[PATCH] blame: add correct paddings in time_buf for align

[Jiang Xin <worldhello.net@gmail.com>]

When show blame information with relative time, the UTF-8 characters in
`time_str` will break the alignment of columns after the date field.
This is because the `time_buf` padding with spaces should have a
constant display width, not a fixed strlen size.  So we should call
utf8_strwidth() instead of strlen() for calibration.

Signed-off-by: Jiang Xin <worldhello.net@gmail.com>
---

Before applying this patch:

        5817da01 builtin-blame.c   (Pierre Habouzit             6 年前                         21) #include "parse-options.h"
        ffaf9cc0 builtin-blame.c   (Geoffrey Thomas             5 年前                         22) #include "utf8.h"
        3b8a12e8 builtin/blame.c   (Axel Bonnet                 3 年 10 个月之前            23) #include "userdiff.h"
        25ed3412 builtin/blame.c   (Bo Yang                     1 年 1 个月之前             24) #include "line-range.h"
        58dbfa2e builtin/blame.c   (Eric Sunshine               9 个月之前                   25) #include "line-log.h"
        cee7f245 builtin-pickaxe.c (Junio C Hamano              8 年前                         26) 

After applying this patch:

        5817da01 builtin-blame.c   (Pierre Habouzit             6 年前                           21) #include "parse-options.h"
        ffaf9cc0 builtin-blame.c   (Geoffrey Thomas             5 年前                           22) #include "utf8.h"
        3b8a12e8 builtin/blame.c   (Axel Bonnet                 3 年 10 个月之前                 23) #include "userdiff.h"
        25ed3412 builtin/blame.c   (Bo Yang                     1 年 1 个月之前                  24) #include "line-range.h"
        58dbfa2e builtin/blame.c   (Eric Sunshine               9 个月之前                       25) #include "line-log.h"
        cee7f245 builtin-pickaxe.c (Junio C Hamano              8 年前                           26) 

 builtin/blame.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/builtin/blame.c b/builtin/blame.c
index 88cb799..c8f6647 100644
--- a/builtin/blame.c
+++ b/builtin/blame.c
@@ -1564,12 +1564,19 @@ static const char *format_time(unsigned long time, const char *tz_str,
 	else {
 		const char *time_str;
 		int time_len;
+		int time_col;
 		int tz;
 		tz = atoi(tz_str);
 		time_str = show_date(time, tz, blame_date_mode);
 		time_len = strlen(time_str);
 		memcpy(time_buf, time_str, time_len);
-		memset(time_buf + time_len, ' ', blame_date_width - time_len);
+		/*
+		 * Add space paddings to time_buf to display a fixed width
+		 * string, and use time_col for display width calibration.
+		 */
+		time_col = utf8_strwidth(time_str);
+		memset(time_buf + time_len, ' ', blame_date_width - time_col);
+		*(time_buf + time_len + blame_date_width - time_col) = 0;
 	}
 	return time_buf;
 }
-- 
1.9.2.474.g17b2a16