busybox/libbb/get_line_from_file.c

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/* vi: set sw=4 ts=4: */
/*
* Utility routines.
*
* Copyright (C) 2005, 2006 Rob Landley <rob@landley.net>
* Copyright (C) 2004 Erik Andersen <andersen@codepoet.org>
* Copyright (C) 2001 Matt Krai
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
#include "libbb.h"
/* This function reads an entire line from a text file, up to a newline
* or NUL byte, inclusive. It returns a malloc'ed char * which
* must be free'ed by the caller. If end is NULL '\n' isn't considered
* end of line. If end isn't NULL, length of the chunk read is stored in it.
* Return NULL if EOF/error */
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char *bb_get_chunk_from_file(FILE *file, int *end)
{
int ch;
int idx = 0;
char *linebuf = NULL;
int linebufsz = 0;
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while ((ch = getc(file)) != EOF) {
/* grow the line buffer as necessary */
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if (idx >= linebufsz) {
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linebufsz += 80;
linebuf = xrealloc(linebuf, linebufsz);
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}
linebuf[idx++] = (char) ch;
if (!ch || (end && ch == '\n'))
break;
}
if (end)
*end = idx;
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if (linebuf) {
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// huh, does fgets discard prior data on error like this?
// I don't think so....
//if (ferror(file)) {
// free(linebuf);
// return NULL;
//}
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linebuf = xrealloc(linebuf, idx+1);
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linebuf[idx] = '\0';
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}
return linebuf;
}
/* Get line, including trailing \n if any */
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char *xmalloc_fgets(FILE *file)
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{
int i;
return bb_get_chunk_from_file(file, &i);
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}
/* Get line. Remove trailing \n */
char *xmalloc_fgetline(FILE *file)
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{
int i;
char *c = bb_get_chunk_from_file(file, &i);
if (i && c[--i] == '\n')
c[i] = '\0';
return c;
}