compat-5.3.c.h

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#include <sol/compatibility/compat-5.3.h>
 
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <stdio.h>
 
/* don't compile it again if it already is included via compat53.h */
#ifndef KEPLER_PROJECT_COMPAT53_C_
#define KEPLER_PROJECT_COMPAT53_C_
 
 
 
/* definitions for Lua 5.1 only */
#if defined(LUA_VERSION_NUM) && LUA_VERSION_NUM == 501
 
#ifndef COMPAT53_FOPEN_NO_LOCK
#if defined(_MSC_VER)
#define COMPAT53_FOPEN_NO_LOCK 1
#else /* otherwise */
#define COMPAT53_FOPEN_NO_LOCK 0
#endif /* VC++ only so far */
#endif /* No-lock fopen_s usage if possible */
 
#if defined(_MSC_VER) && COMPAT53_FOPEN_NO_LOCK
#include <share.h>
#endif /* VC++ _fsopen for share-allowed file read */
 
#ifndef COMPAT53_HAVE_STRERROR_R
#if defined(__GLIBC__) || defined(_POSIX_VERSION) || defined(__APPLE__) || (!defined(__MINGW32__) && defined(__GNUC__) && (__GNUC__ < 6))
#define COMPAT53_HAVE_STRERROR_R 1
#else /* none of the defines matched: define to 0 */
#define COMPAT53_HAVE_STRERROR_R 0
#endif /* have strerror_r of some form */
#endif /* strerror_r */
 
#ifndef COMPAT53_HAVE_STRERROR_S
#if defined(_MSC_VER) || (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L) || (defined(__STDC_LIB_EXT1__) && __STDC_LIB_EXT1__)
#define COMPAT53_HAVE_STRERROR_S 1
#else /* not VC++ or C11 */
#define COMPAT53_HAVE_STRERROR_S 0
#endif /* strerror_s from VC++ or C11 */
#endif /* strerror_s */
 
#ifndef COMPAT53_LUA_FILE_BUFFER_SIZE
#define COMPAT53_LUA_FILE_BUFFER_SIZE 4096
#endif /* Lua File Buffer Size */
 
 
static char* compat53_strerror(int en, char* buff, size_t sz) {
#if COMPAT53_HAVE_STRERROR_R
    /* use strerror_r here, because it's available on these specific platforms */
    if (sz > 0) {
        buff[0] = '\0';
        /* we don't care whether the GNU version or the XSI version is used: */
        if (strerror_r(en, buff, sz)) {
            /* Yes, we really DO want to ignore the return value!
             * GCC makes that extra hard, not even a (void) cast will do. */
        }
        if (buff[0] == '\0') {
            /* Buffer is unchanged, so we probably have called GNU strerror_r which
             * returned a static constant string. Chances are that strerror will
             * return the same static constant string and therefore be thread-safe. */
            return strerror(en);
        }
    }
    return buff; /* sz is 0 *or* strerror_r wrote into the buffer */
#elif COMPAT53_HAVE_STRERROR_S
    /* for MSVC and other C11 implementations, use strerror_s since it's
     * provided by default by the libraries */
    strerror_s(buff, sz, en);
    return buff;
#else
    /* fallback, but strerror is not guaranteed to be threadsafe due to modifying
     * errno itself and some impls not locking a static buffer for it ... but most
     * known systems have threadsafe errno: this might only change if the locale
     * is changed out from under someone while this function is being called */
    (void)buff;
    (void)sz;
    return strerror(en);
#endif
}
 
 
COMPAT53_API int lua_absindex(lua_State* L, int i) {
    if (i < 0 && i > LUA_REGISTRYINDEX)
        i += lua_gettop(L) + 1;
    return i;
}
 
 
static void compat53_call_lua(lua_State* L, char const code[], size_t len, int nargs, int nret) {
    lua_rawgetp(L, LUA_REGISTRYINDEX, (void*)code);
    if (lua_type(L, -1) != LUA_TFUNCTION) {
        lua_pop(L, 1);
        if (luaL_loadbuffer(L, code, len, "=none"))
            lua_error(L);
        lua_pushvalue(L, -1);
        lua_rawsetp(L, LUA_REGISTRYINDEX, (void*)code);
    }
    lua_insert(L, -nargs - 1);
    lua_call(L, nargs, nret);
}
 
