From 9f682eb9e5bb46cee0200c851fded13e1d54b802 Mon Sep 17 00:00:00 2001
From: David Freese <iam_w1hkj@w1hkj.com>
Date: Tue, 11 Aug 2015 15:53:41 -0500
Subject: [PATCH] mg var length

  * implement new mongoose function to read variable length
---
 src/custom/custom.cxx  |  8 ++---
 src/include/mongoose.h |  2 ++
 src/utils/mongoose.c   | 67 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 73 insertions(+), 4 deletions(-)

diff --git a/src/custom/custom.cxx b/src/custom/custom.cxx
index e49942c..1e8e0c8 100644
--- a/src/custom/custom.cxx
+++ b/src/custom/custom.cxx
@@ -413,10 +413,6 @@ void refresh_txt_custom_msg(void *)
 // called by web server thread
 void get_html_vars(struct mg_connection *conn)
 {
-static char buff[65536];
-
-	memset(buff, 0, sizeof(buff));
-
 	size_t p;
 	if (custom_select < 0) return;
 
@@ -435,7 +431,11 @@ static char buff[65536];
 			if ((p = field.find(".")) != string::npos)
 				field.erase(p);
 		}
+
+		int fld_len = mg_get_var_len(conn, field.c_str());
+		char buff[fld_len + 1];
 		memset(buff, 0, sizeof(buff));
+
 		mg_get_var(conn, field.c_str(), buff, sizeof(buff));
 
 		switch (name_values[n].id) {
diff --git a/src/include/mongoose.h b/src/include/mongoose.h
index 4d4c5e5..47bdcc3 100644
--- a/src/include/mongoose.h
+++ b/src/include/mongoose.h
@@ -92,6 +92,8 @@ const char *mg_get_header(const struct mg_connection *, const char *name);
 const char *mg_get_mime_type(const char *name, const char *default_mime_type);
 int mg_get_var(const struct mg_connection *conn, const char *var_name,
                char *buf, size_t buf_len);
+int mg_get_var_len(const struct mg_connection *conn, const char *name);
+
 int mg_parse_header(const char *hdr, const char *var_name, char *buf, size_t);
 int mg_parse_multipart(const char *buf, int buf_len,
                        char *var_name, int var_name_len,
diff --git a/src/utils/mongoose.c b/src/utils/mongoose.c
index 114db75..7841537 100644
--- a/src/utils/mongoose.c
+++ b/src/utils/mongoose.c
@@ -4025,6 +4025,73 @@ int mg_get_var(const struct mg_connection *conn, const char *name,
 	return len;
 }
 
+int mg_url_decode_len(const char *src, int src_len) {
+	int i, j;
+	for (i = j = 0; i < src_len; i++, j++) {
+		if (src[i] == '%' && i < src_len - 2 &&
+				isxdigit(* (const unsigned char *) (src + i + 1)) &&
+				isxdigit(* (const unsigned char *) (src + i + 2))) {
+			i += 2;
+		}
+	}
+	return i >= src_len ? j : -1;
+}
+
+int get_var_len(const char *data, size_t data_len, const char *name) 
+{
+	const char *p, *e, *s;
+	size_t name_len;
+	int len;
+
+	if (data == NULL || name == NULL || data_len == 0)
+		return -1;
+
+	name_len = strlen(name);
+	e = data + data_len;
+	len = -1;
+
+// data is "var1=val1&var2=val2...". Find variable first
+	for (p = data; p + name_len < e; p++) {
+		if ((p == data || p[-1] == '&') && p[name_len] == '=' &&
+				!mg_strncasecmp(name, p, name_len)) {
+
+// Point p to variable value
+			p += name_len + 1;
+
+// Point s to the end of the value
+			s = (const char *) memchr(p, '&', (size_t)(e - p));
+			if (s == NULL) {
+				s = e;
+			}
+			assert(s >= p);
+
+// Decode variable into destination buffer
+			len = mg_url_decode_len(p, (size_t)(s - p));
+
+// Redirect error code from -1 to -2 (destination buffer too small).
+			if (len == -1) {
+				len = -2;
+			}
+			break;
+		}
+	}
+	return len;
+}
+
+int mg_get_var_len(const struct mg_connection *conn, const char *name)
+{
+	int len = get_var_len(
+					conn->query_string, 
+					conn->query_string == NULL ? 0 : strlen(conn->query_string),
+					name);
+	if (len < 0)
+		len = get_var_len(
+					conn->content, 
+					conn->content_len, 
+					name);
+	return len;
+}
+
 static int get_line_len(const char *buf, int buf_len) {
 	int len = 0;
 	while (len < buf_len && buf[len] != '\n') len++;