getline.c revision 42542f5f 
1#include <stdio.h>
2#include <stdlib.h>
3#include <errno.h>
4
5extern int getline(char **line, size_t *len, FILE *file);
6
7int getline(char **line, size_t *len, FILE *file)
8{
9	char *ptr, *end;
10	int c;
11
12	if (*line == NULL) {
13		errno = EINVAL;
14		if (*len == 0)
15			*line = malloc(4096);
16		if (*line == NULL)
17			return -1;
18
19		*len = 4096;
20	}
21
22	ptr = *line;
23	end = *line + *len;
24
25	while ((c = fgetc(file)) != EOF) {
26		if (ptr + 1 >= end) {
27			char *newline;
28			int offset;
29
30			newline = realloc(*line, *len + 4096);
31			if (newline == NULL)
32				return -1;
33
34			offset = ptr - *line;
35
36			*line = newline;
37			*len += 4096;
38
39			ptr = *line + offset;
40			end = *line + *len;
41		}
42
43		*ptr++ = c;
44		if (c == '\n') {
45			*ptr = '\0';
46			return ptr - *line;
47		}
48	}
49	*ptr = '\0';
50	return -1;
51}
52