 
COMPAT53_API void lua_arith(lua_State* L, int op) {
    static const char compat53_arith_code[]
         = "local op,a,b=...\n"
           "if op==0 then return a+b\n"
           "elseif op==1 then return a-b\n"
           "elseif op==2 then return a*b\n"
           "elseif op==3 then return a/b\n"
           "elseif op==4 then return a%b\n"
           "elseif op==5 then return a^b\n"
           "elseif op==6 then return -a\n"
           "end\n";
 
    if (op < LUA_OPADD || op > LUA_OPUNM)
        luaL_error(L, "invalid 'op' argument for lua_arith");
    luaL_checkstack(L, 5, "not enough stack slots");
    if (op == LUA_OPUNM)
        lua_pushvalue(L, -1);
    lua_pushnumber(L, op);
    lua_insert(L, -3);
    compat53_call_lua(L, compat53_arith_code, sizeof(compat53_arith_code) - 1, 3, 1);
}
 
 
COMPAT53_API int lua_compare(lua_State* L, int idx1, int idx2, int op) {
    static const char compat53_compare_code[]
         = "local a,b=...\n"
           "return a<=b\n";
 
    int result = 0;
    switch (op) {
    case LUA_OPEQ:
        return lua_equal(L, idx1, idx2);
    case LUA_OPLT:
        return lua_lessthan(L, idx1, idx2);
    case LUA_OPLE:
        luaL_checkstack(L, 5, "not enough stack slots");
        idx1 = lua_absindex(L, idx1);
        idx2 = lua_absindex(L, idx2);
        lua_pushvalue(L, idx1);
        lua_pushvalue(L, idx2);
        compat53_call_lua(L, compat53_compare_code, sizeof(compat53_compare_code) - 1, 2, 1);
        result = lua_toboolean(L, -1);
        lua_pop(L, 1);
        return result;
    default:
        luaL_error(L, "invalid 'op' argument for lua_compare");
    }
    return 0;
}
 
 
COMPAT53_API void lua_copy(lua_State* L, int from, int to) {
    int abs_to = lua_absindex(L, to);
    luaL_checkstack(L, 1, "not enough stack slots");
    lua_pushvalue(L, from);
    lua_replace(L, abs_to);
}
 
 
COMPAT53_API void lua_len(lua_State* L, int i) {
    switch (lua_type(L, i)) {
    case LUA_TSTRING:
        lua_pushnumber(L, (lua_Number)lua_objlen(L, i));
        break;
    case LUA_TTABLE:
        if (!luaL_callmeta(L, i, "__len"))
            lua_pushnumber(L, (lua_Number)lua_objlen(L, i));
        break;
    case LUA_TUSERDATA:
        if (luaL_callmeta(L, i, "__len"))
            break;
        /* FALLTHROUGH */
    default:
        luaL_error(L, "attempt to get length of a %s value", lua_typename(L, lua_type(L, i)));
    }
}
 
 
COMPAT53_API int lua_rawgetp(lua_State* L, int i, const void* p) {
    int abs_i = lua_absindex(L, i);
    lua_pushlightuserdata(L, (void*)p);
    lua_rawget(L, abs_i);
    return lua_type(L, -1);
}
 
COMPAT53_API void lua_rawsetp(lua_State* L, int i, const void* p) {
    int abs_i = lua_absindex(L, i);
    luaL_checkstack(L, 1, "not enough stack slots");
    lua_pushlightuserdata(L, (void*)p);
    lua_insert(L, -2);
    lua_rawset(L, abs_i);
}
 
 
COMPAT53_API lua_Number lua_tonumberx(lua_State* L, int i, int* isnum) {
    lua_Number n = lua_tonumber(L, i);
    if (isnum != NULL) {
        *isnum = (n != 0 || lua_isnumber(L, i));
    }
    return n;
}
 
