This graph shows which files directly or indirectly include this file:

Classes
struct	dblib_buffer_row

Macros
#define	BUFFER_CHECK(buf) do {} while(0)

Typedefs
typedef struct dblib_buffer_row	DBLIB_BUFFER_ROW

Functions
static void	buffer_struct_print (const DBPROC_ROWBUF *buf)

static RETCODE	buffer_save_row (DBPROCESS *dbproc)
	Save current row into row buffer. More...

static DBLIB_BUFFER_ROW *	buffer_row_address (const DBPROC_ROWBUF *buf, int idx)
	Given an index, return the row storage, including the DBINT row number prefix. More...

static int	buffer_count (const DBPROC_ROWBUF *buf)
	A few words on the buffering design. More...

static int	buffer_is_full (const DBPROC_ROWBUF *buf)
	Can the buffer be written to? More...

static int	buffer_index_valid (const DBPROC_ROWBUF *buf, int idx)

static void	buffer_free_row (DBLIB_BUFFER_ROW *row)

static void	buffer_free (DBPROC_ROWBUF *buf)

static void	buffer_reset (DBPROC_ROWBUF *buf)

static int	buffer_idx_increment (const DBPROC_ROWBUF *buf, int idx)

static DBINT	buffer_idx2row (const DBPROC_ROWBUF *buf, int idx)
	Convert an index to a row number. More...

static int	buffer_row2idx (const DBPROC_ROWBUF *buf, int row_number)
	Convert a row number to an index. More...

static void	buffer_delete_rows (DBPROC_ROWBUF *buf, int count)
	Deleting a row from the buffer doesn't affect memory allocation. More...

static void	buffer_transfer_bound_data (DBPROC_ROWBUF buf, TDS_INT res_type, TDS_INT compute_id, DBPROCESS dbproc, int idx)
	Transfer data from buffer/tds back to client. More...

static int	buffer_current_index (const DBPROCESS *dbproc)
	Return the current row buffer index. More...

static void	buffer_set_capacity (DBPROCESS *dbproc, int nrows)

static void	buffer_alloc (DBPROCESS *dbproc)

static int	buffer_add_row (DBPROCESS dbproc, TDSRESULTINFO resinfo)
	Called by dbnextrow Returns a row buffer index, or -1 to indicate the buffer is full. More...

Macro Definition Documentation

◆ BUFFER_CHECK

#define BUFFER_CHECK ( buf ) do {} while(0)

Definition at line 80 of file buffering.h.

Typedef Documentation

◆ DBLIB_BUFFER_ROW

typedef struct dblib_buffer_row DBLIB_BUFFER_ROW

Function Documentation

◆ buffer_add_row()

static int buffer_add_row	(	DBPROCESS *	dbproc,
		TDSRESULTINFO *	resinfo
	)

static

Called by dbnextrow Returns a row buffer index, or -1 to indicate the buffer is full.

Definition at line 487 of file buffering.h.

References assert, buf, buffer_idx_increment(), buffer_is_full(), buffer_row_address(), tds_column::column_cur_size, tds_result_info::columns, dbproc, free(), i, if(), NULL, tds_result_info::num_cols, tds_result_info::ref_count, row, tds_dblib_dbprocess::row_buf, tds_free_results, tds_free_row, and tds_new0.

◆ buffer_alloc()

static void buffer_alloc ( DBPROCESS * dbproc )

static

Definition at line 463 of file buffering.h.

References assert, buf, buffer_reset(), dbproc, NULL, tds_dblib_dbprocess::row_buf, and tds_new0.

◆ buffer_count()

static int buffer_count ( const DBPROC_ROWBUF * buf )

static

A few words on the buffering design.

DBPROC_ROWBUF::buf is a block of row buffers, managed as a ring, indexed by head, tail, and current:

head – where new elements are inserted. tail – oldest element. current – active row (read by dbgetrow/dbnextrow)

capacity is the number of rows that buf can hold.

Each element in buf is preceded by its row_number: the result_set row number, determined by counting the rows as they're received from the server. Applications communicate to db-lib in row numbers, not buffer indices.

Semantics: head == 0 && tail == capacity is the initial condition. head == tail means the buffer is full, except when capacity is 1. head < tail means the buffer has wrapped around.

Whether or not buffering is active is governed by dbproc->dbopts[DBBUFFER].optactive.

number of rows in the buffer

Definition at line 112 of file buffering.h.

References buf, and BUFFER_CHECK.

Referenced by buffer_delete_rows(), buffer_is_full(), and buffer_struct_print().

◆ buffer_current_index()

static int buffer_current_index ( const DBPROCESS * dbproc )

static

Return the current row buffer index.

We strive to validate it first. It must be: between zero and capacity (obviously), and between the head and the tail, logically.

If the head has wrapped the tail, it shouldn't be in no man's land. IOW, if capacity is 9, head is 3 and tail is 7, good rows are 7-8 and 0-2. (Row 3 is about-to-be-inserted, and 4-6 are not in use.) Here's a diagram: d d d ! ! ! ! d d 0 1 2 3 4 5 6 7 8 ^ ^ Head Tail

The special case is capacity == 1, meaning there's no buffering, and head == tail === 0.

Definition at line 405 of file buffering.h.

References assert, buf, buffer_struct_print(), dbproc, and tds_dblib_dbprocess::row_buf.