Solution credit.lua

c-gaps/credit.c

@@ -1,7 +1,95 @@
 #include <lua.h>
 #include <lauxlib.h>
 
-// implement it here
+#include <stdlib.h>
+
+
+int clear_gaps(lua_State* L)
+{
+	luaL_argcheck(L, lua_istable(L, -1), -1, "Error, table_required\n");
+
+	size_t table_len = lua_objlen(L, -1);
+
+	if ( table_len == 0)
+	{
+		lua_newtable(L);
+		return 1;
+	}
+
+	const char** in_table = (const char**)malloc(sizeof(char*) * table_len);
+
+	// get first string
+	size_t f_size;
+	lua_rawgeti(L, 1, 1);
+	in_table[0] = luaL_checklstring(L, -1, &f_size);
+	lua_pop(L, 1);
+
+	//lua_istable
+
+	int i = 2;
+	for (; i <= table_len; i++)
+	{
+		size_t str_size;
+		lua_rawgeti(L, 1, i);
+
+		in_table[i - 1] = luaL_checklstring(L, -1, &str_size);
+		lua_pop(L, 1);
+
+		luaL_argcheck(L, str_size == f_size, -1, "Error, sequences must have the same length\n");
+	}
+
+	// create place for out table
+	char** out_table = (char**)malloc(sizeof(char*) * table_len);
+	for (i = 0; i < table_len; i++)
+	{
+		out_table[i] = (char*)malloc(sizeof(char) * f_size);
+	}
+
+	int j = 0;
+	size_t new_size = 0;
+
+	// delete only gaps columns
+	for (; j < f_size; j++)
+	{
+		char only_gaps = 1;
+		for (i = 0; i < table_len; i++)
+		{
+			if (in_table[i][j] != '-')
+			{
+				only_gaps = 0;
+			}
+		}
+
+
+		if (! only_gaps) 
+		{
+			for (i = 0; i < table_len; i++)
+			{
+				out_table[i][new_size] = in_table[i][j];
+			}
+			new_size++;
+		}
+	}
+
+
+	lua_newtable(L); // create lua table
+
+	for (i = 0; i < table_len; i++)
+	{
+		lua_pushlstring(L, out_table[i], new_size);
+		lua_rawseti(L, -2, i + 1);
+	}
+
+	// free memory
+
+	for (i = 0; i < table_len; i++)
+	{
+		free(out_table[i]);
+	}
+	free(in_table);
+	free(out_table);
+	return 1; // function returns one argument
+}
 
 int luaopen_gaps(lua_State* L) {
     // return it here