 
COMPAT53_API void luaL_checkversion(lua_State* L) {
    (void)L;
}
 
 
COMPAT53_API void luaL_checkstack(lua_State* L, int sp, const char* msg) {
    if (!lua_checkstack(L, sp + LUA_MINSTACK)) {
        if (msg != NULL)
            luaL_error(L, "stack overflow (%s)", msg);
        else {
            lua_pushliteral(L, "stack overflow");
            lua_error(L);
        }
    }
}
 
 
COMPAT53_API int luaL_getsubtable(lua_State* L, int i, const char* name) {
    int abs_i = lua_absindex(L, i);
    luaL_checkstack(L, 3, "not enough stack slots");
    lua_pushstring(L, name);
    lua_gettable(L, abs_i);
    if (lua_istable(L, -1))
        return 1;
    lua_pop(L, 1);
    lua_newtable(L);
    lua_pushstring(L, name);
    lua_pushvalue(L, -2);
    lua_settable(L, abs_i);
    return 0;
}
 
 
COMPAT53_API lua_Integer luaL_len(lua_State* L, int i) {
    lua_Integer res = 0;
    int isnum = 0;
    luaL_checkstack(L, 1, "not enough stack slots");
    lua_len(L, i);
    res = lua_tointegerx(L, -1, &isnum);
    lua_pop(L, 1);
    if (!isnum)
        luaL_error(L, "object length is not an integer");
    return res;
}
 
 
COMPAT53_API void luaL_setfuncs(lua_State* L, const luaL_Reg* l, int nup) {
    luaL_checkstack(L, nup + 1, "too many upvalues");
    for (; l->name != NULL; l++) { /* fill the table with given functions */
        int i;
        lua_pushstring(L, l->name);
        for (i = 0; i < nup; i++) /* copy upvalues to the top */
            lua_pushvalue(L, -(nup + 1));
        lua_pushcclosure(L, l->func, nup); /* closure with those upvalues */
        lua_settable(L, -(nup + 3));       /* table must be below the upvalues, the name and the closure */
    }
    lua_pop(L, nup); /* remove upvalues */
}
 
 
COMPAT53_API void luaL_setmetatable(lua_State* L, const char* tname) {
    luaL_checkstack(L, 1, "not enough stack slots");
    luaL_getmetatable(L, tname);
    lua_setmetatable(L, -2);
}
 
 
COMPAT53_API void* luaL_testudata(lua_State* L, int i, const char* tname) {
    void* p = lua_touserdata(L, i);
    luaL_checkstack(L, 2, "not enough stack slots");
    if (p == NULL || !lua_getmetatable(L, i))
        return NULL;
    else {
        int res = 0;
        luaL_getmetatable(L, tname);
        res = lua_rawequal(L, -1, -2);
        lua_pop(L, 2);
        if (!res)
            p = NULL;
    }
    return p;
}
 
 
static int compat53_countlevels(lua_State* L) {
    lua_Debug ar;
    int li = 1, le = 1;
    /* find an upper bound */
    while (lua_getstack(L, le, &ar)) {
        li = le;
        le *= 2;
    }
    /* do a binary search */
    while (li < le) {
        int m = (li + le) / 2;
        if (lua_getstack(L, m, &ar))
            li = m + 1;
        else
            le = m;
    }
    return le - 1;
}
 
static int compat53_findfield(lua_State* L, int objidx, int level) {
    if (level == 0 || !lua_istable(L, -1))
        return 0;                               /* not found */
    lua_pushnil(L);                              /* start 'next' loop */
    while (lua_next(L, -2)) {                    /* for each pair in table */
        if (lua_type(L, -2) == LUA_TSTRING) {   /* ignore non-string keys */
            if (lua_rawequal(L, objidx, -1)) { /* found object? */
                lua_pop(L, 1);                /* remove value (but keep name) */
                return 1;
            }
            else if (compat53_findfield(L, objidx, level - 1)) { /* try recursively */
                lua_remove(L, -2);                              /* remove table (but keep name) */
                lua_pushliteral(L, ".");
                lua_insert(L, -2); /* place '.' between the two names */
                lua_concat(L, 3);
                return 1;
            }
        }
        lua_pop(L, 1); /* remove value */
    }
    return 0; /* not found */
}
 
