Encoding
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## Encoding

The encoder calculates the Reed-Solomon code over the given data length and stores the result in the parity buffer. Note that the parity buffer must be initialized before calling the encoder.

The expanded data can be inverted on the fly by providing a non-zero inversion mask. The expanded data is XOR'ed with the mask. This is used e.g. for FLASH ECC, where the all 0xFF is inverted to an all 0x00. The Reed-Solomon code for all 0x00 is all 0x00. The code is inverted before storing to FLASH so it is 0xFF too. This prevents that reading from an erased FLASH results in ECC errors.

The databytes are expanded to the given symbol size on the fly. There is no support for encoding continuous bitstreams with a symbol size != 8 at the moment. If it is necessary it should be not a big deal to implement such functionality.

    /* Parity buffer. Size = number of roots */
    uint16_t par[6];
    /* Initialize the parity buffer */
    memset(par, 0, sizeof(par));
    /* Encode 512 byte in data8. Store parity in buffer par */
    encode_rs8 (rs_decoder, data8, 512, par, 0);

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