struct's Introduction

Introduction

struct is a binary data formatting library inspired by 'The Practice of Programming (Brian W. Kernighan, Rob Pike)' and Python struct module.

Format

struct uses following format characters (note that struct does not fully support the Python struct module's format):

Table 1. Byte order

Character	Byte order
`=`	native
`<`	little-endian
`>`	big-endian
`!`	network (= big-endian)

Table 2. Format characters

Format	C/C++ Type	Standard size
`b`	char	1
`B`	unsigned char	1
`h`	short	2
`H`	unsigned short	2
`i`	int	4
`I`	unsigned int	4
`l`	long	4
`L`	unsigned long	4
`q`	long long	8
`Q`	unsigned long long	8
`f`	float	4
`d`	double	8
`s`	char[]
`p`	char[]
`x`	pad bytes
`v`	go/pbuf svarint
`V`	go/pbuf varint

Pack

#include "struct.h"
...
char buf1[BUFSIZ] = {'\0',};
char buf2[BUFSIZ] = {'\0',};
char str[BUFSIZ] = {'\0',};
char fmt[BUFSIZ] = {'\0',};
int val = 42;

struct_pack(buf1, "i", val);

strcpy(str, "test");
snprintf(fmt, sizeof(fmt), "%ds", strlen(str));

struct_pack(buf2, fmt, str);

Unpack

...
int rval;
char rstr[32] = {'\0',};

struct_unpack(buf1, "i", &rval);

struct_unpack(buf2, fmt, rstr);

Install

CMake

Compile

mkdir build
cd build
cmake ..
make
make install

headers: build/release/include/struct/. library: build/release/lib/.

Test

cmake -DSTRUCT_BUILD_TEST=ON ..
make
make test

or run struct_test.

valgrind memory check:

ctest -T memcheck

Bazel

Compile

bazel build //:struct

Test

bazel test //test:struct_test

bazel test --test_output=all //test:struct_test

you can use git_repository to fetch struct library.

WORKSPACE:

load("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")

git_repository(
    name = "struct",
    branch = "master",
    remote = "https://github.com/svperbeast/struct",
)

BUILD:

cc_binary(
    name = ...,
    srcs = [...],
    deps = [
        "@struct//:struct",
    ],
)

References

The Practice of Programming (9.1 Formatting Data)

Python struct

License

Code released under the MIT license.

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struct's Issues

Does this library work on Arduino IDE?

How can I convert this library so that I can use it with Arduino IDE. I am sending struct.pack() data from RPi4 to ESP32 through UART. In order to decode the received message, I want this library to work on my Arduino IDE for ESP32. How can I do that?

is it possible to unpack strings in place ?

Is it possible to pack/unpack strings in place (I mean source buffer = destination buffer) ? Like this for example:

 char str[32] = {'\0', };
 char fmt[32] = {'\0', };
 
 strcpy(str, "test");
 sprintf(fmt, "%ds", strlen(str));

 struct_pack(str, fmt, str);
 struct_unpack(str, fmt, str);

In my case I am receiving a character string from a TCP socket in a buffer. Then I have to unpack it, and assign it to a std::string object. So I was wondering if I had to recreate a new buffer or if I could just reuse the one that I had.

Recommend Projects

svperbeast / struct Goto Github PK

struct's Introduction

Introduction

Format

Pack

Unpack

Install

CMake

Compile

Test

Bazel

Compile

Test

References

License

struct's People

Contributors

Stargazers

Watchers

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struct's Issues

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