SimpleMixer.cpp

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/**
 * @file mixer_simple.cpp
 *
 * Simple summing mixer.
 */

#include "SimpleMixer.hpp"

#include <stdio.h>
#include <stdlib.h>

#define debug(fmt, args...) do { } while(0)
//#define debug(fmt, args...)   do { printf("[mixer] " fmt "\n", ##args); } while(0)

SimpleMixer::SimpleMixer(ControlCallback control_cb, uintptr_t cb_handle, mixer_simple_s *mixinfo) :
    Mixer(control_cb, cb_handle),
    _pinfo(mixinfo)
{
}

SimpleMixer::~SimpleMixer()
{
    if (_pinfo != nullptr) {
        free(_pinfo);
    }
}

unsigned SimpleMixer::set_trim(float trim)
{
    _pinfo->output_scaler.offset = trim;
    return 1;
}

unsigned SimpleMixer::get_trim(float *trim)
{
    *trim = _pinfo->output_scaler.offset;
    return 1;
}

int
SimpleMixer::parse_output_scaler(const char *buf, unsigned &buflen, mixer_scaler_s &scaler)
{
    int ret;
    int s[5];
    int n = -1;

    buf = findtag(buf, buflen, 'O');

    if ((buf == nullptr) || (buflen < 12)) {
        debug("output parser failed finding tag, ret: '%s'", buf);
        return -1;
    }

    if ((ret = sscanf(buf, "O: %d %d %d %d %d %n",
              &s[0], &s[1], &s[2], &s[3], &s[4], &n)) != 5) {
        debug("out scaler parse failed on '%s' (got %d, consumed %d)", buf, ret, n);
        return -1;
    }

    buf = skipline(buf, buflen);

    if (buf == nullptr) {
        debug("no line ending, line is incomplete");
        return -1;
    }

    scaler.negative_scale   = s[0] / 10000.0f;
    scaler.positive_scale   = s[1] / 10000.0f;
    scaler.offset       = s[2] / 10000.0f;
    scaler.min_output   = s[3] / 10000.0f;
    scaler.max_output   = s[4] / 10000.0f;

    return 0;
}

int
SimpleMixer::parse_control_scaler(const char *buf, unsigned &buflen, mixer_scaler_s &scaler, uint8_t &control_group,
                  uint8_t &control_index)
{
    unsigned u[2];
    int s[5];

    buf = findtag(buf, buflen, 'S');

    if ((buf == nullptr) || (buflen < 16)) {
        debug("control parser failed finding tag, ret: '%s'", buf);
        return -1;
    }

    if (sscanf(buf, "S: %u %u %d %d %d %d %d",
           &u[0], &u[1], &s[0], &s[1], &s[2], &s[3], &s[4]) != 7) {
        debug("control parse failed on '%s'", buf);
        return -1;
    }

    buf = skipline(buf, buflen);

    if (buf == nullptr) {
        debug("no line ending, line is incomplete");
        return -1;
    }

    control_group       = u[0];
    control_index       = u[1];
    scaler.negative_scale   = s[0] / 10000.0f;
    scaler.positive_scale   = s[1] / 10000.0f;
    scaler.offset       = s[2] / 10000.0f;
    scaler.min_output   = s[3] / 10000.0f;
    scaler.max_output   = s[4] / 10000.0f;

    return 0;
}

SimpleMixer *
SimpleMixer::from_text(Mixer::ControlCallback control_cb, uintptr_t cb_handle, const char *buf, unsigned &buflen)
{
    SimpleMixer *sm = nullptr;
    mixer_simple_s *mixinfo = nullptr;
    unsigned inputs;
    int used;
    const char *end = buf + buflen;
    char next_tag;

    /* enforce that the mixer ends with a new line */
    if (!string_well_formed(buf, buflen)) {
        return nullptr;
    }

    /* get the base info for the mixer */
    if (sscanf(buf, "M: %u%n", &inputs, &used) != 1) {
        debug("simple parse failed on '%s'", buf);
        goto out;
    }

    /* at least 1 input is required */
    if (inputs == 0) {
        debug("simple parse got 0 inputs");
        goto out;
    }

    buf = skipline(buf, buflen);

    if (buf == nullptr) {
        debug("no line ending, line is incomplete");
        goto out;
    }

    mixinfo = (mixer_simple_s *)malloc(MIXER_SIMPLE_SIZE(inputs));

    if (mixinfo == nullptr) {
        debug("could not allocate memory for mixer info");
        goto out;
    }

    mixinfo->control_count = inputs;

