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