Wayde-Ouadie / get_next_line-42

GET_NEXT_LINE

Get_next_line is a function that reads an entire line from a file indexed by a file descriptor fd. It then alocates a string with the contents of that line without the linebreak '\n' and points line to it.

We don't have to pass anything allocated to get_next_line, we just pass the address of a pointer that will point to the allocated string. line should be freeable with free() after the function call unless an error occured.

We will incrementally read the file with read(), which advances its position in the file dexample escriptor automatically.

We need to use a static pointer as a read buffer to access what was read in previous calls.

We need to handle the following situations:

1. If the read buffer doesn't have a '\n', we concatenate with the previous buffer and call read again.
2. If the read buffer has a '\n', we concatenate with the previous buffer up to '\n'.
3. If we reach the end of the file (read() == 0), we concatenate with the previous buffer.
4. We finally point line to an allocated string that contains the entire line without the '\n'. Then we release the memory allocated in the intermediate strings and return 1 or 0 for '\n' and end_of_file respectively.
5. If the parameters have any problems (BUFFER_SIZE <= 0), or if in any operation we were unable to allocate memory, we free whatever memory was allocated and return -1.

Usage

The function is written in C language and thus needs the gcc compiler and some standard C libraries to run.

To use the function in your code, simply include its header:

#include "get_next_line.h"

and, when compiling your code, add the source files and the required flag:

get_next_line.c get_next_line_utils.c -D BUFFER_SIZE=<size>