Fix rendering in table with empty cells

`find_emph_char` returns 0 if the char specified is not found in the
current line, but this is also what happens when there's an empty
cell. This patch adds logic to work around this problem.

See uranusjr/macdown#321

4 files changed, 101 insertions, 1 deletions

diff --git a/src/document.c b/src/document.c
index 27c17b2..99596e9 100644
--- a/src/document.c
+++ b/src/document.c
@@ -2225,7 +2225,15 @@ parse_table_row(
 		cell_start = i;
 
 		len = find_emph_char(data + i, size - i, '|');
-		i += len ? len : size - i;
+
+		/* Two possibilities for len == 0:
+		   1) No more pipe char found in the current line.
+		   2) The next pipe is right after the current one, i.e. empty cell.
+		   For case 1, we skip to the end of line; for case 2 we just continue.
+		*/
+		if (len == 0 && data[i] != '|')
+			len = size - i;
+		i += len;
 
 		cell_end = i - 1;
 
diff --git a/test/Tests/Table.html b/test/Tests/Table.html
new file mode 100644
index 0000000..f434598
--- /dev/null
+++ b/test/Tests/Table.html
@@ -0,0 +1,66 @@
+<h1>Standard table</h1>
+
+<table>
+  <thead>
+    <tr>
+      <th>headline1</th>
+      <th>headline2</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td>123</td>
+      <td></td>
+    </tr>
+  </tbody>
+</table>
+
+
+<h1>Cell alignment</h1>
+
+<table>
+  <thead>
+    <tr>
+      <th style="text-align: left">headline1</th>
+      <th style="text-align: center">headline2</th>
+      <th style="text-align: right">headline3</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td style="text-align: left">123</td>
+      <td style="text-align: center"></td>
+      <td style="text-align: right"></td>
+    </tr>
+  </tbody>
+</table>
+
+
+<h1>Malformed table: missing cell at row in body</h1>
+
+<table>
+  <thead>
+    <tr>
+      <th>headline1</th>
+      <th>headline2</th>
+      <th>headline3</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td>12</td>
+      <td></td>
+      <td></td>
+    </tr>
+    <tr>
+      <td>34</td>
+      <td></td>
+      <td></td>
+    </tr>
+    <tr>
+      <td>56</td>
+      <td></td>
+      <td></td>
+    </tr>
+  </tbody>
+</table>
diff --git a/test/Tests/Table.text b/test/Tests/Table.text
new file mode 100644
index 0000000..37df539
--- /dev/null
+++ b/test/Tests/Table.text
@@ -0,0 +1,21 @@
+# Standard table
+
+|headline1|headline2|
+|---------|---------|
+|123      |         |
+
+
+# Cell alignment
+
+|headline1|headline2|headline3|
+|:-------|:------:|------:|
+|123|||
+
+
+# Malformed table: missing cell at row in body
+
+|headline1|headline2|headline3|
+|-------|-------|-------|
+|12
+|34||
+|56|
diff --git a/test/config.json b/test/config.json
index d3e170e..365c7bc 100644
--- a/test/config.json
+++ b/test/config.json
@@ -106,6 +106,11 @@
             "input": "Tests/Underline.text",
             "output": "Tests/Underline.html",
             "flags": ["--underline"]
+        },
+        {
+            "input": "Tests/Table.text",
+            "output": "Tests/Table.html",
+            "flags": ["--tables"]
         }
     ]
 }