Add world list packet structure

Signed-off-by: Graham <gpe@openrs2.org>

share/doc/protocol/world-list.md

@@ -0,0 +1,65 @@
+# World list
+
+## Downstream
+
+| Opcode | Length         | Jagex name                  | Description                        |
+|-------:|---------------:|-----------------------------|------------------------------------|
+|      0 | Variable short | Unknown                     | World list                         |
+
+### 0 (World list)
+
+| Data type    | Description             |
+|--------------|-------------------------|
+| UnsignedByte | Version, must be 1      |
+| Boolean      | Worlds updated          |
+
+The following fields are only present if the worlds updated flag is set:
+
+| Data type          | Description             |
+|--------------------|-------------------------|
+| UnsignedShortSmart | Number of countries (n) |
+| Country\[n\]       | Countries (see below)   |
+| UnsignedShortSmart | Minimum world ID        |
+| UnsignedShortSmart | Maximum world ID        |
+| UnsignedShortSmart | Number of worlds (o)    |
+| World\[o\]         | Worlds (see below)      |
+| Int                | Checksum                |
+
+The following fields are always present:
+
+| Data type          | Description               |
+|--------------------|---------------------------|
+| PlayerCount\[o\]   | Player counts (see below) |
+
+#### Country
+
+| Data type          | Description    |
+|--------------------|----------------|
+| UnsignedShortSmart | Flag sprite ID |
+| VersionedString    | Name           |
+
+#### World
+
+| Data type          | Description                                  |
+|--------------------|----------------------------------------------|
+| UnsignedShortSmart | Offset (world ID minus the minimum world ID) |
+| UnsignedByte       | Country ID (from the list in the packet)     |
+| Int                | Flags (see below)                            |
+| VersionedString    | Activity                                     |
+| VersionedString    | Hostname                                     |
+
+##### Flags
+
+| Flag | Description  |
+|-----:|--------------|
+|  0x1 | Members only |
+|  0x2 | Quick chat   |
+|  0x4 | PvP          |
+|  0x8 | Loot share   |
+
+### Player count
+
+| Data type          | Description                                  |
+|--------------------|----------------------------------------------|
+| UnsignedShortSmart | Offset (world ID minus the minimum world ID) |
+| UnsignedShort      | Players (-1 indicates the world is offline)  |