Question

我正在尝试使用DataInputStream从.dem（反击演示文件）文件中读取。到目前为止，我知道它以标题开头，而在C中它看起来像这样（https://github.com/csgo-data/demoinfogo-linux/blob/master/src/demofile.h）

struct demoheader_t
{
    char    demofilestamp[ 8 ];             // Should be HL2DEMO
    int32   demoprotocol;                   // Should be DEMO_PROTOCOL
    int32   networkprotocol;                // Should be PROTOCOL_VERSION
    char    servername[ MAX_OSPATH ];       // Name of server
    char    clientname[ MAX_OSPATH ];       // Name of client who recorded the game
    char    mapname[ MAX_OSPATH ];          // Name of map
    char    gamedirectory[ MAX_OSPATH ];    // Name of game directory (com_gamedir)
    float   playback_time;                  // Time of track
    int32   playback_ticks;                 // # of ticks in track
    int32   playback_frames;                // # of frames in track
    int32   signonlength;                   // length of sigondata in bytes
};

，这是我的标题类，它负责从流中读取它：

package cropper;

import java.io.DataInputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.PrintStream;

import static cropper.Cropper.*;

public class DemoHeader {

    private final static int MAX_OSPATH = 260;
    private final static int STAMP_L = 8;

    char    demofilestamp[];                // Should be HL2DEMO
    int demoprotocol;                   // Should be DEMO_PROTOCOL
    int networkprotocol;                // Should be PROTOCOL_VERSION
    char    servername[];       // Name of server
    char    clientname[];       // Name of client who recorded the game
    char    mapname[];          // Name of map
    char    gamedirectory[];    // Name of game directory (com_gamedir)
    float   playback_time;                  // Time of track
    int   playback_ticks;                   // # of ticks in track
    int   playback_frames;              // # of frames in track
    int signonlength;                   // length of sigondata in bytes

    private DemoHeader(){
        demofilestamp = new char[STAMP_L];
        servername = new char[MAX_OSPATH];
        clientname = new char[MAX_OSPATH];
        mapname = new char[MAX_OSPATH];
        gamedirectory = new char[MAX_OSPATH];
    }

    public static DemoHeader getHeader(DataInputStream dis) throws IOException{
        DemoHeader header = new DemoHeader();
        for (int i = 0; i < header.demofilestamp.length; header.demofilestamp[i++] = (char) dis.readByte());
        header.demoprotocol = dis.readInt();
        header.networkprotocol = dis.readInt();
        for (int i = 0; i < header.servername.length; header.servername[i++] = (char) dis.readByte());
        for (int i = 0; i < header.clientname.length; header.clientname[i++] = (char) dis.readByte());
        for (int i = 0; i < header.mapname.length; header.mapname[i++] = (char) dis.readByte());
        for (int i = 0; i < header.gamedirectory.length; header.gamedirectory[i++] = (char) dis.readByte());
        header.playback_time = dis.readFloat();
        header.playback_ticks = dis.readInt();
        header.playback_frames = dis.readInt();
        header.signonlength = dis.readInt();    
        return header;
    }

    public void println(){
        PrintStream p = System.out;
        p.print("Filestamp - ");
            for (int i = 0; i < 8; p.print(demofilestamp[i++]));
            p.println();
        p.println("Demo protocol - " + Integer.toUnsignedString( demoprotocol ));
        p.println("Network protocol - " + networkprotocol);
        p.print("Server name - ");
            for (int i = 0; i < servername.length; p.print(servername[i++]));
            p.println();
        p.print("Client name - ");
            for (int i = 0; i < clientname.length; p.print(clientname[i++]));
            p.println();
        p.print("Map name - ");
            for (int i = 0; i < mapname.length; p.print(mapname[i++]));
            p.println();
        p.print("Game directory - ");
            for (int i = 0; i < gamedirectory.length; p.print(gamedirectory[i++]));
            p.println();
        p.println("Play back time - " + playback_time);
        p.println("Play back ticks - " + playback_ticks);
        p.println("Play back frames - " + playback_frames);
        p.println("Sign on length - " + signonlength);

    }

}

读取随机.dem文件的标题并将其打印出来

Filestamp - HL2DEMO
Demo protocol - 67108864
Network protocol - -684457984
Server name - eBot :: ENVYUS vs E-Frag.net
Client name - GOTV Demo
Map name - de_cache
Game directory - csgo
Play back time - 1.9518368E-38
Play back ticks - 1084033024
Play back frames - 345769984
Sign on length - -544012032

这对所有数字都是错误的（例如，demoprotocol必须是4）。我做错了什么？

Answer 1

我从网上下载了a random .dem file。使用您的代码我得到以下输出：

Filestamp - HL2DEMO
Demo protocol - 67108864
Network protocol - -801898496
Server name - eBot :: mousesports vs E-Frag.net
Client name - GOTV Demo
Map name - de_cache
Game directory - csgo
Play back time - 6.5734844E19
Play back ticks - 595788800
Play back frames - -1451097088
Sign on length - -1433729280

请注意我如何获得与Demo protocol相同的数字。

所以我在十六进制编辑器中打开了文件。这是前12个字节的样子：

48 4C 32 44 45 4D 4F 00 04 00 00 00

前8个字节（48 4C 32 44 45 4D 4F 00）构成字符串HL2DEMO（加上终止空字节\0）。但请注意接下来的4个字节：04 00 00 00。这是整数值4，但在Little Endian中。 Java DataInputStream将int读为Big Endian。

使用Guava的LittleEndianDataInputStream代替Java DataInputStream我得到以下输出：

Filestamp - HL2DEMO
Demo protocol - 4
Network protocol - 13520
Server name - eBot :: mousesports vs E-Frag.net
Client name - GOTV Demo
Map name - de_cache
Game directory - csgo
Play back time - 2310.2734
Play back ticks - 295715
Play back frames - 295593
Sign on length - 494506

数据输入流读取的数据与所需的int值不同

1 个答案: