);
+      *p = '/';
+      p = mempcpy (p + insert_slash, base, baselen);
+      *p = '\0';
       return r;
     }
 }
@@ -429,17 +429,16 @@ lf_snarf (struct line_filter *lf, char *buffer, size_t bufsize)
       size_t s = next - start;
       if (bufsize <= s)
         return 0;
-      memcpy (buffer, start, s);
+      buffer = mempcpy (buffer, start, s);
+      bufsize -= s;
       if (next < lf->buflim)
         {
-          buffer[s] = 0;
+          *buffer = 0;
           lf->bufpos = next + 1;
           return 1;
         }
       if (! lf_refill (lf))
         return s ? 0 : EOF;
-      buffer += s;
-      bufsize -= s;
     }
 }
 
@@ -1163,10 +1162,8 @@ temporary_file (void)
 {
   char const *tmpdir = getenv (TMPDIR_ENV);
   char const *dir = tmpdir ? tmpdir : P_tmpdir;
-  size_t dirlen = strlen (dir);
-  char *buf = xmalloc (dirlen + 1 + 5 + 6 + 1);
-  memcpy (buf, dir, dirlen);
-  strcpy (buf + dirlen, "/sdiffXXXXXX");
+  char *buf = xmalloc (strlen (dir) + 1 + 5 + 6 + 1);
+  strcpy (stpcpy (buf, dir), "/sdiffXXXXXX");
   int fd = mkstemp (buf);
   if (fd < 0)
     free (buf);
diff --git a/src/util.c b/src/util.c
index 9963bb4..a8b2fb1 100644
--- a/src/util.c
+++ b/src/util.c
@@ -107,8 +107,6 @@ message5 (char const *format_msgid, char const *arg1, char const *arg2,
     {
       char *p;
       char const *arg[5];
-      int i;
-      size_t size[5];
       size_t total_size = offsetof (struct msg, args);
       struct msg *new;
 
@@ -118,13 +116,17 @@ message5 (char const *format_msgid, char const *arg1, char const *arg2,
       arg[3] = arg3 ? arg3 : "";
       arg[4] = arg4 ? arg4 : "";
 
-      for (i = 0;  i < 5;  i++)
-        total_size += size[i] = strlen (arg[i]) + 1;
+      for (int i = 0; i < 5; i++)
+        total_size += strlen (arg[i]) + 1;
 
       new = xmalloc (total_size);
 
-      for (i = 0, p = new->args;  i < 5;  p += size[i++])
-        memcpy (p, arg[i], size[i]);
+      p = new->args;
+      for (int i = 0; i < 5; i++)
+	{
+	  p = stpcpy (p, arg[i]);
+	  *p++ = 0;
+	}
 
       *msg_chain_end = new;
       new->next = 0;
@@ -578,14 +580,13 @@ parse_diff_color (void)
   const char *p;		/* Pointer to character being parsed */
   char *buf;			/* color_buf buffer pointer */
   int ind_no;			/* Indicator number */
-  char label[3];		/* Indicator label */
+  char label[] = "??";		/* Indicator label */
   struct color_ext_type *ext;	/* Extension we are working on */
 
   if ((p = color_palette) == NULL || *p == '\0')
     return;
 
   ext = NULL;
-  strcpy (label, "??");
 
   /* This is an overly conservative estimate, but any possible
      --palette string will *not* generate a color_buf longer than