Added Lexer class.

CMakeLists.txt

@@ -22,6 +22,7 @@ include_directories(include)
 # QRedis source files.
 set(QREDIS_SRC
     src/client.cpp
+    src/lexer.cpp
     src/request.cpp)
 
 # QRedis header files requiring MOC.
@@ -29,6 +30,7 @@ qt5_wrap_cpp(QREDIS_MOC
     include/qredis/client.h
     include/qredis/request.h
     src/client_p.h
+    src/lexer.h
     src/request_p.h)
 
 # Create the client library.

src/lexer.cpp

@@ -0,0 +1,89 @@
+#include "lexer.h"
+
+Lexer::Lexer(QIODevice * device, QObject * parent)
+    : QObject(parent), device(device), state(DoingNothing), crlf(0)
+{
+    connect(device, SIGNAL(readyRead()), SLOT(readData()));
+}
+
+Lexer::~Lexer()
+{
+}
+
+void Lexer::readData()
+{
+    buffer.append(device->readAll());
+
+    while(true)
+    {
+        if(state == DoingNothing && !readCharacter())
+            break;
+
+        switch(state)
+        {
+            case ReadingLength:
+            case ReadingUnsafeString: if(!readUnsafeString()) return; break;
+            case ReadingSafeString:   if(!readSafeString())   return; break;
+        }
+    }
+}
+
+
+bool Lexer::readCharacter()
+{
+    if(!buffer.size())
+        return false;
+
+    char c = buffer.at(0);
+    buffer.remove(0, 1);
+
+    switch(c)
+    {
+        case '+':
+        case '-':
+        case '*':
+        case ':': state = ReadingUnsafeString; break;
+        case '$': state = ReadingLength;       break;
+        default:
+            emit warning(tr("Unexpected character '%1' encountered").arg(static_cast<int>(c), 0, 16));
+            return true;
+    }
+
+    emit character(c);
+    return true;
+}
+
+bool Lexer::readUnsafeString()
+{
+    crlf = buffer.indexOf("\r\n", crlf);
+    if(crlf == -1)
+    {
+        crlf = buffer.size();
+        return false;
+    }
+
+    QString s = buffer.mid(0, crlf);
+    buffer.remove(0, crlf + 2);
+
+    if(state == ReadingLength)
+    {
+        length = s.toInt();
+        state = ReadingSafeString;
+    }
+    else
+        emit unsafeString(s);
+
+    return true;
+}
+
+bool Lexer::readSafeString()
+{
+    if(buffer.size() < length + 2)
+        return false;
+
+    QByteArray d = buffer.mid(0, length);
+    buffer.remove(0, length + 2);
+
+    emit safeString(d);
+    return true;
+}

src/lexer.h

@@ -0,0 +1,49 @@
+#ifndef LEXER_H
+#define LEXER_H
+
+#include <QIODevice>
+#include <QObject>
+
+class Lexer : public QObject
+{
+    Q_OBJECT
+
+    public:
+
+        Lexer(QIODevice *, QObject * = 0);
+        virtual ~Lexer();
+
+    Q_SIGNALS:
+
+        void character(char);
+        void unsafeString(const QString &);
+        void safeString(const QByteArray &);
+
+        void warning(const QString &);
+
+    private Q_SLOTS:
+
+        void readData();
+
+    private:
+
+        bool readCharacter();
+        bool readLength();
+        bool readUnsafeString();
+        bool readSafeString();
+
+        QIODevice * device;
+        QByteArray buffer;
+
+        enum {
+            DoingNothing,
+            ReadingLength,
+            ReadingUnsafeString,
+            ReadingSafeString
+        } state;
+
+        int crlf;
+        int length;
+};
+
+#endif // LEXER_H