inline links

src/include/util.h

@@ -33,5 +33,6 @@ void freestring(struct string *str);
 int appendcharstring(struct string *str, char c);
 int appendstrstring(struct string *str, char *s);
 void resetstring(struct string *str);
+int isctrl(int c);
 
 #endif

src/inlines.c

@@ -1,5 +1,6 @@
 #include <string.h>
 
+#include <util.h>
 #include <inlines.h>
 
 static const char *punctuation = "!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~";
@@ -11,9 +12,11 @@ struct escape escapes[] = {
 	{'<', "&lt;"},
 	{'>', "&gt;"},
 	{'&', "&amp;"},
+	{'"', "&quot;"},
 };
 
 static int writecodespan(char *data, int i, size_t len, FILE *out);
+static int writelink(char *data, int i, size_t len, FILE *out);
 static void writeescaped(char *data, size_t len, FILE *out);
 static void writechescape(char c, FILE *out);
 
@@ -27,6 +30,8 @@ void writedata(char *data, size_t len, FILE *out) {
 		int newi;
 		if ((newi = writecodespan(data, i, len, out)) >= 0)
 			goto special;
+		if ((newi = writelink(data, i, len, out)) >= 0)
+			goto special;
 		if (data[i] == '\\') {
 			if (strchr(punctuation, data[i + 1]) == NULL)
 				writechescape('\\', out);
@@ -69,6 +74,153 @@ static int writecodespan(char *data, int i, size_t len, FILE *out) {
 	return end + ticklen;
 }
 
+static int writelink(char *data, int i, size_t len, FILE *out) {
+	int textstart, textend, titlestart, titleend, linkstart, linkend;
+	int count;
+	enum {
+		INITIAL,
+		GETTEXT,
+		GETDESTSTART,
+		GETDESTDETERMINE,
+		GETDESTPOINTY,
+		GETDESTNORMAL,
+		GETTITLEDETERMINE,
+		GETTITLEDOUBLEQUOTE,
+		GETTITLESINGLEQUOTE,
+		GETTITLEPAREN,
+		NEARLYTHERE,
+		DONE
+	} state;
+	state = INITIAL;
+	for (; i < len; ++i) {
+		switch (state) {
+		case INITIAL:
+			if (data[i] != '[')
+				return -1;
+			state = GETTEXT;
+			count = 1;
+			textstart = i + 1;
+			break;
+		case GETTEXT:
+			if (data[i] == '[')
+				++count;
+			if (data[i] == ']')
+				--count;
+			if (count == 0) {
+				textend = i;
+				linkstart = i;
+				state = GETDESTSTART;
+			}
+			break;
+		case GETDESTSTART:
+			if (data[i] != '(')
+				return -1;
+			state = GETDESTDETERMINE;
+			break;
+		case GETDESTDETERMINE:
+			if (data[i] == '<') {
+				state = GETDESTPOINTY;
+				linkstart = i + 1;
+			}
+			else {
+				state = GETDESTNORMAL;
+				linkstart = i--;
+				count = 0;
+			}
+			break;
+		case GETDESTPOINTY:
+			if (data[i] == '<' && data[i - 1] != '\\')
+				return -1;
+			if (data[i] == '>' && data[i - 1] != '\\') {
+				linkend = i;
+				state = GETTITLEDETERMINE;
+			}
+			break;
+		case GETDESTNORMAL:
+			if (data[i] == '(')
+				++count;
+			if (data[i] == ')')
+				--count;
+			if (count < 0) {
+				state = GETTITLEDETERMINE;
+				linkend = i--;
+				break;
+			}
+			if (count != 0)
+				break;
+			if (isctrl(data[i]) || data[i] == ' ') {
+				state = GETTITLEDETERMINE;
+				linkend = i;
+			}
+			break;
+		case GETTITLEDETERMINE:
+			switch (data[i]) {
+			case '"':
+				state = GETTITLEDOUBLEQUOTE;
+				titlestart = i + 1;
+				break;
+			case '\'':
+				state = GETTITLESINGLEQUOTE;
+				titlestart = i + 1;
+				break;
+			case '(':
+				state = GETTITLEPAREN;
+				count = 1;
+				titlestart = i + 1;
+				break;
+			default:
+				--i;
+				titlestart = titleend = -1;
+				state = NEARLYTHERE;
+			}
+			break;
+		case GETTITLEDOUBLEQUOTE:
+			if (data[i] == '"' && data[i - 1] != '\\') {
+				titleend = i;
+				state = NEARLYTHERE;
+			}
+			break;
+		case GETTITLESINGLEQUOTE:
+			if (data[i] == '\'' && data[i - 1] != '\\') {
+				titleend = i;
+				state = NEARLYTHERE;
+			}
+			break;
+		case GETTITLEPAREN:
+			if (data[i] == '(' || data[i] == ')') {
+				if (data[i - 1] != '\\') {
+					titleend = i;
+					state = NEARLYTHERE;
+				}
+			}
+			break;
+		case NEARLYTHERE:
+			if (data[i] != ')')
+				return -1;
+			state = DONE;
+			break;
+		case DONE:
+			goto done;
+		}
+	}
+done:
+	if (state != DONE)
+		return -1;
+	fputs("<a", out);
+	fputs(" href='", out);
+	writeescaped(data + linkstart, linkend - linkstart, out);
+	fputc('\'', out);
+	if (titlestart >= 0) {
+		fputs(" title='", out);
+		writeescaped(data + titlestart, titleend - titlestart, out);
+		fputc('\'', out);
+	}
+	fputc('>', out);
+	writeescaped(data + textstart, textend - textstart, out);
+	fputs("</a>", out);
+	return i;
+}
+
 static void writeescaped(char *data, size_t len, FILE *out) {
 	int i;
 	for (i = 0; i < len; ++i)

src/util.c

@@ -77,3 +77,7 @@ int appendstrstring(struct string *str, char *s) {
 void resetstring(struct string *str) {
 	str->len = 0;
 }
+
+int isctrl(int c) {
+	return (0 <= c && c <= 0x1f) || c == 0x7f;
+}