CODEWITHSUNDEEP
powershell
joseph
joseph

Reputation: 2835

In Powershell, how do you redirect a binary file to standard in?

This one does not work for binary files: Redirecting standard input\output in Windows Powershell

Here's a summary of what I'm using for input. You can see ls shows the file is 858320 bytes, but when piped through Get-Content, this is not the case.

PS C:\Users\Joseph\Documents\GitHub\java_hprof_to_txt> ls .\generate_hprof\heap.dump.hprof


    Directory: C:\Users\Joseph\Documents\GitHub\java_hprof_to_txt\generate_hprof


Mode                LastWriteTime         Length Name
----                -------------         ------ ----
-a----        1/28/2017  12:02 PM         858320 heap.dump.hprof

Here is my minimal test program which counts the bytes from standard input until it gets to eof:

#include <stdio.h>  
#include <fcntl.h>  
#include <io.h> 


int main()
{
    char buff;
    int numOfBytesRead;
    int dataLen = 0;

    #ifdef _WIN32
    int result = _setmode(_fileno(stdin), _O_BINARY);
    if (result == -1)
        perror("Cannot set mode");
    else
        printf("'stdin' successfully changed to binary mode\n");
    #endif

    while (true) {
        numOfBytesRead = fread(&buff, 1, 1, stdin);
        if (numOfBytesRead != 1) {
            if (feof(stdin)) {
                fprintf(stdout, "end of file reached\n");
            }
            int errorCode = ferror(stdin);
            if (errorCode) {
                fprintf(stdout, "error reading file %d\n", errorCode);
            }
            perror("The following error occurred:");
            break;
        }
        dataLen++;
    }
    fprintf(stdout, "read %d bytes\n", dataLen);
    return 0;
}

Here's the output. Notice that the bytes to not match with ls.

PS C:\Users\Joseph\Documents\GitHub\java_hprof_to_txt> Get-Content .\generate_hprof\heap.dump.hprof | .\x64\Debug\CountBytes.exe
'stdin' successfully changed to binary mode
end of file reached
The following error occurred:: No error
read 860183 bytes

I've even tried the -Encoding Byte and -Encoding Unknown but that doesn't help:

PS C:\Users\Joseph\Documents\GitHub\java_hprof_to_txt> Get-Content -Encoding Byte  .\generate_hprof\heap.dump.hprof | .\x64\Debug\CountBytes.exe
'stdin' successfully changed to binary mode
end of file reached
The following error occurred:: No error
read 3253650 bytes

PS C:\Users\Joseph\Documents\GitHub\java_hprof_to_txt> Get-Content -Encoding Unknown  .\generate_hprof\heap.dump.hprof | .\x64\Debug\CountBytes.exe
'stdin' successfully changed to binary mode
end of file reached
The following error occurred:: No error
read 429608 bytes

When I run it in a normal command terminal, it works fine:

C:\Users\Joseph\Documents\GitHub\java_hprof_to_txt>.\x64\Debug\CountBytes.exe <  .\generate_hprof\heap.dump.hprof
'stdin' successfully changed to binary mode
end of file reached
The following error occurred:: No error
read 858320 bytes

Upvotes: 5

Views: 2362

Answers (1)

stackprotector
stackprotector

Reputation: 13588

If the addition of the -Raw parameter does not help:

Get-Content .\generate_hprof\heap.dump.hprof -Raw | .\x64\Debug\CountBytes.exe

Using the Start-Process cmdlet will work for sure:

Start-Process .\x64\Debug\CountBytes.exe -RedirectStandardInput .\generate_hprof\heap.dump.hprof

Upvotes: 7

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