Enrico Fraccaroli (Galfurian)
58 lines
1.4 KiB
C
58 lines
1.4 KiB
C
/// @file readline.c
|
|
/// @author Enrico Fraccaroli (enry.frak@gmail.com)
|
|
/// @brief
|
|
/// @version 0.1
|
|
/// @date 2023-08-30
|
|
///
|
|
/// @copyright Copyright (c) 2023
|
|
///
|
|
|
|
#include "readline.h"
|
|
|
|
#include "stdio.h"
|
|
#include "string.h"
|
|
#include "sys/unistd.h"
|
|
|
|
int readline(int fd, char *buffer, size_t buflen, ssize_t *read_len)
|
|
{
|
|
ssize_t length, rollback, num_read;
|
|
memset(buffer, 0, buflen);
|
|
unsigned char found_newline = 1;
|
|
// Read from the file.
|
|
num_read = read(fd, buffer, buflen);
|
|
if (num_read == 0) {
|
|
return 0;
|
|
}
|
|
// Search for termination character.
|
|
char *newline = strchr(buffer, '\n');
|
|
if (newline == NULL) {
|
|
found_newline = 0;
|
|
newline = strchr(buffer, EOF);
|
|
if (newline == NULL) {
|
|
newline = strchr(buffer, 0);
|
|
if (newline == NULL) {
|
|
return 0;
|
|
}
|
|
}
|
|
}
|
|
// Compute the length of the string.
|
|
length = (newline - buffer);
|
|
if (length <= 0) {
|
|
return 0;
|
|
}
|
|
// Close the string.
|
|
buffer[length] = 0;
|
|
// Compute how much we need to rollback.
|
|
rollback = length - num_read + 1;
|
|
if (rollback > 1) {
|
|
return 0;
|
|
}
|
|
// Rollback the reading position in the file.
|
|
lseek(fd, rollback, SEEK_CUR);
|
|
// Set how much we were able to read from the file.
|
|
if (read_len) {
|
|
*read_len = length;
|
|
}
|
|
return (found_newline) ? 1 : -1;
|
|
}
|