static int compat53_pushglobalfuncname(lua_State* L, lua_Debug* ar) {
    int top = lua_gettop(L);
    lua_getinfo(L, "f", ar); /* push function */
    lua_pushvalue(L, LUA_GLOBALSINDEX);
    if (compat53_findfield(L, top + 1, 2)) {
        lua_copy(L, -1, top + 1); /* move name to proper place */
        lua_pop(L, 2);            /* remove pushed values */
        return 1;
    }
    else {
        lua_settop(L, top); /* remove function and global table */
        return 0;
    }
}
 
static void compat53_pushfuncname(lua_State* L, lua_Debug* ar) {
    if (*ar->namewhat != '\0') /* is there a name? */
        lua_pushfstring(L, "function " LUA_QS, ar->name);
    else if (*ar->what == 'm') /* main? */
        lua_pushliteral(L, "main chunk");
    else if (*ar->what == 'C') {
        if (compat53_pushglobalfuncname(L, ar)) {
            lua_pushfstring(L, "function " LUA_QS, lua_tostring(L, -1));
            lua_remove(L, -2); /* remove name */
        }
        else
            lua_pushliteral(L, "?");
    }
    else
        lua_pushfstring(L, "function <%s:%d>", ar->short_src, ar->linedefined);
}
 
#define COMPAT53_LEVELS1 12 /* size of the first part of the stack */
#define COMPAT53_LEVELS2 10 /* size of the second part of the stack */
 
COMPAT53_API void luaL_traceback(lua_State* L, lua_State* L1, const char* msg, int level) {
    lua_Debug ar;
    int top = lua_gettop(L);
    int numlevels = compat53_countlevels(L1);
    int mark = (numlevels > COMPAT53_LEVELS1 + COMPAT53_LEVELS2) ? COMPAT53_LEVELS1 : 0;
    if (msg)
        lua_pushfstring(L, "%s\n", msg);
    lua_pushliteral(L, "stack traceback:");
    while (lua_getstack(L1, level++, &ar)) {
        if (level == mark) {                       /* too many levels? */
            lua_pushliteral(L, "\n\t...");        /* add a '...' */
            level = numlevels - COMPAT53_LEVELS2; /* and skip to last ones */
        }
        else {
            lua_getinfo(L1, "Slnt", &ar);
            lua_pushfstring(L, "\n\t%s:", ar.short_src);
            if (ar.currentline > 0)
                lua_pushfstring(L, "%d:", ar.currentline);
            lua_pushliteral(L, " in ");
            compat53_pushfuncname(L, &ar);
            lua_concat(L, lua_gettop(L) - top);
        }
    }
    lua_concat(L, lua_gettop(L) - top);
}
 
 
COMPAT53_API int luaL_fileresult(lua_State* L, int stat, const char* fname) {
    const char* serr = NULL;
    int en = errno; /* calls to Lua API may change this value */
    char buf[512] = { 0 };
    if (stat) {
        lua_pushboolean(L, 1);
        return 1;
    }
    else {
        lua_pushnil(L);
        serr = compat53_strerror(en, buf, sizeof(buf));
        if (fname)
            lua_pushfstring(L, "%s: %s", fname, serr);
        else
            lua_pushstring(L, serr);
        lua_pushnumber(L, (lua_Number)en);
        return 3;
    }
}
 
 
static int compat53_checkmode(lua_State* L, const char* mode, const char* modename, int err) {
    if (mode && strchr(mode, modename[0]) == NULL) {
        lua_pushfstring(L, "attempt to load a %s chunk (mode is '%s')", modename, mode);
        return err;
    }
    return LUA_OK;
}
 
 
typedef struct {
    lua_Reader reader;
    void* ud;
    int has_peeked_data;
    const char* peeked_data;
    size_t peeked_data_size;
} compat53_reader_data;
 
 
static const char* compat53_reader(lua_State* L, void* ud, size_t* size) {
    compat53_reader_data* data = (compat53_reader_data*)ud;
    if (data->has_peeked_data) {
        data->has_peeked_data = 0;
        *size = data->peeked_data_size;
        return data->peeked_data;
    }
    else
        return data->reader(L, data->ud, size);
}
 
