lua/src/lpf.c

   1 /***
   2  Low Pass Filter
   3  @module liba.lpf
   4 */
   5
   6 #include "lpf.h"
   7 #include "a/lpf.h"
   8
   9 /***
  10  constructor for Low Pass Filter
  11  @tparam number fc cut-off frequency unit(hz)
  12  @tparam number ts sampling time unit(s)
  13  @treturn a.lpf Low Pass Filter userdata
  14  @function new
  15 */
  16 int liba_lpf_new(lua_State *L)
  17 {
  18     int top = lua_gettop(L);
  19     if (top > 1)
  20     {
  21         a_float fc = (a_float)luaL_checknumber(L, 1);
  22         a_float ts = (a_float)luaL_checknumber(L, 2);
  23         a_lpf *const ctx = lua_newclass(L, a_lpf);
  24         lua_registry_get(L, liba_lpf_new);
  25         lua_setmetatable(L, -2);
  26         a_lpf_init(ctx, A_LPF_GEN(fc, ts));
  27         return 1;
  28     }
  29     if (top > 0)
  30     {
  31         a_float alpha = (a_float)luaL_checknumber(L, 1);
  32         a_lpf *const ctx = lua_newclass(L, a_lpf);
  33         lua_registry_get(L, liba_lpf_new);
  34         lua_setmetatable(L, -2);
  35         a_lpf_init(ctx, alpha);
  36         return 1;
  37     }
  38     return 0;
  39 }
  40
  41 /***
  42  generate for Low Pass Filter
  43  @tparam a.lpf ctx Low Pass Filter userdata
  44  @tparam number fc cut-off frequency unit(hz)
  45  @tparam number ts sampling time unit(s)
  46  @treturn a.lpf Low Pass Filter userdata
  47  @function gen
  48 */
  49 int liba_lpf_gen(lua_State *L)
  50 {
  51     int top = lua_gettop(L);
  52     if (top > 2)
  53     {
  54         luaL_checktype(L, 1, LUA_TUSERDATA);
  55         a_lpf *const ctx = (a_lpf *)lua_touserdata(L, 1);
  56         a_float fc = (a_float)luaL_checknumber(L, 2);
  57         a_float ts = (a_float)luaL_checknumber(L, 3);
  58         ctx->alpha = A_LPF_GEN(fc, ts);
  59         lua_pushvalue(L, 1);
  60         return 1;
  61     }
  62     if (top > 1)
  63     {
  64         luaL_checktype(L, 1, LUA_TUSERDATA);
  65         a_lpf *const ctx = (a_lpf *)lua_touserdata(L, 1);
  66         ctx->alpha = (a_float)luaL_checknumber(L, 2);
  67         lua_pushvalue(L, 1);
  68         return 1;
  69     }
  70     return 0;
  71 }
  72
  73 /***
  74  calculate for Low Pass Filter
  75  @tparam a.lpf ctx Low Pass Filter userdata
  76  @tparam number x input value
  77  @treturn number output value
  78  @function iter
  79 */
  80 int liba_lpf_iter(lua_State *L)
  81 {
  82     a_lpf *const ctx = (a_lpf *)lua_touserdata(L, 1);
  83     if (ctx)
  84     {
  85         a_float x = (a_float)luaL_checknumber(L, 2);
  86         lua_pushnumber(L, (lua_Number)a_lpf_iter(ctx, x));
  87         return 1;
  88     }
  89     return 0;
  90 }
  91
  92 /***
  93  zeroing for Low Pass Filter
  94  @tparam a.lpf ctx Low Pass Filter userdata
  95  @treturn a.lpf Low Pass Filter userdata
  96  @function zero
  97 */
  98 int liba_lpf_zero(lua_State *L)
  99 {
 100     a_lpf *const ctx = (a_lpf *)lua_touserdata(L, 1);
 101     if (ctx)
 102     {
 103         a_lpf_zero(ctx);
 104         return 1;
 105     }
 106     return 0;
 107 }
 108
 109 static int liba_lpf_set(lua_State *L)
 110 {
 111     switch (a_hash_bkdr(lua_tostring(L, 2), 0))
 112     {
 113     case 0xE8859EEB: // __name
 114     case 0xE70C48C6: // __call
 115     case 0xA65758B2: // __index
 116     case 0xAEB551C6: // __newindex
 117         break;
 118     default:
 119         lua_getmetatable(L, 1);
 120         lua_replace(L, 1);
 121         lua_rawset(L, 1);
 122     }
 123     return 0;
 124 }
 125
 126 static int liba_lpf_get(lua_State *L)
 127 {
 128     a_lpf const *const ctx = (a_lpf const *)lua_touserdata(L, 1);
 129     switch (a_hash_bkdr(lua_tostring(L, 2), 0))
 130     {
 131     case 0xB5485B9E: // alpha
 132         lua_pushnumber(L, (lua_Number)ctx->alpha);
 133         break;
 134     case 0x23C9C461: // output
 135         lua_pushnumber(L, (lua_Number)ctx->output);
 136         break;
 137     case 0xA65758B2: // __index
 138         lua_registry_get(L, liba_lpf_new);
 139         lua_num_set(L, -1, "alpha", ctx->alpha);
 140         lua_num_set(L, -1, "output", ctx->output);
 141         break;
 142     default:
 143         lua_getmetatable(L, 1);
 144         lua_replace(L, 1);
 145         lua_rawget(L, 1);
 146     }
 147     return 1;
 148 }
 149
 150 static int liba_lpf_(lua_State *L)
 151 {
 152     lua_pushcfunction(L, liba_lpf_new);
 153     lua_replace(L, 1);
 154     lua_call(L, lua_gettop(L) - 1, 1);
 155     return 1;
 156 }
 157
 158 int luaopen_liba_lpf(lua_State *L)
 159 {
 160     static lua_fun const funcs[] = {
 161         {"new", liba_lpf_new},
 162         {"gen", liba_lpf_gen},
 163         {"iter", liba_lpf_iter},
 164         {"zero", liba_lpf_zero},
 165     };
 166     lua_createtable(L, 0, A_LEN(funcs));
 167     lua_fun_reg(L, -1, funcs, A_LEN(funcs));
 168     lua_createtable(L, 0, 1);
 169     lua_fun_set(L, -1, "__call", liba_lpf_);
 170     lua_setmetatable(L, -2);
 171
 172     static lua_fun const metas[] = {
 173         {"__newindex", liba_lpf_set},
 174         {"__index", liba_lpf_get},
 175         {"__call", liba_lpf_iter},
 176     };
 177     lua_createtable(L, 0, A_LEN(metas) + A_LEN(funcs) + 1);
 178     lua_fun_reg(L, -1, metas, A_LEN(metas));
 179     lua_fun_reg(L, -1, funcs, A_LEN(funcs));
 180     lua_str_set(L, -1, "__name", "a.lpf");
 181     lua_registry_set(L, liba_lpf_new);
 182
 183     return 1;
 184 }