[J-u-boot.git] / tools / getline.c

/* 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, [email protected].  */

#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);
}
Commit	Line	Data
64b15021	1	/* getline.c -- Replacement for GNU C library function getline
1a459660 WD	2	*
	3	* Copyright (C) 1993, 1996, 2001, 2002 Free Software Foundation, Inc.
	4	*
	5	* SPDX-License-Identifier: GPL-2.0+
	6	*/
64b15021 MF	7
	8	/* Written by Jan Brittenson, [email protected]. */
	9
	10	#include <assert.h>
	11	#include <stdio.h>
	12
	13	/* Always add at least this many bytes when extending the buffer. */
	14	#define MIN_CHUNK 64
	15
	16	/* Read up to (and including) a TERMINATOR from STREAM into *LINEPTR
	17	+ OFFSET (and null-terminate it). *LINEPTR is a pointer returned from
	18	malloc (or NULL), pointing to *N characters of space. It is realloc'd
	19	as necessary. Return the number of characters read (not including the
	20	null terminator), or -1 on error or EOF.
	21	NOTE: There is another getstr() function declared in <curses.h>. */
	22	static int getstr(char *lineptr, size_t n, FILE *stream,
	23	char terminator, size_t offset)
	24	{
	25	int nchars_avail; /* Allocated but unused chars in LINEPTR. /
	26	char read_pos; / Where we're reading into LINEPTR. /
	27	int ret;
	28
	29	if (!lineptr \|\| !n \|\| !stream)
	30	return -1;
	31
	32	if (!*lineptr) {
	33	*n = MIN_CHUNK;
	34	lineptr = malloc(n);
	35	if (!*lineptr)
	36	return -1;
	37	}
	38
	39	nchars_avail = *n - offset;
	40	read_pos = *lineptr + offset;
	41
	42	for (;;) {
	43	register int c = getc(stream);
	44
	45	/* We always want at least one char left in the buffer, since we
	46	always (unless we get an error while reading the first char)
	47	NUL-terminate the line buffer. */
	48
	49	assert(n - nchars_avail == read_pos - lineptr);
	50	if (nchars_avail < 2) {
	51	if (*n > MIN_CHUNK)
	52	n = 2;
	53	else
	54	*n += MIN_CHUNK;
	55
	56	nchars_avail = n + lineptr - read_pos;
	57	lineptr = realloc(lineptr, *n);
	58	if (!*lineptr)
	59	return -1;
	60	read_pos = n - nchars_avail + lineptr;
	61	assert(n - nchars_avail == read_pos - lineptr);
	62	}
	63
	64	if (c == EOF \|\| ferror (stream)) {
	65	/* Return partial line, if any. */
	66	if (read_pos == *lineptr)
	67	return -1;
	68	else
	69	break;
	70	}
71
72	*read_pos++ = c;
73	nchars_avail--;
74
75	if (c == terminator)
76	/* Return the line. */
77	break;
78	}
79
80	/* Done - NUL terminate and return the number of chars read. */
81	*read_pos = '\0';
82
83	ret = read_pos - (*lineptr + offset);
84	return ret;
85	}
86
87	int getline (char *lineptr, size_t n, FILE *stream)
88	{
89	return getstr(lineptr, n, stream, '\n', 0);
90	}