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att
GitHub Repository: att/ast
 Path: blob/master/src/lib/libcs/csread.c
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/***********************************************************************

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*                                                                      *

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*               This software is part of the ast package               *

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*          Copyright (c) 1990-2011 AT&T Intellectual Property          *

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*                      and is licensed under the                       *

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*                 Eclipse Public License, Version 1.0                  *

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*                    by AT&T Intellectual Property                     *

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*                                                                      *

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*                A copy of the License is available at                 *

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*          http://www.eclipse.org/org/documents/epl-v10.html           *

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*         (with md5 checksum b35adb5213ca9657e911e9befb180842)         *

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*                                                                      *

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*              Information and Software Systems Research               *

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*                            AT&T Research                             *

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*                           Florham Park NJ                            *

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*                                                                      *

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*                 Glenn Fowler <[email protected]>                  *

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*                                                                      *

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***********************************************************************/

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#pragma prototyped

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/*

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 * Glenn Fowler

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 * AT&T Research

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 *

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 * read at most size chars according to op

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 *

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 *	CS_EXACT	read exactly size chars

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 *			multiple reads possible

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 *	CS_LIMIT	one read up to size chars

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 *	CS_LINE		'\n' '\r\n' '\n\r' terminated line up to size

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 *			multiple reads possible

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 *	CS_RESTART	restart on interrupt

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 *

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 * 0 returned on eof

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 */

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#include "cslib.h"

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ssize_t

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csread(Cs_t* state, int fd, void* buf, size_t size, int op)

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{

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	register ssize_t	n;

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	register char*		p;

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	register char*		e;

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	int			restart;

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	if (restart = !!(op & CS_RESTART))

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		op &= ~CS_RESTART;

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	p = (char*)buf;

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	e = p + size;

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	messagef((state->id, NiL, -9, "read(%d,%d,%s) before", fd, size, op == CS_EXACT ? "EXACT" : op == CS_LIMIT ? "LIMIT" : "LINE"));

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	if (op == CS_LINE && size > 1)

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	{

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		if ((n = cspeek(state, fd, buf, size - 1)) > 0 && (p[n] = 0, e = strchr(p, '\n')))

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		{

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			e++;

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			op = CS_EXACT;

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		}

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		else

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		{

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			while (p < e && (n = read(fd, p, 1)) == 1 && *p++ != '\n');

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			if (n <= 0 || p == (char*)buf || *(p - 1) != '\n')

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				goto bad;

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			n = p - (char*)buf;

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			messagef((state->id, NiL, -9, "read(%d,%d,%s) [%d] `%-.*s'", fd, size, op == CS_EXACT ? "EXACT" : op == CS_LIMIT ? "LIMIT" : "LINE", n, n, buf));

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			return n;

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		}

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	}

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	while (n = read(fd, p, e - p))

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	{

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		if (n < 0)

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		{

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			if (restart && errno == EINTR)

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				continue;

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			break;

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		}

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		messagef((state->id, NiL, -9, "read(%d,%d,%s) [%d] `%-.*s'", fd, size, op == CS_EXACT ? "EXACT" : op == CS_LIMIT ? "LIMIT" : "LINE", n, n, p));

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		p += n;

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		if (op == CS_LIMIT || op == CS_LINE && (*(p - 1) == '\n' || n > 1 && *(p - 1) == '\r' && *(p - 2) == '\n'))

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			return p - (char*)buf;

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		if (p >= e)

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		{

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			if (op == CS_EXACT)

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				return p - (char*)buf;

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			break;

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		}

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		messagef((state->id, NiL, -2, "read(%d,%d,%s) again [%d] `%-.*s'", fd, size, op == CS_EXACT ? "EXACT" : op == CS_LIMIT ? "LIMIT" : "LINE", p - (char*)buf, p - (char*)buf, (char*)buf));

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	}

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 bad:

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	if (p != (char*)buf || n < 0)

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	{

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		errno = EINVAL;

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		messagef((state->id, NiL, -2, "read(%d,%d,%s) invalid record [%d] `%-.*s'", fd, size, op == CS_EXACT ? "EXACT" : op == CS_LIMIT ? "LIMIT" : "LINE", p - (char*)buf, p - (char*)buf, (char*)buf));

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		return -1;

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	}

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	messagef((state->id, NiL, -2, "read(%d,%d,%s) eof", fd, size, op == CS_EXACT ? "EXACT" : op == CS_LIMIT ? "LIMIT" : "LINE"));

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	return 0;

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}

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ssize_t

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_cs_read(int fd, void* buf, size_t size, int op)

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{

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	return csread(&cs, fd, buf, size, op);

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}

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