.TH BIO 2.SH NAMEBopen, Binit, Binits, Brdline, Brdstr, Bgetc, Bgetrune, Bgetd, Bungetc, Bungetrune, Bread, Bseek, Boffset, Bfildes, Blinelen, Bputc, Bputrune, Bprint, Bvprint, Bwrite, Bflush, Bterm, Bbuffered \- buffered input/output.SH SYNOPSIS.ta \w'Biobuf* 'u.B #include <u.h>.br.B #include <libc.h>.br.B #include <bio.h>.PP.BBiobuf* Bopen(char *file, int mode).PP.Bint Binit(Biobuf *bp, int fd, int mode).PP.Bint Binits(Biobufhdr *bp, int fd, int mode, uchar *buf, int size).PP.Bint Bterm(Biobufhdr *bp).PP.Bint Bprint(Biobufhdr *bp, char *format, ...).PP.Bint Bvprint(Biobufhdr *bp, char *format, va_list arglist);.PP.Bvoid* Brdline(Biobufhdr *bp, int delim).PP.Bchar* Brdstr(Biobufhdr *bp, int delim, int nulldelim).PP.Bint Blinelen(Biobufhdr *bp).PP.Bvlong Boffset(Biobufhdr *bp).PP.Bint Bfildes(Biobufhdr *bp).PP.Bint Bgetc(Biobufhdr *bp).PP.Blong Bgetrune(Biobufhdr *bp).PP.Bint Bgetd(Biobufhdr *bp, double *d).PP.Bint Bungetc(Biobufhdr *bp).PP.Bint Bungetrune(Biobufhdr *bp).PP.Bvlong Bseek(Biobufhdr *bp, vlong n, int type).PP.Bint Bputc(Biobufhdr *bp, int c).PP.Bint Bputrune(Biobufhdr *bp, long c).PP.Blong Bread(Biobufhdr *bp, void *addr, long nbytes).PP.Blong Bwrite(Biobufhdr *bp, void *addr, long nbytes).PP.Bint Bflush(Biobufhdr *bp).PP.Bint Bbuffered(Biobufhdr *bp).PP.SH DESCRIPTIONThese routines implement fast buffered I/O.I/O on different file descriptors is independent..PP.I Bopenopens.I filefor mode.B OREADor creates for mode.BR OWRITE .It calls.IR malloc (2)to allocate a buffer..PP.I Binitinitializes a standard size buffer, type.IR Biobuf ,with the open file descriptor passed inby the user..I Binitsinitializes a non-standard size buffer, type.IR Biobufhdr ,with the open file descriptor,buffer area, and buffer size passed inby the user..I Biobufand.I Biobufhdrare related by the declaration:.IP.EXtypedef struct Biobuf Biobuf;struct Biobuf{ Biobufhdr; uchar b[Bungetsize+Bsize];};.EE.PPArgumentsof types pointer to Biobuf and pointer to Biobufhdrcan be used interchangeably in the following routines..PP.IR Bopen ,.IR Binit ,or.I Binitsshould be called before any of theother routines on that buffer..I Bfildesreturns the integer file descriptor of the associated open file..PP.I Btermflushes the buffer for.IR bpand returns.IR Bflush 'sreturn value.If the buffer was allocated by.IR Bopen ,the buffer is.I freedand the file is closed..PP.I Brdlinereads a string from the file associated with.I bpup to and including the first.I delimcharacter.The delimiter character at the end of the line isnot altered, thus the returned string probably won't be NUL-terminated..I Brdlinereturns a pointer to the start of the line or.L 0on end-of-file or read error..I Blinelenreturns the length (including the delimiter)of the most recent string returned by.IR Brdline ..PP.I Brdstrreturns a.IR malloc (2)-allocatedbuffer containing the next line of input delimited by.IR delim ,terminated by a NUL (0) byte.Unlike.IR Brdline ,which returns when its buffer is full even if no delimiter has been found,.I Brdstrwill return an arbitrarily long line in a single call.If.I nulldelimis set, the terminal delimiter will be overwritten with a NUL.After a successful call to.IR Brdstr ,the return value of.I Blinelenwill be the length of the returned buffer, excluding the NUL..PP.I Bgetcreturns the next character from.IR bp ,or a negative valueat end of file..I Bungetcmay be called immediately after.I Bgetcto allow the same character to be reread..PP.I Bgetrunecalls.I Bgetcto read the bytes of the next.SM UTFsequence in the input stream and returns the value of the runerepresented by the sequence.It returns a negative valueat end of file..I Bungetrunemay be called immediately after.I Bgetruneto allow the same.SM UTFsequence to be reread as either bytes or a rune..I Bungetcand.I Bungetrunemay back up a maximum of five bytes..PP.I Bgetduses.I charstod(see.IR atof (2))and.I Bgetcto read the formattedfloating-point number in the input stream,skipping initial blanks and tabs.The value is stored in.BR *d..PP.I Breadreads.I nbytesof data from.I bpinto memory starting at.IR addr .The number of bytes read is