Question

我知道我接近完成这个UUEncoder功能;我将使用它与嵌入式设备进行通信。但是对于我的生活，我无法弄清楚如何在末尾正确插入空填充字符。

我一直试图效仿here。

void encode(unsigned char fileData_Hex_String[], int hexDataCharCount)
{
    unsigned char UUE_Encoded_String[MAX_SIZE];
    unsigned char b[2];
    unsigned char d[3];
    int UUE_Encoded_String_Index = 0;

    hexDataCharCount =7;

    for(int hexDataIndex = 0;  hexDataIndex < hexDataCharCount; hexDataIndex)
    {
        // Load chars or nulls
        for (int i = 0; i < 3; ++i)
        {
            b[i] = fileData_Hex_String[hexDataIndex];
            printf("%i\n", (hexDataIndex - hexDataCharCount));
            if ((hexDataIndex - hexDataCharCount) > 0)
            {
                b[1] = '\n';
                b[2] = '\n';
                break;
            }
            hexDataIndex++;
        }


        // UUEncode
        d[0] = (((b[0] >> 2) & 0x3f) + ' ');
        d[1] = ((((b[0] << 4) | ((b[1] >> 4) & 0x0f)) & 0x3f) + ' ');
        d[2] = ((((b[1] << 2) | ((b[2] >> 6) & 0x03)) & 0x3f) + ' ');
        d[3] = ((b[2] & 0x3f) + ' ');

        // Put the UUEncoded chars into their own string.
        for (int i = 0; i < 4; i++)
        {
            UUE_Encoded_String[UUE_Encoded_String_Index] = d[i];
            printf(" 0x%2x \n", UUE_Encoded_String[UUE_Encoded_String_Index]);
            UUE_Encoded_String_Index++;
        }
    }
}

一切正常，但我在末尾0x48和0x2A得到两个不需要的字符。

Answer 1

你的阵列太小了。你已宣布

unsigned char b[2];
unsigned char d[3];

但是索引都超出了范围

d[3] = ((b[2] & 0x3f) + ' ');

所以你应该声明

unsigned char b[3];
unsigned char d[4];

Answer 2

\n不是null它是换行符。如果你把

b[1] = 0;
b[2] = 0;

最后两个字节为0x20 0x20。但是如果你像这样编写循环

，你的代码会更灵活

// Load chars or nulls
for (i = 0; i < 3; ++i)
{
    if (hexDataIndex < hexDataCharCount)
        b[i] = fileData_Hex_String[hexDataIndex];
    else
        b[i] = 0;
    hexDataIndex++;
}

Answer 3

天气风向标帮助了我之后的工作代码。

void encode2(unsigned char fileData_Hex_String[], int hexDataCharCount)
{
    unsigned char UUE_Encoded_String[MAX_SIZE];
    unsigned char b[3];
    unsigned char d[4];

    int paddedIndex = 0;
    int UUE_Encoded_String_Index = 0;

    for(int hexDataIndex = 0;  hexDataIndex < hexDataCharCount; hexDataIndex)
    {   
        // Load chars or nulls
        for (int i = 0; i < 3; i++)
        {

            if (hexDataIndex < hexDataCharCount)
            {
                b[i] = fileData_Hex_String[hexDataIndex];   
            }
            else
            {
                b[i] = 0;
                paddedIndex++;
            }
            //printf("%i\n", (hexDataIndex-hexDataCharCount));
            hexDataIndex++;
        }

        // UUEncode
        d[0] = (((b[0] >> 2) & 0x3f) + ' ');
        d[1] = ((((b[0] << 4) | ((b[1] >> 4) & 0x0f)) & 0x3f) + ' ');
        d[2] = ((((b[1] << 2) | ((b[2] >> 6) & 0x03)) & 0x3f) + ' ');
        d[3] = ((b[2] & 0x3f) + ' ');

        // Put the UUEncoded chars into their own string.
        for (int i = 0; i < 4; i++)
        {
            UUE_Encoded_String[UUE_Encoded_String_Index] = d[i];
            UUE_Encoded_String_Index++;
        }
        //printf("      %i      %i\n", hexDataIndex, hexDataCharCount);

    }
    printf("%i\n", (UUE_Encoded_String_Index-paddedIndex));
    for (int i = 0; i < (UUE_Encoded_String_Index-paddedIndex); ++i)
    {
        printf(" 0x%2x \n", UUE_Encoded_String[i]);

    }
}

在C中向UUEncoder添加空填充

3 个答案: