(svn r8807) -Feature: Add support for loading (some of) the TTDP extra chunks mainly list of GRFIDs and TTDP version the game was saved with.

 GRFID list is read and active GRFs are loaded with the game if present in the data/ directory.
 TTDP versioning information only works for newer versions, old versions will only give rough information but it's not worth the effort to precisely figure out what bit means what where and when.

1 files changed, 57 insertions, 0 deletions

diff --git a/src/oldloader.cpp b/src/oldloader.cpp
index 9c59f1e16..75dc8e5db 100644
--- a/src/oldloader.cpp
+++ b/src/oldloader.cpp
@@ -372,6 +372,7 @@ static bool   _new_ttdpatch_format;
 static uint32 _old_town_index;
 static uint16 _old_string_id;
 static uint16 _old_string_id_2;
+static uint16 _old_extra_chunk_nums;
 
 static void ReadTTDPatchFlags(void)
 {
@@ -397,6 +398,8 @@ static void ReadTTDPatchFlags(void)
 	/* Check if we have a modern TTDPatch savegame (has extra data all around) */
 	_new_ttdpatch_format = (memcmp(&_old_map3[0x1FFFA], "TTDp", 4) == 0);
 
+	_old_extra_chunk_nums = _old_map3[_new_ttdpatch_format ? 0x1FFFE : 0x2];
+
 	/* Clean the misused places */
 	for (i = 0;       i < 17;      i++) _old_map3[i] = 0;
 	for (i = 0x1FE00; i < 0x20000; i++) _old_map3[i] = 0;
@@ -1345,6 +1348,59 @@ static bool LoadOldMapPart2(LoadgameState *ls, int num)
 	return !ls->failed;
 }
 
+static bool LoadTTDPatchExtraChunks(LoadgameState *ls, int num)
+{
+	ReadTTDPatchFlags();
+
+	DEBUG(oldloader, 2, "Found %d extra chunk(s)", _old_extra_chunk_nums);
+
+	for (int i = 0; i != _old_extra_chunk_nums; i++) {
+		uint16 id = ReadUint16(ls);
+		uint32 len = ReadUint32(ls);
+
+		switch (id) {
+			/* List of GRFIDs, used in the savegame
+			 * They are saved in a 'GRFID:4 active:1' format, 5 bytes for each entry */
+			case 0x2:
+			case 0x8004: {
+				/* Skip the first element: TTDP hack for the Action D special variables FFFF0000 01 */
+				ReadUint32(ls); ReadByte(ls); len -= 5;
+
+				ClearGRFConfigList(&_grfconfig);
+				GRFConfig *c = CallocT<GRFConfig>(1);
+				while (len != 0) {
+					uint32 grfid = ReadUint32(ls);
+
+					if (ReadByte(ls) == 1) {
+						c->grfid = grfid;
+						c->filename = "TTDP game, no information";
+
+						AppendToGRFConfigList(&_grfconfig, c);
+						DEBUG(oldloader, 3, "TTDPatch game using GRF file with GRFID %0X", BSWAP32(c->grfid));
+					}
+					len -= 5;
+				};
+				free(c);
+
+				/* Append static NewGRF configuration */
+				AppendStaticGRFConfigs(&_grfconfig);
+			} break;
+			case 0x3: { /* TTDPatch version and configuration */
+				uint32 ttdpv = ReadUint32(ls);
+				DEBUG(oldloader, 3, "Game saved with TTDPatch version %d.%d.%d r%d", GB(ttdpv, 24, 8), GB(ttdpv, 20, 4), GB(ttdpv, 16, 4), GB(ttdpv, 0, 16));
+				len -= 4;
+				while (len-- != 0) ReadByte(ls); // skip the configuration
+			} break;
+			default:
+				DEBUG(oldloader, 4, "Skipping unknown extra chunk %X", id);
+				while (len-- != 0) ReadByte(ls);
+				break;
+		}
+	}
+
+	return !ls->failed;
+}
+
 static uint32 _old_cur_town_ctr;
 static const OldChunks main_chunk[] = {
 	OCL_ASSERT( 0 ),
@@ -1458,6 +1514,7 @@ static const OldChunks main_chunk[] = {
 	OCL_ASSERT( 0x97179 ),
 
 	/* Below any (if available) extra chunks from TTDPatch can follow */
+	OCL_CHUNK(1, LoadTTDPatchExtraChunks),
 
 	OCL_END()
 };