    /* find the next tag */
    next_tag = findnexttag(end - buflen, buflen);

    if (next_tag == 'S') {
        /* No output scalers specified. Use default values.
         * Corresponds to:
         * O:      10000  10000      0 -10000  10000
         */
        mixinfo->output_scaler.negative_scale   = 1.0f;
        mixinfo->output_scaler.positive_scale   = 1.0f;
        mixinfo->output_scaler.offset       = 0.f;
        mixinfo->output_scaler.min_output   = -1.0f;
        mixinfo->output_scaler.max_output   = 1.0f;

    } else {
        if (parse_output_scaler(end - buflen, buflen, mixinfo->output_scaler)) {
            debug("simple mixer parser failed parsing out scaler tag, ret: '%s'", buf);
            goto out;
        }
    }

    for (unsigned i = 0; i < inputs; i++) {
        if (parse_control_scaler(end - buflen, buflen,
                     mixinfo->controls[i].scaler,
                     mixinfo->controls[i].control_group,
                     mixinfo->controls[i].control_index)) {
            debug("simple mixer parser failed parsing ctrl scaler tag, ret: '%s'", buf);
            goto out;
        }
    }

    sm = new SimpleMixer(control_cb, cb_handle, mixinfo);

    if (sm != nullptr) {
        mixinfo = nullptr;
        debug("loaded mixer with %d input(s)", inputs);

    } else {
        debug("could not allocate memory for mixer");
    }

out:

    if (mixinfo != nullptr) {
        free(mixinfo);
    }

    return sm;
}

unsigned
SimpleMixer::mix(float *outputs, unsigned space)
{
    float sum = 0.0f;

    if (_pinfo == nullptr) {
        return 0;
    }

    if (space < 1) {
        return 0;
    }

    for (unsigned i = 0; i < _pinfo->control_count; i++) {
        float input = 0.0f;

        _control_cb(_cb_handle,
                _pinfo->controls[i].control_group,
                _pinfo->controls[i].control_index,
                input);

        sum += scale(_pinfo->controls[i].scaler, input);
    }

    *outputs = scale(_pinfo->output_scaler, sum);
    return 1;
}

void
SimpleMixer::groups_required(uint32_t &groups)
{
    for (unsigned i = 0; i < _pinfo->control_count; i++) {
        groups |= 1 << _pinfo->controls[i].control_group;
    }
}

int
SimpleMixer::check()
{
    float junk;

    /* sanity that presumes that a mixer includes a control no more than once */
    /* max of 32 groups due to groups_required API */
    if (_pinfo->control_count > 32) {
        return -2;
    }

    /* validate the output scaler */
    int ret = scale_check(_pinfo->output_scaler);

    if (ret != 0) {
        return ret;
    }

    /* validate input scalers */
    for (unsigned i = 0; i < _pinfo->control_count; i++) {

        /* verify that we can fetch the control */
        if (_control_cb(_cb_handle,
                _pinfo->controls[i].control_group,
                _pinfo->controls[i].control_index,
                junk) != 0) {
            return -3;
        }

        /* validate the scaler */
        ret = scale_check(_pinfo->controls[i].scaler);

        if (ret != 0) {
            return (10 * i + ret);
        }
    }

    return 0;
}

float
SimpleMixer::scale(const mixer_scaler_s &scaler, float input)
{
    float output;

    if (input < 0.0f) {
        output = (input * scaler.negative_scale) + scaler.offset;

    } else {
        output = (input * scaler.positive_scale) + scaler.offset;
    }

    return math::constrain(output, scaler.min_output, scaler.max_output);
}

int
SimpleMixer::scale_check(mixer_scaler_s &scaler)
{
    if (scaler.offset > 1.001f) {
        return 1;
    }

    if (scaler.offset < -1.001f) {
        return 2;
    }

    if (scaler.min_output > scaler.max_output) {
        return 3;
    }

    if (scaler.min_output < -1.001f) {
        return 4;
    }

    if (scaler.max_output > 1.001f) {
        return 5;
    }

    return 0;
}