source: trunk/lua/util.lua @ 135

--[[
 Copyright (C) 2010-2011 <reyalp (at) gmail dot com>

  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License version 2 as
  published by the Free Software Foundation.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
--]]
--[[
common generic lua utilities
utilities that depend on the chdkptp api go in chdku
]]
local util={}

--[[
to allow overriding, e.g. for gui
--]]
util.util_stderr = io.stderr
util.util_stdout = io.stdout

function util.fprintf(f,...)
        local args={...}
        if #args == 0 or type(args[1]) ~= 'string' then
                args[1]=''
        end
        f:write(string.format(unpack(args)))
end

function util.printf(...)
        fprintf(util.util_stdout,...)
end

function util.warnf(format,...)
        fprintf(util.util_stderr,"WARNING: " .. format,...)
end

function util.errf(format,...)
        fprintf(util.util_stderr,"ERROR: " .. format,...)
end

function util.err_traceback(err)
        return debug.traceback(err,2)
end

util.extend_table_max_depth = 10
local extend_table_r
extend_table_r = function(target,source,seen,depth) 
        if not seen then
                seen = {}
        end
        if not depth then
                depth = 1
        end
        if depth > util.extend_table_max_depth then
                error('extend_table: max depth');
        end
        -- a source could have references to the target, don't want to do that
        seen[target]=true
        if seen[source] then
                error('extend_table: cycles');
        end
        seen[source]=true
        for k,v in pairs(source) do
                if type(v) == 'table' then
                        if type(target[k]) ~= 'table' then
                                target[k] = {}
                        end
                        extend_table_r(target[k],v,seen,depth+1)
                else
                        target[k]=v
                end
        end
        return target
end

--[[ 
copy members of source into target
by default, not deep so any tables will be copied as references
returns target so you can do x=extend_table({},...)
if deep, cycles result in an error
deep does not copy keys which are themselves tables (the key will be a reference to the original key table)
]]
function util.extend_table(target,source,deep)
        if type(target) ~= 'table' then
                error('extend_table: target not table')
        end
        if source == nil then -- easier handling of default options
                return target
        end
        if type(source) ~= 'table' then 
                error('extend_table: source not table')
        end
        if source == target then
                error('extend_table: source == target')
        end
        if deep then
                return extend_table_r(target, source)
        else 
                for k,v in pairs(source) do
                        target[k]=v
                end
                return target
        end
end

--[[
does table have value in it ?
]]
function util.in_table(table,value)
        if table == nil then
                return false
        end
        for k,v in pairs(table) do
                if v == value then
                        return true
                end
        end
end

function util.table_amean(table)
        if #table == 0 then
                return nil
        end
        local sum = 0
        for i=1,#table do
                sum = sum + table[i]
        end
        return sum/#table
end

--[[
very simple meta-table inheritance
]]
function util.mt_inherit(t,base)
        local mt={
                __index=function(table, key)
                        return base[key]
                end
        }
        setmetatable(t,mt)
        return t
end

function util.hexdump(str,offset)
        local c, result, byte
        if not offset then
                offset = 0
        end
        c = 0
        result = ''
        for i=1,#str do
                if c == 0 then
                        result = result .. string.format("%8x: ",offset)
                end
                result = result .. string.format("%02x ",string.byte(str,i))
                c = c + 1
                if c == 16 then
                        c = 0
                        offset = offset + 16
                        result = result .. "| " .. string.gsub(string.sub(str,i-15,i),'[%c%z%s\128-\255]','.') .. '\n'
                end
        end
        if c ~= 0 then
                for i=1,16-c do
                        result = result .. "-- "
                end
                result = result .. "| " .. string.gsub(string.sub(str,-c),'[%c%z%s\128-\255]','.')
        end
        return result
end

local serialize_r
serialize_r = function(v,opts,seen,depth)
        local vt = type(v)
        if vt == 'nil' or  vt == 'boolean' then
                return tostring(v)
        elseif vt == 'number' then
                -- camera has problems with decimal constants that would be negative
                if opts.fix_bignum and v > 0x7FFFFFFF then
                        return string.format("0x%x",v)
                end
                return tostring(v)
        elseif vt == 'string' then
                return string.format('%q',v)
        elseif vt == 'table' then
                if not depth then
                        depth = 1
                end
                if depth >= opts.maxdepth then
                        error('serialize: max depth')
                end
                if not seen then
                        seen={}
                elseif seen[v] then 
                        if opts.err_cycle then
                                error('serialize: cycle')
                        else
                                return '"cycle:'..tostring(v)..'"'
                        end
                end
                seen[v] = true;
                local r='{'
                for k,v1 in pairs(v) do
                        if opts.pretty then
                                r = r .. '\n' ..  string.rep(' ',depth)
                        end
                        -- more compact/friendly format simple string keys
                        -- TODO we could make integers more compact by doing array part first
                        if type(k) == 'string' and string.match(k,'^[_%a][%a%d_]*$') then
                                r = r .. tostring(k)
                        else
                                r = r .. '[' .. serialize_r(k,opts,seen,depth+1) .. ']'
                        end
                        r = r .. '=' .. serialize_r(v1,opts,seen,depth+1) .. ','
                end
                if opts.pretty then
                        r = r .. '\n' .. string.rep(' ',depth-1)
                end
                r = r .. '}'
                return r
        elseif opts.err_type then
                error('serialize: unsupported type ' .. vt, 2)
        else
                return '"'..tostring(v)..'"'
        end
end

util.serialize_defaults = {
        -- maximum nested depth
        maxdepth=10,
        -- ignore or error on various conditions
        err_type=true, -- bad type, e.g. function, userdata
        err_cycle=true, -- cyclic references
        pretty=true, -- indents and newlines
        fix_bignum=true, -- send values > 2^31 as hex, to avoid problems with camera conversion from decimal
--      forceint=false, -- TODO convert numbers to integer
}

--[[
serialize lua values
options as documented above
]]
function util.serialize(v,opts)
        return serialize_r(v,util.extend_table(util.extend_table({},util.serialize_defaults),opts))
end

--[[
turn string back into lua data by executing it and returning the value
the value is sandboxed in an empty function environment
returns the resulting value, or false + an error message on failure
check the message, since the serialized value might be false or nil!
]]
function util.unserialize(s)
        local f,err=loadstring('return ' .. s)
        if not f then
                return false, err
        end
        setfenv(f,{}) -- empty fenv
        local status,r=pcall(f)
        if status then
                return r
        end
        return false,r
end

--[[
hacky hacky
"import" values from a table into globals
]]
function util.import(t,names)
        if names == nil then
                for name,val in pairs(t) do
                        _G[name] = val
                end
                return
        end
        for i,name in ipairs(names) do
                if t[name] ~= nil then
                        _G[name] = t[name]
                end
        end
end
return util