[PATCH v3] pretty.c: add %x00 format specifier.

["Govind Salinas" <govind@sophiasuchtig.com>]

This adds a %x00 format which parses the 00 as hex encoding for a byte and
prints the resulting byte.  This can be used to add null bytes or other bytes
that can make machine parsing easier.  It is also necessary to use fwrite to
print out the data since printf will terminate if you feed it a null.

Junio supplied the hex decoding.

Signed-off-by: Govind Salinas <blix@sophiasuchtig.com>
---
 Documentation/pretty-formats.txt |    1 +
 log-tree.c                       |    6 ++++--
 pretty.c                         |   11 +++++++++++
 3 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/Documentation/pretty-formats.txt b/Documentation/pretty-formats.txt
index 0193c3c..e8bea3e 100644
--- a/Documentation/pretty-formats.txt
+++ b/Documentation/pretty-formats.txt
@@ -123,3 +123,4 @@ The placeholders are:
 - '%Creset': reset color
 - '%m': left, right or boundary mark
 - '%n': newline
+- '%x00': print a byte from a hex code
diff --git a/log-tree.c b/log-tree.c
index 608f697..3bb6e49 100644
--- a/log-tree.c
+++ b/log-tree.c
@@ -308,8 +308,10 @@ void show_log(struct rev_info *opt, const char *sep)
 	if (opt->show_log_size)
 		printf("log size %i\n", (int)msgbuf.len);

-	if (msgbuf.len)
-		printf("%s%s%s", msgbuf.buf, extra, sep);
+	if (msgbuf.len) {
+		fwrite(msgbuf.buf, sizeof(char), msgbuf.len, stdout);
+		printf("%s%s", extra, sep);
+	}
 	strbuf_release(&msgbuf);
 }

diff --git a/pretty.c b/pretty.c
index 703f521..cb4944c 100644
--- a/pretty.c
+++ b/pretty.c
@@ -457,6 +457,7 @@ static size_t format_commit_item(struct strbuf
*sb, const char *placeholder,
 	const struct commit *commit = c->commit;
 	const char *msg = commit->buffer;
 	struct commit_list *p;
+	int h1, h2;

 	/* these are independent of the commit */
 	switch (placeholder[0]) {
@@ -478,6 +479,16 @@ static size_t format_commit_item(struct strbuf
*sb, const char *placeholder,
 	case 'n':		/* newline */
 		strbuf_addch(sb, '\n');
 		return 1;
+	case 'x':
+		/* %x00 == NUL, %x0a == LF, etc. */
+		if (0 <= (h1 = hexval_table[0xff & placeholder[1]]) &&
+		    h1 <= 16 &&
+		    0 <= (h2 = hexval_table[0xff & placeholder[2]]) &&
+		    h2 <= 16) {
+			strbuf_addch(sb, (h1<<4)|h2);
+			return 3;
+		} else
+			return 0;
 	}

 	/* these depend on the commit */
-- 
1.5.4.4.552.g7113.dirty