1#include "getline.h"
 2
 3#include <stdlib.h>
 4#include <errno.h>
 5
 6ssize_t getline(char** lineptr, size_t* n, FILE* stream) {
 7    ssize_t pos = -1;
 8    int c;
 9
10    if (lineptr == nullptr || stream == nullptr || n == nullptr) {
11        errno = EINVAL;
12        return -1;
13    }
14
15    _lock_file(stream);
16
17    c = _getc_nolock(stream);
18    if (c == EOF) {
19        goto exit;
20    }
21
22    if (*lineptr == nullptr) {
23        *lineptr = malloc(128);
24        if (*lineptr == nullptr) {
25            goto exit;
26        }
27        *n = 128;
28    }
29
30    pos = 0;
31    while (c != EOF) {
32        if ((size_t) (pos + 1) >= *n) {
33            size_t new_size = *n + (*n >> 2);
34            if (new_size < 128) {
35                new_size = 128;
36            }
37            char* new_ptr = realloc(*lineptr, new_size);
38            if (new_ptr == nullptr) {
39                pos = -1;
40                goto exit;
41            }
42            *n = new_size;
43            *lineptr = new_ptr;
44        }
45
46        ((char*) (*lineptr))[pos++] = (char) c;
47        if (c == '\n') {
48            break;
49        }
50        c = _getc_nolock(stream);
51    }
52
53    (*lineptr)[pos] = '\0';
54
55exit:
56    _unlock_file(stream);
57    return pos;
58}