In side-by-side diff, add support for marking individual characters.

Refuses to do so if the left hand side of the diff has different amount of
differing lines to the right hand side to avoid confusion.

Note that I use the naive dynamic programming approach for calculating the
longest common subsequence. We could probably be more efficient by using a
better algorithm. The LCS calculating function is O(n*m) and uses up n*m
amount of memory too (so if we we compare two strings of length 100, I use
an array of 10000 for calculating the LCS). Might want to not calculate LCS
if the length of the line is too large.

Signed-off-by: Ragnar Ouchterlony <ragnar@lysator.liu.se>

2 files changed, 130 insertions, 25 deletions

diff --git a/cgit.css b/cgit.css
index 3f37165..9e6d2a4 100644
--- a/cgit.css
+++ b/cgit.css
@@ -1,692 +1,702 @@
 body, table, form {
 	padding: 0em;
 	margin: 0em;
 }
 
 body {
 	font-family: sans-serif;
 	font-size: 10pt;
 	color: #333;
 	background: white;
 	padding: 4px;
 }
 
 a {
 	color: blue;
 	text-decoration: none;
 }
 
 a:hover {
 	text-decoration: underline;
 }
 
 table {
       border-collapse: collapse;
 }
 
 table#header {
 	width: 100%;
 	margin-bottom: 1em;
 }
 
 table#header td.logo {
 	width: 96px;
 }
 
 table#header td.main {
 	font-size: 250%;
 	padding-left: 10px;
 	white-space: nowrap;
 }
 
 table#header td.main a {
 	color: #000;
 }
 
 table#header td.form {
 	text-align: right;
 	vertical-align: bottom;
 	padding-right: 1em;
 	padding-bottom: 2px;
 	white-space: nowrap;
 }
 
 table#header td.form form,
 table#header td.form input,
 table#header td.form select {
 	font-size: 90%;
 }
 
 table#header td.sub {
 	color: #777;
 	border-top: solid 1px #ccc;
 	padding-left: 10px;
 }
 
 table.tabs {
 	/* border-bottom: solid 2px #ccc; */
 	border-collapse: collapse;
 	margin-top: 2em;
 	margin-bottom: 0px;
 	width: 100%;
 }
 
 table.tabs td {
 	padding: 0px 1em;
 	vertical-align: bottom;
 }
 
 table.tabs td a {
 	padding: 2px 0.75em;
 	color: #777;
 	font-size: 110%;
 }
 
 table.tabs td a.active {
 	color: #000;
 	background-color: #ccc;
 }
 
 table.tabs td.form {
 	text-align: right;
 }
 
 table.tabs td.form form {
 	padding-bottom: 2px;
 	font-size: 90%;
 	white-space: nowrap;
 }
 
 table.tabs td.form input,
 table.tabs td.form select {
 	font-size: 90%;
 }
 
 div.content {
 	margin: 0px;
 	padding: 2em;
 	border-top: solid 3px #ccc;
 	border-bottom: solid 3px #ccc;
 }
 
 
 table.list {
 	width: 100%;
 	border: none;
 	border-collapse: collapse;
 }
 
 table.list tr {
 	background: white;
 }
 
 table.list tr.logheader {
 	background: #eee;
 }
 
 table.list tr:hover {
 	background: #eee;
 }
 
 table.list tr.nohover:hover {
 	background: white;
 }
 
 table.list th {
 	font-weight: bold;
 	/* color: #888;
 	border-top: dashed 1px #888;
 	border-bottom: dashed 1px #888;
 	*/
 	padding: 0.1em 0.5em 0.05em 0.5em;
 	vertical-align: baseline;
 }
 
 table.list td {
 	border: none;
 	padding: 0.1em 0.5em 0.1em 0.5em;
 }
 
 table.list td.logsubject {
 	font-family: monospace;
 	font-weight: bold;
 }
 
 table.list td.logmsg {
 	font-family: monospace;
 	white-space: pre;
 	padding: 1em 0.5em 2em 0.5em;
 }
 
 table.list td a {
 	color: black;
 }
 
 table.list td a:hover {
 	color: #00f;
 }
 
 img {
 	border: none;
 }
 
 input#switch-btn {
 	margin: 2px 0px 0px 0px;
 }
 
 td#sidebar input.txt {
 	width: 100%;
 	margin: 2px 0px 0px 0px;
 }
 
 table#grid {
 	margin: 0px;
 }
 
 td#content {
 	vertical-align: top;
 	padding: 1em 2em 1em 1em;
 	border: none;
 }
 
