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1.1     ! misho       1: .\" Copyright (c) 2001-2002 Packet Design, LLC.
        !             2: .\" All rights reserved.
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        !             4: .\" Subject to the following obligations and disclaimer of warranty,
        !             5: .\" use and redistribution of this software, in source or object code
        !             6: .\" forms, with or without modifications are expressly permitted by
        !             7: .\" Packet Design; provided, however, that:
        !             8: .\" 
        !             9: .\"    (i)  Any and all reproductions of the source or object code
        !            10: .\"         must include the copyright notice above and the following
        !            11: .\"         disclaimer of warranties; and
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        !            17: .\" THIS SOFTWARE IS BEING PROVIDED BY PACKET DESIGN "AS IS", AND
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        !            35: .\"
        !            36: .\" Author: Archie Cobbs <archie@freebsd.org>
        !            37: .\"
        !            38: .\" $Id: string_fp.3,v 1.8 2004/06/02 17:24:37 archie Exp $
        !            39: .\"
        !            40: .Dd April 22, 2002
        !            41: .Dt STRING_FP 3
        !            42: .Os
        !            43: .Sh NAME
        !            44: .Nm string_buf_input ,
        !            45: .Nm string_buf_output ,
        !            46: .Nm string_buf_content ,
        !            47: .Nm string_buf_length
        !            48: .Nd string buffer streams
        !            49: .Sh LIBRARY
        !            50: PDEL Library (libpdel, \-lpdel)
        !            51: .Sh SYNOPSIS
        !            52: .In sys/types.h
        !            53: .In stdio.h
        !            54: .In pdel/io/string_fp.h
        !            55: .Ft "FILE *"
        !            56: .Fn string_buf_input "const void *buf" " size_t len" "int copy"
        !            57: .Ft "FILE *"
        !            58: .Fn string_buf_output "const void *mtype"
        !            59: .Ft "char *"
        !            60: .Fn string_buf_content "FILE *fp" "int reset"
        !            61: .Ft "int"
        !            62: .Fn string_buf_length "FILE *fp"
        !            63: .Sh DESCRIPTION
        !            64: These functions allow string buffers to be read and written as streams.
        !            65: .Pp
        !            66: .Fn string_buf_input
        !            67: creates a read-only stream that reads from the buffer pointed to by
        !            68: .Fa buf
        !            69: having length
        !            70: .Fa len .
        !            71: If
        !            72: .Fa copy
        !            73: is non-zero, the contents of the buffer are copied and therefore
        !            74: .Fa buf
        !            75: doesn't need to remain valid while the stream is open.
        !            76: Otherwise, the data pointed to by
        !            77: .Fa buf
        !            78: is not copied and must remain valid while the stream is open.
        !            79: .Xr fclose 3
        !            80: should be used to close the stream.
        !            81: .Pp
        !            82: .Fn string_buf_output
        !            83: creates a write-only stream that writes into an internal buffer that
        !            84: grows dynamically.
        !            85: .Xr fclose 3
        !            86: should be used to close the stream; this also frees the internal buffer.
        !            87: The current buffer length is returned by
        !            88: .Fn string_buf_length .
        !            89: .Pp
        !            90: .Fn string_buf_content
        !            91: returns the contents of the internal buffer.
        !            92: As with
        !            93: .Fn string_buf_length ,
        !            94: the
        !            95: .Fa fp
        !            96: argument must be a stream created by
        !            97: .Fn string_buf_output .
        !            98: If
        !            99: .Fa reset
        !           100: is zero, then the internal buffer remains valid and the returned pointer
        !           101: should be treated as read-only and not be freed; it also becomes invalid
        !           102: with the next operation on the stream.
        !           103: If
        !           104: .Fa reset
        !           105: is non-zero, the current buffer contents are "detached" and returned by
        !           106: .Fn string_buf_content ,
        !           107: and a new, empty internal buffer is created; in this case, the caller is
        !           108: responsible for eventually freeing the returned buffer,
        !           109: which is allocated with
        !           110: .Xr typed_mem 3
        !           111: type
        !           112: .Fa mtype ,
        !           113: and its contents remain valid until then.
        !           114: .Pp
        !           115: In either case, the data returned by
        !           116: .Fn string_buf_content
        !           117: is guaranteed to have one additional '\\0' byte appended.
        !           118: Therefore, it is always safe to treat this pointer as a normal C string.
        !           119: However, any '\\0' bytes previously written to the stream will cause
        !           120: this string to appear truncated.
        !           121: .Sh RETURN VALUES
        !           122: .Fn string_buf_input ,
        !           123: .Fn string_buf_output ,
        !           124: and
        !           125: .Fn string_buf_content
        !           126: return
        !           127: .Dv NULL
        !           128: to indicate an error, with
        !           129: .Va errno
        !           130: set appropriately.
        !           131: .Pp
        !           132: Even if 
        !           133: .Fn string_buf_content
        !           134: returns
        !           135: .Dv NULL ,
        !           136: the stream will still need to be closed.
        !           137: .Sh IMPLEMENTATION NOTES
        !           138: .Fn string_buf_content
        !           139: and
        !           140: .Fn string_buf_length
        !           141: attempt to verify that the supplied stream was indeed created by
        !           142: .Fn string_buf_output .
        !           143: If they detect otherwise, an immediate assertion failure is generated.
        !           144: .Sh SEE ALSO
        !           145: .Xr base64 3 ,
        !           146: .Xr filter 3 ,
        !           147: .Xr fopen 3 ,
        !           148: .Xr libpdel 3 ,
        !           149: .Xr typed_mem 3
        !           150: .Sh HISTORY
        !           151: The PDEL library was developed at Packet Design, LLC.
        !           152: .Dv "http://www.packetdesign.com/"
        !           153: .Sh AUTHORS
        !           154: .An Archie Cobbs Aq archie@freebsd.org