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repackaged wrap into a standalone cwrap module
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@andresy
andresy committed Feb 14, 2014
1 parent 28c1771 commit b2b35a6
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Showing 3 changed files with 320 additions and 565 deletions.
308 changes: 308 additions & 0 deletions cinterface.lua
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Original file line number Diff line number Diff line change
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local CInterface = {}

function CInterface.new()
self = {}
self.txt = {}
self.registry = {}
setmetatable(self, {__index=CInterface})
return self
end

function CInterface:luaname2wrapname(name)
return string.format("wrapper_%s", name)
end

function CInterface:print(str)
table.insert(self.txt, str)
end

function CInterface:wrap(luaname, ...)
local txt = self.txt
local varargs = {...}

assert(#varargs > 0 and #varargs % 2 == 0, 'must provide both the C function name and the corresponding arguments')

-- add function to the registry
table.insert(self.registry, {name=luaname, wrapname=self:luaname2wrapname(luaname)})

table.insert(txt, string.format("static int %s(lua_State *L)", self:luaname2wrapname(luaname)))
table.insert(txt, "{")
table.insert(txt, "int narg = lua_gettop(L);")

if #varargs == 2 then
local cfuncname = varargs[1]
local args = varargs[2]

local helpargs, cargs, argcreturned = self:__writeheaders(txt, args)
self:__writechecks(txt, args)

table.insert(txt, 'else')
table.insert(txt, string.format('luaL_error(L, "expected arguments: %s");', table.concat(helpargs, ' ')))

self:__writecall(txt, args, cfuncname, cargs, argcreturned)
else
local allcfuncname = {}
local allargs = {}
local allhelpargs = {}
local allcargs = {}
local allargcreturned = {}

table.insert(txt, "int argset = 0;")

for k=1,#varargs/2 do
allcfuncname[k] = varargs[(k-1)*2+1]
allargs[k] = varargs[(k-1)*2+2]
end

local argoffset = 0
for k=1,#varargs/2 do
allhelpargs[k], allcargs[k], allargcreturned[k] = self:__writeheaders(txt, allargs[k], argoffset)
argoffset = argoffset + #allargs[k]
end

for k=1,#varargs/2 do
self:__writechecks(txt, allargs[k], k)
end

table.insert(txt, 'else')
local allconcathelpargs = {}
for k=1,#varargs/2 do
table.insert(allconcathelpargs, table.concat(allhelpargs[k], ' '))
end
table.insert(txt, string.format('luaL_error(L, "expected arguments: %s");', table.concat(allconcathelpargs, ' | ')))

for k=1,#varargs/2 do
if k == 1 then
table.insert(txt, string.format('if(argset == %d)', k))
else
table.insert(txt, string.format('else if(argset == %d)', k))
end
table.insert(txt, '{')
self:__writecall(txt, allargs[k], allcfuncname[k], allcargs[k], allargcreturned[k])
table.insert(txt, '}')
end

table.insert(txt, 'return 0;')
end

table.insert(txt, '}')
table.insert(txt, '')
end

function CInterface:register(name)
local txt = self.txt
table.insert(txt, string.format('static const struct luaL_Reg %s [] = {', name))
for _,reg in ipairs(self.registry) do
table.insert(txt, string.format('{"%s", %s},', reg.name, reg.wrapname))
end
table.insert(txt, '{NULL, NULL}')
table.insert(txt, '};')
table.insert(txt, '')
self.registry = {}
end

function CInterface:clearhistory()
self.txt = {}
self.registry = {}
end

function CInterface:tostring()
return table.concat(self.txt, '\n')
end

function CInterface:tofile(filename)
local f = io.open(filename, 'w')
f:write(table.concat(self.txt, '\n'))
f:close()
end

local function bit(p)
return 2 ^ (p - 1) -- 1-based indexing
end

local function hasbit(x, p)
return x % (p + p) >= p
end

local function beautify(txt)
local indent = 0
for i=1,#txt do
if txt[i]:match('}') then
indent = indent - 2
end
if indent > 0 then
txt[i] = string.rep(' ', indent) .. txt[i]
end
if txt[i]:match('{') then
indent = indent + 2
end
end
end

