/*

** $Id: lundump.c $

** load precompiled Lua chunks

** See Copyright Notice in lua.h

*/

#define lundump_c

#define LUA_CORE

#include "lprefix.h"

#include <limits.h>

#include <string.h>

#include "lua.h"

#include "ldebug.h"

#include "ldo.h"

#include "lfunc.h"

#include "lmem.h"

#include "lobject.h"

#include "lstring.h"

#include "ltable.h"

#include "lundump.h"

#include "lzio.h"

#if !defined(luai_verifycode)

#define luai_verifycode(L,f)  /* empty */

#endif

typedef struct {

  lua_State *L;

  ZIO *Z;

  const char *name;

  Table *h;  /* list for string reuse */

  size_t offset;  /* current position relative to beginning of dump */

  lua_Unsigned nstr;  /* number of strings in the list */

  lu_byte fixed;  /* dump is fixed in memory */

} LoadState;

static l_noret error (LoadState *S, const char *why) {

  luaO_pushfstring(S->L, "%s: bad binary format (%s)", S->name, why);

  luaD_throw(S->L, LUA_ERRSYNTAX);

}

/*

** All high-level loads go through loadVector; you can change it to

** adapt to the endianness of the input

*/

#define loadVector(S,b,n) loadBlock(S,b,cast_sizet(n)*sizeof((b)[0]))

static void loadBlock (LoadState *S, void *b, size_t size) {

  if (luaZ_read(S->Z, b, size) != 0)

    error(S, "truncated chunk");

  S->offset += size;

}

static void loadAlign (LoadState *S, unsigned align) {

  unsigned padding = align - cast_uint(S->offset % align);

  if (padding < align) {  /* (padding == align) means no padding */

    lua_Integer paddingContent;

    loadBlock(S, &paddingContent, padding);

    lua_assert(S->offset % align == 0);

  }

}

#define getaddr(S,n,t)  cast(t *, getaddr_(S,cast_sizet(n) * sizeof(t)))

static const void *getaddr_ (LoadState *S, size_t size) {

  const void *block = luaZ_getaddr(S->Z, size);

  S->offset += size;

  if (block == NULL)

    error(S, "truncated fixed buffer");

  return block;

}

#define loadVar(S,x)    loadVector(S,&x,1)

static lu_byte loadByte (LoadState *S) {

  int b = zgetc(S->Z);

  if (b == EOZ)

    error(S, "truncated chunk");

  S->offset++;

  return cast_byte(b);

}

static lua_Unsigned loadVarint (LoadState *S, lua_Unsigned limit) {

  lua_Unsigned x = 0;

  int b;

  limit >>= 7;

  do {

    b = loadByte(S);

    if (x > limit)

      error(S, "integer overflow");

    x = (x << 7) | (b & 0x7f);

  } while ((b & 0x80) != 0);

  return x;

}

static size_t loadSize (LoadState *S) {

  return cast_sizet(loadVarint(S, MAX_SIZE));

}

static int loadInt (LoadState *S) {

  return cast_int(loadVarint(S, cast_sizet(INT_MAX)));

}

static lua_Number loadNumber (LoadState *S) {

  lua_Number x;

  loadVar(S, x);

  return x;

}

static lua_Integer loadInteger (LoadState *S) {

  lua_Unsigned cx = loadVarint(S, LUA_MAXUNSIGNED);

  /* decode unsigned to signed */

  if ((cx & 1) != 0)

    return l_castU2S(~(cx >> 1));

  else

    return l_castU2S(cx >> 1);

}

/*

** Load a nullable string into slot 'sl' from prototype 'p'. The

** assignment to the slot and the barrier must be performed before any

** possible GC activity, to anchor the string. (Both 'loadVector' and

** 'luaH_setint' can call the GC.)

*/

static void loadString (LoadState *S, Proto *p, TString **sl) {

  lua_State *L = S->L;

  TString *ts;

  TValue sv;

  size_t size = loadSize(S);

  if (size == 0) {  /* no string? */

    lua_assert(*sl == NULL);  /* must be prefilled */

    return;

  }

  else if (size == 1) {  /* previously saved string? */

    lua_Unsigned idx = loadVarint(S, LUA_MAXUNSIGNED);  /* get its index */

    TValue stv;

    if (novariant(luaH_getint(S->h, l_castU2S(idx), &stv)) != LUA_TSTRING)

      error(S, "invalid string index");