 
COMPAT53_API int lua_load(lua_State* L, lua_Reader reader, void* data, const char* source, const char* mode) {
    int status = LUA_OK;
    compat53_reader_data compat53_data = { reader, data, 1, 0, 0 };
    compat53_data.peeked_data = reader(L, data, &(compat53_data.peeked_data_size));
    if (compat53_data.peeked_data && compat53_data.peeked_data_size && compat53_data.peeked_data[0] == LUA_SIGNATURE[0]) /* binary file? */
        status = compat53_checkmode(L, mode, "binary", LUA_ERRSYNTAX);
    else
        status = compat53_checkmode(L, mode, "text", LUA_ERRSYNTAX);
    if (status != LUA_OK)
        return status;
        /* we need to call the original 5.1 version of lua_load! */
#undef lua_load
    return lua_load(L, compat53_reader, &compat53_data, source);
#define lua_load COMPAT53_CONCAT(COMPAT53_PREFIX, _load_53)
}
 
 
typedef struct {
    int n;                                    /* number of pre-read characters */
    FILE* f;                                  /* file being read */
    char buff[COMPAT53_LUA_FILE_BUFFER_SIZE]; /* area for reading file */
} compat53_LoadF;
 
 
static const char* compat53_getF(lua_State* L, void* ud, size_t* size) {
    compat53_LoadF* lf = (compat53_LoadF*)ud;
    (void)L;            /* not used */
    if (lf->n > 0) {    /* are there pre-read characters to be read? */
        *size = lf->n; /* return them (chars already in buffer) */
        lf->n = 0;     /* no more pre-read characters */
    }
    else { /* read a block from file */
          /* 'fread' can return > 0 *and* set the EOF flag. If next call to
          'compat53_getF' called 'fread', it might still wait for user input.
          The next check avoids this problem. */
        if (feof(lf->f))
            return NULL;
        *size = fread(lf->buff, 1, sizeof(lf->buff), lf->f); /* read block */
    }
    return lf->buff;
}
 
 
static int compat53_errfile(lua_State* L, const char* what, int fnameindex) {
    char buf[512] = { 0 };
    const char* serr = compat53_strerror(errno, buf, sizeof(buf));
    const char* filename = lua_tostring(L, fnameindex) + 1;
    lua_pushfstring(L, "cannot %s %s: %s", what, filename, serr);
    lua_remove(L, fnameindex);
    return LUA_ERRFILE;
}
 
 
static int compat53_skipBOM(compat53_LoadF* lf) {
    const char* p = "\xEF\xBB\xBF"; /* UTF-8 BOM mark */
    int c;
    lf->n = 0;
    do {
        c = getc(lf->f);
        if (c == EOF || c != *(const unsigned char*)p++)
            return c;
        lf->buff[lf->n++] = (char)c; /* to be read by the parser */
    } while (*p != '\0');
    lf->n = 0;          /* prefix matched; discard it */
    return getc(lf->f); /* return next character */
}
 
 
/*
** reads the first character of file 'f' and skips an optional BOM mark
** in its beginning plus its first line if it starts with '#'. Returns
** true if it skipped the first line.  In any case, '*cp' has the
** first "valid" character of the file (after the optional BOM and
** a first-line comment).
*/
static int compat53_skipcomment(compat53_LoadF* lf, int* cp) {
    int c = *cp = compat53_skipBOM(lf);
    if (c == '#') { /* first line is a comment (Unix exec. file)? */
        do {       /* skip first line */
            c = getc(lf->f);
        } while (c != EOF && c != '\n');
        *cp = getc(lf->f); /* skip end-of-line, if present */
        return 1;          /* there was a comment */
    }
    else
        return 0; /* no comment */
}
 
