332 lines
11 KiB
Ruby
332 lines
11 KiB
Ruby
# frozen_string_literal: true
|
|
|
|
module Rdb
|
|
# Fast-access methods for tables. Rows are found by byte offset, so a record
|
|
# can be blanked or replaced in place without rewriting the file.
|
|
#
|
|
# -ms sequential (no index file) -mb binary search on a sorted table
|
|
# -mr record numbers table.r -mi inverted index table.i
|
|
# -mh hash table.h
|
|
#
|
|
# table.r and table.h hold fixed-width entries (a head line, a dash line,
|
|
# then "%8d\n" per entry), so one entry can be rewritten in place.
|
|
module Fast
|
|
ENTRY_WIDTH = 9
|
|
SUFFIX = { 'h' => '.h', 'i' => '.i', 'r' => '.r' }.freeze
|
|
FIXED_HEAD = "Offset\n------\n"
|
|
|
|
Row = Struct.new(:from, :to, :line) do
|
|
def cells
|
|
@cells ||= line.split("\t", -1)
|
|
end
|
|
|
|
def blank?
|
|
line.delete("\t ").empty?
|
|
end
|
|
end
|
|
|
|
Hit = Struct.new(:row, :xfrom, :xto)
|
|
|
|
# A table file read as bytes with the offset of every row.
|
|
class Data
|
|
attr_reader :path, :head, :rows
|
|
|
|
def initialize(path)
|
|
@path = path
|
|
File.exist?(path) or Rdb.die("#{path}: no such table")
|
|
bytes = File.binread(path)
|
|
lines = []
|
|
off = 0
|
|
bytes.each_line("\n") do |l|
|
|
lines << Row.new(off, off + l.bytesize, l.chomp("\n"))
|
|
off += l.bytesize
|
|
end
|
|
Rdb.die("#{path}: is a list; fast access needs a table") if bytes.start_with?("\n")
|
|
@head = lines.shift&.line.to_s.split("\t", -1)
|
|
lines.shift if lines.first && Table.dash_line?(lines.first.cells)
|
|
@rows = lines
|
|
@by_from = lines.to_h { |r| [r.from, r] }
|
|
end
|
|
|
|
def live
|
|
@live ||= @rows.reject(&:blank?)
|
|
end
|
|
|
|
def column(name)
|
|
Rdb.column_index(@head, name) || Rdb.die("#{path}: no column named '#{name}'")
|
|
end
|
|
|
|
def row_at(offset)
|
|
@by_from[offset]
|
|
end
|
|
end
|
|
|
|
module_function
|
|
|
|
def index_path(path, method)
|
|
SUFFIX[method] ? path + SUFFIX[method] : nil
|
|
end
|
|
|
|
def key_of(cells, idx)
|
|
cells[idx].to_s
|
|
end
|
|
|
|
def norm(str, fold)
|
|
s = str.to_s.strip
|
|
fold ? s.downcase : s
|
|
end
|
|
|
|
def fmt_entry(num)
|
|
format("%8d\n", num)
|
|
end
|
|
|
|
def hash_slot(slots, key)
|
|
key.delete(" \t").bytes.sum % slots
|
|
end
|
|
|
|
def live_rows(data)
|
|
data.live
|
|
end
|
|
|
|
# ---- building indexes -------------------------------------------------
|
|
|
|
def build(path, method, keycol, fold: false)
|
|
data = Data.new(path)
|
|
rows = live_rows(data)
|
|
case method
|
|
when 'r'
|
|
File.binwrite(path + '.r', FIXED_HEAD + rows.map { |r| fmt_entry(r.from) }.join)
|
|
when 'i'
|
|
k = data.column(keycol)
|
|
ents = rows.map { |r| [r.cells[k].to_s, r.from] }
|
|
ents = ents.sort_by { |key, off| [fold ? key.downcase : key, off] }
|
|
File.binwrite(path + '.i', "#{keycol}\tOffset\n#{'-' * keycol.size}\t------\n" + ents.map { |key, off| "#{key}\t#{off}\n" }.join)
|
|
when 'h'
|
|
k = data.column(keycol)
|
|
slots = [rows.size * 2, 2].max
|
|
table = Array.new(slots, 0)
|
|
rows.each { |r| table[free_slot(table, hash_slot(slots, r.cells[k].to_s))] = r.from }
|
|
File.binwrite(path + '.h', FIXED_HEAD + table.map { |o| fmt_entry(o) }.join)
|
|
when 'b'
|
|
k = data.column(keycol)
|
|
body = live_rows(data).sort_by { |r| r.cells[k].to_s }.map { |r| r.line + "\n" }
|
|
File.binwrite(path, data.head.join("\t") + "\n" + Table.dash_row(data.head) + "\n" + body.join)
|
|
end
|
|
end
|
|
|
|
def free_slot(table, start)
|
|
i = start
|
|
i = (i + 1) % table.size while table[i] != 0 && table[i] != -1
|
|
i
|
|
end
|
|
|
|
# ---- searching ----------------------------------------------------------
|
|
|
|
def read_fixed(path)
|
|
File.binread(path).byteslice(FIXED_HEAD.bytesize..).to_s.lines.map { |l| l.to_i }
|
|
end
|
|
|
|
def read_inverted(path)
|
|
off = 0
|
|
ents = []
|
|
File.binread(path).each_line("\n").with_index do |l, n|
|
|
ents << { from: off, to: off + l.bytesize, key: l.chomp("\n").split("\t", 2)[0], offset: l.chomp("\n").split("\t", 2)[1].to_i } if n >= 2
|
|
off += l.bytesize
|
|
end
|
|
ents
|
|
end
|
|
|
|
def matches?(cell, key, partial, exact)
|
|
if partial
|
|
norm(cell, true).start_with?(norm(key, true))