local function tableinsertcheck(tbl, stuff)
if stuff and not stuff:match('^%s*$') then
table.insert(tbl, stuff)
end
end

function CInterface:__writeheaders(txt, args, argoffset)
local argtypes = self.argtypes
local helpargs = {}
local cargs = {}
local argcreturned
argoffset = argoffset or 0

for i,arg in ipairs(args) do
arg.i = i+argoffset
arg.args = args -- in case we want to do stuff depending on other args
assert(argtypes[arg.name], 'unknown type ' .. arg.name)
setmetatable(arg, {__index=argtypes[arg.name]})
arg.__metatable = argtypes[arg.name]
tableinsertcheck(txt, arg:declare())
local helpname = arg:helpname()
if arg.returned then
helpname = string.format('*%s*', helpname)
end
if arg.invisible and arg.default == nil then
error('Invisible arguments must have a default! How could I guess how to initialize it?')
end
if arg.default ~= nil then
if not arg.invisible then
table.insert(helpargs, string.format('[%s]', helpname))
end
elseif not arg.creturned then
table.insert(helpargs, helpname)
end
if arg.creturned then
if argcreturned then
error('A C function can only return one argument!')
end
if arg.default ~= nil then
error('Obviously, an "argument" returned by a C function cannot have a default value')
end
if arg.returned then
error('Options "returned" and "creturned" are incompatible')
end
argcreturned = arg
else
table.insert(cargs, arg:carg())
end
end

return helpargs, cargs, argcreturned
end

function CInterface:__writechecks(txt, args, argset)
local argtypes = self.argtypes

local multiargset = argset
argset = argset or 1

local nopt = 0
for i,arg in ipairs(args) do
if arg.default ~= nil and not arg.invisible then
nopt = nopt + 1
end
end

for variant=0,math.pow(2, nopt)-1 do
local opt = 0
local currentargs = {}
local optargs = {}
local hasvararg = false
for i,arg in ipairs(args) do
if arg.invisible then
table.insert(optargs, arg)
elseif arg.default ~= nil then
opt = opt + 1
if hasbit(variant, bit(opt)) then
table.insert(currentargs, arg)
else
table.insert(optargs, arg)
end
elseif not arg.creturned then
table.insert(currentargs, arg)
end
end

for _,arg in ipairs(args) do
if arg.vararg then
if hasvararg then
error('Only one argument can be a "vararg"!')
end
hasvararg = true
end
end

if hasvararg and not currentargs[#currentargs].vararg then
error('Only the last argument can be a "vararg"')
end

local compop
if hasvararg then
compop = '>='
else
compop = '=='
end

if variant == 0 and argset == 1 then
table.insert(txt, string.format('if(narg %s %d', compop, #currentargs))
else
table.insert(txt, string.format('else if(narg %s %d', compop, #currentargs))
end

for stackidx, arg in ipairs(currentargs) do
table.insert(txt, string.format("&& %s", arg:check(stackidx)))
end
table.insert(txt, ')')
table.insert(txt, '{')

if multiargset then
table.insert(txt, string.format('argset = %d;', argset))
end

for stackidx, arg in ipairs(currentargs) do
tableinsertcheck(txt, arg:read(stackidx))
end

for _,arg in ipairs(optargs) do
tableinsertcheck(txt, arg:init())
end

table.insert(txt, '}')

end
end

function CInterface:__writecall(txt, args, cfuncname, cargs, argcreturned)
local argtypes = self.argtypes

for _,arg in ipairs(args) do
tableinsertcheck(txt, arg:precall())
end

if argcreturned then
table.insert(txt, string.format('%s = %s(%s);', argtypes[argcreturned.name].creturn(argcreturned), cfuncname, table.concat(cargs, ',')))
else
table.insert(txt, string.format('%s(%s);', cfuncname, table.concat(cargs, ',')))
end

for _,arg in ipairs(args) do
tableinsertcheck(txt, arg:postcall())
end

local nret = 0
if argcreturned then
nret = nret + 1
end
for _,arg in ipairs(args) do
if arg.returned then
nret = nret + 1
end
end
table.insert(txt, string.format('return %d;', nret))
end

return CInterface


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