/*
** $Id: lundump.c,v 2.7.1.4 2008/04/04 19:51:41 roberto Exp $
** load precompiled Lua chunks
** See Copyright Notice in lua.h
*/

#include <string.h>

#define lundump_c
#define LUA_CORE

#include "lua.h"

#include "ldebug.h"
#include "ldo.h"
#include "lfunc.h"
#include "lmem.h"
#include "lobject.h"
#include "lstring.h"
#include "lundump.h"
#include "lzio.h"

typedef struct {
    lua_State *L;
    ZIO *Z;
    Mbuffer *b;
    const char *name;
} LoadState;

#ifdef LUAC_TRUST_BINARIES
    #define IF(c, s)
    #define error(S, s)
#else
    #define IF(c, s)                                                           \
        if (c)                                                                 \
        error(S, s)

static void error(LoadState *S, const char *why)
{
    luaO_pushfstring(S->L, "%s: %s in precompiled chunk", S->name, why);
    luaD_throw(S->L, LUA_ERRSYNTAX);
}
#endif

#define LoadMem(S, b, n, size) LoadBlock(S, b, (n) * (size))
#define LoadByte(S) (lu_byte) LoadChar(S)
#define LoadVar(S, x) LoadMem(S, &x, 1, sizeof(x))
#define LoadVector(S, b, n, size) LoadMem(S, b, n, size)

static void LoadBlock(LoadState *S, void *b, size_t size)
{
    size_t r = luaZ_read(S->Z, b, size);
    IF(r != 0, "unexpected end");
}

static int LoadChar(LoadState *S)
{
    char x;
    LoadVar(S, x);
    return x;
}

static int LoadInt(LoadState *S)
{
    int x;
    LoadVar(S, x);
    IF(x < 0, "bad integer");
    return x;
}

static lua_Number LoadNumber(LoadState *S)
{
    lua_Number x;
    LoadVar(S, x);
    return x;
}

static TString *LoadString(LoadState *S)
{
    size_t size;
    LoadVar(S, size);
    if (size == 0)
        return NULL;
    else {
        char *s = luaZ_openspace(S->L, S->b, size);
        LoadBlock(S, s, size);
        return luaS_newlstr(S->L, s, size - 1); /* remove trailing '\0' */
    }
}

static void LoadCode(LoadState *S, Proto *f)
{
    int n = LoadInt(S);
    f->code = luaM_newvector(S->L, n, Instruction);
    f->sizecode = n;
    LoadVector(S, f->code, n, sizeof(Instruction));
}

static Proto *LoadFunction(LoadState *S, TString *p);

static void LoadConstants(LoadState *S, Proto *f)
{
    int i, n;
    n = LoadInt(S);
    f->k = luaM_newvector(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 = LoadChar(S);
        switch (t) {
        case LUA_TNIL:
            setnilvalue(o);
            break;
        case LUA_TBOOLEAN:
            setbvalue(o, LoadChar(S) != 0);
            break;
        case LUA_TNUMBER:
            setnvalue(o, LoadNumber(S));
            break;
        case LUA_TSTRING:
            setsvalue2n(S->L, o, LoadString(S));
            break;
        default:
            error(S, "bad constant");
            break;
        }
    }
    n = LoadInt(S);
    f->p = luaM_newvector(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] = LoadFunction(S, f->source);
}

static void LoadDebug(LoadState *S, Proto *f)
{
    int i, n;
    n = LoadInt(S);
    f->lineinfo = luaM_newvector(S->L, n, int);
    f->sizelineinfo = n;
    LoadVector(S, f->lineinfo, n, sizeof(int));
    n = LoadInt(S);
    f->locvars = luaM_newvector(S->L, n, LocVar);
    f->sizelocvars = n;
    for (i = 0; i < n; i++)
        f->locvars[i].varname = NULL;
    for (i = 0; i < n; i++) {
        f->locvars[i].varname = LoadString(S);
        f->locvars[i].startpc = LoadInt(S);
        f->locvars[i].endpc = LoadInt(S);
    }
    n = LoadInt(S);
    f->upvalues = luaM_newvector(S->L, n, TString *);
    f->sizeupvalues = n;
    for (i = 0; i < n; i++)
        f->upvalues[i] = NULL;
    for (i = 0; i < n; i++)
        f->upvalues[i] = LoadString(S);
}

static Proto *LoadFunction(LoadState *S, TString *p)
{
    Proto *f;
    if (++S->L->nCcalls > LUAI_MAXCCALLS)
        error(S, "code too deep");
    f = luaF_newproto(S->L);
    setptvalue2s(S->L, S->L->top, f);
    incr_top(S->L);
    f->source = LoadString(S);
    if (f->source == NULL)
        f->source = p;
    f->linedefined = LoadInt(S);
    f->lastlinedefined = LoadInt(S);
    f->nups = LoadByte(S);
    f->numparams = LoadByte(S);
    f->is_vararg = LoadByte(S);
    f->maxstacksize = LoadByte(S);
    LoadCode(S, f);
    LoadConstants(S, f);
    LoadDebug(S, f);
    IF(!luaG_checkcode(f), "bad code");
    S->L->top--;
    S->L->nCcalls--;
    return f;
}

static void LoadHeader(LoadState *S)
{
    char h[LUAC_HEADERSIZE];
    char s[LUAC_HEADERSIZE];
    luaU_header(h);
    LoadBlock(S, s, LUAC_HEADERSIZE);
    IF(memcmp(h, s, LUAC_HEADERSIZE) != 0, "bad header");
}

/*
** load precompiled chunk
*/
Proto *luaU_undump(lua_State *L, ZIO *Z, Mbuffer *buff, const char *name)
{
    LoadState S;
    if (*name == '@' || *name == '=')
        S.name = name + 1;
    else if (*name == LUA_SIGNATURE[0])
        S.name = "binary string";
    else
        S.name = name;
    S.L = L;
    S.Z = Z;
    S.b = buff;
    LoadHeader(&S);
    return LoadFunction(&S, luaS_newliteral(L, "=?"));
}

/*
* make header
*/
void luaU_header(char *h)
{
    int x = 1;
    memcpy(h, LUA_SIGNATURE, sizeof(LUA_SIGNATURE) - 1);
    h += sizeof(LUA_SIGNATURE) - 1;
    *h++ = (char)LUAC_VERSION;
    *h++ = (char)LUAC_FORMAT;
    *h++ = (char)*(char *)&x; /* endianness */
    *h++ = (char)sizeof(int);
    *h++ = (char)sizeof(size_t);
    *h++ = (char)sizeof(Instruction);
    *h++ = (char)sizeof(lua_Number);
    *h++ = (char)(((lua_Number)0.5) == 0); /* is lua_Number integral? */
}
