Reallocating/resizing Lua 5.1 userdata in C -

-

how resize lua 5.1 userdata object in c during runtime?

i change size of numarray structure described in roberto ierusalimschy's book programming in lua, 2nd edition, pp. 260, lua 5.1 console.

my numarray userdata can either store unsigned chars or lua_numbers. played around calling unmodified luam_realloc_ function defined in lmem.c, call c's realloc (via l_alloc) function returns null, not enough memory error message.

would please me ?

--- lapi.c -------------------------------------------------------------------------------------------------  lua_api void *agn_resizeud (lua_state *l, void *block, size_t osize, size_t nsize) {   udata *u = (udata *)luam_realloc_(l, block, osize + sizeof(udata), nsize + sizeof(udata));   u->uv.len = nsize;   if (u == null)     lual_error(l, "error in " lua_qs ": failed allocate memory.", "api/agn_resizeud");   return u; }  --- numarray.c ---------------------------------------------------------------------------------------------  #define checkarray(l, n) (numarray *)lual_checkudata(l, n, "numarray")  [...]  /* auxiliary c function call luam_realloc_ via lua c api */  void *reallocud (lua_state *l, void *block, size_t o, size_t n, size_t sizeofelem, size_t sizeofnumarray) {   if (n + 1 > max_sizet/sizeofelem)     lual_error(l, "error in " lua_qs ": memory allocation error: block big.", "(reallocud)", n);   else     return agn_resizeud(l, block, sizeofnumarray + o*sizeofelem, sizeofnumarray + n*sizeofelem); }  /* function resize numarray */  static int numarray_resize (lua_state *l) {   size_t i;   global_state *g = g(l);   numarray *a = checkarray(l, 1);   int n = lual_checkinteger(l, 2);   if (n < 1)     lual_error(l, "error in " lua_qs ": new size %d non-positive.", "numarray.resize", n);   if (n == a->size) {   /* nothing , not complain */     lua_pushinteger(l, a->size);     return 1;   }   if (n > a->size) {  /* extend */     = reallocud(l, a, a->size, n, a->isnumber ? sizeof(lua_number) : sizeof(char), sizeof(numarray));     if (a->isnumber) {       (i=a->size; < n; i++) a->data.n[i] = 0;     } else {       (i=a->size; < n; i++) a->data.c[i] = 0;     }   } else {  /* reduce */     if (a->isnumber) {       (i=a->size - 1; > n - 1; i--) a->data.n[i] = 0;     } else {       (i=a->size - 1; > n - 1; i--) a->data.c[i] = 0;     }     = reallocud(l, a, a->size, n, a->isnumber ? sizeof(lua_number) : sizeof(char), sizeof(numarray));   }   a->size = n;   lua_pushnumber(l, a->size);   return 1; }  [...]  typedef struct numarray {   size_t size;           /* number of slots */   char isnumber;   union data {     lua_number n[1];  /* pointer various lua_number values */     unsigned char c[1];   } data; } numarray;

there no need mess internals of lua.

but need change how userdata created: instead of allocating struct , data in same memory block, allocate them separately, using lua_newuserdata allocate struct , malloc allocate data.

then, resize data part, update size in struct , realloc data part.


Comments

Post a Comment

Popular posts from this blog

java - Custom OutputStreamAppender not run: LOGBACK: No context given for <MYAPPENDER> -

-
i wish write custom appender on basis of outputstreamappender . wrote following class package tests; import java.io.ioexception; import java.io.outputstream; import ch.qos.logback.core.outputstreamappender; public class myappender<e> extends outputstreamappender<e> { public myappender() { system.out.println("myappender created"); setoutputstream(new outputstream() { @override public void write(int b) throws ioexception { throw new unsupportedoperationexception(); } }); } } then wrote following runner: package tests; import org.slf4j.loggerfactory; import ch.qos.logback.classic.logger; public class runner { private static final logger log = (logger) loggerfactory.getlogger(runner.class); public static void main(string[] args) { //log.addappender(new myappender<iloggingevent>()); log.info("hello world"); } } finall...
Read more

java - UML - How would you draw a try catch in a sequence diagram? -

-
Image
is there standard way of drawing try catch sequence diagrams? i've made attempt based on this feel end result doesn't feel right. code diagram based around: public static void save () { try { filehandle filehandle = gdx.files.external(file); filehandle.writestring(boolean.tostring(constantshandler.soundenabled)+"\n", false); (int = 0; < 5; i++) { filehandle.writestring(integer.tostring(constantshandler.highscores[i])+"\n", true); } } catch (throwable e) { } } my attempt note: know still need add loop. that's ok. fragments meant show conditional control flow in sequence diagram. superstructures puts limitations on use of fragments (see pp. 467 of ss2.1.1). should use critical region try part above. , option catch . however, keep telling can take quite freedom in using uml. it's language , such changes in life time. long reader ge...
Read more

c++ - No viable overloaded operator for references a map -

-
i trying use map can make tag names reference number. when try , use it, in code error (6 in total every time reference map): src/main.cpp:25:45: error: no viable overloaded operator[] type 'std::map<std::string, std::string>' const char* idcs = node.child_value(tagmap[3]); this code: #include "pugi/pugixml.hpp" #include <iostream> #include <string> #include <map> int main() { pugi::xml_document doca, docb; std::map<std::string, pugi::xml_node> mapa, mapb; std::map<std::string, std::string> tagmap {{"1", "data"}, {"2", "entry"}, {"3", "id"}, {"4", "content"}}; if (!doca.load_file("a.xml") || !docb.load_file("b.xml")) { std::cout << "can't find input files"; return 1; } (auto& node: doca.child(tagmap[1]).children(tagmap[2])) { co...
Read more