done

mmapcp.cc

@@ -6,54 +6,28 @@
 #include <string.h>
 #include <sys/stat.h>
 
-int main(int argc, char *argv[])
-{
+int main (int argc, char *argv[]) {
   int s, s2, d;
-  struct stat st;
-  struct stat s2t;
+  struct stat st, s2t;
   void *sp, *s2p, *dp;
   s = open(argv[1], O_RDONLY);
-  if (s == -1) {
-    perror("open source");
-    exit(1);
-  }
+  if (s == -1) { perror("open source"); exit(1); }
   s2 = open(argv[2], O_RDONLY);
-  if (s2 == -1) {
-    perror("open source2");
-    exit(1);
-  }
-  d = open(argv[3], O_RDWR | O_CREAT | O_TRUNC, 0644);
-  if (d == -1) {
-    perror("open destination");
-    exit(1);
-  }
-  if (fstat(s, &st)) {
-    perror("stat source");
-    exit(1);
-  }
-  if (fstat(s2, &s2t)) {
-    perror("stat source2");
-    exit(1);
-  }
-  if (ftruncate(d, st.st_size + s2t.st_size)) {
-    perror("truncate destination");
-    exit(1);
-  }
+  if (s2 == -1) { perror("open source2"); exit(1); }
+  d = open(argv[3], O_WRONLY | O_CREAT, 0644);
+  if (d == -1) { perror("open destination"); exit(1); }
+  if (fstat(s, &st)) { perror("stat source"); exit(1); }
+  if (fstat(s2, &s2t)) { perror("stat source2"); exit(1); }
+  if (ftruncate(d, st.st_size + s2t.st_size)) { perror("truncate destination"); exit(1); }
   sp = mmap(NULL, st.st_size, PROT_READ, MAP_SHARED, s, 0);
-  if (sp == MAP_FAILED) {
-    perror("map source");
-    exit(1);
-  }
+  if (sp == MAP_FAILED) { perror("map source"); exit(1); }
+  madvise(sp, st.st_size, MADV_SEQUENTIAL);
   s2p = mmap(NULL, s2t.st_size, PROT_READ, MAP_SHARED, s2, 0);
-  if (s2p == MAP_FAILED) {
-    perror("map source2");
-    exit(1);
-  }
+  if (s2p == MAP_FAILED) { perror("map source2"); exit(1); }
+  madvise(s2p, s2t.st_size, MADV_SEQUENTIAL);
   dp = mmap(NULL, st.st_size + s2t.st_size, PROT_WRITE | PROT_READ, MAP_SHARED, d, 0);
-  if (dp == MAP_FAILED) {
-    perror("map destination");
-    exit(1);
-  }
-  memcpy(dp, sp, st.st_size);
+  if (dp == MAP_FAILED) { perror("map destination"); exit(1); }
+  madvise(dp, st.st_size + s2t.st_size, MADV_SEQUENTIAL);
+  memcpy(mempcpy(dp, sp, st.st_size), s2p, s2t.st_size);
   return 0;
 }