Commit cada82f4 authored by Bob Halley's avatar Bob Halley
Browse files

add active region

parent 26b0f58b
......@@ -43,6 +43,12 @@
* region. The size of the consumed region can be changed using various
* buffer commands. Initially, the consumed region is empty.
*
* The 'active region' is an (optional) subregion of the remaining region.
* It extends from the current offset to an offset in the remaining region
* that is selected with isc_buffer_setactive(). Initially, the active region
* is empty. If the current offset advances beyond the chosen offset, the
* active region will also be empty.
*
* The following invariants are maintained by all routines:
*
* length > 0
......@@ -53,6 +59,8 @@
*
* 0 <= current <= used
*
* 0 <= active <= used
*
* MP:
* Buffers have no synchronization. Clients must ensure exclusive
* access.
......@@ -101,6 +109,7 @@ typedef struct isc_buffer {
unsigned int length;
unsigned int used;
unsigned int current;
unsigned int active;
} isc_buffer_t;
......@@ -251,6 +260,30 @@ isc_buffer_remaining(isc_buffer_t *b, isc_region_t *r);
* 'r' points to a region structure.
*/
void
isc_buffer_active(isc_buffer_t *b, isc_region_t *r);
/*
* Make 'r' refer to the active region of 'b'.
*
* Requires:
*
* 'b' is a valid buffer.
*
* 'r' points to a region structure.
*/
void
isc_buffer_setactive(isc_buffer_t *b, unsigned int n);
/*
* Sets the end of the active region 'n' bytes after current.
*
* Requires:
*
* 'b' is a valid buffer.
*
* current + n <= used
*/
void
isc_buffer_first(isc_buffer_t *b);
/*
......
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