使用 fopen_s读取一个wav文件并对其求WVD并输出WVD结果不使用库函数C语言并解释代码

以下是使用 C 语言实现读取 WAV 文件并计算其 WVD 的代码：

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

#define PI 3.14159265358979323846

typedef struct {
    char        ChunkID[4];
    uint32_t    ChunkSize;
    char        Format[4];
    char        Subchunk1ID[4];
    uint32_t    Subchunk1Size;
    uint16_t    AudioFormat;
    uint16_t    NumChannels;
    uint32_t    SampleRate;
    uint32_t    ByteRate;
    uint16_t    BlockAlign;
    uint16_t    BitsPerSample;
    char        Subchunk2ID[4];
    uint32_t    Subchunk2Size;
} wav_header_t;

int read_wav_header(FILE *fp, wav_header_t *header) {
    if (fread(header, sizeof(wav_header_t), 1, fp) != 1) {
        return -1;
    }
    return 0;
}

int32_t read_sample(FILE *fp, uint16_t bits_per_sample) {
    int32_t sample = 0;
    if (bits_per_sample == 8) {
        uint8_t value;
        if (fread(&value, sizeof(uint8_t), 1, fp) != 1) {
            return 0;
        }
        sample = ((int32_t)value - 128) * (1 << 23);
    } else if (bits_per_sample == 16) {
        int16_t value;
        if (fread(&value, sizeof(int16_t), 1, fp) != 1) {
            return 0;
        }
        sample = (int32_t)value * (1 << 15);
    } else if (bits_per_sample == 24) {
        uint8_t buf[3];
        if (fread(buf, sizeof(uint8_t), 3, fp) != 3) {
            return 0;
        }
        sample = (((int32_t)buf[2] << 16) | ((int32_t)buf[1] << 8) | buf[0]) * (1 << 7);
    } else if (bits_per_sample == 32) {
        int32_t value;
        if (fread(&value, sizeof(int32_t), 1, fp) != 1) {
            return 0;
        }
        sample = value;
    }
    return sample;
}

void calc_wvd(int32_t *samples, int32_t num_samples, int32_t *wvd, int32_t num_wvd) {
    const double alpha = 1.0 / (sqrt(2.0) * num_samples);
    for (int32_t n = 0; n < num_wvd; n++) {
        for (int32_t k = 0; k < num_samples; k++) {
            double t = (double)n * k / num_wvd;
            double w = alpha * exp(-2.0 * PI * pow((double)k / num_samples, 2.0));
            double x = (double)samples[k] / (1 << 31);
            wvd[n] += x * x * w * cos(2.0 * PI * t * k / num_samples);
        }
    }
}

int main(int argc, char *argv[]) {
    if (argc != 3) {
        fprintf(stderr, "Usage: %s input.wav output.wvd\n", argv[0]);
        return EXIT_FAILURE;
    }

    FILE *input_file = NULL, *output_file = NULL;

    if (fopen_s(&input_file, argv[1], "rb") != 0) {
        fprintf(stderr, "Failed to open input file: %s\n", argv[1]);
        return EXIT_FAILURE;
    }

    if (fopen_s(&output_file, argv[2], "wb") != 0) {
        fprintf(stderr, "Failed to open output file: %s\n", argv[2]);
        fclose(input_file);
        return EXIT_FAILURE;
    }

    wav_header_t header;
    if (read_wav_header(input_file, &header) != 0) {
        fprintf(stderr, "Failed to read WAV header\n");
        fclose(input_file);
        fclose(output_file);
        return EXIT_FAILURE;
    }

    if (header.NumChannels != 1) {
        fprintf(stderr, "Only mono WAV files are supported\n");
        fclose(input_file);
        fclose(output_file);
        return EXIT_FAILURE;
    }

    if (header.AudioFormat != 1) {
        fprintf(stderr, "Only PCM WAV files are supported\n");
        fclose(input_file);
        fclose(output_file);
        return EXIT_FAILURE;
    }

    int32_t num_samples = header.Subchunk2Size / (header.BitsPerSample / 8);
    int32_t *samples = (int32_t *)malloc(num_samples * sizeof(int32_t));
    if (samples == NULL) {
        fprintf(stderr, "Failed to allocate memory\n");
        fclose(input_file);
        fclose(output_file);
        return EXIT_FAILURE;
    }

    for (int32_t i = 0; i < num_samples; i++) {
        samples[i] = read_sample(input_file, header.BitsPerSample);
    }

    int32_t num_wvd = num_samples;
    int32_t *wvd = (int32_t *)calloc(num_wvd, sizeof(int32_t));
    if (wvd == NULL) {
        fprintf(stderr, "Failed to allocate memory\n");
        free(samples);
        fclose(input_file);
        fclose(output_file);
        return EXIT_FAILURE;
    }

    calc_wvd(samples, num_samples, wvd, num_wvd);

    fwrite(wvd, sizeof(int32_t), num_wvd, output_file);

    free(wvd);
    free(samples);
    fclose(input_file);
    fclose(output_file);
    return EXIT_SUCCESS;
}

代码的执行流程如下：

1. 打开输入文件和输出文件；
2. 读取 WAV 文件头信息；
3. 分配内存并读取 WAV 文件中的 PCM 数据；
4. 计算 WVD；
5. 将 WVD 结果写入输出文件；
6. 释放内存并关闭文件。

其中，`wav_header_t` 结构体定义了 WAV 文件的头信息。函数 `read_wav_header` 用于读取 WAV 文件头，函数 `read_sample` 用于读取一个样本。函数 `calc_wvd` 用于计算 WVD。在主函数中，首先根据命令行参数打开输入文件和输出文件，然后读取 WAV 文件头信息，接着读取 PCM 数据并计算 WVD，最后将 WVD 结果写入输出文件。注意，这里只支持单声道、PCM 编码的 WAV 文件。