 div#summary {
 	vertical-align: top;
 	margin-bottom: 1em;
 }
 
 table#downloads {
 	float: right;
 	border-collapse: collapse;
 	border: solid 1px #777;
 	margin-left: 0.5em;
 	margin-bottom: 0.5em;
 }
 
 table#downloads th {
 	background-color: #ccc;
 }
 
 div#blob {
 	border: solid 1px black;
 }
 
 div.error {
 	color: red;
 	font-weight: bold;
 	margin: 1em 2em;
 }
 
 a.ls-blob, a.ls-dir, a.ls-mod {
 	font-family: monospace;
 }
 
 td.ls-size {
 	text-align: right;
 	font-family: monospace;
 	width: 10em;
 }
 
 td.ls-mode {
 	font-family: monospace;
 	width: 10em;
 }
 
 table.blob {
 	margin-top: 0.5em;
 	border-top: solid 1px black;
 }
 
 table.blob td.lines {
 	margin: 0; padding: 0 0 0 0.5em;
 	vertical-align: top;
 	color: black;
 }
 
 table.blob td.linenumbers {
 	margin: 0; padding: 0 0.5em 0 0.5em;
 	vertical-align: top;
 	text-align: right;
 	border-right: 1px solid gray;
 }
 
 table.blob pre {
 	padding: 0; margin: 0;
 }
 
 table.blob a.no {
 	color: gray;
 	text-align: right;
 	text-decoration: none;
 }
 
 table.blob a.no a:hover {
 	color: black;
 }
 
 table.bin-blob {
 	margin-top: 0.5em;
 	border: solid 1px black;
 }
 
 table.bin-blob th {
 	font-family: monospace;
 	white-space: pre;
 	border: solid 1px #777;
 	padding: 0.5em 1em;
 }
 
 table.bin-blob td {
 	font-family: monospace;
 	white-space: pre;
 	border-left: solid 1px #777;
 	padding: 0em 1em;
 }
 
 table.nowrap td {
 	white-space: nowrap;
 }
 
 table.commit-info {
 	border-collapse: collapse;
 	margin-top: 1.5em;
 }
 
 table.commit-info th {
 	text-align: left;
 	font-weight: normal;
 	padding: 0.1em 1em 0.1em 0.1em;
 	vertical-align: top;
 }
 
 table.commit-info td {
 	font-weight: normal;
 	padding: 0.1em 1em 0.1em 0.1em;
 }
 
 div.commit-subject {
 	font-weight: bold;
 	font-size: 125%;
 	margin: 1.5em 0em 0.5em 0em;
 	padding: 0em;
 }
 
 div.commit-msg {
 	white-space: pre;
 	font-family: monospace;
 }
 
 div.diffstat-header {
 	font-weight: bold;
 	padding-top: 1.5em;
 }
 
 table.diffstat {
 	border-collapse: collapse;
 	border: solid 1px #aaa;
 	background-color: #eee;
 }
 
 table.diffstat th {
 	font-weight: normal;
 	text-align: left;
 	text-decoration: underline;
 	padding: 0.1em 1em 0.1em 0.1em;
 	font-size: 100%;
 }
 
 table.diffstat td {
 	padding: 0.2em 0.2em 0.1em 0.1em;
 	font-size: 100%;
 	border: none;
 }
 
 table.diffstat td.mode {
 	white-space: nowrap;
 }
 
 table.diffstat td span.modechange {
 	padding-left: 1em;
 	color: red;
 }
 
 table.diffstat td.add a {
 	color: green;
 }
 
 table.diffstat td.del a {
 	color: red;
 }
 
 table.diffstat td.upd a {
 	color: blue;
 }
 
 table.diffstat td.graph {
 	width: 500px;
 	vertical-align: middle;
 }
 
 table.diffstat td.graph table {
 	border: none;
 }
 
 table.diffstat td.graph td {
 	padding: 0px;
 	border: 0px;
 	height: 7pt;
 }
 
 table.diffstat td.graph td.add {
 	background-color: #5c5;
 }
 
 table.diffstat td.graph td.rem {
 	background-color: #c55;
 }
 
 div.diffstat-summary {
 	color: #888;
 	padding-top: 0.5em;
 }
 
 table.diff {
 	width: 100%;
 }
 
 table.diff td {
 	font-family: monospace;
 	white-space: pre;
 }
 
 table.diff td div.head {
 	font-weight: bold;
 	margin-top: 1em;
 	color: black;
 }
 
