wch-code/ch32v307_mp3_dac/User/audio/audio_player.c

#include "audio_player.h"
#include <stdlib.h>
#include "debug.h"
#include "bsp_key.h"
#include "bsp_led.h"
#include "ff.h"
#include "tlsf.h"

#define AUDIO_PLAYER_MUSIC_FILE_LIST_MAX 600 //最大音频文件数量
#define AUDIO_PLAYER_MUSIC_FILE_NAME_LENGTH 13 //FAT32中短文件名占用13字节
#define AUDIO_PLAYER_MUSIC_DEFAULT_DIR "" //默认音频文件存储目录

static const char* audio_player_music_ext_names[] = {"MP3", "WAV", ""};

typedef enum {
    audio_player_mode_normal, //顺序播放
    audio_player_mode_single_repeat, //单曲循环
} audio_player_mode_e;

audio_hal_result_t audio_player_playing_routine(void)
{
    bsp_key_event_e key_event = bsp_key_get_event();

    switch (key_event){
    case bsp_key_none:
        return audio_hal_ok;

    case bsp_key_next_short:
        return audio_hal_result_next;

    case bsp_key_prev_short:
        return audio_hal_result_prev;

    case bsp_key_pause_short:
        return audio_hal_result_pause;

    case bsp_key_next_long:
        return audio_hal_result_random;

    case bsp_key_prev_long:
        return audio_hal_result_repeat;

    default:
        LOG_W("unhandled key event: %s", bsp_key_get_event_string(key_event));
    }

    return audio_hal_ok;
}

audio_hal_result_t audio_player_play_file(const char *path)
{
    char* ext_name = strrchr(path, '.') + 1; //指针定位到扩展名

    if(!strcasecmp(ext_name, "MP3")) {
        return audio_mp3_play(path, audio_player_playing_routine);
    } else if(!strcasecmp(ext_name, "WAV")) {
        return audio_wav_play(path, audio_player_playing_routine);
    }

    LOG_W("unknown file format \"%s\" of %s", ext_name, path);
    return audio_hal_error_unsupported_format;
}

bool audio_player_check_file_ext(const char* path, const char** ext_table)
{
    char* ext_name = strrchr(path,'.') + 1; //指针定位到扩展名

    if(ext_name == NULL) { //不存在扩展名
        return false;
    }

    if(ext_table[0][0] == '\0') {
        return true;//未指定扩展名 均返回真
    }

    uint8_t i = 0;
    while(ext_table[i][0] != '\0') { //以此检查是否与每个扩展名匹配
        if(!strcasecmp(ext_name, ext_table[i])) {
            return true;
        }

        i ++;
    }

    return false;
}

uint32_t audio_player_search_file(const char* music_dir, char *file_list)
{
    uint16_t file_count = 0;

    DIR dir;
    FRESULT f_result = f_opendir(&dir, music_dir);
    if (f_result != FR_OK) {
        LOG_E("error while reading directory, error code=%d", f_result);
        return 0;
    }

    while (1) {
        FILINFO fileinfo;
        f_result = f_readdir(&dir, &fileinfo);
        if (f_result != FR_OK) {
            LOG_E("error while reading directory, error code=%d", f_result);
            break;
        }

        if (fileinfo.fname[0] == '\0') { //文件夹遍历完毕
            LOG_I("%d files saved in list", file_count);
            break;
        }

        if(audio_player_check_file_ext(fileinfo.fname, audio_player_music_ext_names) == 0) { //不受支持的文件类型
            continue;
        }

        if(fileinfo.fattrib & AM_DIR) { //是一个目录
            continue;
        }

        if (file_list != NULL) { //如果指针非空 则复制到文件列表中
            strcpy(file_list + file_count * AUDIO_PLAYER_MUSIC_FILE_NAME_LENGTH, fileinfo.fname);
        }

        file_count ++;
        if (file_count >= AUDIO_PLAYER_MUSIC_FILE_LIST_MAX) {
            LOG_W("more than %d files are found, discarding more files", AUDIO_PLAYER_MUSIC_FILE_LIST_MAX);
            break;
        }
    }

    f_result = f_closedir(&dir);
    if (f_result != FR_OK) {
        LOG_E("error while closing directory, error code=%d", f_result);
    }

    return file_count;
}

void audio_player(void)
{
    RCC_AHBPeriphClockCmd(RCC_AHBPeriph_RNG, ENABLE);
    RNG_Cmd(ENABLE);

    uint32_t current_file_index = 0;
    uint32_t audio_file_count = audio_player_search_file(AUDIO_PLAYER_MUSIC_DEFAULT_DIR, NULL); //首先搜索音频文件数
    if (audio_file_count == 0) {
        LOG_E("error while searching for music files");
        return;
    }

    LOG_D("allocating %d bytes of memory for music file list", audio_file_count * AUDIO_PLAYER_MUSIC_FILE_NAME_LENGTH);
    char *audio_file_list = tlsf_malloc(audio_file_count * AUDIO_PLAYER_MUSIC_FILE_NAME_LENGTH); //为文件列表申请内存
    if (audio_file_list == NULL) {
        LOG_E("error while allocating memory for music file list");
        return;
    }

    audio_player_search_file(AUDIO_PLAYER_MUSIC_DEFAULT_DIR, audio_file_list); //然后将文件名保存到列表中

    uint8_t switch_direction = 1; //1为下一首 0为上一首
    while(1) {
        char dir[20];
        sprintf(dir, AUDIO_PLAYER_MUSIC_DEFAULT_DIR "/%s", audio_file_list + current_file_index * AUDIO_PLAYER_MUSIC_FILE_NAME_LENGTH);

        LOG_D("index of playing file: %d, total files: %d", current_file_index+1, audio_file_count);
        audio_hal_result_t play_result = audio_player_play_file(dir);

        switch (play_result)
        {
        case audio_hal_error_open_file:
        case audio_hal_error_read_file: //文件系统错误
            goto error;

        case audio_hal_error_insufficient_memory: //无法恢复的错误
            LOG_E("unrecoverable error, resetting system");
            NVIC_SystemReset();
            break;

        case audio_hal_error_unsupported_format:
        case audio_hal_error_unsupported_parameter: //文件不支持
            if (switch_direction == 1) { //根据上次切换方向逐一尝试
                goto next_file;
            } else {
                goto prev_file;
            }
            break;

        case audio_hal_result_repeat: //重复播放当前文件
            break;

        case audio_hal_ok: //正常播放完成
next_file:
        case audio_hal_result_next:
            switch_direction = 1;
            current_file_index ++;
            if(current_file_index >= audio_file_count) {
                current_file_index = 0;
            }
            break;

prev_file:
        case audio_hal_result_prev:
            switch_direction = 0;
            if(current_file_index != 0) {
                current_file_index --;
            } else {
                current_file_index = audio_file_count - 1;
            }
            break;

        case audio_hal_result_random:
            uint32_t new_file_index = RNG_GetRandomNumber() % audio_file_count;
            if (new_file_index > current_file_index) {
                switch_direction = 1;
            } else {
                switch_direction = 0;
            }
            current_file_index = new_file_index;
            break;

        default:
            LOG_W("unhandled play result: %d", play_result);
            break;
        }
    }

error:
    if (audio_file_list != NULL) {
        tlsf_free(audio_file_list);
    }
}