63 lines
1.4 KiB
C
63 lines
1.4 KiB
C
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/// A sample C extension.
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// Demonstrates using ldoc's C/C++ support. Can either use /// or /*** */ etc.
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// @module mylib
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#include <string.h>
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#include <math.h>
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// includes for Lua
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#include <lua.h>
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#include <lauxlib.h>
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#include <lualib.h>
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/***
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Create a table with given array and hash slots.
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@function createtable
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@param narr initial array slots, default 0
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@param nrec initial hash slots, default 0
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*/
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static int l_createtable (lua_State *L) {
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int narr = luaL_optint(L,1,0);
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int nrec = luaL_optint(L,2,0);
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lua_createtable(L,narr,nrec);
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return 1;
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}
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/***
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Solve a quadratic equation.
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@function solve
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@param a coefficient of x^2
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@param b coefficient of x
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@param c constant
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@return first root
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@return second root
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*/
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static int l_solve (lua_State *L) {
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double a = lua_tonumber(L,1); // coeff of x*x
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double b = lua_tonumber(L,2); // coef of x
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double c = lua_tonumber(L,3); // constant
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double abc = b*b - 4*a*c;
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if (abc < 0.0) {
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lua_pushnil(L);
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lua_pushstring(L,"imaginary roots!");
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return 2;
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} else {
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abc = sqrt(abc);
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a = 2*a;
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lua_pushnumber(L,(-b + abc)/a);
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lua_pushnumber(L,(+b - abc)/a);
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return 2;
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}
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}
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static const luaL_reg mylib[] = {
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{"createtable",l_createtable},
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{"solve",l_solve},
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{NULL,NULL}
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};
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int luaopen_mylib(lua_State *L)
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{
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luaL_register (L, "mylib", mylib);
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return 1;
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}
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