 table.diff td div.hunk {
 	color: #009;
 }
 
 table.diff td div.add {
 	color: green;
 }
 
 table.diff td div.del {
 	color: red;
 }
 
 .sha1 {
 	font-family: monospace;
 	font-size: 90%;
 }
 
 .left {
 	text-align: left;
 }
 
 .right {
 	text-align: right;
 }
 
 table.list td.reposection {
 	font-style: italic;
 	color: #888;
 }
 
 a.button {
 	font-size: 80%;
 	padding: 0em 0.5em;
 }
 
 a.primary {
 	font-size: 100%;
 }
 
 a.secondary {
 	font-size: 90%;
 }
 
 td.toplevel-repo {
 
 }
 
 table.list td.sublevel-repo {
 	padding-left: 1.5em;
 }
 
 div.pager {
 	text-align: center;
 	margin: 1em 0em 0em 0em;
 }
 
 div.pager a {
 	color: #777;
 	margin: 0em 0.5em;
 }
 
 span.age-mins {
 	font-weight: bold;
 	color: #080;
 }
 
 span.age-hours {
 	color: #080;
 }
 
 span.age-days {
 	color: #040;
 }
 
 span.age-weeks {
 	color: #444;
 }
 
 span.age-months {
 	color: #888;
 }
 
 span.age-years {
 	color: #bbb;
 }
 div.footer {
 	margin-top: 0.5em;
 	text-align: center;
 	font-size: 80%;
 	color: #ccc;
 }
 a.branch-deco {
 	margin: 0px 0.5em;
 	padding: 0px 0.25em;
 	background-color: #88ff88;
 	border: solid 1px #007700;
 }
 a.tag-deco {
 	margin: 0px 0.5em;
 	padding: 0px 0.25em;
 	background-color: #ffff88;
 	border: solid 1px #777700;
 }
 a.remote-deco {
 	margin: 0px 0.5em;
 	padding: 0px 0.25em;
 	background-color: #ccccff;
 	border: solid 1px #000077;
 }
 a.deco {
 	margin: 0px 0.5em;
 	padding: 0px 0.25em;
 	background-color: #ff8888;
 	border: solid 1px #770000;
 }
 
 div.commit-subject a {
 	margin-left: 1em;
 	font-size: 75%;
 }
 
 table.stats {
 	border: solid 1px black;
 	border-collapse: collapse;
 }
 
 table.stats th {
 	text-align: left;
 	padding: 1px 0.5em;
 	background-color: #eee;
 	border: solid 1px black;
 }
 
 table.stats td {
 	text-align: right;
 	padding: 1px 0.5em;
 	border: solid 1px black;
 }
 
 table.stats td.total {
 	font-weight: bold;
 	text-align: left;
 }
 
 table.stats td.sum {
 	color: #c00;
 	font-weight: bold;
 /*	background-color: #eee; */
 }
 
 table.stats td.left {
 	text-align: left;
 }
 
 table.vgraph {
 	border-collapse: separate;
 	border: solid 1px black;
 	height: 200px;
 }
 
 table.vgraph th {
 	background-color: #eee;
 	font-weight: bold;
 	border: solid 1px white;
 	padding: 1px 0.5em;
 }
 
 table.vgraph td {
 	vertical-align: bottom;
 	padding: 0px 10px;
 }
 
 table.vgraph div.bar {
 	background-color: #eee;
 }
 
 table.hgraph {
 	border: solid 1px black;
 	width: 800px;
 }
 
 table.hgraph th {
 	background-color: #eee;
 	font-weight: bold;
 	border: solid 1px black;
 	padding: 1px 0.5em;
 }
 
 table.hgraph td {
 	vertical-align: center;
 	padding: 2px 2px;
 }
 
 table.hgraph div.bar {
 	background-color: #eee;
 	height: 1em;
 }
 
 table.ssdiff {
 	width: 100%;
 }
 
 table.ssdiff td {
 	font-size: 75%;
 	font-family: monospace;
 	white-space: pre;
 	padding: 1px 4px 1px 4px;
 	border-left: solid 1px #aaa;
 	border-right: solid 1px #aaa;
 }
 
 table.ssdiff td.add {
 	color: black;
 	background: #cfc;
 	min-width: 50%;
 }
 
 table.ssdiff td.add_dark {
 	color: black;
 	background: #aca;
 	min-width: 50%;
 }
 
