compat: Add simplified merge sort implementation from glibc

diff --git a/builtin-stripspace.c b/builtin-stripspace.c
index c4cf2f05ca13adeb340b3274b0f029c7734af834..c0b21301ba4c126a49ed38b6983756b99a25aae0 100644 (file)
--- a/builtin-stripspace.c
+++ b/builtin-stripspace.c
@@ -1,6 +1,5 @@
 #include "builtin.h"
 #include "cache.h"
-#include "strbuf.h"
 
 /*
  * Returns the length of a line, without trailing spaces.
@@ -9,17 +8,13 @@
  */
 static size_t cleanup(char *line, size_t len)
 {
-       if (len) {
-               if (line[len - 1] == '\n')
-                       len--;
-
-               while (len) {
-                       unsigned char c = line[len - 1];
-                       if (!isspace(c))
-                               break;
-                       len--;
-               }
+       while (len) {
+               unsigned char c = line[len - 1];
+               if (!isspace(c))
+                       break;
+               len--;
        }
+
        return len;
 }
 
@@ -35,42 +30,42 @@ static size_t cleanup(char *line, size_t len)
  * If the input has only empty lines and spaces,
  * no output will be produced.
  *
- * If last line has a newline at the end, it will be removed.
+ * If last line does not have a newline at the end, one is added.
  *
  * Enable skip_comments to skip every line starting with "#".
  */
-size_t stripspace(char *buffer, size_t length, int skip_comments)
+void stripspace(struct strbuf *sb, int skip_comments)
 {
-       int empties = -1;
+       int empties = 0;
        size_t i, j, len, newlen;
        char *eol;
 
-       for (i = j = 0; i < length; i += len, j += newlen) {
-               eol = memchr(buffer + i, '\n', length - i);
-               len = eol ? eol - (buffer + i) + 1 : length - i;
+       /* We may have to add a newline. */
+       strbuf_grow(sb, 1);
 
-               if (skip_comments && len && buffer[i] == '#') {
+       for (i = j = 0; i < sb->len; i += len, j += newlen) {
+               eol = memchr(sb->buf + i, '\n', sb->len - i);
+               len = eol ? eol - (sb->buf + i) + 1 : sb->len - i;
+
+               if (skip_comments && len && sb->buf[i] == '#') {
                        newlen = 0;
                        continue;
                }
-               newlen = cleanup(buffer + i, len);
+               newlen = cleanup(sb->buf + i, len);
 
                /* Not just an empty line? */
                if (newlen) {
-                       if (empties != -1)
-                               buffer[j++] = '\n';
-                       if (empties > 0)
-                               buffer[j++] = '\n';
+                       if (empties > 0 && j > 0)
+                               sb->buf[j++] = '\n';
                        empties = 0;
-                       memmove(buffer + j, buffer + i, newlen);
-                       continue;
+                       memmove(sb->buf + j, sb->buf + i, newlen);
+                       sb->buf[newlen + j++] = '\n';
+               } else {
+                       empties++;
                }
-               if (empties < 0)
-                       continue;
-               empties++;
        }
 
-       return j;
+       strbuf_setlen(sb, j);
 }
 
 int cmd_stripspace(int argc, const char **argv, const char *prefix)
@@ -86,9 +81,7 @@ int cmd_stripspace(int argc, const char **argv, const char *prefix)
        if (strbuf_read(&buf, 0, 1024) < 0)
                die("could not read the input");
 
-       strbuf_setlen(&buf, stripspace(buf.buf, buf.len, strip_comments));
-       if (buf.len)
-               strbuf_addch(&buf, '\n');
+       stripspace(&buf, strip_comments);
 
        write_or_die(1, buf.buf, buf.len);
        strbuf_release(&buf);