Question

我有一些用于创建wave文件的代码，我想将其转换为易于使用，可移植性和简单性的库。我目前有约150行代码，因此我想将该代码移到一个库中，然后仅使用几行来准备它，等等。我将以库形式一次删除一些行，但是我有点卡住。我是一个非常关心库的业余爱好者，但是我对普通的c ++编码了解很多。到目前为止，我只是使一个功能（文件大小（））工作，但我一直在出错。

当我添加行时

#include "stdafx.h"

在我的代码中，出现错误：

1>------ Build started: Project: wavlib, Configuration: Debug Win32 ------
1>wavlib.cpp
1>c:\users\rowan\onedrive\documents\wavlib\wavlib\wavlib.cpp(5): error C2653: 'wavlib': is not a class or namespace name
1>c:\users\rowan\onedrive\documents\wavlib\wavlib\wavlib.cpp(5): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>c:\users\rowan\onedrive\documents\wavlib\wavlib\wavlib.cpp(5): error C2146: syntax error: missing ';' before identifier 'filesize'
1>c:\users\rowan\onedrive\documents\wavlib\wavlib\wavlib.cpp(6): error C2143: syntax error: missing ';' before '{'
1>c:\users\rowan\onedrive\documents\wavlib\wavlib\wavlib.cpp(6): error C2447: '{': missing function header (old-style formal list?)
1>Done building project "wavlib.vcxproj" -- FAILED.
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

如果我删除该#include语句，这些错误将消失，但我得到的错误是：

1>------ Build started: Project: wavlib, Configuration: Debug Win32 ------
1>wavlib.cpp
1>c:\users\rowan\onedrive\documents\wavlib\wavlib\wavlib.cpp(8): fatal error C1010: unexpected end of file while looking for precompiled header. Did you forget to add '#include "stdafx.h"' to your source?
1>Done building project "wavlib.vcxproj" -- FAILED.
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

当前代码（完整）：

#include "stdafx.h"
using namespace std;

#include <iostream>
#include <fstream>
fstream wav("C:\\Users\\rowan\\OneDrive\\Desktop\\test.wav", ios::out | ios::binary | ios::trunc);

#include <chrono>
using namespace std::chrono_literals; // ns, us, ms, s, h, etc.
using std::chrono::system_clock;

#include <thread>
using namespace std::this_thread;     // sleep_for, sleep_until

#include <random>

#define sampleRate 44100
#define bitDepth 16
#define channels 2

uint32_t kbps = (sampleRate * channels * bitDepth / 32) / 1024;
uint32_t bps = sampleRate * channels * bitDepth / 32;

uint32_t filesize();
void writeHeader(uint32_t rate, uint16_t depth, uint16_t chan);
void writeVal(uint32_t val);
bool state = 0;

int main()
{
    //enlarge to 44 bytes, so there is room for the header
    for (int i = 0; i < 44; i++) {
        wav << '.';
    }
    for (uint64_t a = 0; a < bps; a++) {
        writeVal(state * INT16_MAX);
        state = !state;
    }/**/
    writeHeader(sampleRate, bitDepth, channels);
    cout << "File size (kb): " << filesize() / 1024 << endl;
    cout << "KBPS: " << kbps << endl;
    cout << "Length: " << filesize() / bps / 4; 
    wav.close();
    sleep_for(5s);
    return 0;
}

uint32_t filesize()
{
    streampos pos = wav.tellp();
    wav.seekp(0);
    streampos begin = wav.tellp();
    wav.seekp(0, ios::end);
    streampos size = wav.tellp() - begin;
    wav.seekp(pos);
    return uint32_t(size);
}

void writeHeader(uint32_t rate, uint16_t depth, uint16_t chan) {
    uint16_t u16;
    uint32_t u32;
    char c2[2];
    char c4[4];
    //seek to start
    wav.seekp(0);

    // '----' is for file size, computed at end
    wav << "RIFF----WAVEfmt ";

    //size of format data
    c4[0] = 16;
    c4[1] = 0;
    c4[2] = 0;
    c4[3] = 0;
    wav.write(c4, 4);

    //type of format (1 = pcm)
    c2[0] = 1;
    c2[1] = 0;
    wav.write(c2, 2);

    //channels
    c2[0] = char(chan);
    c2[1] = char(chan >> 8);
    wav.write(c2, 2);

    //sample rate
    c4[0] = char(rate);
    c4[1] = char(rate >> 8);
    c4[2] = char(rate >> 16);
    c4[3] = char(rate >> 24);
    wav.write(c4, 4);


    //memory used per second
    u32 = (rate * depth * chan) / 8;
    c4[0] = char(u32);
    c4[1] = char(u32 >> 8);
    c4[2] = char(u32 >> 16);
    c4[3] = char(u32 >> 24);
    wav.write(c4, 4);

    //bytes per frame
    u16 = (depth * chan) / 8;
    c2[0] = char(u16);
    c2[1] = char(u16 >> 8);
    wav.write(c2, 2);

    //bit depth
    c2[0] = char(depth);
    c2[1] = char(depth >> 8);
    wav.write(c2, 2);

    //data chunk header
    c4[0] = 'd';
    c4[1] = 'a';
    c4[2] = 't';
    c4[3] = 'a';
    wav.write(c4, 4);

    //size of data section, file size - header size(44 bytes)
    uint32_t datasize = filesize() - 44;
    c4[0] = char(datasize);
    c4[1] = char(datasize >> 8);
    c4[2] = char(datasize >> 16);
    c4[3] = char(datasize >> 24);
    wav.write(c4, 4);

    //write file size
    wav.seekp(4);
    u32 = filesize();
    c4[0] = char(u32);
    c4[1] = char(u32 >> 8);
    c4[2] = char(u32 >> 16);
    c4[3] = char(u32 >> 24);
    wav.write(c4, 4);
}

void writeVal(uint32_t val) {
    char c4[4];
    c4[0] = char(val);
    c4[1] = char(val >> 8);
    c4[2] = char(val >> 16);
    c4[3] = char(val >> 24);
    wav.write(c4, 4);
}

void writeVal(uint16_t l, uint16_t r) {
    char c4[4];
    c4[0] = char(l);
    c4[1] = char(l >> 8);
    c4[2] = char(r >> 16);
    c4[3] = char(r >> 24);
    wav.write(c4, 4);
}

为了使其更有用，我将添加一个参数（fstream wav）

filesize（）：

uint32_t filesize()
{
    streampos pos = wav.tellp();
    wav.seekp(0);
    streampos begin = wav.tellp();
    wav.seekp(0, ios::end);
    streampos size = wav.tellp() - begin;
    wav.seekp(pos);
    return uint32_t(size);
}

库代码：

wavlib.h：

#pragma once

#include <iostream>
#include <fstream>

//include random for random noise to test files
#include <random>
using namespace std;

class wavlib 
{
    public:
        uint32_t filesize(string filename); //return the size of the file
};

wavlib.cpp：

#include "wavlib.h"
#include "stdafx.h"
using namespace std;

uint32_t wavlib::filesize(string filename)
{
    fstream file(filename);
    streampos pos = file.tellp();
    file.seekp(0);
    streampos begin = file.tellp();
    file.seekp(0, ios::end);
    streampos size = file.tellp() - begin;
    file.seekp(pos);
    return uint32_t(size);
}/**/

将代码转换为库，仍然能够编辑库（C ++）

0 个答案: