/* getline.c -- Replacement for GNU C library function getline * * Copyright (C) 1993, 1996, 2001, 2002 Free Software Foundation, Inc. * * SPDX-License-Identifier: GPL-2.0+ */ /* Written by Jan Brittenson, bson@gnu.ai.mit.edu. */ #include <assert.h> #include <stdio.h> /* Always add at least this many bytes when extending the buffer. */ #define MIN_CHUNK 64 /* Read up to (and including) a TERMINATOR from STREAM into *LINEPTR + OFFSET (and null-terminate it). *LINEPTR is a pointer returned from malloc (or NULL), pointing to *N characters of space. It is realloc'd as necessary. Return the number of characters read (not including the null terminator), or -1 on error or EOF. NOTE: There is another getstr() function declared in <curses.h>. */ static int getstr(char **lineptr, size_t *n, FILE *stream, char terminator, size_t offset) { int nchars_avail; /* Allocated but unused chars in *LINEPTR. */ char *read_pos; /* Where we're reading into *LINEPTR. */ int ret; if (!lineptr || !n || !stream) return -1; if (!*lineptr) { *n = MIN_CHUNK; *lineptr = malloc(*n); if (!*lineptr) return -1; } nchars_avail = *n - offset; read_pos = *lineptr + offset; for (;;) { register int c = getc(stream); /* We always want at least one char left in the buffer, since we always (unless we get an error while reading the first char) NUL-terminate the line buffer. */ assert(*n - nchars_avail == read_pos - *lineptr); if (nchars_avail < 2) { if (*n > MIN_CHUNK) *n *= 2; else *n += MIN_CHUNK; nchars_avail = *n + *lineptr - read_pos; *lineptr = realloc(*lineptr, *n); if (!*lineptr) return -1; read_pos = *n - nchars_avail + *lineptr; assert(*n - nchars_avail == read_pos - *lineptr); } if (c == EOF || ferror (stream)) { /* Return partial line, if any. */ if (read_pos == *lineptr) return -1; else break; } *read_pos++ = c; nchars_avail--; if (c == terminator) /* Return the line. */ break; } /* Done - NUL terminate and return the number of chars read. */ *read_pos = '\0'; ret = read_pos - (*lineptr + offset); return ret; } int getline (char **lineptr, size_t *n, FILE *stream) { return getstr(lineptr, n, stream, '\n', 0); }