Data update

Task/Use-another-language-to-call-a-function/Julia/use-another-language-to-call-a-function-1.jl

@@ -0,0 +1,21 @@
+// Save this section as main.c
+#include <stdio.h>
+
+extern int Query (char * Data, size_t * Length);
+
+int main (int argc, char * argv [])
+{
+   char     Buffer [1024];
+   size_t   Size = sizeof (Buffer);
+
+   if (0 == Query (Buffer, &Size))
+   {
+      printf ("failed to call Query\n");
+   }
+   else
+   {
+      char * Ptr = Buffer;
+      while (Size-- > 0) putchar (*Ptr++);
+      putchar ('\n');
+   }
+}

Task/Use-another-language-to-call-a-function/Julia/use-another-language-to-call-a-function-2.jl

@@ -0,0 +1,17 @@
+# Save this section as a file called query.jl
+
+function Query(buffer::Ptr{UInt8}, length::Ptr{Csize_t})::Cint
+    """ Define the Query function to be called from C """
+
+    max_size = unsafe_load(length)
+    data = "Hello from Julia!"
+    bytes = codeunits(data)
+    max_size < length(bytes) && return 0  # Failure: buffer too small
+    for i in 1:length(bytes)
+        unsafe_store!(buffer, bytes[i], i)
+    end
+    unsafe_store!(length, length(bytes))
+    return 1
+end
+
+Base.@export Query

Task/Use-another-language-to-call-a-function/Julia/use-another-language-to-call-a-function-3.jl

@@ -0,0 +1,33 @@
+// save this section as query_wrapper.c
+
+#include <julia.h>
+
+JULIA_DEFINE_FAST_TLS()
+
+int Query(char *Data, size_t *Length) {
+    jl_init();
+
+    jl_eval_string("include(\"query.jl\")"); // Include the Julia file containing Query function
+
+    jl_function_t *func = jl_get_function(jl_main_module, "Query");
+    if (!func) {
+        jl_atexit_hook(0);
+        return 0;
+    }
+
+    jl_value_t *buffer = jl_ptr_to_array_1d(jl_uint8_type, Data, *Length, 0);
+    jl_value_t *length = jl_box_uint64((uint64_t)Length);
+
+    // Call the query function within Julia
+    jl_value_t *result = jl_call2(func, buffer, length);
+    if (jl_exception_occurred()) {
+        jl_atexit_hook(0);
+        return 0;
+    }
+
+    // Get return value
+    int ret = jl_unbox_int32(result);
+
+    jl_atexit_hook(0);
+    return ret; // Return the result of the Query function from the C shared library
+}

Task/Use-another-language-to-call-a-function/Julia/use-another-language-to-call-a-function-4.jl

@@ -0,0 +1,19 @@
+# Save this section as compile.sh and run it in a terminal with all files in same directory
+gcc -shared -fPIC -o libquery.so query_wrapper.c -I$JULIA_DIR/include/julia -L$JULIA_DIR/lib -ljulia -Wl,-rpath,$JULIA_DIR/lib
+if [ $? -ne 0 ]; then
+    echo "Error: Compilation of libquery.so failed."
+    exit 1
+fi
+echo "libquery.so compiled successfully."
+
+gcc -o main main.c -L. -lquery
+if [ $? -ne 0 ]; then
+    echo "Error: Compilation of main failed."
+    exit 1
+fi
+echo "main compiled successfully."
+
+export LD_LIBRARY_PATH=.:$JULIA_DIR/lib:$LD_LIBRARY_PATH
+./main
+
+echo "Script finished."

Task/Use-another-language-to-call-a-function/Lua/use-another-language-to-call-a-function-1.lua

@@ -0,0 +1,24 @@
+-- Query.lua
+
+--  basic kv dbase
+function qdb_init ()
+   qdb = {} -- global in lua
+   qdb["who are you?"]   = "I am Lua"
+   qdb["what are you?"]  = "I am a Lua virtual machine"
+   qdb["when are you?"]  = "I am live"
+   qdb["where are you?"] = "Here I am"
+   qdb["how are you?"]   = "I am a fine"
+   qdb["default"]        = "unknown query"
+
+end
+
+-- call from C with key => Data
+function Query(k)
+
+   local key  = string.lower(k)
+
+   if (qdb[key] == nil) then key = "default" end
+
+   lua_response = qdb[key]
+
+end

Task/Use-another-language-to-call-a-function/Lua/use-another-language-to-call-a-function-2.lua

