小编Tom*_*asz的帖子

我在使用 Ruby on Rails Webpacker 在视图中包含图像时遇到问题。当我尝试使用 html img 标签和 asset_pack_path 在我的视图中插入图像时，出现错误。我的图像位于app/javascript/images/logo.png. 根据 webpacker 文档，我应该将 /media/ 附加到文件中，但这无济于事。我尝试了不同的路径，但仍然无法正常工作。我认为 webpacker 不会编译我的图像。

Webpacker::Manifest::MissingEntryError in Home#index
Showing app/views/layouts/application.html.haml where line #14 raised:

Webpacker can't find media/logo.png in public/packs/manifest.json. Possible causes:
1. You want to set webpacker.yml value of compile to true for your environment
   unless you are using the `webpack -w` or the webpack-dev-server.
2. webpack has not yet re-run to reflect updates.
3. You have misconfigured Webpacker's config/webpacker.yml file.
4. Your webpack …

我对 Rails API 应用程序主动存储有疑问。我有 React 从我想上传文件的地方。

import React from "react";
import {DirectUpload} from "activestorage";

class SignIn extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      file: null
    };
    this.handleFileChange = this.handleFileChange.bind(this);
    this.handleFileSubmit = this.handleFileSubmit.bind(this);
  }

  handleFileChange(e){
    this.setState({file: e.target.files[0]})
  }

  handleFileSubmit(){
    const upload = new DirectUpload(this.state.file, "/rails/active_storage/direct_uploads");

    upload.create((error, blob) => {
      if(error){
        console.log(error)
      } else {
        console.log(blob)
      }
    })
  }

  render() {

    return (
      <React.Fragment>
          <Form>
          <Form.Item>
            <Input type="file" onChange={this.handleFileChange}/>
          </Form.Item>

          <Form.Item>
            <Button type="primary" htmlType="submit">
              Register
            </Button>
          </Form.Item>
        </Form>
      </React.Fragment>
    ); …

我正在寻找解决方案如何生成16位,65536元素查找表来计算设置位.我知道生成8位表我可以使用:

static const unsigned char BitsSetTable256[256] = 
{
#   define B2(n) n,     n+1,     n+1,     n+2
#   define B4(n) B2(n), B2(n+1), B2(n+1), B2(n+2)
#   define B6(n) B4(n), B4(n+1), B4(n+1), B4(n+2)
    B6(0), B6(1), B6(1), B6(2)
};

但我不知道如何在16位中做到这一点