+table.ssdiff span.add {
+	background: #cfc;
+	font-weight: bold;
+}
+
 table.ssdiff td.del {
 	color: black;
 	background: #fcc;
 	min-width: 50%;
 }
 
 table.ssdiff td.del_dark {
 	color: black;
 	background: #caa;
 	min-width: 50%;
 }
 
+table.ssdiff span.del {
+	background: #fcc;
+	font-weight: bold;
+}
+
 table.ssdiff td.changed {
 	color: black;
 	background: #ffc;
 	min-width: 50%;
 }
 
 table.ssdiff td.changed_dark {
 	color: black;
 	background: #cca;
 	min-width: 50%;
 }
 
 table.ssdiff td.lineno {
 	color: black;
 	background: #eee;
 	text-align: right;
 	width: 3em;
 	min-width: 3em;
 }
 
 table.ssdiff td.hunk {
 	color: #black;
 	background: #ccf;
 	border-top: solid 1px #aaa;
 	border-bottom: solid 1px #aaa;
 }
 
 table.ssdiff td.head {
 	border-top: solid 1px #aaa;
 	border-bottom: solid 1px #aaa;
 }
 
 table.ssdiff td.head div.head {
 	font-weight: bold;
 	color: black;
 }
 
 table.ssdiff td.foot {
 	border-top: solid 1px #aaa;
         border-left: none;
         border-right: none;
         border-bottom: none;
 }
 
 table.ssdiff td.space {
 	border: none;
 }
 
 table.ssdiff td.space div {
 	min-height: 3em;
 }
\ No newline at end of file
diff --git a/ui-ssdiff.c b/ui-ssdiff.c
index 5673642..408e620 100644
--- a/ui-ssdiff.c
+++ b/ui-ssdiff.c
@@ -1,274 +1,369 @@
 #include "cgit.h"
 #include "html.h"
 #include "ui-shared.h"
 
 extern int use_ssdiff;
 
 static int current_old_line, current_new_line;
 
 struct deferred_lines {
 	int line_no;
 	char *line;
 	struct deferred_lines *next;
 };
 
 static struct deferred_lines *deferred_old, *deferred_old_last;
 static struct deferred_lines *deferred_new, *deferred_new_last;
 
+static char *longest_common_subsequence(char *A, char *B)
+{
+	int i, j, ri;
+	int m = strlen(A);
+	int n = strlen(B);
+	int L[m + 1][n + 1];
+	int tmp1, tmp2;
+	int lcs_length;
+	char *result;
+
+	for (i = m; i >= 0; i--) {
+		for (j = n; j >= 0; j--) {
+			if (A[i] == '\0' || B[j] == '\0') {
+				L[i][j] = 0;
+			} else if (A[i] == B[j]) {
+				L[i][j] = 1 + L[i + 1][j + 1];
+			} else {
+				tmp1 = L[i + 1][j];
+				tmp2 = L[i][j + 1];
+				L[i][j] = (tmp1 > tmp2 ? tmp1 : tmp2);
+			}
+		}
+	}
+
+	lcs_length = L[0][0];
+	result = xmalloc(lcs_length + 2);
+	memset(result, 0, sizeof(*result) * (lcs_length + 2));
+
+	ri = 0;
+	i = 0;
+	j = 0;
+	while (i < m && j < n) {
+		if (A[i] == B[j]) {
+			result[ri] = A[i];
+			ri += 1;
+			i += 1;
+			j += 1;
+		} else if (L[i + 1][j] >= L[i][j + 1]) {
+			i += 1;
+		} else {
+			j += 1;
+		}
+	}
+	return result;
+}
+
 static int line_from_hunk(char *line, char type)
 {
 	char *buf1, *buf2;
 	int len;
 
 	buf1 = strchr(line, type);
 	if (buf1 == NULL)
 		return 0;
 	buf1 += 1;
 	buf2 = strchr(buf1, ',');
 	if (buf2 == NULL)
 		return 0;
 	len = buf2 - buf1;
 	buf2 = xmalloc(len + 1);
 	strncpy(buf2, buf1, len);
 	buf2[len] = '\0';
 	int res = atoi(buf2);
 	free(buf2);
 	return res;
 }
 
 static char *replace_tabs(char *line)
 {
 	char *prev_buf = line;
 	char *cur_buf;
 	int linelen = strlen(line);
 	int n_tabs = 0;
 	int i;
 	char *result;
 	char *spaces = "        ";
 
 	if (linelen == 0) {
 		result = xmalloc(1);
 		result[0] = '\0';
 		return result;
 	}
 
 	for (i = 0; i < linelen; i++)
 		if (line[i] == '\t')
 			n_tabs += 1;
 	result = xmalloc(linelen + n_tabs * 8 + 1);
 	result[0] = '\0';
 
 	while (1) {
 		cur_buf = strchr(prev_buf, '\t');
 		if (!cur_buf) {
 			strcat(result, prev_buf);
 			break;
 		} else {
 			strcat(result, " ");
 			strncat(result, spaces, 8 - (strlen(result) % 8));
 			strncat(result, prev_buf, cur_buf - prev_buf);
 		}
 		prev_buf = cur_buf + 1;
 	}
 	return result;
 }
 