 
COMPAT53_API int luaL_loadfilex(lua_State* L, const char* filename, const char* mode) {
    compat53_LoadF lf;
    int status, readstatus;
    int c;
    int fnameindex = lua_gettop(L) + 1; /* index of filename on the stack */
    if (filename == NULL) {
        lua_pushliteral(L, "=stdin");
        lf.f = stdin;
    }
    else {
        lua_pushfstring(L, "@%s", filename);
#if defined(_MSC_VER)
        /* This code is here to stop a deprecation error that stops builds
         * if a certain macro is defined. While normally not caring would
         * be best, some header-only libraries and builds can't afford to
         * dictate this to the user. A quick check shows that fopen_s this
         * goes back to VS 2005, and _fsopen goes back to VS 2003 .NET,
         * possibly even before that so we don't need to do any version
         * number checks, since this has been there since forever.  */
 
        /* TO USER: if you want the behavior of typical fopen_s/fopen,
         * which does lock the file on VC++, define the macro used below to 0 */
#if COMPAT53_FOPEN_NO_LOCK
        lf.f = _fsopen(filename, "r", _SH_DENYNO); /* do not lock the file in any way */
        if (lf.f == NULL)
            return compat53_errfile(L, "open", fnameindex);
#else  /* use default locking version */
        if (fopen_s(&lf.f, filename, "r") != 0)
            return compat53_errfile(L, "open", fnameindex);
#endif /* Locking vs. No-locking fopen variants */
#else
        lf.f = fopen(filename, "r"); /* default stdlib doesn't forcefully lock files here */
        if (lf.f == NULL)
            return compat53_errfile(L, "open", fnameindex);
#endif
    }
    if (compat53_skipcomment(&lf, &c))       /* read initial portion */
        lf.buff[lf.n++] = '\n';             /* add line to correct line numbers */
    if (c == LUA_SIGNATURE[0] && filename) { /* binary file? */
#if defined(_MSC_VER)
        if (freopen_s(&lf.f, filename, "rb", lf.f) != 0)
            return compat53_errfile(L, "reopen", fnameindex);
#else
        lf.f = freopen(filename, "rb", lf.f); /* reopen in binary mode */
        if (lf.f == NULL)
            return compat53_errfile(L, "reopen", fnameindex);
#endif
        compat53_skipcomment(&lf, &c); /* re-read initial portion */
    }
    if (c != EOF)
        lf.buff[lf.n++] = (char)c; /* 'c' is the first character of the stream */
    status = lua_load(L, &compat53_getF, &lf, lua_tostring(L, -1), mode);
    readstatus = ferror(lf.f);
    if (filename)
        fclose(lf.f); /* close file (even in case of errors) */
    if (readstatus) {
        lua_settop(L, fnameindex); /* ignore results from 'lua_load' */
        return compat53_errfile(L, "read", fnameindex);
    }
    lua_remove(L, fnameindex);
    return status;
}
 
 
COMPAT53_API int luaL_loadbufferx(lua_State* L, const char* buff, size_t sz, const char* name, const char* mode) {
    int status = LUA_OK;
    if (sz > 0 && buff[0] == LUA_SIGNATURE[0]) {
        status = compat53_checkmode(L, mode, "binary", LUA_ERRSYNTAX);
    }
    else {
        status = compat53_checkmode(L, mode, "text", LUA_ERRSYNTAX);
    }
    if (status != LUA_OK)
        return status;
    return luaL_loadbuffer(L, buff, sz, name);
}
 
 
#if !defined(l_inspectstat) \
     && (defined(unix) || defined(__unix) || defined(__unix__) || defined(__TOS_AIX__) || defined(_SYSTYPE_BSD) || (defined(__APPLE__) && defined(__MACH__)))
/* some form of unix; check feature macros in unistd.h for details */
#include <unistd.h>
/* check posix version; the relevant include files and macros probably
 * were available before 2001, but I'm not sure */
#if defined(_POSIX_VERSION) && _POSIX_VERSION >= 200112L
#include <sys/wait.h>
#define l_inspectstat(stat, what)   \
    if (WIFEXITED(stat)) {         \
        stat = WEXITSTATUS(stat); \
    }                              \
    else if (WIFSIGNALED(stat)) {  \
        stat = WTERMSIG(stat);    \
        what = "signal";          \
    }
#endif
#endif
 
/* provide default (no-op) version */
#if !defined(l_inspectstat)
#define l_inspectstat(stat, what) ((void)0)
#endif
 
