Basic port but not fully supported windower packets lua lib

wlibs/pack.lua

@@ -0,0 +1,235 @@
+local bit = require('bit')
+local ffi = require('ffi')
+local string = require('string')
+local table = require('table')
+
+local codes =
+{
+    c = {size = 1, type = 'number', ctype = 'signed char'},
+    h = {size = 2, type = 'number', ctype = 'signed short'},
+    i = {size = 4, type = 'number', ctype = 'signed int'},
+    C = {size = 1, type = 'number', ctype = 'unsigned char'},
+    H = {size = 2, type = 'number', ctype = 'unsigned short'},
+    I = {size = 4, type = 'number', ctype = 'unsigned int'},
+    f = {size = 4, type = 'number', ctype = 'float'},
+    d = {size = 8, type = 'number', ctype = 'double'},
+    B = {size = 1, type = 'boolean', ctype = 'bool'},
+    S = {size = 1, type = 'string', ctype = 'char', var_size = true},
+    z = {size = 1, type = 'string', ctype = 'char'},
+    b = {size = 0.125, type = 'number', var_size = true},
+    q = {size = 0.125, type = 'boolean'},
+    x = {size = 1, type = 'string', var_size = true},
+}
+
+for code, info in pairs(codes) do
+    info.code = code
+end
+
+local pack_value = function(info, count, value)
+    local ctype = ('%s[%i]'):format(info.ctype, count)
+    return ffi.string(ffi.new(ctype, value), ffi.sizeof(ctype))
+end
+
+local convert_number = function(number, offset, limit)
+    local str = ''
+    while offset > limit do
+        str = str .. string.char(tonumber(number % 0x100))
+        number = bit.rshift(number, 8)
+        offset = offset - 8
+    end
+
+    if offset >= 0 then
+        return str, offset, number
+    end
+
+    return str, 0, 0ULL
+end
+
+local nul = string.char(0)
+
+string.pack = function(format, ...)
+    local res = {}
+    local index = 0
+    local args = select('#', ...)
+    local current = 0ULL
+    local offset = 0
+    local term = false
+
+    for code, count_str in format:gmatch('(%a)(%d*)') do
+        assert(not term, 'Packing cannot continue after "z" code')
+
+        local info = codes[code]
+        assert(info ~= nil, 'Unknown code \'' .. code .. '\'')
+
+        assert(not info.var_size or count_str ~= '', 'Missing length parameter for code "' .. info.code .. '"')
+
+        if offset > 0 and info.size >= 1 then
+            res[#res + 1], offset, current = convert_number(current, offset, 0)
+        end
+
+        local count = count_str ~= '' and tonumber(count_str) or 1
+
+        while count > 0 do
+            index = index + 1
+            assert(index <= args, 'Bad argument #' .. tostring(index + 1) .. ' to \'pack\' (' .. info.type .. ' expected, got no value)')
+
+            local value = select(index, ...)
+            assert(type(value) == info.type, 'Bad argument #' .. tostring(index + 1) .. ' to \'pack\' (' .. info.type .. ' expected, got ' .. type(value) .. ')')
+
+            if offset >= 8 then
+                res[#res + 1], offset, current = convert_number(current, offset, 7)
+            end
+
+            if info.code == 'b' then
+                current = bit.bor(current, bit.lshift(bit.bor(0LL, value), offset))
+                offset = offset + count
+
+            elseif info.code == 'q' then
+                current = bit.bor(current, value == true and 2^offset or 0)
+                offset = offset + 1
+
+            elseif info.code == 'x' then
+                res[#res + 1] = value
+
+            elseif info.code == 'S' then
+                assert(#value <= count, 'Unable to pack string ' .. value .. ' into a "' .. code .. count_str .. '" field')
+                res[#res + 1] = pack_value(info, count, value .. nul:rep(count - #value))
+
+            elseif info.code == 'z' then
+                assert(count <= 1, 'Code "z" cannot appear multiple times')
+                res[#res + 1] = pack_value(info, #value + 1, value .. nul)
+                term = true
+                break
+
+            else
+                res[#res + 1] = pack_value(info, 1, value)
+
+            end
+
+            if info.var_size then
+                break
+            end
+
+            count = count - 1
+        end
+    end
+
+    assert(index >= args, 'Bad argument #' .. tostring(index + 2) .. ' to \'pack\' (no value expected, got ' .. type(select(index + 1, ...) or nil) .. ')')
+
+    if offset > 0 then
+        res[#res + 1] = convert_number(current, offset, 0)
+    end
+
+    return table.concat(res)
+end
+
+local cstring = ffi.typeof('char const*')
+local unpack_value = function(data, index, info, count)
+    local ctype = ('%s[%i]'):format(info.ctype, info.var_size and count or 1)
+    local size = ffi.sizeof(ctype)
+
+    local buffer = ffi.new(ctype)
+    local cstr = cstring(data)
+    ffi.copy(buffer, cstr + index - 1, size)
+
+    local new_index = index + size
+    if info.type == 'number' then
+        return tonumber(buffer[0]), new_index
+
+    elseif info.type == 'boolean' then
+        return buffer[0] == true, new_index
+
+    end
+
+    error('Unhandled valid code "' .. info.code .. '"')
+end
+
+string.unpack = function(data, format, index, offset)
+    index = index or 1
+    offset = offset or 0
+
+    local res = {}
+    local term = false
+    for code, count_str in format:gmatch('(%a)(%d*)') do
+        assert(not term, 'Unpacking cannot continue after "z" code')
+
+        local info = codes[code]
+        assert(info ~= nil, 'Unknown code \'' .. code .. '\'')
+
+        assert(not info.var_size or count_str ~= '', 'Missing length parameter for code "' .. info.code .. '"')
+
+        if offset > 0 and info.size >= 1 then
+            index = index + math.ceil(offset / 8)
+            offset = 0
+        end
+
+        local count = count_str ~= '' and tonumber(count_str) or 1
+
+        assert(index + info.size * count <= #data + 1, 'Data to unpack too small for the provided format')
+
+        while count > 0 do
+            while offset >= 8 do
+                index = index + 1
+                offset = offset - 8
+            end
+
+            if info.code == 'q' then
+                res[#res + 1] = bit.band(bit.rshift(data:byte(index), offset), 0x01) == 1
+                offset = offset + 1
+            elseif info.code == 'b' then
+                local buffer = ffi.new('uint64_t[1]')
+                ffi.copy(buffer, data:sub(index, ffi.sizeof(buffer)))
+                res[#res + 1] = tonumber(bit.band(bit.rshift(buffer[0], offset), 2^count - 1))
+                offset = offset + count
+            elseif info.code == 'x' then
+                res[#res + 1] = data:sub(index, count)
+                index = index + count
+            elseif info.code == 'S' then
+                res[#res + 1] = tostring(ffi.string(data:sub(index, index + count - 1)))
+                index = index + count
+            elseif info.code == 'z' then
+                res[#res + 1] = tostring(ffi.string(data:sub(index)))
+                index = #data
+                term = true
+            else
+                res[#res + 1], index = unpack_value(data, index, info, count)
+            end
+
+            if info.var_size then
+                break
+            end
+
+            count = count - 1
+        end
+    end
+
+    return unpack(res)
+end
+
+--[[
+Copyright © 2018, Windower Dev Team
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer in the
+      documentation and/or other materials provided with the distribution.
+    * Neither the name of the Windower Dev Team nor the
+      names of its contributors may be used to endorse or promote products
+      derived from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE WINDOWER DEV TEAM BE LIABLE FOR ANY
+DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+]]