+static int calc_deferred_lines(struct deferred_lines *start)
+{
+	struct deferred_lines *item = start;
+	int result = 0;
+	while (item) {
+		result += 1;
+		item = item->next;
+	}
+	return result;
+}
+
 static void deferred_old_add(char *line, int line_no)
 {
 	struct deferred_lines *item = xmalloc(sizeof(struct deferred_lines));
 	item->line = xstrdup(line);
 	item->line_no = line_no;
 	item->next = NULL;
 	if (deferred_old) {
 		deferred_old_last->next = item;
 		deferred_old_last = item;
 	} else {
 		deferred_old = deferred_old_last = item;
 	}
 }
 
 static void deferred_new_add(char *line, int line_no)
 {
 	struct deferred_lines *item = xmalloc(sizeof(struct deferred_lines));
 	item->line = xstrdup(line);
 	item->line_no = line_no;
 	item->next = NULL;
 	if (deferred_new) {
 		deferred_new_last->next = item;
 		deferred_new_last = item;
 	} else {
 		deferred_new = deferred_new_last = item;
 	}
 }
 
-static void print_ssdiff_line(char *class, int old_line_no, char *old_line,
-			      int new_line_no, char *new_line)
+static void print_part_with_lcs(char *class, char *line, char *lcs)
+{
+	int line_len = strlen(line);
+	int i, j;
+	char c[2] = " ";
+	int same = 1;
+
+	j = 0;
+	for (i = 0; i < line_len; i++) {
+		c[0] = line[i];
+		if (same) {
+			if (line[i] == lcs[j])
+				j += 1;
+			else {
+				same = 0;
+				htmlf("<span class='%s'>", class);
+			}
+		} else if (line[i] == lcs[j]) {
+			same = 1;
+			htmlf("</span>");
+			j += 1;
+		}
+		html_txt(c);
+	}
+}
+
+static void print_ssdiff_line(char *class,
+			      int old_line_no,
+			      char *old_line,
+			      int new_line_no,
+			      char *new_line, int individual_chars)
 {
+	char *lcs = NULL;
+	if (old_line)
+		old_line = replace_tabs(old_line + 1);
+	if (new_line)
+		new_line = replace_tabs(new_line + 1);
+	if (individual_chars && old_line && new_line)
+		lcs = longest_common_subsequence(old_line, new_line);
 	html("<tr>");
 	if (old_line_no > 0)
 		htmlf("<td class='lineno'>%d</td><td class='%s'>",
 		      old_line_no, class);
 	else if (old_line)
 		htmlf("<td class='lineno'></td><td class='%s'>", class);
 	else
 		htmlf("<td class='lineno'></td><td class='%s_dark'>", class);
-
 	if (old_line) {
-		old_line = replace_tabs(old_line + 1);
-		html_txt(old_line);
-		free(old_line);
+		if (lcs)
+			print_part_with_lcs("del", old_line, lcs);
+		else
+			html_txt(old_line);
 	}
 
 	html("</td>");
-
 	if (new_line_no > 0)
 		htmlf("<td class='lineno'>%d</td><td class='%s'>",
 		      new_line_no, class);
 	else if (new_line)
 		htmlf("<td class='lineno'></td><td class='%s'>", class);
 	else
 		htmlf("<td class='lineno'></td><td class='%s_dark'>", class);
-
 	if (new_line) {
-		new_line = replace_tabs(new_line + 1);
-		html_txt(new_line);
-		free(new_line);
+		if (lcs)
+			print_part_with_lcs("add", new_line, lcs);
+		else
+			html_txt(new_line);
 	}
 
 	html("</td></tr>");
+	if (lcs)
+		free(lcs);
+	if (new_line)
+		free(new_line);
+	if (old_line)
+		free(old_line);
 }
 