    *sl = ts = tsvalue(&stv);  /* get its value */

    luaC_objbarrier(L, p, ts);

    return;  /* do not save it again */

  }

  else if ((size -= 2) <= LUAI_MAXSHORTLEN) {  /* short string? */

    char buff[LUAI_MAXSHORTLEN + 1];  /* extra space for '\0' */

    loadVector(S, buff, size + 1);  /* load string into buffer */

    *sl = ts = luaS_newlstr(L, buff, size);  /* create string */

    luaC_objbarrier(L, p, ts);

  }

  else if (S->fixed) {  /* for a fixed buffer, use a fixed string */

    const char *s = getaddr(S, size + 1, char);  /* get content address */

    *sl = ts = luaS_newextlstr(L, s, size, NULL, NULL);

    luaC_objbarrier(L, p, ts);

  }

  else {  /* create internal copy */

    *sl = ts = luaS_createlngstrobj(L, size);  /* create string */

    luaC_objbarrier(L, p, ts);

    loadVector(S, getlngstr(ts), size + 1);  /* load directly in final place */

  }

  /* add string to list of saved strings */

  S->nstr++;

  setsvalue(L, &sv, ts);

  luaH_setint(L, S->h, l_castU2S(S->nstr), &sv);

  luaC_objbarrierback(L, obj2gco(S->h), ts);

}

static void loadCode (LoadState *S, Proto *f) {

  int n = loadInt(S);

  loadAlign(S, sizeof(f->code[0]));

  if (S->fixed) {

    f->code = getaddr(S, n, Instruction);

    f->sizecode = n;

  }

  else {

    f->code = luaM_newvectorchecked(S->L, n, Instruction);

    f->sizecode = n;

    loadVector(S, f->code, n);

  }

}

static void loadFunction(LoadState *S, Proto *f);

static void loadConstants (LoadState *S, Proto *f) {

  int i;

  int n = loadInt(S);

  f->k = luaM_newvectorchecked(S->L, n, TValue);

  f->sizek = n;

  for (i = 0; i < n; i++)

    setnilvalue(&f->k[i]);

  for (i = 0; i < n; i++) {

    TValue *o = &f->k[i];

    int t = loadByte(S);

    switch (t) {

      case LUA_VNIL:

        setnilvalue(o);

        break;

      case LUA_VFALSE:

        setbfvalue(o);

        break;

      case LUA_VTRUE:

        setbtvalue(o);

        break;

      case LUA_VNUMFLT:

        setfltvalue(o, loadNumber(S));

        break;

      case LUA_VNUMINT:

        setivalue(o, loadInteger(S));

        break;

      case LUA_VSHRSTR:

      case LUA_VLNGSTR: {

        lua_assert(f->source == NULL);

        loadString(S, f, &f->source);  /* use 'source' to anchor string */

        if (f->source == NULL)

          error(S, "bad format for constant string");

        setsvalue2n(S->L, o, f->source);  /* save it in the right place */

        f->source = NULL;

        break;

      }

      default: error(S, "invalid constant");

    }

  }

}

static void loadProtos (LoadState *S, Proto *f) {

  int i;

  int n = loadInt(S);

  f->p = luaM_newvectorchecked(S->L, n, Proto *);

  f->sizep = n;

  for (i = 0; i < n; i++)

    f->p[i] = NULL;

  for (i = 0; i < n; i++) {

    f->p[i] = luaF_newproto(S->L);

    luaC_objbarrier(S->L, f, f->p[i]);

    loadFunction(S, f->p[i]);

  }

}

/*

** Load the upvalues for a function. The names must be filled first,

** because the filling of the other fields can raise read errors and

** the creation of the error message can call an emergency collection;

** in that case all prototypes must be consistent for the GC.

*/

static void loadUpvalues (LoadState *S, Proto *f) {

  int i;

  int n = loadInt(S);

  f->upvalues = luaM_newvectorchecked(S->L, n, Upvaldesc);

  f->sizeupvalues = n;

  for (i = 0; i < n; i++)  /* make array valid for GC */

    f->upvalues[i].name = NULL;

  for (i = 0; i < n; i++) {  /* following calls can raise errors */

    f->upvalues[i].instack = loadByte(S);

    f->upvalues[i].idx = loadByte(S);

    f->upvalues[i].kind = loadByte(S);

  }

}

static void loadDebug (LoadState *S, Proto *f) {

  int i;

  int n = loadInt(S);

  if (S->fixed) {

    f->lineinfo = getaddr(S, n, ls_byte);

    f->sizelineinfo = n;

  }

  else {

    f->lineinfo = luaM_newvectorchecked(S->L, n, ls_byte);

    f->sizelineinfo = n;

    loadVector(S, f->lineinfo, n);

