DataView

DataView is similar to javascript DataView. It can read or write by from uint8 to double.

Contents

• DataView
  • Contents
  • How to use
  • Examples
  • Usages
    • DataView
    • Read
    • Write

How to use

To use data_view, add the followings to your WORKSPACE file.

load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")

http_archive(
    name = "data_view",
    sha256 = "<sha256>",
    strip_prefix = "data_view-<commit>",
    urls = [
        "https://github.com/chokobole/data_view/archive/<commit>.tar.gz",
    ],
)

Then, in your BUILD files, import and use the rules.

load("@data_view//bazel:data_view_cc.bzl", "data_view_copts")

cc_library(
    name = "...",
    copts = data_view_copts(),
    deps = [
      "@data_view",
    ]
)

Examples

Build example.

bazel run //examples:example

#include <iostream>

#include "data_view/data_view.h"

int main() {
  const char buf[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11};
  size_t buf_len = sizeof(buf);
  data_view::ConstDataView data_view(buf, buf_len);

  uint16_t v;
  data_view.Read(0, &v, true);
  std::cout << v << std::endl;  // 256
  data_view.Read(0, &v, false);
  std::cout << v << std::endl;  // 1

  return 0;
}

Usages

DataView

If you want to just read bytes, then use ConstDataView. If you want to modify bytes, then use DataView.

Read

Signature of Read is like below.

// Returns true if succeeded to read. (offset + sizeof(T) <= |length_|)
template <typename T>
bool Read(size_t offset, T* value, bool little_endian) const;

• offset: byte offset to read from.
• value
• little_endian: If set true, read as little endian, Otherwise read as big endian.

For example,

data_view::ConstDataView data_view;
uint16_t v;
data_view.Read(0, &v, true);

Write

Signature of Write is like below.

// Returns true if succeeded to write. (offset + sizeof(T) <= |length_|)
template <typename T>
bool Write(size_t offset, T value, bool little_endian);

• offset: byte offset to write to.
• value
• little_endian: If set true, write as little endian, Otherwise write as big endian.

For example,

char buf[16] = {0,};
size_t buf_len = sizeof(buf);
data_view::DataView data_view(buf, buf_len);
data_view.Write(0, 127, true);