当运行时设置缓冲区长度时，如何使用 read(ubyte[] buffer) 读取 BufferedFile？

发布于 2024-12-24 01:50:01 字数 775 浏览 0 评论 0原文

我有一个二进制文件，实际上是一堆文件，格式为：

lengh_of_subfile,subfile

length_of_subfile 是一个 64 位整数。我可以毫无问题地读取long，但是当我尝试为子文件创建缓冲区时，我收到编译错误，指出它无法在编译时读取。我缺少什么？我用 erlang、PHP 和 C# 编写了一个相同的提取工具...D 让我陷入了困境。

void main(string args[]) {
    Stream file = new BufferedFile(args[1], FileMode.In);
    int counter = 0;
    while(file.position < file.size) {
        ulong len;
        file.read(len);
        ubyte[len] ogg;
        file.read(ogg);
        string outname = getcwd() ~ "/" ~ to!string(counter) ~ ".ogg";
        Stream oggout = new BufferedFile(outname, FileMode.OutNew);
        oggout.write(ogg);
        writefln("Creating file " ~ to!string(counter) ~ ".ogg");
        counter++;
    }   
}

原文

I have a binary file that is really a stack of files, the format is:

lengh_of_subfile,subfile

length_of_subfile is a 64-bit integer. I can read the long no problem but when I try to create a buffer for the subfile I get compile errors saying it cannot be read at compile time. What am I missing? I've written an identical extraction tool in erlang, PHP and C#... D is throwing me for a loop.

void main(string args[]) {
    Stream file = new BufferedFile(args[1], FileMode.In);
    int counter = 0;
    while(file.position < file.size) {
        ulong len;
        file.read(len);
        ubyte[len] ogg;
        file.read(ogg);
        string outname = getcwd() ~ "/" ~ to!string(counter) ~ ".ogg";
        Stream oggout = new BufferedFile(outname, FileMode.OutNew);
        oggout.write(ogg);
        writefln("Creating file " ~ to!string(counter) ~ ".ogg");
        counter++;
    }   
}

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ぃ双果 2024-12-31 01:50:01

而不是

        ubyte[len] ogg;

写

        ubyte[] ogg = new ubyte[len];

Instead of

        ubyte[len] ogg;

write

        ubyte[] ogg = new ubyte[len];

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携余温的黄昏 2024-12-31 01:50:01

切掉您想要填充的内容

ubyte[1024*8] ogg;
ogg=ogg[0..len]
file.read(ogg);

或使用循环进行复制（因为 2^64 字节数组无法容纳在内存中）

ubyte[1024*16] ogg;
while(len>0 && (int read=file.read(ogg[0..gt;len?len:$]))!=0){
    oggout.write(ogg[0..read]);
    len-=read;//len is the amount still to be read
}

旁注 writeln("Creating file ",counter, ".ogg"); 比 concat then write （java 方式）更有效，因为它不会创建无用的字符串（并且在运行时创建格式字符串迟早会在您的第一个 % 上询问错误）不考虑）

slice off what you want to fill

ubyte[1024*8] ogg;
ogg=ogg[0..len]
file.read(ogg);

or use a loop to do the copying (as a 2^64 byte array wont fit in memory)

ubyte[1024*16] ogg;
while(len>0 && (int read=file.read(ogg[0..gt;len?len:$]))!=0){
    oggout.write(ogg[0..read]);
    len-=read;//len is the amount still to be read
}

side note writeln("Creating file ",counter, ".ogg"); is more efficient than concat then write (the java way) because it doesn't create useless strings (and creating the format string at runtime is asking for a error sooner or later on the first % you don't account for)

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