int aws_huffman_encode()

in source/huffman.c [131:187]

• 43 lines of code
• 8 McCabe index (conditional complexity)

int aws_huffman_encode(
    struct aws_huffman_encoder *encoder,
    struct aws_byte_cursor *to_encode,
    struct aws_byte_buf *output) {

    AWS_ASSERT(encoder);
    AWS_ASSERT(encoder->coder);
    AWS_ASSERT(to_encode);
    AWS_ASSERT(output);

    struct encoder_state state = {
        .working = 0,
        .bit_pos = 8,
    };
    state.encoder = encoder;
    state.output_buf = output;

    /* Write any bits leftover from previous invocation */
    if (encoder->overflow_bits.num_bits) {
        if (output->len == output->capacity) {
            return aws_raise_error(AWS_ERROR_SHORT_BUFFER);
        }

        if (encode_write_bit_pattern(&state, encoder->overflow_bits)) {
            return AWS_OP_ERR;
        }

        encoder->overflow_bits.num_bits = 0;
    }

    while (to_encode->len) {
        if (output->len == output->capacity) {
            return aws_raise_error(AWS_ERROR_SHORT_BUFFER);
        }

        uint8_t new_byte = 0;
        aws_byte_cursor_read_u8(to_encode, &new_byte);
        struct aws_huffman_code code_point = encoder->coder->encode(new_byte, encoder->coder->userdata);

        if (encode_write_bit_pattern(&state, code_point)) {
            return AWS_OP_ERR;
        }
    }

    /* The following code only runs when the buffer has written successfully */

    /* If whole buffer processed, write EOS */
    if (state.bit_pos != 8) {
        struct aws_huffman_code eos_cp;
        eos_cp.pattern = encoder->eos_padding;
        eos_cp.num_bits = state.bit_pos;
        encode_write_bit_pattern(&state, eos_cp);
        AWS_ASSERT(state.bit_pos == 8);
    }

    return AWS_OP_SUCCESS;
}