highway issue 25 patch

hw-issue25.patch

diff --git a/src/search.c b/src/search.c
index 6248612..009b15d 100644
--- a/src/search.c
+++ b/src/search.c
@@ -69,8 +69,16 @@ char *grow_buf_if_shortage(size_t *cur_buf_size,
     char *new_buf;
     if (*cur_buf_size < need_size + buf_offset + NMAX) {
         *cur_buf_size += need_size + (NMAX - need_size % NMAX);
+        ptrdiff_t copy_buf_size;
+        size_t size;
         new_buf = (char *)hw_calloc(*cur_buf_size, SIZE_OF_CHAR);
-        memcpy(new_buf, copy_buf, need_size);
+        copy_buf_size = copy_buf - current_buf;
+        if (need_size < copy_buf_size) {
+            size = need_size;
+        } else {
+            size = copy_buf_size;
+        }
+        memcpy(new_buf, copy_buf, size);
         tc_free(current_buf);
     } else {
         new_buf = copy_buf;
@@ -418,7 +426,7 @@ int search(int fd,
         // Search end position of the last line in the buffer. We search from the first position
         // and end position of the last line.
         size_t search_len;
-        if (read_len < NMAX) {
+        if (read_len < NMAX && read_sum < n) {
             last_line_end = buf + read_sum;
             search_len = read_sum;
             buf[read_sum] = eol;