Added some map loading draft

info/map_serialization.md

@@ -0,0 +1,69 @@
+```
+MAP_MAGIC_HEADER : 'WRPG_MAP'    <=> 8 bytes
+MAP_WIDTH        : unsigned int  <=> 4 bytes
+MAP_HEIGHT       : unsigned int  <=> 4 bytes
+MAP_N_LAYERS     : unsigned char <=> 4 byte
+MAP_COMPRESSION  : enumeration   <=> 4 bytes (IIRC, unless we force using some sort of enum class and use a smaller size)
+  - 0 : RAW
+  - 1 : RLE_PER_LAYER (stop when a layer ends)
+  - 2 : RLE_ALL_LAYERS (stop at the end of the last layer)
+  - 3 : ZLIB (?)
+  - 4 : ...
+MAP_DATA         : variable size <=> n*4 bytes
+// MAP_CHECKSUM?
+Size for a map of n*m * l layers = 24 bytes + up to n*m*l*4 bytes
+```
+
+Loader draft:
+```
+struct Map_Data {
+    char magic_string[8];
+    unsigned width : 4;
+    unsigned height : 4;
+    unsigned n_layers : 4;
+    enum Map_Compression compression;
+}
+/*
+#include <cstring>
+  Map load_map(void* data) throw MapLoadException {
+    struct Map_Data mdata = (struct Map_Data *) data[0]; // HAHA, wait, there is a problem : padding the address to the size of the header.
+    return Map();
+  }
+*/
+#include <cstring>
+  Map load_map(void* data) throw MapLoadException {
+    unsigned map_width = 0, map_height = 0, map_n_layers = 0;
+    enum Map_Compression map_compression = RAW; // or whatever Map_Compression will be
+    char* cdata = (char*) data;
+    unsigned* udata = (unsigned*) data;
+    if(cdata == NULL) throw NPE(); // Null Pointer Exception
+    if(strncmp(cdata, "WRPG_MAP", 8)) throw MLE("Bad map header.");
+    // Assuming big endian
+    map_width = ((cdata[8]&7) << 24) | ((cdata[9]&7) << 16) | ((cdata[10]&7) << 8) | (((cdata[11]&7)));
+    map_height = ((cdata[12]&7) << 24) | ((cdata[13]&7) << 16) | ((cdata[14]&7) << 8) | (((cdata[15]&7)));
+    map_n_layers = ((cdata[16]&7) << 24) | ((cdata[17]&7) << 16) | ((cdata[18]&7) << 8) | (((cdata[19]&7)));
+    if(map_n_layers < 1 || map_n_layers > 2) thorw MLE("Wrong map layer number.");
+
+    map_compression = ((cdata[20]&7) << 24) | ((cdata[21]&7) << 16) | ((cdata[22]&7) << 8) | (((cdata[23]&7)));
+
+    unsigned *layer0, *layer1;
+    switch(map_compression) {
+      // copy layers from &udata[6] and &udata[6*(map_width*map_height/sizeof(unsigned))]
+      case RAW:
+      // TODO
+      break;
+      case RLE_PER_LAYER:
+      // TDOO
+      break;
+      case RLE_ALL_LAYERS:
+      // TODO
+      break;
+      case ZLIB:
+      // TODO
+      break;
+      default:
+        throw MLE("Wrong compression");
+    }
+
+    return Map(map_width, map_height, layer0, layer1);
+  }