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staging: android: logger: clarify code in clock_interval

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Add commentary, rename the function and make the code easier to read.

Signed-off-by: Tim Bird <tim.bird@am.sony.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Tim Bird 2012-02-07 18:32:02 -08:00 committed by Greg Kroah-Hartman
parent c76c7ca31f
commit 169c843aff
1 changed files with 20 additions and 8 deletions
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28
drivers/staging/android/logger.c
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@ -242,16 +242,28 @@ static size_t get_next_entry(struct logger_log *log, size_t off, size_t len)
}
/*
* clock_interval - is a < c < b in mod-space? Put another way, does the line
* from a to b cross c?
* is_between - is a < c < b, accounting for wrapping of a, b, and c
* positions in the buffer
*
* That is, if a<b, check for c between a and b
* and if a>b, check for c outside (not between) a and b
*
* |------- a xxxxxxxx b --------|
* c^
*
* |xxxxx b --------- a xxxxxxxxx|
* c^
* or c^
*/
static inline int clock_interval(size_t a, size_t b, size_t c)
static inline int is_between(size_t a, size_t b, size_t c)
{
if (b < a) {
if (a < c || b >= c)
if (a < b) {
/* is c between a and b? */
if (a < c && c <= b)
return 1;
} else {
if (a < c && b >= c)
/* is c outside of b through a? */
if (c <= b || a < c)
return 1;
}
@ -272,11 +284,11 @@ static void fix_up_readers(struct logger_log *log, size_t len)
size_t new = logger_offset(log, old + len);
struct logger_reader *reader;
if (clock_interval(old, new, log->head))
if (is_between(old, new, log->head))
log->head = get_next_entry(log, log->head, len);
list_for_each_entry(reader, &log->readers, list)
if (clock_interval(old, new, reader->r_off))
if (is_between(old, new, reader->r_off))
reader->r_off = get_next_entry(log, reader->r_off, len);
}