  }

  n = loadInt(S);

  if (n > 0) {

    loadAlign(S, sizeof(int));

    if (S->fixed) {

      f->abslineinfo = getaddr(S, n, AbsLineInfo);

      f->sizeabslineinfo = n;

    }

    else {

      f->abslineinfo = luaM_newvectorchecked(S->L, n, AbsLineInfo);

      f->sizeabslineinfo = n;

      loadVector(S, f->abslineinfo, n);

    }

  }

  n = loadInt(S);

  f->locvars = luaM_newvectorchecked(S->L, n, LocVar);

  f->sizelocvars = n;

  for (i = 0; i < n; i++)

    f->locvars[i].varname = NULL;

  for (i = 0; i < n; i++) {

    loadString(S, f, &f->locvars[i].varname);

    f->locvars[i].startpc = loadInt(S);

    f->locvars[i].endpc = loadInt(S);

  }

  n = loadInt(S);

  if (n != 0)  /* does it have debug information? */

    n = f->sizeupvalues;  /* must be this many */

  for (i = 0; i < n; i++)

    loadString(S, f, &f->upvalues[i].name);

}

static void loadFunction (LoadState *S, Proto *f) {

  f->linedefined = loadInt(S);

  f->lastlinedefined = loadInt(S);

  f->numparams = loadByte(S);

  f->flag = loadByte(S) & PF_ISVARARG;  /* get only the meaningful flags */

  if (S->fixed)

    f->flag |= PF_FIXED;  /* signal that code is fixed */

  f->maxstacksize = loadByte(S);

  loadCode(S, f);

  loadConstants(S, f);

  loadUpvalues(S, f);

  loadProtos(S, f);

  loadString(S, f, &f->source);

  loadDebug(S, f);

}

static void checkliteral (LoadState *S, const char *s, const char *msg) {

  char buff[sizeof(LUA_SIGNATURE) + sizeof(LUAC_DATA)]; /* larger than both */

  size_t len = strlen(s);

  loadVector(S, buff, len);

  if (memcmp(s, buff, len) != 0)

    error(S, msg);

}

static l_noret numerror (LoadState *S, const char *what, const char *tname) {

  const char *msg = luaO_pushfstring(S->L, "%s %s mismatch", tname, what);

  error(S, msg);

}

static void checknumsize (LoadState *S, int size, const char *tname) {

  if (size != loadByte(S))

    numerror(S, "size", tname);

}

static void checknumformat (LoadState *S, int eq, const char *tname) {

  if (!eq)

    numerror(S, "format", tname);

}

#define checknum(S,tvar,value,tname)  \

  { tvar i; checknumsize(S, sizeof(i), tname); \

    loadVar(S, i); \

    checknumformat(S, i == value, tname); }

static void checkHeader (LoadState *S) {

  /* skip 1st char (already read and checked) */

  checkliteral(S, &LUA_SIGNATURE[1], "not a binary chunk");

  if (loadByte(S) != LUAC_VERSION)

    error(S, "version mismatch");

  if (loadByte(S) != LUAC_FORMAT)

    error(S, "format mismatch");

  checkliteral(S, LUAC_DATA, "corrupted chunk");

  checknum(S, int, LUAC_INT, "int");

  checknum(S, Instruction, LUAC_INST, "instruction");

  checknum(S, lua_Integer, LUAC_INT, "Lua integer");

  checknum(S, lua_Number, LUAC_NUM, "Lua number");

}

/*

** Load precompiled chunk.

*/

LClosure *luaU_undump (lua_State *L, ZIO *Z, const char *name, int fixed) {

  LoadState S;

  LClosure *cl;

  if (*name == '@' || *name == '=')

    name = name + 1;

  else if (*name == LUA_SIGNATURE[0])

    name = "binary string";

  S.name = name;

  S.L = L;

  S.Z = Z;

  S.fixed = cast_byte(fixed);

  S.offset = 1;  /* fist byte was already read */

  checkHeader(&S);

  cl = luaF_newLclosure(L, loadByte(&S));

  setclLvalue2s(L, L->top.p, cl);

  luaD_inctop(L);

  S.h = luaH_new(L);  /* create list of saved strings */

  S.nstr = 0;

  sethvalue2s(L, L->top.p, S.h);  /* anchor it */

  luaD_inctop(L);

  cl->p = luaF_newproto(L);

  luaC_objbarrier(L, cl, cl->p);

  loadFunction(&S, cl->p);

  if (cl->nupvalues != cl->p->sizeupvalues)

    error(&S, "corrupted chunk");

  luai_verifycode(L, cl->p);

  L->top.p--;  /* pop table */

  return cl;

}