vi: improve motion by paragraph

When moving by paragraph ('{' and '}'):

- Treat multiple empty lines as a single paragraph separator.

- When no paragraph separator is found move to the start or end of
  the file depending on the direction of motion.

function                                             old     new   delta
do_cmd                                              4821    4900     +79
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/0 up/down: 79/0)               Total: 79 bytes

Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 11 insertions, 3 deletions

diff --git a/editors/vi.c b/editors/vi.c
index e3e0f4b44..5d4b0f20e 100644
--- a/editors/vi.c
+++ b/editors/vi.c
@@ -3515,12 +3515,20 @@ static void do_cmd(int c)
         case '{':                       // {- move backward paragraph
         case '}':                       // }- move forward paragraph
                 do {
-                        q = char_search(dot, "\n\n", c == '{' ?
-                                                ((unsigned)BACK << 1) | FULL :
-                                                (FORWARD << 1) | FULL);
+                        dir = c == '}' ? FORWARD : BACK;
+                        // skip over consecutive empty lines
+                        while ((dir == FORWARD ? dot < end - 1 : dot > text) &&
+                                                *dot == '\n' && dot[dir] == '\n') {
+                                dot += dir;
+                        }
+                        q = char_search(dot, "\n\n", ((unsigned)dir << 1) | FULL);
                         if (q != NULL) {        // found blank line
                                 dot = next_line(q);     // move to next blank line
                         }
+                        else {  // blank line not found, move to end of file
+                                dot = dir == FORWARD ? end - 1 : text;
+                                break;
+                        }
                 } while (--cmdcnt > 0);
                 break;
 #endif /* FEATURE_VI_SEARCH */