@@ -0,0 +1,205 @@
+/* Query_lua.c */
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <string.h>
+
+#include <lua.h>
+#include <lauxlib.h>
+#include <lualib.h>
+
+// tell lua how many args for a function
+typedef enum { NOARG, ONEARG, TWOARGS, THREEARGS } argcount;
+//              0     1       2        3
+
+// diagnostics when things go wrong
+typedef enum { C_OK, C_FAILURE, LUA_FAILURE} exitcode;
+//             0     1          2
+
+/* lua vars we will create or use */
+const char* lua_Query    = "Query";
+const char* lua_Data     = "Data";
+const char* lua_qdb_init = "qdb_init";
+const char* lua_qdb      = "qdb";
+const char* lua_response = "lua_response";
+
+
+int LTop; // global  C index to top of lua stack
+
+/* function prototypes */
+
+int Query(char* Data, size_t * Length);
+
+void fail(const char* fmsg, const char* errstr, exitcode ret);
+
+lua_State* C_lua_init(const char*  luafile);
+
+bool C_push_string(lua_State* L, const char* name,
+		   const char* str, const size_t n);
+
+bool C_get_string( lua_State * L, const char* src,
+		   char* dest, size_t max);
+
+
+// exit program with diagnostice and exitcode
+void fail(const char* fmsg, const char* errstr, exitcode ret) {
+
+  fprintf(stderr, "%s ", fmsg);
+
+  if (errstr != NULL){ fprintf(stderr, "%s ", errstr); }
+
+  fprintf(stderr, "\n");
+
+  exit(ret);
+}
+
+
+// push C string to lua
+bool C_push_string(lua_State* L, const char* name,
+		   const char* str, const size_t n){
+  (void) n;
+  lua_pushstring(L, str);
+  lua_setglobal(L, name);
+  return true;
+}
+
+// get C string from lua string by variable var
+bool C_get_string( lua_State * L, const char* luavar,
+		   char* dest, size_t max){
+
+  const char* lstring = NULL;
+  size_t len = 0;
+
+  lua_getglobal(L, luavar);
+
+  if(!lua_isstring(L, -1)) {
+    fail("expected a string", lua_tostring(L, -1), LUA_FAILURE);
+  }
+
+  LTop = lua_gettop(L);
+
+  lstring = lua_tolstring(L, LTop, &max );
+  len =  strlen(lstring);
+
+  if (len > 0) {
+    strncpy(dest, lstring, len);
+    dest[len+1] = '\0';
+    return true;
+  }
+
+  return false;
+}
+
+
+/*
+  initialize the lua vm
+  load up the lua file
+  any commands in the global area will run
+*/
+
+lua_State* C_lua_init(const char*  luafile) {
+
+  exitcode status = C_OK;
+
+  /// creates Lua machine & env
+  lua_State* L = luaL_newstate();
+  if (L == NULL) {
+    fail("could not create lua state", "lua internal failure", LUA_FAILURE);
+  }
+
+  // imports basic libs like string, io, os, table, utf-8, math
+  luaL_openlibs(L);
+
+  // lua file to load
+  status = luaL_loadfile(L, luafile);
+
+  if (status != LUA_OK){
+    fail("loadfile failed",  lua_tostring(L, -1), LUA_FAILURE);
+  }
+
+  /* "priming run"
+      SEE http://www.troubleshooters.com/codecorn/lua/lua_c_calls_lua.htm
+  */
+  if (lua_pcall(L, 0, 0, 0) != LUA_OK) {
+    fail("priming run failed",lua_tostring(L, -1), LUA_FAILURE);
+  }
+
+  return L;
+}
+
+/* --------------------------------------------------
+   function called by main in Query.c
+*/
+
+int Query(char* Data, size_t * Length) {
+
+  /* ======= SETUP LUA ====== */
+  // create Lua vm with file
+  lua_State* L = C_lua_init("Query.lua");
+
+  // call db init
+  lua_getglobal(L, lua_qdb_init);
+  luaL_checktype(L, -1, LUA_TFUNCTION); // optionally check lua type
+
+  int result = lua_pcall(L, NOARG, 0, 0); // execute lua func
+  if (result != LUA_OK) {
+    fail("failed to run qdb_init function", lua_tostring(L, -1), LUA_FAILURE);
+  }
+
+  /* ======= RUN LUA CODE ========= */
+
+  // put Data into Lua env as a string
+  C_push_string(L, lua_Data, Data, *Length-1);
+
+  /* set function to call and 1 arg(s) */
+  lua_getglobal(L, lua_Query); // function
+  luaL_checktype(L, -1, LUA_TFUNCTION);
+
+  lua_getglobal(L, lua_Data); // arg
+  luaL_checktype(L, -1, LUA_TSTRING);
+
+  // call lua function with 1 arg*
+  result = lua_pcall(L, ONEARG, LUA_MULTRET, 0);
+  if (result != LUA_OK) {
+    fail("failed to run Query function", lua_tostring(L, -1), LUA_FAILURE);
+  }
+
+  // lua_response should have our answer
+  char* response = calloc(*Length, sizeof(char));
+  if (response == NULL) {
+    fail("calloc failed allocation", NULL, C_FAILURE);
+  }
+
+  // created within lua
+  C_get_string(L, lua_response, response, *Length);
+
+
+  /* ======== CLEANUP LUA ====== */
+
+  // clean up lua vars and close vm
+  // (assign var = nil)
+  lua_pushnil(L); lua_setglobal(L, lua_response);
+  lua_pushnil(L); lua_setglobal(L, lua_Data);
+  lua_pushnil(L); lua_setglobal(L, lua_Query);
+  lua_pushnil(L); lua_setglobal(L, lua_qdb);
+  lua_close(L);   // lua is done
+
+
+  /* ======= REPORT ====== */
+
+  size_t rlen = strlen(response);
+
+  if (rlen > 0) {
+    strncpy(Data, response, *Length-1);
+    Data[rlen] = '\0';
+    free(response);  // because dynamically allocated
+  } else {
+    fail("lua", "no response", LUA_FAILURE);
+  }
+
+
+  return 1;
+}
+
+
+// end

Task/Use-another-language-to-call-a-function/Lua/use-another-language-to-call-a-function-3.lua

@@ -0,0 +1,4 @@
+gcc -std=c2x -Wall -Wextra \
+    -I/usr/include/lua5.3 -o query  \
+    Query.c Query_lua.c \
+    -L/usr/lib/x84_64-linux-gnu/ -l lua5.3