+/* Read a complete file into memory. */
+
+static const char *
+slurp_file (const char *fn, size_t *size)
+{
+#ifdef HAVE_MMAP
+ int ps = getpagesize ();
+ size_t msize;
+#endif
+ const char *map;
+ struct stat st;
+ int fd = open (fn, O_RDONLY | O_BINARY);
+
+ if (fd < 0)
+ return NULL;
+ if (fstat (fd, &st) < 0)
+ return NULL;
+ *size = st.st_size;
+#ifdef HAVE_MMAP
+ msize = (*size + ps - 1) & ~(ps - 1);
+ map = mmap (NULL, msize, PROT_READ, MAP_SHARED, fd, 0);
+ if (map != (char *)-1L)
+ {
+ close(fd);
+ return map;
+ }
+#endif
+ map = (const char *) malloc (*size);
+ if (!map || (size_t) read (fd, (char *)map, *size) != *size)
+ {
+ free ((void *)map);
+ map = NULL;
+ }
+ close (fd);
+ return map;
+}
+
+#define line_map_decrease 5
+
+/* Precompute array of lines for a mapped file. */
+
+static const char **
+index_file (const char *map, size_t size, unsigned int *maxline)
+{
+ const char *p, *lstart, *end;
+ int chars_per_line = 45; /* First iteration will use 40. */
+ unsigned int lineno;
+ const char **linemap = NULL;
+ unsigned long line_map_size = 0;
+
+ lineno = 0;
+ lstart = map;
+ end = map + size;
+
+ for (p = map; p < end; p++)
+ {
+ if (*p == '\n')
+ {
+ if (p + 1 < end && p[1] == '\r')
+ p++;
+ }
+ else if (*p == '\r')
+ {
+ if (p + 1 < end && p[1] == '\n')
+ p++;
+ }
+ else
+ continue;
+
+ /* End of line found. */
+
+ if (linemap == NULL || line_map_size < lineno + 1)
+ {
+ unsigned long newsize;
+
+ chars_per_line -= line_map_decrease;
+ if (chars_per_line <= 1)
+ chars_per_line = 1;
+ line_map_size = size / chars_per_line + 1;
+ if (line_map_size < lineno + 1)
+ line_map_size = lineno + 1;
+ newsize = line_map_size * sizeof (char *);
+ linemap = (const char **) xrealloc (linemap, newsize);
+ }
+
+ linemap[lineno++] = lstart;
+ lstart = p + 1;
+ }
+
+ *maxline = lineno;
+ return linemap;
+}
+