如何轉義utf-8並將utf-8代碼轉換為字節

Question

我需要將字符串（char []）轉換為帶有unicode轉義的字符串（格式為：\\ u0105）。 我編寫unicode代碼來從文件示例轉換字符串：

“ąćżźóÓŻŹĆĄŚśƐƑƁƂЁЂ”=>“\\ u0105 \\ u0107 \\ u017C \\ u017A \\ u00F3 \\ u00D3 \\ u017B \\ u0176 \\ u0104 \\ u015A \\ u015B \\ u0190 \\ u0191 \\ u0181 \\ u0182 \\ u0401 \\ u0402”。

現在我需要寫反向，例如：“\\ u0105”=>“±”（char [] = {0xC4,0x85}）。

怎么做（只使用C）？
假設我在uint32_t code = 0x0105;有utf-8代碼uint32_t code = 0x0105;

這里我的代碼將字符串轉換為unicode轉義：

static const uint32_t unicode[48] = {
    0x0000, 0x0040, 0x0080, 0x00C0, 0x0100, 0x0140, 0x0180, 0x01C0, 0x0200, 0x0240, 0x0280, 0x02C0, 0x0300, 0x0340, 0x0380, 0x03C0, 
    0x0400, 0x0440, 0x0480, 0x04C0, 0x0500, 0x0540, 0x0580, 0x05C0, 0x0600, 0x0640, 0x0680, 0x06C0, 0x0700, 0x0740, 0x0780, 0x07C0, 
    0x0800, 0x1000, 0x2000, 0x3000, 0x4000, 0x5000, 0x6000, 0x7000, 0x8000, 0x9000, 0xA000, 0xB000, 0xC000, 0xD000, 0xE000, 0xF000, 
};

...

    FILE* fh = fopen("utf.txt", "r");
    char* result;
    char* tmpMemoryBuffer;
    size_t currentSize = 255, currentIndex = 0;
    result = (char*) malloc(sizeof(char) * currentSize);
    memset(result, 0, sizeof(char) * currentSize);


    if (fh != NULL)
    {
        uint8_t c2, c = (uint8_t) getc(fh);
        uint32_t tmp = 0;

        while (c != EOF && c != 0xFF)
        {
            if ((currentIndex - 1) == currentSize)
            {
                tmpMemoryBuffer = (char*) malloc(sizeof(char) * currentSize);
                memcpy(tmpMemoryBuffer, result, sizeof(char) * currentSize);
                result = (char*) realloc(result, sizeof(char) * (currentSize + 255));
                memcpy(result, tmpMemoryBuffer, sizeof(char) * currentSize);
                currentSize += 255;
            }

            if (c >= 0x20 && c <= 0x7E)
            {
                //Is normal char
                printf("Normal:\t%c\n", c);
                result[currentIndex++] = (char) c;
            }
            else if (c >= 0xC0 && c <= 0xEF && (c2 = (uint8_t) getc(fh)) != EOF)
            {
                //Is unicode
                c &= 0x3F;
                c2 &= 0x7F;
                tmp = unicode[c];
                tmp += c2;
                sprintf(result + currentIndex, "\\u%04X", tmp);
                currentIndex += 6;
                printf("Unicode:\t%04X\n", tmp);

            }
            else
            {
                printf("Wrong format for 0x%X\n", c);
                break;
            }
            c = (uint8_t) getc(fh);
        }

        result[currentIndex] = '\0';
        fclose(fh);
...
        free(result);     

還有更好的方法嗎？

Answer 1

如果有人會搜索我寫這個作為問題的延續：

char result[] = "\ą\ć\ż\ź\ó";

char* resultStr = (char*)malloc(sizeof(char) * currentIndex + 1);
size_t reIndex = 0;

for (size_t i = 0; i < strlen(result); i++) 
{
    if (result[i] == '\\')
    {
        if (result[i + 1] != '\0')
        {
            i++;
            switch (result[i])
            {
                case 'u':
                    if (result[i + 1] != '\0' && result[i + 2] != '\0' && result[i + 3] != '\0' && result[i + 4] != '\0')
                    {
                        const char hexstring[5] = {result[i + 1], result[i + 2], result[i + 3], result[i + 4], '\0'};
                        uint32_t code = (uint32_t)strtol(hexstring, NULL, 16);
                        printf ("Code = 0x%X\n", code);
                        uint8_t firstByte = 47;
                        uint8_t secondByte = 0;

                        for (size_t i = 1; i < 48; i++)
                        {
                            if (unicode[i] > code)
                            {
                                firstByte = i - 1;
                                secondByte = (uint8_t)(code - unicode[i - 1]);
                                break;
                            }
                        }

                        firstByte |= 0xC0;
                        secondByte |= 0x80;
                        resultStr[reIndex++] = (char)firstByte;
                        resultStr[reIndex++] = (char)secondByte;
                        i += 4;
                    }
                break;
            }
        }
        else
        {
            //Error
        }
    }
    else
    {
        resultStr[reIndex++] = result[i];
    }
}

resultStr[reIndex] = '\0';
printf("Result = %s\n", resultStr);

這需要重構並添加一些功能，如句柄'\\ n'，'\\ t'，'\\ r'，但是輕巧快速。

誰有更好的想法？