zset.lua

local skiplist = require "skiplist.c"

local mt = {}
mt.__index = mt

function mt:add(score, member)
    local old = self.tbl[member]
    if old then
        if old == score then
            return
        end
        self.sl:delete(old, member)
    end

    self.sl:insert(score, member)
    self.tbl[member] = score
end

function mt:rem(member)
    local score = self.tbl[member]
    if score then
        self.sl:delete(score, member)
    end
end

function mt:count()
    return self.sl:get_count()
end

function mt:_reverse_rank(r)
    return self.sl:get_count() - r + 1
end

function mt:rev_range(r1, r2)
    local r1 = self:_reverse_rank(r1)
    local r2 = self:_reverse_rank(r2)
    print(r1, r2)
    return self:range(r1, r2)
end

function mt:range(r1, r2)
    if r1 < 1 then
        r1 = 1
    end

    if r2 < 1 then
        r2 = 1
    end
    return self.sl:get_rank_range(r1, r2)
end

function mt:rev_rank(member)
    local r = self:rank(member)
    if r then
        return self:_reverse_rank(r)
    end
    return r
end

function mt:rank(member)
    local score = self.tbl[member]
    if not score then
        return nil
    end
    return self.sl:get_rank(score, member)
end

function mt:range_by_score(s1, s2)
    return self.sl:get_score_range(s1, s2)
end

function mt:score(member)
    return self.tbl[member]
end

local M = {}
function M.new()
    local obj = {}
    obj.sl = skiplist()
    obj.tbl = {}
    return setmetatable(obj, mt)
end
return M