Initial Query

Write a c program that calculates the crc32 hash of the string "correct horse battery staple" and prints it to stdout. Dont call any builtin crc32 functions.

LLM Generation

Query

Write a c program that calculates the crc32 hash of the string "correct horse battery staple" and prints it to stdout. Dont call any builtin crc32 functions.

Output

**CRC32 Hash Calculation in C** ===================================== Below is a simple C program that calculates the CRC32 hash of the string "correct horse battery staple" using the CRC32 algorithm. 

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#include <stdio.h>

// CRC32 polynomial: 0xedb88320
#define CRC32_POLY 0xedb88320

// Function to calculate CRC32 hash
unsigned int crc32(const unsigned char* data, unsigned int length) {
    unsigned int crc = 0xffffffff;
    for (unsigned int i = 0; i < length; i++) {
        crc = crc ^ data[i];
        for (int j = 0; j < 8; j++) {
            if (crc & 1) {
                crc = (crc >> 1) ^ CRC32_POLY;
            } else {
                crc = crc >> 1;
            }
        }
    }
    return ~crc;
}

int main() {
    const unsigned char* data = "correct horse battery staple";
    unsigned int length = 0;
    while (data[length] != '\0') {
        length++;
    }
    unsigned int crc = crc32(data, length);
    printf("CRC32 hash of '%s': 0x%08x\n", data, crc);
    return 0;
}
**Explanation** --------------- * The program uses the CRC32 polynomial `0xedb88320` to calculate the hash. * The `crc32` function takes a pointer to the data and its length as input, and returns the calculated CRC32 hash. * The hash is calculated by iterating over each byte of the data, XORing it with the current CRC value, and then performing eight iterations of bit-shifting and XORing with the polynomial if the least significant bit is 1. * The final CRC value is inverted by XORing it with all ones (`~crc`) before being returned. * In the `main` function, the string "correct horse battery staple" is used as the input data, and its CRC32 hash is calculated and printed to the console. **Compile and Run** ------------------- To compile and run the program, save it to a file (e.g., `crc32.c`), and then use the following commands: 
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gcc -o crc32 crc32.c
./crc32
This will output the CRC32 hash of the string "correct horse battery staple".

Extract Code

I extracted the following code from that output: 

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#include <stdio.h>

// CRC32 polynomial: 0xedb88320
#define CRC32_POLY 0xedb88320

// Function to calculate CRC32 hash
unsigned int crc32(const unsigned char* data, unsigned int length) {
    unsigned int crc = 0xffffffff;
    for (unsigned int i = 0; i < length; i++) {
        crc = crc ^ data[i];
        for (int j = 0; j < 8; j++) {
            if (crc & 1) {
                crc = (crc >> 1) ^ CRC32_POLY;
            } else {
                crc = crc >> 1;
            }
        }
    }
    return ~crc;
}

int main() {
    const unsigned char* data = "correct horse battery staple";
    unsigned int length = 0;
    while (data[length] != '\0') {
        length++;
    }
    unsigned int crc = crc32(data, length);
    printf("CRC32 hash of '%s': 0x%08x\n", data, crc);
    return 0;
}

Run Code Interpreter

Running the following program: 

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#include <stdio.h>

// CRC32 polynomial: 0xedb88320
#define CRC32_POLY 0xedb88320

// Function to calculate CRC32 hash
unsigned int crc32(const unsigned char* data, unsigned int length) {
    unsigned int crc = 0xffffffff;
    for (unsigned int i = 0; i < length; i++) {
        crc = crc ^ data[i];
        for (int j = 0; j < 8; j++) {
            if (crc & 1) {
                crc = (crc >> 1) ^ CRC32_POLY;
            } else {
                crc = crc >> 1;
            }
        }
    }
    return ~crc;
}

int main() {
    const unsigned char* data = "correct horse battery staple";
    unsigned int length = 0;
    while (data[length] != '\0') {
        length++;
    }
    unsigned int crc = crc32(data, length);
    printf("CRC32 hash of '%s': 0x%08x\n", data, crc);
    return 0;
}
And got the output: CRC32 hash of 'correct horse battery staple': 0xcb7e6e10

Substring Evaluation

Testing if the previous output contains the string cb7e6e10: True