From e95b16c5ca94ff060cf18bec57875e90d63f8741 Mon Sep 17 00:00:00 2001
From: artemp <artem@mapnik.org>
Date: Wed, 1 Mar 2017 10:27:12 +0100
Subject: [PATCH 1/2] make hex parser strict (expecting two characters after
 \x) to avoid greedy parsing of trailing characters as in
 "\xF0\x9F\x8D\xB7abc" ==>  ... + "\xB7" +  "abc" not "\xB7abc"

---
 include/mapnik/expression_grammar_x3_def.hpp | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/mapnik/expression_grammar_x3_def.hpp b/include/mapnik/expression_grammar_x3_def.hpp
index 0be7fb483..23735e5de 100644
--- a/include/mapnik/expression_grammar_x3_def.hpp
+++ b/include/mapnik/expression_grammar_x3_def.hpp
@@ -63,7 +63,7 @@ namespace mapnik { namespace grammar {
     using x3::no_case;
     using x3::alpha;
     using x3::alnum;
-    using x3::hex;
+    x3::uint_parser<char, 16, 2, 2> const hex2 {};
 
     auto do_assign = [] (auto const& ctx)
     {
@@ -302,8 +302,8 @@ namespace mapnik { namespace grammar {
     x3::rule<class regex_replace_expression, std::pair<std::string,std::string> > const regex_replace_expression("regex replace expression");
 
     // strings
-    auto const single_quoted_string = x3::rule<class single_quoted_string, std::string> {} = lit('\'') >> no_skip[*(unesc_char | ("\\x" > hex) | (char_ - '\''))] > '\'';
-    auto const double_quoted_string = x3::rule<class double_quoted_string, std::string> {} = lit('"') >> no_skip[*(unesc_char | ("\\x" > hex) | (char_ - '"'))] > '"';
+    auto const single_quoted_string = x3::rule<class single_quoted_string, std::string> {} = lit('\'') >> no_skip[*(unesc_char | ("\\x" > hex2) | (char_ - '\''))] > '\'';
+    auto const double_quoted_string = x3::rule<class double_quoted_string, std::string> {} = lit('"') >> no_skip[*(unesc_char | ("\\x" > hex2) | (char_ - '"'))] > '"';
     auto const quoted_string = x3::rule<class quoted_string, std::string> {} = single_quoted_string | double_quoted_string;
 
     auto const unquoted_ustring = x3::rule<class ustring, std::string> {} = no_skip[alpha > *alnum] - lit("not");

From 131f785dcee698b2bb6545511c948c45978b7303 Mon Sep 17 00:00:00 2001
From: artemp <artem@mapnik.org>
Date: Wed, 1 Mar 2017 11:25:43 +0100
Subject: [PATCH 2/2] Make parsing `\xXX` format strict via hex2 parser +
 append UTF8 encoded `\xXX` characters directly (fixes #3631)

---
 include/mapnik/json/unicode_string_grammar_x3_def.hpp | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/include/mapnik/json/unicode_string_grammar_x3_def.hpp b/include/mapnik/json/unicode_string_grammar_x3_def.hpp
index d58293cf3..788ea7247 100644
--- a/include/mapnik/json/unicode_string_grammar_x3_def.hpp
+++ b/include/mapnik/json/unicode_string_grammar_x3_def.hpp
@@ -48,6 +48,8 @@ void push_utf8_impl(std::string & str, uchar code_point)
 }
 }
 
+auto push_char = [](auto const& ctx) { _val(ctx).push_back(_attr(ctx));};
+
 auto push_utf8 = [](auto const& ctx) { detail::push_utf8_impl(_val(ctx), _attr(ctx));};
 
 auto push_esc = [] (auto const& ctx)
@@ -79,10 +81,10 @@ auto push_esc = [] (auto const& ctx)
 
 using x3::lit;
 using x3::char_;
-using x3::hex;
 using x3::eol;
 using x3::no_skip;
 
+x3::uint_parser<char,  16, 2, 2> const hex2 {};
 x3::uint_parser<uchar, 16, 4, 4> const hex4 {};
 x3::uint_parser<uchar, 16, 8, 8> const hex8 {};
 
@@ -95,7 +97,7 @@ x3::rule<class escaped_tag, std::string> const escaped("Escaped Characted");
 auto unicode_string_def = double_quoted
     ;
 auto const escaped_def = lit('\\') >
-    ((lit('x') > hex[push_utf8])
+    ((lit('x') > hex2[push_char])
      |
      (lit('u') > hex4[push_utf8])
      |