1 files changed, 97 insertions, 1 deletions
diff --git a/Swiften/Base/String.cpp b/Swiften/Base/String.cpp
index 4a5e4c9..bbc3003 100644
--- a/Swiften/Base/String.cpp
+++ b/Swiften/Base/String.cpp
@@ -17,6 +17,54 @@
 #include <Swiften/Base/String.h>
 #include <Swiften/Base/ByteArray.h>
 
+namespace {
+const static std::uint32_t UTF8_ACCEPT = 0;
+
+const static std::uint8_t UTF8D[] = {
+    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 00..1f
+    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 20..3f
+    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 40..5f
+    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 60..7f
+    1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9, // 80..9f
+    7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, // a0..bf
+    8,8,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, // c0..df
+    0xa,0x3,0x3,0x3,0x3,0x3,0x3,0x3,0x3,0x3,0x3,0x3,0x3,0x4,0x3,0x3, // e0..ef
+    0xb,0x6,0x6,0x6,0x5,0x8,0x8,0x8,0x8,0x8,0x8,0x8,0x8,0x8,0x8,0x8, // f0..ff
+    0x0,0x1,0x2,0x3,0x5,0x8,0x7,0x1,0x1,0x1,0x4,0x6,0x1,0x1,0x1,0x1, // s0..s0
+    1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,1,1,1,1,1,0,1,0,1,1,1,1,1,1, // s1..s2
+    1,2,1,1,1,1,1,2,1,2,1,1,1,1,1,1,1,1,1,1,1,1,1,2,1,1,1,1,1,1,1,1, // s3..s4
+    1,2,1,1,1,1,1,1,1,2,1,1,1,1,1,1,1,1,1,1,1,1,1,3,1,3,1,1,1,1,1,1, // s5..s6
+    1,3,1,1,1,1,1,3,1,3,1,1,1,1,1,1,1,3,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // s7..s8
+};
+
+//http://bjoern.hoehrmann.de/utf-8/decoder/dfa/
+std::uint32_t decode(std::uint32_t & state, std::uint32_t & codepoint, std::uint8_t byte) {
+    const auto type = UTF8D[byte];
+    codepoint = (state != UTF8_ACCEPT) ? (byte & 0x3fu) | (codepoint << 6) : (0xff >> type) & (byte);
+    state = UTF8D[256 + state * 16 + type];
+    return state;
+}
+
+std::uint32_t getNextCodepoint(const char * begin, const char * end, std::size_t & consumed, bool & ok) {
+    consumed = 0;
+    ok = true;
+
+    std::uint32_t state = 0;
+    std::uint32_t codepoint = 0;
+
+    for (auto it = begin; it != end; ++it) {
+        ++consumed;
+        if (!decode(state, codepoint, static_cast<std::uint8_t>(*it)))
+            return codepoint;
+    }
+    if (state != UTF8_ACCEPT) {
+        ok = false;
+    }
+    return codepoint;
+}
+
+}
+
 namespace Swift {
 
 static inline size_t sequenceLength(char firstByte) {
@@ -86,6 +134,55 @@ void String::replaceAll(std::string& src, char c, const std::string& s) {
     }
 }
 
+bool String::isValidXMPPCharacter(std::uint32_t codepoint) {
+    // Special accepted characters:
+    if (codepoint == '\t' || codepoint == '\r' || codepoint == '\n')
+        return true;
+    // Discouraged characters:
+    if (codepoint >= 0x7Fu && codepoint <= 0x84u)
+        return false;
+    if (codepoint >= 0x86u && codepoint <= 0x9Fu)
+        return false;
+    if (codepoint >= 0xFDD0u && codepoint <= 0xFDEFu)
+        return false;
+    if (((codepoint & 0xFFFEu) == 0xFFEEu) || ((codepoint & 0xFFFFu) == 0xFFFFu))
+        return false;
+    // Other valid characters (after filtering for discouraged ones above)
+    if (codepoint >= 0x20u && codepoint <= 0xD7FFu)
+        return true;
+    if (codepoint >= 0xE000u && codepoint <= 0xFFFDu)
+        return true;
+    if (codepoint >= 0x10000u && codepoint <= 0x10FFFFu)
+        return true;
+    return false;
+}
+
+std::string String::sanitizeXMPPString(const std::string& input) {
+    std::string result;
+    result.reserve(input.length());
+
+    auto it = input.data();
+    const auto end = it + input.length();
+
+    std::size_t consumed;
+    bool status = UTF8_ACCEPT;
+
+    while (it < end) {
+        const auto codepoint = getNextCodepoint(it, end, consumed, status);
+        if (status) {
+            if (isValidXMPPCharacter(codepoint)) {
+                std::copy(it, it + consumed, std::back_inserter(result));
+            }
+            it += consumed;
+        }
+        else {
+            ++it;
+        }
+    }
+    result.shrink_to_fit();
+    return result;
+}
+
 std::vector<std::string> String::split(const std::string& s, char c) {
     assert((c & 0x80) == 0);
     std::vector<std::string> result;
@@ -119,7 +216,6 @@ int String::convertHexStringToInt(const std::string& s) {
     return h;
 }
 
-
 #ifdef SWIFTEN_PLATFORM_WINDOWS
 std::string convertWStringToString(const std::wstring& s) {
     int utf8Size = WideCharToMultiByte(CP_UTF8, 0, s.c_str(), -1, NULL, 0, NULL, NULL);