parse_date(): '@' prefix forces git-timestamp

diff --git a/date.c b/date.c
index 00f9eb5d0b9730107a8e08e92eb04d4cc9233595..bf8e088e6aec6278ec4be054732e517ce3abaafc 100644 (file)
--- a/date.c
+++ b/date.c
@@ -129,8 +129,9 @@ const char *show_date_relative(unsigned long time, int tz,
        }
        /* Give years and months for 5 years or so */
        if (diff < 1825) {
-               unsigned long years = diff / 365;
-               unsigned long months = (diff % 365 + 15) / 30;
+               unsigned long totalmonths = (diff * 12 * 2 + 365) / (365 * 2);
+               unsigned long years = totalmonths / 12;
+               unsigned long months = totalmonths % 12;
                int n;
                n = snprintf(timebuf, timebuf_size, "%lu year%s",
                                years, (years > 1 ? "s" : ""));
@@ -584,6 +585,33 @@ static int date_string(unsigned long date, int offset, char *buf, int len)
        return snprintf(buf, len, "%lu %c%02d%02d", date, sign, offset / 60, offset % 60);
 }
 
+/*
+ * Parse a string like "0 +0000" as ancient timestamp near epoch, but
+ * only when it appears not as part of any other string.
+ */
+static int match_object_header_date(const char *date, unsigned long *timestamp, int *offset)
+{
+       char *end;
+       unsigned long stamp;
+       int ofs;
+
+       if (*date < '0' || '9' <= *date)
+               return -1;
+       stamp = strtoul(date, &end, 10);
+       if (*end != ' ' || stamp == ULONG_MAX || (end[1] != '+' && end[1] != '-'))
+               return -1;
+       date = end + 2;
+       ofs = strtol(date, &end, 10);
+       if ((*end != '\0' && (*end != '\n')) || end != date + 4)
+               return -1;
+       ofs = (ofs / 100) * 60 + (ofs % 100);
+       if (date[-1] == '-')
+               ofs = -ofs;
+       *timestamp = stamp;
+       *offset = ofs;
+       return 0;
+}
+
 /* Gr. strptime is crap for this; it doesn't have a way to require RFC2822
    (i.e. English) day/month names, and it doesn't work correctly with %z. */
 int parse_date_basic(const char *date, unsigned long *timestamp, int *offset)
@@ -609,6 +637,9 @@ int parse_date_basic(const char *date, unsigned long *timestamp, int *offset)
        *offset = -1;
        tm_gmt = 0;
 
+       if (*date == '@' &&
+           !match_object_header_date(date + 1, timestamp, offset))
+               return 0; /* success */
        for (;;) {
                int match = 0;
                unsigned char c = *date;