marshal.c

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/**********************************************************************

  marshal.c -

  $Author: akr $
  $Date: 2005/12/14 03:04:14 $
  created at: Thu Apr 27 16:30:01 JST 1995

  Copyright (C) 1993-2003 Yukihiro Matsumoto

**********************************************************************/

#include "ruby.h"
#include "rubyio.h"
#include "st.h"
#include "util.h"

#include <math.h>
#ifdef HAVE_FLOAT_H
#include <float.h>
#endif
#ifdef HAVE_IEEEFP_H
#include <ieeefp.h>
#endif

#define BITSPERSHORT (2*CHAR_BIT)
#define SHORTMASK ((1<<BITSPERSHORT)-1)
#define SHORTDN(x) RSHIFT(x,BITSPERSHORT)

#if SIZEOF_SHORT == SIZEOF_BDIGITS
#define SHORTLEN(x) (x)
#else
static int
shortlen(len, ds)
    long len;
    BDIGIT *ds;
{
    BDIGIT num;
    int offset = 0;

    num = ds[len-1];
    while (num) {
        num = SHORTDN(num);
        offset++;
    }
    return (len - 1)*sizeof(BDIGIT)/2 + offset;
}
#define SHORTLEN(x) shortlen((x),d)
#endif

#define MARSHAL_MAJOR   4
#define MARSHAL_MINOR   8

#define TYPE_NIL        '0'
#define TYPE_TRUE       'T'
#define TYPE_FALSE      'F'
#define TYPE_FIXNUM     'i'

#define TYPE_EXTENDED   'e'
#define TYPE_UCLASS     'C'
#define TYPE_OBJECT     'o'
#define TYPE_DATA       'd'
#define TYPE_USERDEF    'u'
#define TYPE_USRMARSHAL 'U'
#define TYPE_FLOAT      'f'
#define TYPE_BIGNUM     'l'
#define TYPE_STRING     '"'
#define TYPE_REGEXP     '/'
#define TYPE_ARRAY      '['
#define TYPE_HASH       '{'
#define TYPE_HASH_DEF   '}'
#define TYPE_STRUCT     'S'
#define TYPE_MODULE_OLD 'M'
#define TYPE_CLASS      'c'
#define TYPE_MODULE     'm'

#define TYPE_SYMBOL     ':'
#define TYPE_SYMLINK    ';'

#define TYPE_IVAR       'I'
#define TYPE_LINK       '@'

static ID s_dump, s_load, s_mdump, s_mload;
static ID s_dump_data, s_load_data, s_alloc;
static ID s_getc, s_read, s_write, s_binmode;

struct dump_arg {
    VALUE obj;
    VALUE str, dest;
    st_table *symbols;
    st_table *data;
    int taint;
};

struct dump_call_arg {
    VALUE obj;
    struct dump_arg *arg;
    int limit;
};

static VALUE
class2path(klass)
    VALUE klass;
{
    VALUE path = rb_class_path(klass);
    char *n = RSTRING(path)->ptr;

    if (n[0] == '#') {
        rb_raise(rb_eTypeError, "can't dump anonymous %s %s",
                 (TYPE(klass) == T_CLASS ? "class" : "module"),
                 n);
    }
    if (rb_path2class(n) != rb_class_real(klass)) {
        rb_raise(rb_eTypeError, "%s can't be referred", n);
    }
    return path;
}

static void w_long (long, struct dump_arg*);

static void
w_nbyte(s, n, arg)
    char *s;
    int n;
    struct dump_arg *arg;
{
    VALUE buf = arg->str;
    rb_str_buf_cat(buf, s, n);
    if (arg->dest && RSTRING(buf)->len >= BUFSIZ) {
        if (arg->taint) OBJ_TAINT(buf);
        rb_io_write(arg->dest, buf);
        rb_str_resize(buf, 0);
    }
}

static void
w_byte(c, arg)
    char c;
    struct dump_arg *arg;
{
    w_nbyte(&c, 1, arg);
}

static void
w_bytes(s, n, arg)
    char *s;
    int n;
    struct dump_arg *arg;
{
    w_long(n, arg);
    w_nbyte(s, n, arg);
}

static void
w_short(x, arg)
    int x;
    struct dump_arg *arg;
{
    w_byte((x >> 0) & 0xff, arg);
    w_byte((x >> 8) & 0xff, arg);
}

static void
w_long(x, arg)
    long x;
    struct dump_arg *arg;
{
    char buf[sizeof(long)+1];
    int i, len = 0;

#if SIZEOF_LONG > 4
    if (!(RSHIFT(x, 31) == 0 || RSHIFT(x, 31) == -1)) {
        /* big long does not fit in 4 bytes */
        rb_raise(rb_eTypeError, "long too big to dump");
    }
#endif

    if (x == 0) {
        w_byte(0, arg);
        return;
    }
    if (0 < x && x < 123) {
        w_byte(x + 5, arg);
        return;
    }
    if (-124 < x && x < 0) {
        w_byte((x - 5)&0xff, arg);
        return;
    }
    for (i=1;i<sizeof(long)+1;i++) {
        buf[i] = x & 0xff;
        x = RSHIFT(x,8);
        if (x == 0) {
            buf[0] = i;
            break;
        }
        if (x == -1) {
            buf[0] = -i;
            break;
        }
    }
    len = i;
    for (i=0;i<=len;i++) {
        w_byte(buf[i], arg);
    }
}

#ifdef DBL_MANT_DIG
#define DECIMAL_MANT (53-16)    /* from IEEE754 double precision */

