Parser: unescape strings

include/ArduinoJson/Internals/EscapedString.h

@@ -15,6 +15,8 @@ namespace ArduinoJson
         {
         public:
             static size_t printTo(const char*, Print*);
+
+            static char* extractFrom(char* input, char** end);
         };
     }
 }

src/Internals/EscapedString.cpp

@@ -42,4 +42,47 @@ size_t EscapedString::printTo(const char* s, Print* p)
     }
 
     return n + p->write('\"');
+}
+
+static char unescapeChar(char c)
+{
+    // Optimized for code size on a 8-bit AVR
+
+    const char* p = "b\bf\fn\nr\rt\t";
+
+    while (true)
+    {
+        if (p[0] == 0) return c;
+        if (p[0] == c) return p[1];
+        p += 2;
+    }
+}
+
+char* EscapedString::extractFrom(char* input, char** end)
+{
+    char* start = input + 1; // skip quote
+    char* readPtr = start;
+    char* writePtr = start;
+    char c;
+
+    do
+    {
+        c = *readPtr++;
+
+        if (c == '\"')
+            break;
+
+        if (c == '\\')
+        {
+            c = unescapeChar(*readPtr++);
+        }
+
+        *writePtr++ = c;
+    } while (c != 0);
+
+    *writePtr = 0;
+
+    *end = readPtr;
+
+    return start;
 }

src/Internals/JsonParser.cpp

@@ -1,8 +1,13 @@
 #include "ArduinoJson/Internals/JsonParser.h"
-#include "ArduinoJson/JsonBuffer.h"
+
 #include <stdlib.h> // for strtol, strtod
 #include <ctype.h>
 
+#include "ArduinoJson/JsonBuffer.h"
+#include "ArduinoJson/Internals/EscapedString.h"
+
+using namespace ArduinoJson::Internals;
+
 bool JsonParser::isArrayStart()
 {
     return *_ptr == '[';
@@ -179,12 +184,6 @@ JsonNode* JsonParser::parseNull()
 
 JsonNode* JsonParser::parseString()
 {
-    const char* s = ++_ptr;
-
-    while (*_ptr != '\"')
-        _ptr++;
-    *_ptr = 0;
-    _ptr++;
-    
+    const char* s = EscapedString::extractFrom(_ptr, &_ptr);
     return _buffer->createStringNode(s);
 }

test/JsonParser_String_Tests.cpp

@@ -21,6 +21,13 @@ protected:
     const char* _result;
 };
 
+
+TEST_F(JsonParser_String_Tests, EmptyString)
+{
+    whenInputIs("\"\"");
+    outputMustBe("");
+}
+
 TEST_F(JsonParser_String_Tests, SimpleString)
 {
     whenInputIs("\"hello world\"");
@@ -39,8 +46,14 @@ TEST_F(JsonParser_String_Tests, SquareBraquets)
     outputMustBe("[hello,world]");
 }
 
-TEST_F(JsonParser_String_Tests, EscapedQuote)
+TEST_F(JsonParser_String_Tests, EscapedDoubleQuote)
 {
     whenInputIs("\"hello \\\"world\\\"\"");
     outputMustBe("hello \"world\"");
+}
+
+TEST_F(JsonParser_String_Tests, EscapedSingleQuote)
+{
+    whenInputIs("\"hello \\\'world\\\'\"");
+    outputMustBe("hello 'world'");
 }