libdeng2|Reader|Write: Reading/writing fixed-size byte arrays

Added more convenient methods for reading and writing byte arrays of
preset size, which means the size itself won't be read/written, only
the bytes.

doomsday/libdeng2/include/de/data/block.h

@@ -32,6 +32,11 @@ class IIStream;
 /**
  * Data buffer that implements the byte array interface.
  *
+ * Note that Block is based on QByteArray, and thus automatically always ensures
+ * that the data is followed by a terminating \0 character (even if one is not
+ * part of the actual Block contents). Therefore it is safe to use it in functions
+ * that assume zero-terminated strings.
+ *
  * @ingroup data
  */
 class DENG2_PUBLIC Block : public QByteArray, public IByteArray, public IBlock

doomsday/libdeng2/include/de/data/reader.h

@@ -168,6 +168,17 @@ class DENG2_PUBLIC Reader
      */
     Reader &readBytes(dsize count, IByteArray &destination);
 
+    /**
+     * Reads a fixed number of bytes and puts them into a destination
+     * byte array. The complete @a destination is filled with new bytes;
+     * its size won't change.
+     *
+     * @param destination  Destination array. The size of this array
+     *                     determines how many bytes to read.
+     * @return Reference to the Reader.
+     */
+    Reader &readPresetSize(IByteArray &destination);
+
     /// Reads a Block from the source buffer.
     Reader &operator >> (Block &block);
 

doomsday/libdeng2/include/de/data/writer.h

@@ -157,6 +157,30 @@ class DENG2_PUBLIC Writer
      */
     Writer &operator << (FixedByteArray const &fixedByteArray);
 
+    /**
+     * Writes a fixed-size sequence of bytes to the destination buffer.
+     * The size of the sequence is @em NOT included in the written data.
+     * When reading, the reader must know the size beforehand.
+     *
+     * @param count  Number of bytes to write.
+     * @param array  Data to write.
+     *
+     * @return  Reference to the Writer.
+     */
+    Writer &writeBytes(dsize count, IByteArray const &array);
+
+    /**
+     * Writes a fixed-size sequence of bytes to the destination buffer.
+     * The size of the sequence is @em NOT included in the written data.
+     * When reading, the reader must know the size beforehand
+     * (Reader::readPresetSize()).
+     *
+     * @param array  Array to write.
+     *
+     * @return Reference to the Writer.
+     */
+    Writer &writePresetSize(IByteArray const &array);
+
     /**
      * Writes @a block into the destination buffer. Writes the size of the
      * block in addition to its contents, so a Reader will not need to know

doomsday/libdeng2/src/data/reader.cpp

@@ -353,6 +353,12 @@ Reader &Reader::readBytes(dsize count, IByteArray &destination)
     return *this >> dest;
 }
 
+Reader &Reader::readPresetSize(IByteArray &destination)
+{
+    FixedByteArray dest(destination);
+    return *this >> dest;
+}
+
 Reader &Reader::operator >> (Block &block)
 {
     duint size = 0;

doomsday/libdeng2/src/data/writer.cpp

@@ -210,6 +210,16 @@ Writer &Writer::operator << (FixedByteArray const &fixedByteArray)
     return *this;
 }
 
+Writer &Writer::writeBytes(dsize count, IByteArray const &array)
+{
+    return *this << FixedByteArray(array, 0, count);
+}
+
+Writer &Writer::writePresetSize(IByteArray const &array)
+{
+    return *this << FixedByteArray(array);
+}
+
 Writer &Writer::operator << (Block const &block)
 {
     // First write the length of the block.