From 83776c115c013f78496ccc0d82f10e24c53e9430 Mon Sep 17 00:00:00 2001
From: chris mikkelson <chris@mikk.net>
Date: Wed, 28 Jan 2009 21:53:02 -0600
Subject: [PATCH] Added code to split multipart media into parts.  At a
 boundary, data is flushed downstream, the downstream processors are
 terminated, and if more parts are expected, a new downstream processor is
 started.

Downstream processor is the "part" type, which looks for headers
to decide content type / encoding.
---
 multipart.c | 166 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 166 insertions(+)
 create mode 100644 multipart.c

diff --git a/multipart.c b/multipart.c
new file mode 100644
index 0000000..ac5a984
--- /dev/null
+++ b/multipart.c
@@ -0,0 +1,166 @@
+/* 
+ * Copyright (c) 2009  Christopher L. Mikkelson <chris@mikk.net>
+ * All Rights Reserved, for now.
+ */
+
+#include <string.h>
+#include "msgproc.h"
+
+/* needs to be published for other callers */
+#define MULTIPART_BOUNDARY 1
+
+struct multipart_state {
+	char *boundary;
+	int blen;
+	char *line;
+	int l;
+	int state;
+};
+
+static void 
+multipart_start(msgproc *m)
+{
+	struct multipart_state *mps = malloc(sizeof(struct multipart_state));
+	if (mps) {
+		bzero(mps, sizeof(*mps));
+	}
+	msgproc_setpriv(m, (void*)mps);
+}
+
+static void
+setboundary(msgproc *m, int type, void *data, size_t size)
+{
+	struct multipart_state *mps = msgproc_getpriv(m);
+	if (type != MULTIPART_BOUNDARY) return;
+	if (mps) {
+		mps->boundary = malloc(size + 2);
+		if (!mps->boundary) return;
+		mps->boundary[0] = mps->boundary[1] = '-';
+		memcpy(mps->boundary + 2, data, size);
+		mps->blen = size + 2;
+	}
+}
+
+#define STATE_INMATCH 0
+#define STATE_MATCH 1
+#define STATE_MATCHEOL 2
+#define STATE_NOMATCH 3
+#define STATE_NOMATCHEOL 4
+#define STATE_MATCHEND 5
+#define STATE_DONE 6
+
+static void
+multipart_process(msgproc *m, char *buf, size_t len)
+{
+	struct multipart_state *mps = msgproc_getpriv(m);
+	msgproc *next;
+	char *s, *t;
+	int r, n;
+
+	/* r = number of characters in current line which match
+		boundary and resided in previous buffer.
+
+	   n = number of characters in current line which match
+		boundary and reside in current buffer.
+
+	   mps->l = number of characters in boundary matched by
+		    current line (regardless of which buffer(s)).
+
+	   s = current character in buffer.
+
+	   t = beginning of current part in current buffer.
+	*/
+
+	if (!mps) return;
+	if (mps->state == STATE_DONE) return;
+	if (!mps->boundary) return;
+	r = mps->l;
+	next = msgproc_next(m);
+
+	for (s = t = buf; s < buf + len; s++) {
+
+		switch (mps->state) {
+	 	case STATE_INMATCH: 
+			if (mps->boundary[mps->l++] != *s) {
+				mps->state = STATE_NOMATCH;
+				n = mps->l = 0;
+				continue;
+			}
+			n++;
+			if (mps->l < mps->blen) continue;
+			mps->state = STATE_MATCH;
+			if (*s == '\r') mps->state = STATE_MATCHEOL;
+			if (*s == '-') mps->state = STATE_MATCHEND;
+			continue;
+		case STATE_MATCH:
+			if (*s == '\r') mps->state = STATE_MATCHEOL;
+			continue;
+		case STATE_NOMATCH:
+			if (*s == '\r') mps->state = STATE_NOMATCHEOL;
+			continue;
+		case STATE_MATCHEOL:
+			if (*s == '\n') {
+				mps->state = STATE_INMATCH;
+				n = mps->l;
+				mps->l = 0;
+				break;
+			}
+			mps->state = STATE_MATCH;
+			continue;
+		case STATE_NOMATCHEOL:
+			if (*s == '\n') mps->state = STATE_INMATCH;
+			mps->state = STATE_NOMATCH;
+			continue;;
+		case STATE_MATCHEND:
+			if (*s != '-') {
+				mps->state = STATE_MATCH;
+				continue;
+			}
+			mps->state = STATE_DONE;
+			n = mps->l;
+			mps->l = 0;
+			break;
+		case STATE_DONE:
+			t=s;
+			continue;
+		}
+
+		/* "break" above lands down here, continue skips to next char */
+		/* send stuff downstream.  (including a chunk of
+			boundary if partial match happened at end
+			of previous segment) */
+		if (r) {
+			msgproc_process(next, mps->boundary, r);
+			r = 0;
+		} 
+		msgproc_process(next, t, s - t - n);
+		n = 0;
+
+		if (mps->state == STATE_DONE) return;
+	}
+
+	/* reached end of buffer.  Process what we have. */
+	msgproc_process(next, t, s - t - n);
+}
+
+void
+multipart_finish(msgproc *m)
+{
+	struct multipart_state *mps = msgproc_getpriv(m);
+	if (mps) {
+		free(mps->boundary);
+	}
+	free(mps);
+	msgproc_free(m);
+}
+
+msgproc_module msgproc_multipart = {
+	MSGPROC_MULTIPART,		/* type */
+	NULL,				/* module init */
+	setboundary,			/* set module parameter */
+	multipart_start,		/* start module instance */
+	NULL,				/* set module instance parameter */
+	multipart_process,		/* process data */
+	multipart_finish,		/* shut down, free module instance */
+	NULL				/* shut down, free module */
+};
-- 
2.50.1