returned on successand a negative value is returned if a read error occurred..PP.I Bseekapplies.IR seek (2)to.IR bp .It returns the new file offset..I Boffsetreturns the file offset of the next character to be processed..PP.I Bputcoutputs the low order 8 bits of.I con.IR bp .If this causes a.IR writeto occur and there is an error,a negative value is returned.Otherwise, a zero is returned..PP.I Bputrunecalls.I Bputcto output the low order16 bits of.I cas a runein.SM UTFformaton the output stream..PP.I Bprintis a buffered interface to.IR print (2).If this causes a.IR writeto occur and there is an error,a negative value.RB ( Beof )is returned.Otherwise, .I Bprintreturns the number of bytes written..I Bvprintdoes the same except it takes as argument a.B va_listparameter, so it can be called within a variadic function..PP.I Bwriteoutputs.I nbytesof data starting at.I addrto.IR bp .If this causes a.IR writeto occur and there is an error,a negative value is returned.Otherwise, the number of bytes written is returned..PP.I Bflushcauses any buffered output associated with.I bpto be written.The return is as for.IR Bputc ..I Bflushis called onexit for every buffer still openfor writing..PP.I Bbufferedreturns the number of bytes in the buffer.When reading, this is the number of bytes still available from the lastread on the file; when writing, it is the number of bytes ready to bewritten..SH SOURCE.B /sys/src/libbio.SH SEE ALSO.IR open (2),.IR print (2),.IR exits (2),.IR utf (6),.SH DIAGNOSTICS.I Bioroutines that return integers yield.B Beofif .I bpis not the descriptor of an open file..I Bopenreturns zero if the file cannot be opened in the given mode.All routines set.I errstron error..SH BUGS.I Brdlinereturns an error on strings longer than the buffer associatedwith the fileand also if the end-of-file is encounteredbefore a delimiter..I Blinelenwill tell how many characters are availablein these cases.In the case of a true end-of-file,.I Blinelenwill return zero.At the cost of allocating a buffer,.I Brdstrsidesteps these issues..PPOnly the low byte of.IR Brdstr 's.I delimis examined, so.I delimcannot be an arbitrary rune..PPThe data returned by.I Brdlinemay be overwritten by calls to any other.I bioroutine on the same.IR bp.
.TH BIO 2
.SH NAME
Bopen, Binit, Binits, Brdline, Brdstr, Bgetc, Bgetrune, Bgetd, Bungetc, Bungetrune, Bread, Bseek, Boffset, Bfildes, Blinelen, Bputc, Bputrune, Bprint, Bvprint, Bwrite, Bflush, Bterm, Bbuffered \- buffered input/output
.SH SYNOPSIS
.ta \w'Biobuf* 'u
.B #include <u.h>
.br
.B #include <libc.h>
.br
.B #include <bio.h>
.PP
.B
Biobuf* Bopen(char *file, int mode)
.PP
.B
int Binit(Biobuf *bp, int fd, int mode)
.PP
.B
int Binits(Biobufhdr *bp, int fd, int mode, uchar *buf, int size)
.PP
.B
int Bterm(Biobufhdr *bp)
.PP
.B
int Bprint(Biobufhdr *bp, char *format, ...)
.PP
.B
int Bvprint(Biobufhdr *bp, char *format, va_list arglist);
.PP
.B
void* Brdline(Biobufhdr *bp, int delim)
.PP
.B
char* Brdstr(Biobufhdr *bp, int delim, int nulldelim)
.PP
.B
int Blinelen(Biobufhdr *bp)
.PP
.B
vlong Boffset(Biobufhdr *bp)
.PP
.B
int Bfildes(Biobufhdr *bp)
.PP
.B
int Bgetc(Biobufhdr *bp)
.PP
.B
long Bgetrune(Biobufhdr *bp)
.PP
.B
int Bgetd(Biobufhdr *bp, double *d)
.PP
.B
int Bungetc(Biobufhdr *bp)
.PP
.B
int Bungetrune(Biobufhdr *bp)
.PP
.B
vlong Bseek(Biobufhdr *bp, vlong n, int type)
.PP
.B
int Bputc(Biobufhdr *bp, int c)
.PP
.B
int Bputrune(Biobufhdr *bp, long c)
.PP
.B
long Bread(Biobufhdr *bp, void *addr, long nbytes)
.PP
.B
long Bwrite(Biobufhdr *bp, void *addr, long nbytes)
.PP
.B
int Bflush(Biobufhdr *bp)
.PP
.B
int Bbuffered(Biobufhdr *bp)
.PP
.SH DESCRIPTION
These routines implement fast buffered I/O.
I/O on different file descriptors is independent.
.PP
.I Bopen
opens
.I file
for mode
.B OREAD
or creates for mode
.BR OWRITE .
It calls
.IR malloc (2)
to allocate a buffer.
.PP
.I Binit
initializes a standard size buffer, type
.IR Biobuf ,
with the open file descriptor passed in
by the user.
.I Binits
initializes a non-standard size buffer, type
.IR Biobufhdr ,
with the open file descriptor,
buffer area, and buffer size passed in
by the user.
