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-rw-r--r--degesch.c154
1 files changed, 154 insertions, 0 deletions
diff --git a/degesch.c b/degesch.c
index 2cc7944..10a82c8 100644
--- a/degesch.c
+++ b/degesch.c
@@ -2239,6 +2239,160 @@ init_readline (void)
return 0;
}
+// --- CTCP decoding -----------------------------------------------------------
+
+#define CTCP_M_QUOTE '\020'
+#define CTCP_X_DELIM '\001'
+#define CTCP_X_QUOTE '\\'
+
+struct ctcp_chunk
+{
+ LIST_HEADER (struct ctcp_chunk)
+
+ bool is_extended; ///< Is this a tagged extended message?
+ struct str tag; ///< The tag, if any
+ struct str text; ///< Message contents
+};
+
+static struct ctcp_chunk *
+ctcp_chunk_new (void)
+{
+ struct ctcp_chunk *self = xcalloc (1, sizeof *self);
+ str_init (&self->tag);
+ str_init (&self->text);
+ return self;
+}
+
+static void
+ctcp_chunk_destroy (struct ctcp_chunk *self)
+{
+ str_free (&self->tag);
+ str_free (&self->text);
+ free (self);
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+static void
+ctcp_low_level_decode (const char *message, struct str *output)
+{
+ bool escape = false;
+ for (const char *p = message; *p; p++)
+ {
+ if (escape)
+ {
+ switch (*p)
+ {
+ case '0': str_append_c (output, '\0'); break;
+ case 'r': str_append_c (output, '\r'); break;
+ case 'n': str_append_c (output, '\n'); break;
+ default: str_append_c (output, *p);
+ }
+ escape = false;
+ }
+ else if (*p == CTCP_M_QUOTE)
+ escape = true;
+ else
+ str_append_c (output, *p);
+ }
+}
+
+static void
+ctcp_intra_decode (const char *chunk, size_t len, struct str *output)
+{
+ bool escape = false;
+ for (size_t i = 0; i < len; i++)
+ {
+ char c = chunk[i];
+ if (escape)
+ {
+ if (c == 'a')
+ str_append_c (output, CTCP_X_DELIM);
+ else
+ str_append_c (output, c);
+ escape = false;
+ }
+ else if (c == CTCP_X_QUOTE)
+ escape = true;
+ else
+ str_append_c (output, c);
+ }
+}
+
+static void
+ctcp_parse_tagged (const char *chunk, size_t len, struct ctcp_chunk *output)
+{
+ // We may search for the space before doing the higher level decoding,
+ // as it doesn't concern space characters at all
+ size_t tag_end = len;
+ for (size_t i = 0; i < len; i++)
+ if (chunk[i] == ' ')
+ {
+ tag_end = i;
+ break;
+ }
+
+ output->is_extended = true;
+ ctcp_intra_decode (chunk, tag_end, &output->tag);
+ if (tag_end++ != len)
+ ctcp_intra_decode (chunk + tag_end, len - tag_end, &output->text);
+}
+
+static struct ctcp_chunk *
+ctcp_parse (const char *message)
+{
+ struct str m;
+ str_init (&m);
+ ctcp_low_level_decode (message, &m);
+
+ struct ctcp_chunk *result = NULL, *result_tail = NULL;
+
+ size_t start = 0;
+ bool in_ctcp = false;
+ for (size_t i = 0; i < m.len; i++)
+ {
+ char c = m.str[i];
+ if (c != CTCP_X_DELIM)
+ continue;
+
+ // Remember the current state
+ size_t my_start = start;
+ bool my_is_ctcp = in_ctcp;
+
+ start = i + 1;
+ in_ctcp = !in_ctcp;
+
+ // Skip empty chunks
+ if (my_start == i)
+ continue;
+
+ struct ctcp_chunk *chunk = ctcp_chunk_new ();
+ if (my_is_ctcp)
+ ctcp_parse_tagged (m.str + my_start, i - my_start, chunk);
+ else
+ ctcp_intra_decode (m.str + my_start, i - my_start, &chunk->text);
+ LIST_APPEND_WITH_TAIL (result, result_tail, chunk);
+ }
+
+ // Finish the last text part. We ignore unended tagged chunks.
+ if (!in_ctcp && start != m.len)
+ {
+ struct ctcp_chunk *chunk = ctcp_chunk_new ();
+ ctcp_intra_decode (m.str + start, m.len - start, &chunk->text);
+ LIST_APPEND_WITH_TAIL (result, result_tail, chunk);
+ }
+
+ str_free (&m);
+ return result;
+}
+
+static void
+ctcp_destroy (struct ctcp_chunk *list)
+{
+ LIST_FOR_EACH (struct ctcp_chunk, iter, list)
+ ctcp_chunk_destroy (iter);
+}
+
// --- Input handling ----------------------------------------------------------
// TODO: we will need a proper mode parser; to be shared with kike