It is possible to convert a Python function in C?

Hello!

I have to write a small program in C for work.

The main block of this program is a function that calculate the modbus checksum, but is written in python.

Is prossibile to convert it in C?

Code:

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def crc16(data, bits=8):
    crc = 0xFFFF
    for op, code in zip(data[0::2], data[1::2]):
        crc = crc ^ int(op+code, 16)
        for bit in range(0, bits):
            if (crc&0x0001)  == 0x0001:
                crc = ((crc >> 1) ^ 0xA001)
            else:
                crc = crc >> 1
    msb = crc >> 8
    lsb = crc & 0x00FF
    return '{:X}{:X}'.format(lsb, msb)
 
print crc16('11010003000C')

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There is an online converter or something similar?

Of course!

...but in general the one getting paid should be doing the work.

Quote:

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Originally Posted by hamster_nz

Of course!

...but in general the one getting paid should be doing the work.

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Surely. I don't ask to convert it for me, I ask only if there is an online converter.

Quote:

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Originally Posted by Bokka

Surely. I don't ask to convert it for me, I ask only if there is an online converter.

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Yes, it can be converted, but no online converter exists, but this does:

Nuitka Downloads — Nuitka the Python Compiler documentation

The generated code is usually of very low quality compared to actual C code.

Here's your python module converted to C:

I'll take a look at it. Thanks a lot!

Code:

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#include <stdio.h>
 
unsigned crc16(const char *data, int bits/*=8*/) {
    unsigned crc = 0xFFFF;
    for (int i = 0; data[i * 2] && data[i * 2 + 1]; ++i) {
        unsigned n;
        sscanf(data + i * 2, "%2x", &n);
        crc ^= n;
        for (int bit = 0; bit < bits; ++bit)
            if (crc & 0x1) crc = (crc >> 1) ^ 0xA001;
            else          crc = (crc >> 1);
    }
    return (crc >> 8) | ((crc & 0xff) << 8);
}
 
int main() {
    unsigned crc = crc16("11010003000C", 8);
    printf("%04X\n", crc);
    return 0;
}

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Kinda weird thing to ask, since the Python would itself have been the result of a conversion from an older C source to begin with.

The python even has a bug since it concatenates the two hex strings together without zero-padding to two-digits per byte.

Quote:

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Originally Posted by john.c

The python even has a bug since it concatenates the two hex strings together without zero-padding to two-digits per byte.

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That's a feature, not a bug! (If both 42 and 402 should compare equal, that is.)