88 lines
2.7 KiB
HolyC
88 lines
2.7 KiB
HolyC
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U8* @base64_chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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U8* @base64_decode(U8* input, I64* output_length)
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{
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I64 input_length = StrLen(input);
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if (input_length % 4 != 0) {
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return NULL; // Invalid Base64 input length
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}
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// Calculate the expected output length
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*output_length = (3 * input_length) / 4;
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if (input[input_length - 1] == '=') {
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(*output_length)--;
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}
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if (input[input_length - 2] == '=') {
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(*output_length)--;
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}
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// Allocate memory for the decoded data
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U8* decoded_data = CAlloc(*output_length, adam_task);
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if (decoded_data == NULL) {
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return NULL; // Memory allocation failed
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}
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// Initialize variables for decoding process
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I32 i, j = 0;
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U32 sextet_bits = 0;
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I64 sextet_count = 0;
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U32 base64_value;
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U8* char_pointer;
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U8 input_find_buf[2];
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input_find_buf[1] = NULL;
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// Loop through the Base64 input and decode it
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for (i = 0; i < input_length; i++) {
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// Convert Base64 character to a 6-bit value
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base64_value = 0;
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if (input[i] == '=') {
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base64_value = 0;
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} else {
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input_find_buf[0] = input[i];
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char_pointer = StrFirstOcc(@base64_chars, input_find_buf);
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if (char_pointer == NULL) {
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Free(decoded_data);
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return NULL; // Invalid Base64 character
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}
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base64_value = char_pointer - @base64_chars;
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}
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// Combine 6-bit values into a 24-bit sextet
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sextet_bits = (sextet_bits << 6) | base64_value;
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sextet_count++;
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// When a sextet is complete, decode it into three bytes
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if (sextet_count == 4) {
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decoded_data[j++] = (sextet_bits >> 16) & 0xFF;
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decoded_data[j++] = (sextet_bits >> 8) & 0xFF;
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decoded_data[j++] = sextet_bits & 0xFF;
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sextet_bits = 0;
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sextet_count = 0;
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}
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}
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return decoded_data;
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}
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U8* @base64_encode(U8* input, I64 input_length)
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{
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I64 i;
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U8 buf[3];
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I64 c = 0;
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U8* output = CAlloc(input_length * 2, adam_task);
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for (i = 0; i < input_length; i += 3) {
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buf[0] = input[i];
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buf[1] = @t((i + 1 < input_length), input[i + 1], 0);
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buf[2] = @t((i + 2 < input_length), input[i + 2], 0);
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output[c++] = @base64_chars[(buf[0] & 0xfc) >> 2];
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output[c++] = @base64_chars[((buf[0] & 0x03) << 4) + ((buf[1] & 0xf0) >> 4)];
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output[c++] = @t((i + 1 < input_length), @base64_chars[((buf[1] & 0x0f) << 2) + ((buf[2] & 0xc0) >> 6)], '=');
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output[c++] = @t((i + 2 < input_length), @base64_chars[buf[2] & 0x3f], '=');
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}
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output[c] = '\0';
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return output;
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}
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