 static void print_deferred_old_lines()
 {
 	struct deferred_lines *iter_old, *tmp;
-
 	iter_old = deferred_old;
 	while (iter_old) {
 		print_ssdiff_line("del", iter_old->line_no,
-				  iter_old->line, -1, NULL);
+				  iter_old->line, -1, NULL, 0);
 		tmp = iter_old->next;
 		free(iter_old);
 		iter_old = tmp;
 	}
 }
 
 static void print_deferred_new_lines()
 {
 	struct deferred_lines *iter_new, *tmp;
-
 	iter_new = deferred_new;
 	while (iter_new) {
-		print_ssdiff_line("add", -1, NULL, iter_new->line_no,
-				  iter_new->line);
+		print_ssdiff_line("add", -1, NULL,
+				  iter_new->line_no, iter_new->line, 0);
 		tmp = iter_new->next;
 		free(iter_new);
 		iter_new = tmp;
 	}
 }
 
 static void print_deferred_changed_lines()
 {
 	struct deferred_lines *iter_old, *iter_new, *tmp;
+	int n_old_lines = calc_deferred_lines(deferred_old);
+	int n_new_lines = calc_deferred_lines(deferred_new);
+	int individual_chars = (n_old_lines == n_new_lines ? 1 : 0);
 
 	iter_old = deferred_old;
 	iter_new = deferred_new;
 	while (iter_old || iter_new) {
 		if (iter_old && iter_new)
 			print_ssdiff_line("changed", iter_old->line_no,
 					  iter_old->line,
-					  iter_new->line_no, iter_new->line);
+					  iter_new->line_no, iter_new->line,
+					  individual_chars);
 		else if (iter_old)
 			print_ssdiff_line("changed", iter_old->line_no,
-					  iter_old->line, -1, NULL);
+					  iter_old->line, -1, NULL, 0);
 		else if (iter_new)
 			print_ssdiff_line("changed", -1, NULL,
-					  iter_new->line_no, iter_new->line);
-
+					  iter_new->line_no, iter_new->line, 0);
 		if (iter_old) {
 			tmp = iter_old->next;
 			free(iter_old);
 			iter_old = tmp;
 		}
 
 		if (iter_new) {
 			tmp = iter_new->next;
 			free(iter_new);
 			iter_new = tmp;
 		}
 	}
 }
 
 void cgit_ssdiff_print_deferred_lines()
 {
 	if (!deferred_old && !deferred_new)
 		return;
-
 	if (deferred_old && !deferred_new)
 		print_deferred_old_lines();
 	else if (!deferred_old && deferred_new)
 		print_deferred_new_lines();
 	else
 		print_deferred_changed_lines();
-
 	deferred_old = deferred_old_last = NULL;
 	deferred_new = deferred_new_last = NULL;
 }
 
 /*
  * print a single line returned from xdiff
  */
 void cgit_ssdiff_line_cb(char *line, int len)
 {
 	char c = line[len - 1];
-
 	line[len - 1] = '\0';
-
 	if (line[0] == '@') {
 		current_old_line = line_from_hunk(line, '-');
 		current_new_line = line_from_hunk(line, '+');
 	}
 
 	if (line[0] == ' ') {
 		if (deferred_old || deferred_new)
 			cgit_ssdiff_print_deferred_lines();
 		print_ssdiff_line("ctx", current_old_line, line,
-				  current_new_line, line);
+				  current_new_line, line, 0);
 		current_old_line += 1;
 		current_new_line += 1;
 	} else if (line[0] == '+') {
 		deferred_new_add(line, current_new_line);
 		current_new_line += 1;
 	} else if (line[0] == '-') {
 		deferred_old_add(line, current_old_line);
 		current_old_line += 1;
 	} else if (line[0] == '@') {
 		html("<tr><td colspan='4' class='hunk'>");
 		html_txt(line);
 		html("</td></tr>");
 	} else {
 		html("<tr><td colspan='4' class='ctx'>");
 		html_txt(line);
 		html("</td></tr>");
 	}
 	line[len - 1] = c;
 }
 
 void cgit_ssdiff_header_begin()
 {
 	current_old_line = -1;
 	current_new_line = -1;
 	html("<tr><td class='space' colspan='4'><div></div></td></tr>");
 	html("<tr><td class='head' colspan='4'>");
 }
 
 void cgit_ssdiff_header_end()
 {
 	html("</td><tr>");
 }
 
 void cgit_ssdiff_footer()
 {
 	if (deferred_old || deferred_new)
 		cgit_ssdiff_print_deferred_lines();
 	html("<tr><td class='foot' colspan='4'></td></tr>");
 }