buffer.h File Reference

String Buffer Operations. More...

#include <stdlib.h>
#include <stdarg.h>
#include <string.h>

Go to the source code of this file.

Data Structures
struct	buffer

Macros
#define	buffer_dup(b, buf)   (buffer_dupl(b,buf,NULL))
	Make a heap allocated copy of the buffer. More...
#define	buffer_putstring(b, s)   (buffer_putlstring(b,s,strlen(s)))
	Appends the string to the end of the buffer. More...
#define	buffer_putliteral(b, l)   (buffer_putlstring(b,l "",sizeof(l)-1))
	Appends the string literal to the end of the buffer. More...
#define	buffer_tostring(b)   buffer_tolstring(b, NULL)
	Returns the buffer as a string. More...
#define	BUFFER_STACK(name, size)
	Allocate a buffer named `name' on the stack of at most `size' bytes. More...
#define	BUFFER_STACK_ABORT(name, size)
	Allocate a buffer named `name' on the stack of at most `size' bytes. More...
#define	BUFFER_STACK_PRINT(name, size,...)
	Allocate and print to a buffer named `name' on the stack of at most `size' bytes. More...

Functions
void	buffer_init (buffer_t *b)
	Initialize a buffer. More...
void	buffer_ubuf (buffer_t *b, char *buf, size_t len)
	Use the provided buffer as a starting buffer. More...
void	buffer_max (buffer_t *b, size_t max)
	Set the maximum size of the buffer. More...
void	buffer_abortonfailure (buffer_t *b, int abortonfailure)
	Set the buffer to call fatal(...) on error instead of returning an error code. More...
void	buffer_free (buffer_t *b)
	Free any resources and memory in use by a buffer. More...
int	buffer_dupl (buffer_t *b, char **buf, size_t *l)
	Make a heap allocated copy of the buffer. More...
int	buffer_putvfstring (buffer_t *b, const char *format, va_list ap)
	Print the formatted output to the buffer. More...
int	buffer_putfstring (buffer_t *b, const char *format,...) __attribute__((format(printf
	Appends the formatted output to the buffer. More...
int	buffer_putlstring (buffer_t *b, const char *str, size_t len)
	Appends the string to the end of the buffer. More...
const char *	buffer_tolstring (buffer_t *b, size_t *size)
	Returns the buffer as a string. More...
void	buffer_rewind (buffer_t *b, size_t n)
	Rewinds the buffer to position n. More...
size_t	buffer_pos (buffer_t *b)
	Get the current position in the buffer. More...
int	buffer_grow (buffer_t *b, size_t n)
	Make room for at least n additional chars. More...
int	buffer_seek (buffer_t *b, size_t pos)
	Seek to a position. More...

Detailed Description

String Buffer Operations.

You can use the buffer in the same way you would print to a file. Use the buffer to do formatted printing. When you are done retrieve the final string using buffer_tostring.

Macro Definition Documentation

#define buffer_dup	(		b,
			buf
	)		(buffer_dupl(b,buf,NULL))

Make a heap allocated copy of the buffer.

Parameters

b	The buffer to copy.
buf	A place to store the copy pointer.

Returns

-1 on error.

#define buffer_putstring	(		b,
			s
	)		(buffer_putlstring(b,s,strlen(s)))

Appends the string to the end of the buffer.

Length derived via strlen.

Parameters

b	The buffer to fill.
s	The string to append.

Returns

bytes added (excluding NUL) or -1 on error.

#define buffer_putliteral	(		b,
			l
	)		(buffer_putlstring(b,l "",sizeof(l)-1))

Appends the string literal to the end of the buffer.

Length derived via sizeof.

Parameters

b	The buffer to fill.
l	The literal string to append.

Returns

bytes added (excluding NUL) or -1 on error.

#define buffer_tostring

(

b

)

buffer_tolstring(b, NULL)

Returns the buffer as a string.

The string is no longer valid after deleting the buffer. A final ASCII NUL character is guaranteed to terminate the string.

Parameters

b	The buffer.

Returns

The buffer as a string with a NUL terminator.

#define BUFFER_STACK	(		name,
			size
	)

Value:

buffer_t name[1];\
        char name##_ubuf[size > BUFFER_INISIZ ? size : 1]; /* Unfortunately, we can't conditionally allocate this ubuf array. Use char[1] if less than BUFFER_INISIZ */\
	buffer_init(name);\
	buffer_max(name, size);\
	buffer_ubuf(name, name##_ubuf, size); /* if this is less than BUFFER_INISIZ, then B->initial is still used. */

Allocate a buffer named `name' on the stack of at most `size' bytes.

Does not abort on failure, but hits the max size and drops further bytes written. You can turn on aborts on failure manually using buffer_abortonfailure or using BUFFER_STACK_ABORT. You do not need to call buffer_free(name) because nothing is ever allocated on the heap. This is defined as a macro.