 
COMPAT53_API int luaL_execresult(lua_State* L, int stat) {
    const char* what = "exit";
    if (stat == -1)
        return luaL_fileresult(L, 0, NULL);
    else {
        l_inspectstat(stat, what);
        if (*what == 'e' && stat == 0)
            lua_pushboolean(L, 1);
        else
            lua_pushnil(L);
        lua_pushstring(L, what);
        lua_pushinteger(L, stat);
        return 3;
    }
}
 
 
COMPAT53_API void luaL_buffinit(lua_State* L, luaL_Buffer_53* B) {
    /* make it crash if used via pointer to a 5.1-style luaL_Buffer */
    B->b.p = NULL;
    B->b.L = NULL;
    B->b.lvl = 0;
    /* reuse the buffer from the 5.1-style luaL_Buffer though! */
    B->ptr = B->b.buffer;
    B->capacity = LUAL_BUFFERSIZE;
    B->nelems = 0;
    B->L2 = L;
}
 
 
COMPAT53_API char* luaL_prepbuffsize(luaL_Buffer_53* B, size_t s) {
    if (B->capacity - B->nelems < s) { /* needs to grow */
        char* newptr = NULL;
        size_t newcap = B->capacity * 2;
        if (newcap - B->nelems < s)
            newcap = B->nelems + s;
        if (newcap < B->capacity) /* overflow */
            luaL_error(B->L2, "buffer too large");
#if defined(LUA_VERSION_NUM) && LUA_VERSION_NUM >= 504
        newptr = (char*)lua_newuserdatauv(B->L2, newcap, 0);
#else
        newptr = (char*)lua_newuserdata(B->L2, newcap);
#endif
        memcpy(newptr, B->ptr, B->nelems);
        if (B->ptr != B->b.buffer)
            lua_replace(B->L2, -2); /* remove old buffer */
        B->ptr = newptr;
        B->capacity = newcap;
    }
    return B->ptr + B->nelems;
}
 
 
COMPAT53_API void luaL_addlstring(luaL_Buffer_53* B, const char* s, size_t l) {
    memcpy(luaL_prepbuffsize(B, l), s, l);
    luaL_addsize(B, l);
}
 
 
COMPAT53_API void luaL_addvalue(luaL_Buffer_53* B) {
    size_t len = 0;
    const char* s = lua_tolstring(B->L2, -1, &len);
    if (!s)
        luaL_error(B->L2, "cannot convert value to string");
    if (B->ptr != B->b.buffer)
        lua_insert(B->L2, -2); /* userdata buffer must be at stack top */
    luaL_addlstring(B, s, len);
    lua_remove(B->L2, B->ptr != B->b.buffer ? -2 : -1);
}
 
 
void luaL_pushresult(luaL_Buffer_53* B) {
    lua_pushlstring(B->L2, B->ptr, B->nelems);
    if (B->ptr != B->b.buffer)
        lua_replace(B->L2, -2); /* remove userdata buffer */
}
 
 
#endif /* Lua 5.1 */
 
 
 
/* definitions for Lua 5.1 and Lua 5.2 */
#if defined(LUA_VERSION_NUM) && LUA_VERSION_NUM <= 502
 
 
COMPAT53_API int lua_geti(lua_State* L, int index, lua_Integer i) {
    index = lua_absindex(L, index);
    lua_pushinteger(L, i);
    lua_gettable(L, index);
    return lua_type(L, -1);
}
 
 
COMPAT53_API int lua_isinteger(lua_State* L, int index) {
    if (lua_type(L, index) == LUA_TNUMBER) {
        lua_Number n = lua_tonumber(L, index);
        lua_Integer i = lua_tointeger(L, index);
        if (i == n)
            return 1;
    }
    return 0;
}
 
