Allow to use long argument list

Refactored entrance method to remove hardcoded argument list and buffer
sizes. Memory for arguments is allocated dynamically, lines from stdin
are read with growing buffer.

src/pdf/wkhtmltopdf.cc

@@ -49,7 +49,11 @@ using namespace wkhtmltopdf;
  * \param nargv on return will hold the arguments read and be NULL terminated
  */
 enum State {skip, tok, q1, q2, q1_esc, q2_esc, tok_esc};
-void parseString(char * buff, int &nargc, char **nargv) {
+void parseString(char * buff, int &nargc, char ***nargv) {
+	int nargv_size = 1024;
+	*nargv = (char**)malloc(sizeof(char*) * nargv_size);
+	if (!*nargv) exit(1);
+
 	State state = skip;
 	int write_start=0;
 	int write=0;
@@ -72,8 +76,13 @@ void parseString(char * buff, int &nargc, char **nargv) {
 				next_state=skip;
 				if (write_start != write) {
 					buff[write++]='\0';
-					nargv[nargc++] = buff+write_start;
-					if (nargc > 998) exit(1);
+					if (nargc+1 >= nargv_size)
+					{
+						nargv_size *= 2;
+						*nargv = (char**)realloc(*nargv, sizeof(char*) * nargv_size);
+						if (!*nargv) exit(1);
+					}
+					(*nargv)[nargc++] = buff+write_start;
 				}
 				write_start = write;
 			} else buff[write++] = buff[read];
@@ -108,12 +117,49 @@ void parseString(char * buff, int &nargc, char **nargv) {
 		}
 		state=next_state;
 	}
+	if (nargc+1 + 2 >= nargv_size)
+	{
+		nargv_size *= 2;
+		*nargv = (char**)realloc(*nargv, sizeof(char*) * nargv_size);
+		if (!*nargv) exit(1);
+	}
 	//Remember the last parameter
 	if (write_start != write) {
 		buff[write++]='\0';
-		nargv[nargc++] = buff+write_start;
+		(*nargv)[nargc++] = buff+write_start;
 	}
-	nargv[nargc]=NULL;
+	(*nargv)[nargc]=NULL;
+}
+
+/*
+ * Returns a line from a FILE stream. Caller must free buffer.
+ * Derived from getline function from DHCPD client daemon.
+ * Needed because of Windows and systems before POSIX 2008.
+ */
+char * fgets_large(FILE * fp)
+{
+	const size_t bufsize_grow = 1024;
+	size_t bytes = 0, buflen = 0;
+	char *p, *buf = NULL;
+
+	do {
+		if (feof(fp))
+			break;
+		if (buf == NULL || bytes != 0) {
+			buflen += bufsize_grow;
+			buf = (char *)realloc(buf, buflen);
+			if (buf == NULL)
+				return NULL;
+		}
+		p = buf + bytes;
+		memset(p, 0, bufsize_grow);
+		if (fgets(p, bufsize_grow, fp) == NULL)
+			break;
+		bytes += strlen(p);
+	} while (bytes == 0 || *(buf + (bytes - 1)) != '\n');
+	if (bytes == 0)
+		return NULL;
+	return buf;
 }
 
 int main(int argc, char * argv[]) {
@@ -145,13 +191,12 @@ int main(int argc, char * argv[]) {
 	a.setStyle(style);
 
 	if (parser.readArgsFromStdin) {
-		char buff[20400];
-		char *nargv[1000];
-		nargv[0] = argv[0];
-		for (int i=0; i < argc; ++i) nargv[i] = argv[i];
-		while (fgets(buff,20398,stdin)) {
+		char *buff;
+		while ((buff = fgets_large(stdin)) != NULL) {
 			int nargc=argc;
-			parseString(buff,nargc,nargv);
+			char **nargv;
+			parseString(buff,nargc,&nargv);
+			for (int i=0; i < argc; ++i) nargv[i] = argv[i];
 
 			PdfGlobal globalSettings;
 			QList<PdfObject> objectSettings;
@@ -169,6 +214,8 @@ int main(int argc, char * argv[]) {
 
 			if (!converter.convert())
 				exit(EXIT_FAILURE);
+			free(buff);
+			free(nargv);
 		}
 		exit(EXIT_SUCCESS);
 	}