Parameters

name	The name of the buffer.
size	The maximum size of the buffer.

#define BUFFER_STACK_ABORT	(		name,
			size
	)

Value:

BUFFER_STACK(name,size);\
	buffer_abortonfailure(name, 1);

Allocate a buffer named `name' on the stack of at most `size' bytes.

This works the same as BUFFER_STACK but also sets the abort flag on the buffer. This is defined as a macro.

Parameters

name	The name of the buffer.
size	The maximum size of the buffer.

#define BUFFER_STACK_PRINT	(		name,
			size,
			...
	)

Value:

BUFFER_STACK(name,size);\
	buffer_putfstring(name, __VA_ARGS__);

Allocate and print to a buffer named `name' on the stack of at most `size' bytes.

This macro uses BUFFER_STACK to allocate the buffer. Variable arguments are passed to buffer_putfstring, starting with the format string.

Parameters

name	The name of the buffer.
size	The maximum size of the buffer.

Function Documentation

void buffer_init

(

buffer_t *

b

)

Initialize a buffer.

The buffer includes a reasonably sized starting buffer as part of its definition. Usually this means for small strings being built, nothing is ever allocated on the heap. You can specify a larger starting buffer if this is inadequate.

Parameters

b	The buffer to initialize.

void buffer_ubuf	(	buffer_t *	b,
		char *	buf,
		size_t	len
	)

Use the provided buffer as a starting buffer.

This function should only be called before any work is done on the buffer. The user buffer is only used if it is larger than the internal starting buffer.

Parameters

b	The buffer.
buf	A starting buffer to initially use to avoid allocating memory on the heap. (can be NULL)
len	The length of the buffer. (ignored if buf == NULL)

void buffer_max	(	buffer_t *	b,
		size_t	max
	)

Set the maximum size of the buffer.

Parameters

b	The buffer.
max	The maximum amount of memory to allocate. (0 is unlimited)

void buffer_abortonfailure	(	buffer_t *	b,
		int	abortonfailure
	)

Set the buffer to call fatal(...) on error instead of returning an error code.

Parameters

b	The buffer.
abortonfailure	Kill the process on errors. (you no longer have to check returns)

void buffer_free

(

buffer_t *

b

)

Free any resources and memory in use by a buffer.

Parameters

b	The buffer to free.

int buffer_dupl	(	buffer_t *	b,
		char **	buf,
		size_t *	l
	)

Make a heap allocated copy of the buffer.

Parameters

b	The buffer to copy.
buf	A place to store the copy pointer.
l	The length of the string.

Returns

-1 on error.

int buffer_putvfstring	(	buffer_t *	b,
		const char *	format,
		va_list	ap
	)

Print the formatted output to the buffer.

The format string follows the same semantics as the UNIX vprintf function. buffer_putvfstring does not call the variable argument macros va_(start|end) on ap.

Parameters

b	The buffer to fill.
format	The format string.
ap	The variable argument list for the format string.

Returns

bytes added (excluding NUL) or -1 on error.

int buffer_putfstring	(	buffer_t *	b,
		const char *	format,
			...
	)

Appends the formatted output to the buffer.

The format string follows the same semantics as the UNIX vprintf function.

Parameters

b	The buffer to fill.
format	The format string.
...	The variable arguments for the format string.

Returns

bytes added (excluding NUL) or -1 on error.

int buffer_putlstring	(	buffer_t *	b,
		const char *	str,
		size_t	len
	)

Appends the string to the end of the buffer.

Parameters

b	The buffer to fill.
str	The string to append.
len	The length of the string.

Returns

bytes added (excluding NUL) or -1 on error.

const char* buffer_tolstring	(	buffer_t *	b,
		size_t *	size
	)

Returns the buffer as a string.

The string is no longer valid after deleting the buffer. A final ASCII NUL character is guaranteed to terminate the string.

Parameters

b	The buffer.
size	The size of the string is placed in this variable. Can be NULL.

Returns

The buffer as a string with a NUL terminator.

void buffer_rewind	(	buffer_t *	b,
		size_t	n
	)

Rewinds the buffer to position n.

Parameters

b	The buffer.
n	The position to rewind to.

size_t buffer_pos

(

buffer_t *

b

)

Get the current position in the buffer.

Parameters

b	The buffer.

Returns

The current position.

int buffer_grow	(	buffer_t *	b,
		size_t	n
	)

Make room for at least n additional chars.

Parameters

b	The buffer.
n	Number of bytes to add to existing buffer.

Returns

-1 on error.

int buffer_seek	(	buffer_t *	b,
		size_t	pos
	)

Seek to a position.

Similar to buffer_rewind(), but allows seeking past the end of the buffer. Note that seeking beyond the currently allocated memory may result in a buffer filled with garbage data (but still null-terminated).

Parameters

b	The buffer.
pos	Absolute position to seek to.

Returns

-1 on error.