|
|
elsif exact
|
|
cell == key
|
|
else
|
|
cell.strip == key.strip
|
|
end
|
|
end
|
|
|
|
# Find rows for one key. method is one of s b h i r; keycols are column names.
|
|
def search(data, method, keycols, key, first: false, partial: false, exact: false)
|
|
path = data.path
|
|
idxs = keycols.map { |c| data.column(c) }
|
|
keyvals = Array(key)
|
|
hits = []
|
|
case method
|
|
when 'b'
|
|
rows = live_rows(data)
|
|
k = idxs[0]
|
|
lo = rows.bsearch_index { |r| (partial ? norm(r.cells[k], true)[0, keyvals[0].strip.size] : r.cells[k].strip) >= (partial ? norm(keyvals[0], true) : keyvals[0].strip) }
|
|
if lo
|
|
rows[lo..].each do |r|
|
|
break unless matches?(r.cells[k], keyvals[0], partial, exact)
|
|
|
|
hits << Hit.new(r, 0, 8)
|
|
break if first
|
|
end
|
|
end
|
|
when 'r'
|
|
ents = read_fixed(path + '.r')
|
|
n = keyvals[0].to_i
|
|
if n.positive? && n <= ents.size
|
|
r = data.row_at(ents[n - 1]) and hits << Hit.new(r, FIXED_HEAD.bytesize + ENTRY_WIDTH * (n - 1), FIXED_HEAD.bytesize + ENTRY_WIDTH * n)
|
|
end
|
|
when 'i'
|
|
ents = read_inverted(path + '.i')
|
|
lo = ents.bsearch_index { |e| (partial ? norm(e[:key], true)[0, keyvals[0].strip.size] : e[:key].strip) >= (partial ? norm(keyvals[0], true) : keyvals[0].strip) }
|
|
if lo
|
|
ents[lo..].each do |e|
|
|
break unless matches?(e[:key], keyvals[0], partial, exact)
|
|
|
|
r = data.row_at(e[:offset])
|
|
hits << Hit.new(r, e[:from], e[:to]) if r
|
|
break if first
|
|
end
|
|
end
|
|
when 'h'
|
|
ents = read_fixed(path + '.h')
|
|
slots = ents.size
|
|
i = hash_slot(slots, keyvals[0])
|
|
slots.times do
|
|
o = ents[i]
|
|
break if o.zero?
|
|
|
|
if o.positive? && (r = data.row_at(o)) && matches?(r.cells[idxs[0]], keyvals[0], false, exact)
|
|
hits << Hit.new(r, FIXED_HEAD.bytesize + ENTRY_WIDTH * i, FIXED_HEAD.bytesize + ENTRY_WIDTH * (i + 1))
|
|
break if first
|
|
end
|
|
i = (i + 1) % slots
|
|
end
|
|
else
|
|
live_rows(data).each do |r|
|
|
c = r.cells
|
|
next unless idxs.each_with_index.all? { |ci, n| matches?(c[ci].to_s, keyvals[n].to_s, partial, exact) }
|
|
|
|
hits << Hit.new(r, 0, 8)
|
|
break if first
|
|
end
|
|
end
|
|
hits
|
|
end
|
|
|
|
# ---- changing rows --------------------------------------------------------
|
|
|
|
def blanked(line)
|
|
line.gsub(/[^\t]/, ' ')
|
|
end
|
|
|
|
def splice(path, from, to, text)
|
|
b = File.binread(path)
|
|
File.binwrite(path, b.byteslice(0, from) + text + b.byteslice(to..).to_s)