.I Biobuf
and
.I Biobufhdr
are related by the declaration:
.IP
.EX
typedef struct Biobuf Biobuf;
struct Biobuf
{
Biobufhdr;
uchar b[Bungetsize+Bsize];
};
.EE
.PP
Arguments
of types pointer to Biobuf and pointer to Biobufhdr
can be used interchangeably in the following routines.
.PP
.IR Bopen ,
.IR Binit ,
or
.I Binits
should be called before any of the
other routines on that buffer.
.I Bfildes
returns the integer file descriptor of the associated open file.
.PP
.I Bterm
flushes the buffer for
.IR bp
and returns
.IR Bflush 's
return value.
If the buffer was allocated by
.IR Bopen ,
the buffer is
.I freed
and the file is closed.
.PP
.I Brdline
reads a string from the file associated with
.I bp
up to and including the first
.I delim
character.
The delimiter character at the end of the line is
not altered, thus the returned string probably won't be NUL-terminated.
.I Brdline
returns a pointer to the start of the line or
.L 0
on end-of-file or read error.
.I Blinelen
returns the length (including the delimiter)
of the most recent string returned by
.IR Brdline .
.PP
.I Brdstr
returns a
.IR malloc (2)-allocated
buffer containing the next line of input delimited by
.IR delim ,
terminated by a NUL (0) byte.
Unlike
.IR Brdline ,
which returns when its buffer is full even if no delimiter has been found,
.I Brdstr
will return an arbitrarily long line in a single call.
If
.I nulldelim
is set, the terminal delimiter will be overwritten with a NUL.
After a successful call to
.IR Brdstr ,
the return value of
.I Blinelen
will be the length of the returned buffer, excluding the NUL.
.PP
.I Bgetc
returns the next character from
.IR bp ,
or a negative value
at end of file.
.I Bungetc
may be called immediately after
.I Bgetc
to allow the same character to be reread.
.PP
.I Bgetrune
calls
.I Bgetc
to read the bytes of the next
.SM UTF
sequence in the input stream and returns the value of the rune
represented by the sequence.
It returns a negative value
at end of file.
.I Bungetrune
may be called immediately after
.I Bgetrune
to allow the same
.SM UTF
sequence to be reread as either bytes or a rune.
.I Bungetc
and
.I Bungetrune
may back up a maximum of five bytes.
.PP
.I Bgetd
uses
.I charstod
(see
.IR atof (2))
and
.I Bgetc
to read the formatted
floating-point number in the input stream,
skipping initial blanks and tabs.
The value is stored in
.BR *d.
.PP
.I Bread
reads
.I nbytes
of data from
.I bp
into memory starting at
.IR addr .
The number of bytes read is returned on success
and a negative value is returned if a read error occurred.
.PP
.I Bseek
applies
.IR seek (2)
to
.IR bp .
It returns the new file offset.
.I Boffset
returns the file offset of the next character to be processed.
.PP
.I Bputc
outputs the low order 8 bits of
.I c
on
.IR bp .
If this causes a
.IR write
to occur and there is an error,
a negative value is returned.
Otherwise, a zero is returned.
.PP
.I Bputrune
calls
.I Bputc
to output the low order
16 bits of
.I c
as a rune
in
.SM UTF
format
on the output stream.
.PP
.I Bprint
is a buffered interface to
.IR print (2).
If this causes a
.IR write
to occur and there is an error,
a negative value
.RB ( Beof )
is returned.
Otherwise,
.I Bprint
returns the number of bytes written.
.I Bvprint
does the same except it takes as argument a
.B va_list
parameter, so it can be called within a variadic function.
.PP
.I Bwrite
outputs
.I nbytes
of data starting at
.I addr
to
.IR bp .
If this causes a
.IR write
to occur and there is an error,
a negative value is returned.
Otherwise, the number of bytes written is returned.
.PP
.I Bflush
causes any buffered output associated with
.I bp
to be written.
The return is as for
.IR Bputc .
.I Bflush
is called on
exit for every buffer still open
for writing.
.PP
.I Bbuffered
returns the number of bytes in the buffer.
When reading, this is the number of bytes still available from the last
read on the file; when writing, it is the number of bytes ready to be
written.
.SH SOURCE
.B /sys/src/libbio
.SH SEE ALSO
.IR open (2),
.IR print (2),
.IR exits (2),
.IR utf (6),
.SH DIAGNOSTICS
.I Bio
routines that return integers yield
.B Beof
if
.I bp
is not the descriptor of an open file.
.I Bopen
returns zero if the file cannot be opened in the given mode.
All routines set
.I errstr
on error.
.SH BUGS
.I Brdline
returns an error on strings longer than the buffer associated
with the file
and also if the end-of-file is encountered
before a delimiter.
.I Blinelen
will tell how many characters are available
in these cases.
In the case of a true end-of-file,
.I Blinelen
will return zero.
At the cost of allocating a buffer,
.I Brdstr
sidesteps these issues.
.PP
Only the low byte of
.IR Brdstr 's
.I delim
is examined, so
.I delim
cannot be an arbitrary rune.
.PP
The data returned by
.I Brdline
may be overwritten by calls to any other
.I bio
routine on the same
.IR bp.