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ImHex/lib/third_party/microtar/README.md
iTrooz f0465c63ed
build: move third party libraries to lib/third_party (#1417)
Co-authored-by: Nik <werwolv98@gmail.com>
2023-11-12 02:02:54 +01:00

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# microtar
A lightweight tar library written in ANSI C
## Basic Usage
The library consists of `microtar.c` and `microtar.h`. These two files can be
dropped into an existing project and compiled along with it.
#### Reading
```c
mtar_t tar;
mtar_header_t h;
char *p;
/* Open archive for reading */
mtar_open(&tar, "test.tar", "r");
/* Print all file names and sizes */
while ( (mtar_read_header(&tar, &h)) != MTAR_ENULLRECORD ) {
printf("%s (%d bytes)\n", h.name, h.size);
mtar_next(&tar);
}
/* Load and print contents of file "test.txt" */
mtar_find(&tar, "test.txt", &h);
p = calloc(1, h.size + 1);
mtar_read_data(&tar, p, h.size);
printf("%s", p);
free(p);
/* Close archive */
mtar_close(&tar);
```
#### Writing
```c
mtar_t tar;
const char *str1 = "Hello world";
const char *str2 = "Goodbye world";
/* Open archive for writing */
mtar_open(&tar, "test.tar", "w");
/* Write strings to files `test1.txt` and `test2.txt` */
mtar_write_file_header(&tar, "test1.txt", strlen(str1));
mtar_write_data(&tar, str1, strlen(str1));
mtar_write_file_header(&tar, "test2.txt", strlen(str2));
mtar_write_data(&tar, str2, strlen(str2));
/* Finalize -- this needs to be the last thing done before closing */
mtar_finalize(&tar);
/* Close archive */
mtar_close(&tar);
```
## Error handling
All functions which return an `int` will return `MTAR_ESUCCESS` if the operation
is successful. If an error occurs an error value less-than-zero will be
returned; this value can be passed to the function `mtar_strerror()` to get its
corresponding error string.
## Wrapping a stream
If you want to read or write from something other than a file, the `mtar_t`
struct can be manually initialized with your own callback functions and a
`stream` pointer.
All callback functions are passed a pointer to the `mtar_t` struct as their
first argument. They should return `MTAR_ESUCCESS` if the operation succeeds
without an error, or an integer below zero if an error occurs.
After the `stream` field has been set, all required callbacks have been set and
all unused fields have been zeroset the `mtar_t` struct can be safely used with
the microtar functions. `mtar_open` *should not* be called if the `mtar_t`
struct was initialized manually.
#### Reading
The following callbacks should be set for reading an archive from a stream:
Name | Arguments | Description
--------|------------------------------------------|---------------------------
`read` | `mtar_t *tar, void *data, unsigned size` | Read data from the stream
`seek` | `mtar_t *tar, unsigned pos` | Set the position indicator
`close` | `mtar_t *tar` | Close the stream
#### Writing
The following callbacks should be set for writing an archive to a stream:
Name | Arguments | Description
--------|------------------------------------------------|---------------------
`write` | `mtar_t *tar, const void *data, unsigned size` | Write data to the stream
## License
This library is free software; you can redistribute it and/or modify it under
the terms of the MIT license. See [LICENSE](LICENSE) for details.