1 files changed, 170 insertions, 0 deletions
diff --git a/plugin-irc.c b/plugin-irc.c
index 0dfc528..0daff0c 100644
--- a/plugin-irc.c
+++ b/plugin-irc.c
@@ -22,3 +22,173 @@
 #include "plugin-api.h"
 
 // TODO
+
+// --- IRC utilities -----------------------------------------------------------
+
+struct irc_message
+{
+	struct str_map tags;                ///< IRC 3.2 message tags
+	char *prefix;                       ///< Message prefix
+	char *command;                      ///< IRC command
+	struct str_vector params;           ///< Command parameters
+};
+
+static void
+irc_parse_message_tags (const char *tags, struct str_map *out)
+{
+	struct str_vector v;
+	str_vector_init (&v);
+	split_str_ignore_empty (tags, ';', &v);
+
+	for (size_t i = 0; i < v.len; i++)
+	{
+		char *key = v.vector[i], *equal_sign = strchr (key, '=');
+		if (equal_sign)
+		{
+			*equal_sign = '\0';
+			str_map_set (out, key, xstrdup (equal_sign + 1));
+		}
+		else
+			str_map_set (out, key, xstrdup (""));
+	}
+
+	str_vector_free (&v);
+}
+
+static void
+irc_parse_message (struct irc_message *msg, const char *line)
+{
+	str_map_init (&msg->tags);
+	msg->tags.free = free;
+
+	msg->prefix = NULL;
+	msg->command = NULL;
+	str_vector_init (&msg->params);
+
+	// IRC 3.2 message tags
+	if (*line == '@')
+	{
+		size_t tags_len = strcspn (++line, " ");
+		char *tags = xstrndup (line, tags_len);
+		irc_parse_message_tags (tags, &msg->tags);
+		free (tags);
+
+		line += tags_len;
+		while (*line == ' ')
+			line++;
+	}
+
+	// Prefix
+	if (*line == ':')
+	{
+		size_t prefix_len = strcspn (++line, " ");
+		msg->prefix = xstrndup (line, prefix_len);
+		line += prefix_len;
+	}
+
+	// Command name
+	{
+		while (*line == ' ')
+			line++;
+
+		size_t cmd_len = strcspn (line, " ");
+		msg->command = xstrndup (line, cmd_len);
+		line += cmd_len;
+	}
+
+	// Arguments
+	while (true)
+	{
+		while (*line == ' ')
+			line++;
+
+		if (*line == ':')
+		{
+			str_vector_add (&msg->params, ++line);
+			break;
+		}
+
+		size_t param_len = strcspn (line, " ");
+		if (!param_len)
+			break;
+
+		str_vector_add_owned (&msg->params, xstrndup (line, param_len));
+		line += param_len;
+	}
+}
+
+static void
+irc_free_message (struct irc_message *msg)
+{
+	str_map_free (&msg->tags);
+	free (msg->prefix);
+	free (msg->command);
+	str_vector_free (&msg->params);
+}
+
+static void
+irc_process_buffer (struct str *buf,
+	void (*callback)(const struct irc_message *, const char *, void *),
+	void *user_data)
+{
+	char *start = buf->str, *end = start + buf->len;
+	for (char *p = start; p + 1 < end; p++)
+	{
+		// Split the input on newlines
+		if (p[0] != '\r' || p[1] != '\n')
+			continue;
+
+		*p = 0;
+
+		struct irc_message msg;
+		irc_parse_message (&msg, start);
+		callback (&msg, start, user_data);
+		irc_free_message (&msg);
+
+		start = p + 2;
+	}
+
+	// XXX: we might want to just advance some kind of an offset to avoid
+	//   moving memory around unnecessarily.
+	str_remove_slice (buf, 0, start - buf->str);
+}
+
+static int
+irc_tolower (int c)
+{
+	if (c == '[')   return '{';
+	if (c == ']')   return '}';
+	if (c == '\\')  return '|';
+	if (c == '~')   return '^';
+	return c >= 'A' && c <= 'Z' ? c + ('a' - 'A') : c;
+}
+
+static size_t
+irc_strxfrm (char *dest, const char *src, size_t n)
+{
+	size_t len = strlen (src);
+	while (n-- && (*dest++ = irc_tolower (*src++)))
+		;
+	return len;
+}
+
+static int
+irc_strcmp (const char *a, const char *b)
+{
+	int x;
+	while (*a || *b)
+		if ((x = irc_tolower (*a++) - irc_tolower (*b++)))
+			return x;
+	return 0;
+}
+
+static int
+irc_fnmatch (const char *pattern, const char *string)
+{
+	size_t pattern_size = strlen (pattern) + 1;
+	size_t string_size  = strlen (string)  + 1;
+	char x_pattern[pattern_size], x_string[string_size];
+	irc_strxfrm (x_pattern, pattern, pattern_size);
+	irc_strxfrm (x_string,  string,  string_size);
+	return fnmatch (x_pattern, x_string, 0);
+}