Documentation change (s/stack/fifo/).

This commit is contained in:
Philippe PITTOLI 2024-05-25 05:57:46 +02:00
parent 14ed5dda5c
commit ceaa9a6af8
3 changed files with 16 additions and 13 deletions

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@ -35,7 +35,7 @@ end
# │   └── Corvet -> ../../data/0000000000
# ```
#
# WARNING: beware of the RAM use, see `DODB::Storage::Stacked` for a less memory-hungry option.
# WARNING: beware of the RAM use, see `DODB::Storage::Common` for a less memory-hungry option.
class DODB::Storage::Cached(V) < DODB::Storage(V)
@indexers = [] of Index(V)
property data = Hash(Int32, V).new

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@ -12,7 +12,7 @@
# constantly ask for the same data over and over.
#
# ```
# # Creates a DODB stacked database.
# # Creates a DODB database for common usage (a limited number of cached entries).
# car_database = DODB::Storage::Common.new "/path/to/db"
#
# # Creates a (cached) index.
@ -37,7 +37,7 @@ class DODB::Storage::Common(V) < DODB::Storage::Cached(V)
# In case the number of stored entries exceeds what is allowed, the least recently used entry is removed.
property fifo : FIFO(Int32)
# Initializes the `StackedDataBase` with a maximum number of entries in the cache.
# Initializes the `DODB::Storage::Common` database with a maximum number of entries in the cache.
def initialize(@directory_name : String, max_entries : UInt32)
@fifo = FIFO(Int32).new max_entries
Dir.mkdir_p data_path

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@ -1,25 +1,28 @@
# This class enables to keep track of used data.
#
# Each time a value is pushed, it is put on top of a FIFO stack.
# Stack size is configurable, so in case the stack size exceeds what is allowed,
# Each time a value is added, it is put in a FIFO structure.
# Adding a value several times is considered as "using the value",
# so it is pushed back at the entry of the FIFO (as a new value).
# In case the number of entries exceeds what is allowed,
# the least recently used value is removed.
#
# ```
# fifo = FIFO(Int32).new 3 # Only 3 allowed entries.
#
# pp! fifo << 1 # -> nil (there is still room in the stack)
# pp! fifo << 2 # -> nil (there is still room in the stack)
# pp! fifo << 1 # -> nil (there is still room in the FIFO structure)
# pp! fifo << 2 # -> nil (there is still room in the FIFO structure)
# pp! fifo << 3 # -> nil (last entry without exceeding the allowed size)
# pp! fifo << 4 # -> 1 (least recently used data)
# pp! fifo << 4 # -> nil (already in the stack)
# pp! fifo << 2 # -> nil (already in the stack)
# pp! fifo << 4 # -> nil (already in the structure)
# pp! fifo << 2 # -> nil (already in the structure)
# pp! fifo << 5 # -> 3 (least recently used data)
# ```
#
# The number of entries in the FIFO structure is configurable.
class FIFO(V)
# This array is used as a *stack*.
# This array is used as the *fifo structure*.
property data : Array(V)
# Maximum allowed entries in the stack.
# Maximum allowed entries in the structure.
property max_entries : UInt32
def initialize(@max_entries : UInt32)
@ -31,7 +34,7 @@ class FIFO(V)
# WARNING: implementation is extremely simple (3 lines) and not designed to be highly efficient.
def <<(v : V) : V?
@data.select! { |x| v != x } # remove dups
@data.unshift v # push on top of the stack
@data.unshift v # push as the first value of the structure
@data.pop if @data.size > @max_entries # remove least recently used entry if `@data` is too big
end