 
COMPAT53_API lua_Integer lua_tointegerx(lua_State* L, int i, int* isnum) {
    int ok = 0;
    lua_Number n = lua_tonumberx(L, i, &ok);
    if (ok) {
        if (n == (lua_Integer)n) {
            if (isnum)
                *isnum = 1;
            return (lua_Integer)n;
        }
    }
    if (isnum)
        *isnum = 0;
    return 0;
}
 
 
static void compat53_reverse(lua_State* L, int a, int b) {
    for (; a < b; ++a, --b) {
        lua_pushvalue(L, a);
        lua_pushvalue(L, b);
        lua_replace(L, a);
        lua_replace(L, b);
    }
}
 
 
COMPAT53_API void lua_rotate(lua_State* L, int idx, int n) {
    int n_elems = 0;
    idx = lua_absindex(L, idx);
    n_elems = lua_gettop(L) - idx + 1;
    if (n < 0)
        n += n_elems;
    if (n > 0 && n < n_elems) {
        luaL_checkstack(L, 2, "not enough stack slots available");
        n = n_elems - n;
        compat53_reverse(L, idx, idx + n - 1);
        compat53_reverse(L, idx + n, idx + n_elems - 1);
        compat53_reverse(L, idx, idx + n_elems - 1);
    }
}
 
 
COMPAT53_API void lua_seti(lua_State* L, int index, lua_Integer i) {
    luaL_checkstack(L, 1, "not enough stack slots available");
    index = lua_absindex(L, index);
    lua_pushinteger(L, i);
    lua_insert(L, -2);
    lua_settable(L, index);
}
 
 
#if !defined(lua_str2number)
#define lua_str2number(s, p) strtod((s), (p))
#endif
 
COMPAT53_API size_t lua_stringtonumber(lua_State* L, const char* s) {
    char* endptr;
    lua_Number n = lua_str2number(s, &endptr);
    if (endptr != s) {
        while (*endptr != '\0' && isspace((unsigned char)*endptr))
            ++endptr;
        if (*endptr == '\0') {
            lua_pushnumber(L, n);
            return endptr - s + 1;
        }
    }
    return 0;
}
 
 
COMPAT53_API const char* luaL_tolstring(lua_State* L, int idx, size_t* len) {
    if (!luaL_callmeta(L, idx, "__tostring")) {
        int t = lua_type(L, idx), tt = 0;
        char const* name = NULL;
        switch (t) {
        case LUA_TNIL:
            lua_pushliteral(L, "nil");
            break;
        case LUA_TSTRING:
        case LUA_TNUMBER:
            lua_pushvalue(L, idx);
            break;
        case LUA_TBOOLEAN:
            if (lua_toboolean(L, idx))
                lua_pushliteral(L, "true");
            else
                lua_pushliteral(L, "false");
            break;
        default:
            tt = luaL_getmetafield(L, idx, "__name");
            name = (tt == LUA_TSTRING) ? lua_tostring(L, -1) : lua_typename(L, t);
            lua_pushfstring(L, "%s: %p", name, lua_topointer(L, idx));
            if (tt != LUA_TNIL)
                lua_replace(L, -2);
            break;
        }
    }
    else {
        if (!lua_isstring(L, -1))
            luaL_error(L, "'__tostring' must return a string");
    }
    return lua_tolstring(L, -1, len);
}
 
 
COMPAT53_API void luaL_requiref(lua_State* L, const char* modname, lua_CFunction openf, int glb) {
    luaL_checkstack(L, 3, "not enough stack slots available");
    luaL_getsubtable(L, LUA_REGISTRYINDEX, "_LOADED");
    if (lua_getfield(L, -1, modname) == LUA_TNIL) {
        lua_pop(L, 1);
        lua_pushcfunction(L, openf);
        lua_pushstring(L, modname);
        lua_call(L, 1, 1);
        lua_pushvalue(L, -1);
        lua_setfield(L, -3, modname);
    }
    if (glb) {
        lua_pushvalue(L, -1);
        lua_setglobal(L, modname);
    }
    lua_replace(L, -2);
}
 
 
#endif /* Lua 5.1 and 5.2 */
 
 
#endif /* KEPLER_PROJECT_COMPAT53_C_ */
 
 
/*********************************************************************
 * This file contains parts of Lua 5.2's and Lua 5.3's source code:
 *
 * Copyright (C) 1994-2014 Lua.org, PUC-Rio.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *********************************************************************/