Reformat _Wikitext_utf8_to_utf32 for better readability

Reduce line lengths to make the _Wikitext_utf8_to_utf32
function more readable, most notably by splitting lengthy
condition expressions and bitwise-OR expressions across
multiple lines.

Signed-off-by: Wincent Colaiuta <win@wincent.com>

diff --git a/ext/parser.c b/ext/parser.c
index 2dff381fff5fd76ffbf3f1b8e7250de9f474ad23..379fd9300275ffcef7dafa4a9a0ab2342ec4dec5 100644 (file)
--- a/ext/parser.c
+++ b/ext/parser.c
@@ -618,52 +618,86 @@ void _Wikitext_pop_excess_elements(parser_t *parser)
 
 #define INVALID_ENCODING(msg)  do { if (dest_ptr) free(dest_ptr); rb_raise(eWikitextParserError, "invalid encoding: " msg); } while(0)
 
-// convert a single UTF-8 codepoint to UTF-32
-// expects an input buffer, src, containing a UTF-8 encoded character (which may be multi-byte)
-// the end of the input buffer, end, is also passed in to allow the detection of invalidly truncated codepoints
-// the number of bytes in the UTF-8 character (between 1 and 4) is returned by reference in width_out
-// raises a RangeError if the supplied character is invalid UTF-8
-// (in which case it also frees the block of memory indicated by dest_ptr if it is non-NULL)
+// Convert a single UTF-8 codepoint to UTF-32
+//
+// Expects an input buffer, src, containing a UTF-8 encoded character (which
+// may be multi-byte). The end of the input buffer, end, is also passed in to
+// allow the detection of invalidly truncated codepoints. The number of bytes
+// in the UTF-8 character (between 1 and 4) is returned by reference in
+// width_out.
+//
+// Raises a RangeError if the supplied character is invalid UTF-8 (in which
+// case it also frees the block of memory indicated by dest_ptr if it is
+// non-NULL).
 uint32_t _Wikitext_utf8_to_utf32(char *src, char *end, long *width_out, void *dest_ptr)
 {
     uint32_t dest;
-    if ((unsigned char)src[0] <= 0x7f)                      // ASCII
+    if ((unsigned char)src[0] <= 0x7f)
     {
+        // ASCII
         dest = src[0];
         *width_out = 1;
     }
-    else if ((src[0] & 0xe0) == 0xc0)                       // byte starts with 110..... : this should be a two-byte sequence
+    else if ((src[0] & 0xe0) == 0xc0)
     {
+        // byte starts with 110..... : this should be a two-byte sequence
         if (src + 1 >= end)
-            INVALID_ENCODING("truncated byte sequence");    // no second byte
-        else if (((unsigned char)src[0] == 0xc0) || ((unsigned char)src[0] == 0xc1))
-            INVALID_ENCODING("overlong encoding");          // overlong encoding: lead byte of 110..... but code point <= 127
+            // no second byte
+            INVALID_ENCODING("truncated byte sequence");
+        else if (((unsigned char)src[0] == 0xc0) ||
+                ((unsigned char)src[0] == 0xc1))
+            // overlong encoding: lead byte of 110..... but code point <= 127
+            INVALID_ENCODING("overlong encoding");
         else if ((src[1] & 0xc0) != 0x80 )
-            INVALID_ENCODING("malformed byte sequence");    // should have second byte starting with 10......
-        dest = ((uint32_t)(src[0] & 0x1f)) << 6 | (src[1] & 0x3f);
+            // should have second byte starting with 10......
+            INVALID_ENCODING("malformed byte sequence");
+
+        dest =
+            ((uint32_t)(src[0] & 0x1f)) << 6 |
+            (src[1] & 0x3f);
         *width_out = 2;
     }
-    else if ((src[0] & 0xf0) == 0xe0)                       // byte starts with 1110.... : this should be a three-byte sequence
+    else if ((src[0] & 0xf0) == 0xe0)
     {
+        // byte starts with 1110.... : this should be a three-byte sequence
         if (src + 2 >= end)
-            INVALID_ENCODING("truncated byte sequence");    // missing second or third byte
-        else if (((src[1] & 0xc0) != 0x80 ) || ((src[2] & 0xc0) != 0x80 ))
-            INVALID_ENCODING("malformed byte sequence");    // should have second and third bytes starting with 10......
-        dest = ((uint32_t)(src[0] & 0x0f)) << 12 | ((uint32_t)(src[1] & 0x3f)) << 6 | (src[2] & 0x3f);
+            // missing second or third byte
+            INVALID_ENCODING("truncated byte sequence");
+        else if (((src[1] & 0xc0) != 0x80 ) ||
+                ((src[2] & 0xc0) != 0x80 ))
+            // should have second and third bytes starting with 10......
+            INVALID_ENCODING("malformed byte sequence");
+
+        dest =
+            ((uint32_t)(src[0] & 0x0f)) << 12 |
+            ((uint32_t)(src[1] & 0x3f)) << 6 |
+            (src[2] & 0x3f);
         *width_out = 3;
     }
-    else if ((src[0] & 0xf8) == 0xf0)                       // bytes starts with 11110... : this should be a four-byte sequence
+    else if ((src[0] & 0xf8) == 0xf0)
     {
+        // bytes starts with 11110... : this should be a four-byte sequence
         if (src + 3 >= end)
-            INVALID_ENCODING("truncated byte sequence");    // missing second, third, or fourth byte
-        else if ((unsigned char)src[0] >= 0xf5 && (unsigned char)src[0] <= 0xf7)
-            INVALID_ENCODING("overlong encoding");          // disallowed by RFC 3629 (codepoints above 0x10ffff)
-        else if (((src[1] & 0xc0) != 0x80 ) || ((src[2] & 0xc0) != 0x80 ) || ((src[3] & 0xc0) != 0x80 ))
-            INVALID_ENCODING("malformed byte sequence");    // should have second and third bytes starting with 10......
-        dest = ((uint32_t)(src[0] & 0x07)) << 18 | ((uint32_t)(src[1] & 0x3f)) << 12 | ((uint32_t)(src[1] & 0x3f)) << 6 | (src[2] & 0x3f);
+            // missing second, third, or fourth byte
+            INVALID_ENCODING("truncated byte sequence");
+        else if ((unsigned char)src[0] >= 0xf5 &&
+                (unsigned char)src[0] <= 0xf7)
+            // disallowed by RFC 3629 (codepoints above 0x10ffff)
+            INVALID_ENCODING("overlong encoding");
+        else if (((src[1] & 0xc0) != 0x80 ) ||
+                ((src[2] & 0xc0) != 0x80 ) ||
+                ((src[3] & 0xc0) != 0x80 ))
+            // should have second and third bytes starting with 10......
+            INVALID_ENCODING("malformed byte sequence");
+
+        dest =
+            ((uint32_t)(src[0] & 0x07)) << 18 |
+            ((uint32_t)(src[1] & 0x3f)) << 12 |
+            ((uint32_t)(src[1] & 0x3f)) << 6 |
+            (src[2] & 0x3f);
         *width_out = 4;
     }
-    else                                                    // invalid input
+    else
         INVALID_ENCODING("unexpected byte");
     return dest;
 }