xtc/src/mixer/model.c

#include "../project/project_internal.h"
#include <math.h>
#include <string.h>

/**
 * @brief Finds the dense index of a project track by stable ID.
 *
 * @param p Project to search; must not be NULL.
 * @param id Stable track identifier.
 * @return Dense track index, or SIZE_MAX when no track has the ID.
 */
static size_t find_track(const xtc_project *p, uint64_t id)
{
    size_t i;
    for (i = 0; i < p->track_count; ++i)
        if (p->tracks[i].id == id)
            return i;
    return SIZE_MAX;
}

/**
 * @brief Sets a track's gain, pan, mute, and solo controls after validation.
 *
 * @param p Project model; borrowed for this call.
 * @param id Stable identifier of the object to find or edit.
 * @param gain Linear gain, 0 to 4 for track controls.
 * @param pan Pan position from -1 (left) to 1 (right).
 * @param mute Track mute flag, 0 or 1.
 * @param solo Track solo flag, 0 or 1.
 * @return XTC_OK on success, or an error code describing the failure.
 */
xtc_result xtc_project_set_mix(xtc_project *p, uint64_t id, float gain, float pan, int mute, int solo)
{
    size_t i;
    if (!p || !isfinite(gain) || gain < 0 || gain > 4 || !isfinite(pan) || pan < -1 || pan > 1 ||
        (mute != 0 && mute != 1) || (solo != 0 && solo != 1))
        return XTC_ERR_INVALID_ARGUMENT;
    i = find_track(p, id);
    if (i == SIZE_MAX)
        return XTC_ERR_NOT_FOUND;
    p->tracks[i].gain = gain;
    p->tracks[i].pan = pan;
    p->tracks[i].mute = mute;
    p->tracks[i].solo = solo;
    return XTC_OK;
}

/**
 * @brief Inserts an automation point, replacing any point at the same track, parameter, and tick.
 *
 * @param p Project model; borrowed for this call.
 * @param a Automation point to read or update.
 * @return XTC_OK on success, or an error code describing the failure.
 */
xtc_result xtc_project_set_automation(xtc_project *p, const xtc_automation_point *a)
{
    size_t i;
    if (!p || !a || !isfinite(a->value) || a->tick > XTC_PROJECT_MAX_TICK ||
        (a->parameter != XTC_AUTOMATION_GAIN && a->parameter != XTC_AUTOMATION_PAN) ||
        a->value < (a->parameter == XTC_AUTOMATION_GAIN ? 0 : -1) ||
        a->value > (a->parameter == XTC_AUTOMATION_GAIN ? 4 : 1))
        return XTC_ERR_INVALID_ARGUMENT;
    if (find_track(p, a->track_id) == SIZE_MAX)
        return XTC_ERR_NOT_FOUND;
    for (i = 0; i < p->automation_count; ++i)
        if (p->automation[i].track_id == a->track_id && p->automation[i].parameter == a->parameter &&
            p->automation[i].tick == a->tick)
            break;
    if (i == XTC_MAX_AUTOMATION_POINTS)
        return XTC_ERR_CAPACITY;
    if (i == p->automation_count)
        ++p->automation_count;
    p->automation[i] = *a;
    return XTC_OK;
}

/**
 * @brief Removes the automation point at the specified track, parameter, and tick.
 *
 * @param p Project model; borrowed for this call.
 * @param id Stable identifier of the object to find or edit.
 * @param param Automation lane selector.
 * @param tick Musical position in ticks.
 * @return XTC_OK on success, or an error code describing the failure.
 */
xtc_result xtc_project_remove_automation(xtc_project *p, uint64_t id, xtc_automation_parameter param, uint64_t tick)
{
    size_t i;
    if (!p || (param != XTC_AUTOMATION_GAIN && param != XTC_AUTOMATION_PAN) || tick > XTC_PROJECT_MAX_TICK)
        return XTC_ERR_INVALID_ARGUMENT;
    for (i = 0; i < p->automation_count; ++i)
        if (p->automation[i].track_id == id && p->automation[i].parameter == param && p->automation[i].tick == tick)
            break;
    if (i == p->automation_count)
        return XTC_ERR_NOT_FOUND;
    memmove(p->automation + i, p->automation + i + 1, (--p->automation_count - i) * sizeof(*p->automation));
    return XTC_OK;
}

/**
 * @brief Copies the number of automation points in the project.
 *
 * @param p Project model; borrowed for this call.
 * @param n Receives the item count.
 * @return XTC_OK on success, or an error code describing the failure.
 */
xtc_result xtc_project_automation_count(const xtc_project *p, size_t *n)
{
    if (!p || !n)
        return XTC_ERR_INVALID_ARGUMENT;
    *n = p->automation_count;
    return XTC_OK;
}

/**
 * @brief Copies an automation point selected by dense list index.
 *
 * @param p Project model; borrowed for this call.
 * @param i Zero-based index in the dense list.
 * @param a Automation point to read or update.
 * @return XTC_OK on success, or an error code describing the failure.
 */
xtc_result xtc_project_get_automation(const xtc_project *p, size_t i, xtc_automation_point *a)
{
    if (!p || !a)
        return XTC_ERR_INVALID_ARGUMENT;
    if (i >= p->automation_count)
        return XTC_ERR_NOT_FOUND;
    *a = p->automation[i];
    return XTC_OK;
}