将 C 数组中的字节转换为 long [英] Convert bytes in a C array as longs

问题描述

我有一个小端字节序的字节数组.如何将其转换为长(四字节)数组?

I have a byte array in little endian byte order. How do I convert it to a long (four bytes) array?

通俗地说，我想每四个字节合并一次.

In layman's terms, I want to merge every four bytes.

推荐答案

byte b[4];  // Contains bytes
int x= 0;

x= (x << 8) + b[3];
x= (x << 8) + b[2];
x= (x << 8) + b[1];
x= (x << 8) + b[0];

我很快写了一个样本.不过，它没有经过测试.

I quickly wrote a sample. It's not tested, though.

unsigned char b[35];

int sizeOfB = sizeof b / sizeof(unsigned char);

int sizeOfL = sizeOfB / 4;
if(sizeOfB % 4 != 0) ++sizeOfL;
    int lcount=0;

long* l = new long[sizeOfL];

for(int i = 0; i < sizeOfB; i+=4){
    long currentLong = 0;

    if(i + 3 < sizeOfB)
        currentLong = (currentLong << 8) + b[i+3];
    if(i + 2 < sizeOfB)
        currentLong = (currentLong << 8) + b[i+2];
    if(i + 1 < sizeOfB)
        currentLong = (currentLong << 8) + b[i+1];

    currentLong = (currentLong << 8) + b[i+0];

    l[lcount]=currentlong;
    lcount++;
}

// Use l...
delete l;

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