如何将CStringArray数据以十六进制格式赋值到unsigned char数组

Got it, let's tackle this problem step by step. You have a CStringArray named m_arrSecurityAES storing 2-character hex strings (like "00", "01", all the way to "0F"), and you need to convert each of these into their corresponding byte values (e.g., 0x00, 0x01) and populate an unsigned char private_key[16] array. Here's a robust MFC-compliant solution:

Step-by-Step Implementation #

First, we'll write a helper function to handle the conversion, with error checking to avoid unexpected behavior:

#include <cstring> // For memset
#include <afxwin.h> // MFC core headers (if not already included)

void ConvertSecurityAESToPrivateKey(unsigned char private_key[16])
{
    // Initialize the output array to 0 by default
    memset(private_key, 0, sizeof(unsigned char) * 16);

    // First, validate we have exactly 16 elements (matching AES-128 key size)
    if (m_arrSecurityAES.GetSize() != 16)
    {
        TRACE(_T("Error: m_arrSecurityAES must contain exactly 16 hex string elements!\n"));
        return;
    }

    // Loop through each element in the CStringArray
    for (int i = 0; i < 16; ++i)
    {
        CString hexStr = m_arrSecurityAES.GetAt(i);
        hexStr.Trim(); // Remove any leading/trailing whitespace (just in case)

        // Validate the string length is exactly 2 characters
        if (hexStr.GetLength() != 2)
        {
            TRACE(_T("Warning: Element %d has invalid length (expected 2, got %d)\n"), 
                  i, hexStr.GetLength());
            continue;
        }

        // Convert the hex string to an unsigned integer
        unsigned int byteValue = 0;
        int conversionResult = _stscanf_s(hexStr, _T("%2X"), &byteValue);

        // Check if conversion succeeded
        if (conversionResult != 1)
        {
            TRACE(_T("Warning: Failed to convert element %d ('%s') to hex\n"), 
                  i, hexStr);
            continue;
        }

        // Cast the integer to unsigned char and store it in the key array
        private_key[i] = static_cast<unsigned char>(byteValue);
    }
}

How to Use This Function #

Call the helper function wherever you need to populate your private key array, then verify the results if needed:

// Declare your private key array
unsigned char private_key[16];

// Convert the CStringArray to the key array
ConvertSecurityAESToPrivateKey(private_key);

// Optional: Print the results to debug output
for (int i = 0; i < 16; ++i)
{
    TRACE(_T("private_key[%d] = 0x%02X\n"), i, private_key[i]);
}

Key Details to Note #

• Error Handling: The function includes checks for invalid array sizes, malformed string lengths, and failed conversions, using TRACE to log warnings in debug mode.
• Case Insensitivity: The %2X format specifier works with both uppercase ("0F") and lowercase ("0f") hex strings.
• Safety: We use _stscanf_s (the secure version of sscanf) to avoid buffer overflows, which is recommended for MFC applications.

内容的提问来源于stack exchange，提问作者NIKHIL