|
|
end
|
|
|
|
# Remove a record's entry from the secondary index for method.
|
|
def index_remove(path, method, row_from)
|
|
case method
|
|
when 'r'
|
|
ip = path + '.r'
|
|
ents = read_fixed(ip)
|
|
ents.delete(row_from)
|
|
File.binwrite(ip, FIXED_HEAD + ents.map { |o| fmt_entry(o) }.join)
|
|
when 'h'
|
|
ip = path + '.h'
|
|
ents = read_fixed(ip).map { |o| o == row_from ? -1 : o }
|
|
File.binwrite(ip, FIXED_HEAD + ents.map { |o| fmt_entry(o) }.join)
|
|
when 'i'
|
|
ip = path + '.i'
|
|
e = read_inverted(ip).find { |x| x[:offset] == row_from }
|
|
splice(ip, e[:from], e[:to], '') if e
|
|
end
|
|
end
|
|
|
|
def index_add(path, method, row_from, cells, data_head, keycol)
|
|
case method
|
|
when 'r'
|
|
File.binwrite(path + '.r', File.binread(path + '.r') + fmt_entry(row_from))
|
|
when 'i'
|
|
ip = path + '.i'
|
|
name = File.binread(ip).lines.first.split("\t")[0]
|
|
key = cells[data_head.index(name)].to_s
|
|
ents = read_inverted(ip)
|
|
pos = ents.find { |e| e[:key] > key }
|
|
line = "#{key}\t#{row_from}\n"
|
|
if pos then splice(ip, pos[:from], pos[:from], line)
|
|
else File.binwrite(ip, File.binread(ip) + line)
|
|
end
|
|
when 'h'
|
|
ip = path + '.h'
|
|
ents = read_fixed(ip)
|
|
if ents.any? { |o| o <= 0 }
|
|
key = cells[data_head.index(keycol)].to_s
|
|
ents[free_slot(ents, hash_slot(ents.size, key))] = row_from
|
|
File.binwrite(ip, FIXED_HEAD + ents.map { |o| fmt_entry(o) }.join)
|
|
else
|
|
build(path, 'h', keycol)
|
|
end
|
|
when 'b'
|
|
build(path, 'b', keycol)
|
|
end
|
|
end
|
|
|
|
def append_row(path, cells, method, keycol)
|
|
line = cells.join("\t")
|
|
b = File.binread(path)
|
|
b += "\n" unless b.empty? || b.end_with?("\n")
|
|
from = b.bytesize
|
|
File.binwrite(path, b + line + "\n")
|
|
index_add(path, method, from, cells, Data.new(path).head, keycol) if SUFFIX[method] || method == 'b'
|
|
from
|
|
end
|
|
|
|
def delete_hit(path, hit, method)
|
|
r = hit.row
|
|
splice(path, r.from, r.to, blanked(r.line) + "\n")
|
|
index_remove(path, method, r.from)
|
|
end
|
|
|
|
# Put cells where the record at hit was. If the new record is too long
|
|
# even after trimming blanks, append it (unless append is false).
|
|
def replace_row(path, from, to, cells, method, xfrom, xto, keycol, allow_append: true)
|
|
room = to - from - 1
|
|
line = cells.join("\t")
|
|
line = cells.map(&:strip).join("\t") if line.bytesize > room
|
|
if line.bytesize <= room
|
|
splice(path, from, to, line + ' ' * (room - line.bytesize) + "\n")
|
|
return from
|
|
end
|
|
return nil unless allow_append
|
|
|
|
old = File.binread(path).byteslice(from, room)
|
|
splice(path, from, to, blanked(old) + "\n")
|
|
newfrom = append_row(path, cells.map(&:strip), 'x', keycol)
|
|
reindex_entry(path, method, xfrom, xto, newfrom, cells, keycol)
|
|
newfrom
|
|
end
|
|
|
|
def reindex_entry(path, method, xfrom, xto, newfrom, cells, keycol)
|
|
case method
|
|
when 'r', 'h'
|
|
splice(path + SUFFIX[method], xfrom, xto, fmt_entry(newfrom))
|
|
when 'i'
|
|
ip = path + '.i'
|
|
name = File.binread(ip).lines.first.split("\t")[0]
|
|
head = Data.new(path).head
|
|
splice(ip, xfrom, xto, "#{cells[head.index(name)].to_s.strip}\t#{newfrom}\n")
|
|
end
|
|
end
|
|
|
|
# Read keys: a table of keys, or one key per line.
|
|
def read_keys(io, ncols)
|
|
text = io.read.to_s
|
|
return [] if text.empty?
|
|
|
|
lines = text.lines.map { |l| l.chomp("\n") }
|
|
if lines.size >= 2 && Table.dash_line?(lines[1].split("\t", -1))
|
|
lines.drop(2).reject(&:empty?).map { |l| l.split("\t", -1).first(ncols) }
|
|
else
|
|
lines.reject(&:empty?).map { |l| l.split("\t", -1).first(ncols) }
|
|
end
|
|
end
|
|
end
|
|
end
|