basic 'buffered I/O' object structure for 'FileBuf' APIs More...

#include <file_help.h>

Data Fields
struct __file_help_buf__ *	pPrev
	pointer to 'previous' item in linked list (NULL for owner object)

struct __file_help_buf__ *	pNext
	pointer to 'next' item in linked list (NULL for last object)

long	lBufferSize
	size of entire buffer

long	lBufferCount
	number of bytes of valid data

long	lLineCount
	number of lines in 'cData' when ppLineBuf not NULL

long	lLineBufSize
	size of memory block pointed to by 'ppLineBuf'

int	iFlags
	various bit flags

char **	ppLineBuf
	array of pointers to beginning of each line (WBAlloc'd TODO: make it part of 'cData'?)

char	cData [sizeof(char *)]
	the data itself (aligned to size of a pointer)

Detailed Description

basic 'buffered I/O' object structure for 'FileBuf' APIs

This structure is intended to assist implementing buffered I/O for files that contain multiple lines separated by linefeeds. A 'file edit' window or dialog control could use one of these objects to assist with displaying and editing text based on the contents of a file. It would also be possible to construct a file_help_buf_t object from a memory buffer as well as from a text file.

typedef struct __file_help_buf__
{
  struct __file_help_buf__ *pPrev; // pointer to 'previous' item in linked list (NULL for owner object)
  struct __file_help_buf__ *pNext; // pointer to 'next' item in linked list (NULL for last object)
  long lBufferSize;                // size of entire buffer
  long lBufferCount;               // number of bytes of valid data
  long lLineCount;                 // number of lines in 'cData' when ppLineBuf not NULL
  long lLineBufSize;               // size of memory block pointed to by 'ppLineBuf'
  int  iFlags;                     // various bit flags
  char **ppLineBuf;                // array of pointers to beginning of each line (WBAlloc'd TODO: make it part of 'cData'?)
  char cData[sizeof(char *)];      // the data itself (aligned to size of a pointer)
} file_help_buf_t;

TODO: 'ppLineBuf' should point to an area within cData. If 'pNext' is valid, subsequent lines could be pointed to by the 'ppLineBuf' within the structure pointed to by 'pNext'. In this way line pointers can be re-structured without re-allocating memory. Additionally, there is no reason why lines must be contiguous, so inserting and removing lines can make use of the additional allocated space pointed to by 'pNext'.
As it would become fragmented, it would also be a good idea to re-build the structure periodically using FBParseFileBuf()

header file: file_help.h

Definition at line 162 of file file_help.h.

The documentation for this struct was generated from the following file:

file_help.h

Data Fields

Detailed Description