diff options
Diffstat (limited to '075channel.mu')
| -rw-r--r-- | 075channel.mu | 30 |
1 files changed, 25 insertions, 5 deletions
diff --git a/075channel.mu b/075channel.mu index da5ca7e2..d9a252fd 100644 --- a/075channel.mu +++ b/075channel.mu @@ -32,8 +32,8 @@ container channel:_elem [ first-full:num # for write first-free:num # for read # A circular buffer contains values from index first-full up to (but not - # including) index first-empty. The reader always modifies it at first-full, - # while the writer always modifies it at first-empty. + # including) index first-free. The reader always modifies it at first-full, + # while the writer always modifies it at first-free. data:&:@:_elem ] @@ -63,6 +63,7 @@ def new-channel capacity:num -> in:&:source:_elem, out:&:sink:_elem [ *out <- put *out, chan:offset, result ] +# write a value to a channel def write out:&:sink:_elem, val:_elem -> out:&:sink:_elem [ local-scope load-ingredients @@ -108,6 +109,7 @@ def write out:&:sink:_elem, val:_elem -> out:&:sink:_elem [ reset lock ] +# read a value from a channel def read in:&:source:_elem -> result:_elem, eof?:bool, in:&:source:_elem [ local-scope load-ingredients @@ -166,6 +168,7 @@ def clear in:&:source:_elem -> in:&:source:_elem [ empty?:bool <- channel-empty? chan break-if empty? _, _, in <- read in + loop } ] @@ -301,6 +304,23 @@ scenario channel-read-not-full [ ] ] +scenario channel-clear [ + local-scope + # create a channel with a few items + source:&:source:num, sink:&:sink:num <- new-channel 3/capacity + chan:&:channel:num <- get *sink, chan:offset + write sink, 30 + write sink, 31 + write sink, 32 + run [ + clear source + 10:bool/raw <- channel-empty? chan + ] + memory-should-contain [ + 10 <- 1 # after the call to 'clear', the channel should be empty + ] +] + ## cancelling channels # every channel comes with a boolean signifying if it's been closed @@ -346,7 +366,7 @@ after <channel-read-empty> [ ## helpers -# An empty channel has first-empty and first-full both at the same value. +# An empty channel has first-free and first-full both at the same value. def channel-empty? chan:&:channel:_elem -> result:bool [ local-scope load-ingredients @@ -356,8 +376,8 @@ def channel-empty? chan:&:channel:_elem -> result:bool [ result <- equal full, free ] -# A full channel has first-empty just before first-full, wasting one slot. -# (Other alternatives: https://en.wikipedia.org/wiki/Circular_buffer#Full_.2F_Empty_Buffer_Distinction) +# A full channel has first-free just before first-full, wasting one slot. +# (Other alternatives: https://www.snellman.net/blog/archive/2016-12-13-ring-buffers) def channel-full? chan:&:channel:_elem -> result:bool [ local-scope load-ingredients |