wsd: Message supports new find and contains operations

Change-Id: Id5112dda76fe2aaa27392d59f9b8ecfa3cfabe54
Signed-off-by: Ashod Nakashian <ashod.nakashian@collabora.co.uk>
(cherry picked from commit bb1978770a79453542cca112f9af55c0279b9c9e)

2 files changed, 33 insertions, 0 deletions

diff --git a/common/Message.hpp b/common/Message.hpp
index 3e9c8d0b42..9cb0616ccd 100644
--- a/common/Message.hpp
+++ b/common/Message.hpp
@@ -8,6 +8,7 @@
 #pragma once
 
 #include <atomic>
+#include <cstring>
 #include <string>
 #include <vector>
 #include <functional>
@@ -15,6 +16,7 @@
 #include "Protocol.hpp"
 #include "StringVector.hpp"
 #include "Log.hpp"
+#include "Util.hpp"
 
 /// The payload type used to send/receive data.
 class Message
@@ -76,6 +78,15 @@ public:
     bool firstTokenMatches(const std::string& target) const { return _tokens[0] == target; }
     std::string operator[](size_t index) const { return _tokens[index]; }
 
+    /// Find a subarray in the raw message.
+    int find(const char* sub, const std::size_t subLen) const
+    {
+        return Util::findSubArray(&_data[0], _data.size(), sub, subLen);
+    }
+
+    /// Returns true iff the subarray exists in the raw message.
+    bool contains(const char* p, const std::size_t len) const { return find(p, len) >= 0; }
+
     const std::string& firstLine()
     {
         assignFirstLineIfEmpty();
diff --git a/common/Util.hpp b/common/Util.hpp
index d403476402..9cdd720c27 100644
--- a/common/Util.hpp
+++ b/common/Util.hpp
@@ -864,6 +864,28 @@ int main(int argc, char**argv)
         return 0;
     }
 
+    /// Return the position of sub-array @sub in array @data, if found, -1 otherwise.
+    inline int findSubArray(const char* data, const std::size_t dataLen, const char* sub,
+                            const std::size_t subLen)
+    {
+        assert(subLen < std::numeric_limits<int>::max() && "Invalid sub-array length to find");
+        if (sub && subLen && dataLen >= subLen)
+        {
+            for (std::size_t i = 0; i < dataLen; ++i)
+            {
+                std::size_t j;
+                for (j = 0; j < subLen && i + j < dataLen && data[i + j] == sub[j]; ++j)
+                {
+                }
+
+                if (j >= subLen)
+                    return i;
+            }
+        }
+
+        return -1;
+    }
+
     inline
     std::string getDelimitedInitialSubstring(const char *message, const int length, const char delim)
     {