#if DBL_MANT_DIG > 32
#define MANT_BITS 32
#elif DBL_MANT_DIG > 24
#define MANT_BITS 24
#elif DBL_MANT_DIG > 16
#define MANT_BITS 16
#else
#define MANT_BITS 8
#endif

static int
save_mantissa(d, buf)
    double d;
    char *buf;
{
    int e, i = 0;
    unsigned long m;
    double n;

    d = modf(ldexp(frexp(fabs(d), &e), DECIMAL_MANT), &d);
    if (d > 0) {
        buf[i++] = 0;
        do {
            d = modf(ldexp(d, MANT_BITS), &n);
            m = (unsigned long)n;
#if MANT_BITS > 24
            buf[i++] = m >> 24;
#endif
#if MANT_BITS > 16
            buf[i++] = m >> 16;
#endif
#if MANT_BITS > 8
            buf[i++] = m >> 8;
#endif
            buf[i++] = m;
        } while (d > 0);
        while (!buf[i - 1]) --i;
    }
    return i;
}

static double
load_mantissa(d, buf, len)
    double d;
    const char *buf;
    int len;
{
    if (--len > 0 && !*buf++) { /* binary mantissa mark */
        int e, s = d < 0, dig = 0;
        unsigned long m;

        modf(ldexp(frexp(fabs(d), &e), DECIMAL_MANT), &d);
        do {
            m = 0;
            switch (len) {
              default: m = *buf++ & 0xff;
#if MANT_BITS > 24
              case 3: m = (m << 8) | (*buf++ & 0xff);
#endif
#if MANT_BITS > 16
              case 2: m = (m << 8) | (*buf++ & 0xff);
#endif
#if MANT_BITS > 8
              case 1: m = (m << 8) | (*buf++ & 0xff);
#endif
            }
            dig -= len < MANT_BITS / 8 ? 8 * (unsigned)len : MANT_BITS;
            d += ldexp((double)m, dig);
        } while ((len -= MANT_BITS / 8) > 0);
        d = ldexp(d, e - DECIMAL_MANT);
        if (s) d = -d;
    }
    return d;
}
#else
#define load_mantissa(d, buf, len) (d)
#define save_mantissa(d, buf) 0
#endif

#ifdef DBL_DIG
#define FLOAT_DIG (DBL_DIG+2)
#else
#define FLOAT_DIG 17
#endif

static void
w_float(d, arg)
    double d;
    struct dump_arg *arg;
{
    char buf[100];

    if (isinf(d)) {
        if (d < 0) strcpy(buf, "-inf");
        else       strcpy(buf, "inf");
    }
    else if (isnan(d)) {
        strcpy(buf, "nan");
    }
    else if (d == 0.0) {
        if (1.0/d < 0) strcpy(buf, "-0");
        else           strcpy(buf, "0");
    }
    else {
        int len;

        /* xxx: should not use system's sprintf(3) */
        sprintf(buf, "%.*g", FLOAT_DIG, d);
        len = strlen(buf);
        w_bytes(buf, len + save_mantissa(d, buf + len), arg);
        return;
    }
    w_bytes(buf, strlen(buf), arg);
}

static void
w_symbol(id, arg)
    ID id;
    struct dump_arg *arg;
{
    char *sym = rb_id2name(id);
    st_data_t num;

    if (st_lookup(arg->symbols, id, &num)) {
        w_byte(TYPE_SYMLINK, arg);
        w_long((long)num, arg);
    }
    else {
        w_byte(TYPE_SYMBOL, arg);
        w_bytes(sym, strlen(sym), arg);
        st_add_direct(arg->symbols, id, arg->symbols->num_entries);
    }
}

static void
w_unique(s, arg)
    char *s;
    struct dump_arg *arg;
{
    if (s[0] == '#') {
        rb_raise(rb_eTypeError, "can't dump anonymous class %s", s);
    }
    w_symbol(rb_intern(s), arg);
}

static void w_object (VALUE,struct dump_arg*,int);

static int
hash_each(key, value, arg)
    VALUE key, value;
    struct dump_call_arg *arg;
{
    w_object(key, arg->arg, arg->limit);
    w_object(value, arg->arg, arg->limit);
    return ST_CONTINUE;
}

static void
w_extended(klass, arg, check)
    VALUE klass;
    struct dump_arg *arg;
    int check;
{
    char *path;

    if (FL_TEST(klass, FL_SINGLETON)) {
        if (check && RCLASS(klass)->m_tbl->num_entries ||
            (RCLASS(klass)->iv_tbl && RCLASS(klass)->iv_tbl->num_entries > 1)) {
            rb_raise(rb_eTypeError, "singleton can't be dumped");
        }
        klass = RCLASS(klass)->super;
    }
    while (BUILTIN_TYPE(klass) == T_ICLASS) {
        path = rb_class2name(RBASIC(klass)->klass);
        w_byte(TYPE_EXTENDED, arg);
        w_unique(path, arg);
        klass = RCLASS(klass)->super;
    }
}

static void
w_class(type, obj, arg, check)
    int type;
    VALUE obj;
    struct dump_arg *arg;
    int check;
{
    char *path;

    VALUE klass = CLASS_OF(obj);
    w_extended(klass, arg, check);
    w_byte(type, arg);
    path = RSTRING(class2path(rb_class_real(klass)))->ptr;
    w_unique(path, arg);
}

static void
w_uclass(obj, base_klass, arg)
    VALUE obj, base_klass;
    struct dump_arg *arg;
{
    VALUE klass = CLASS_OF(obj);

    w_extended(klass, arg, Qtrue);
    klass = rb_class_real(klass);
    if (klass != base_klass) {
        w_byte(TYPE_UCLASS, arg);
        w_unique(RSTRING(class2path(klass))->ptr, arg);
    }
}

static int
w_obj_each(id, value, arg)
    ID id;
    VALUE value;
    struct dump_call_arg *arg;
{
    w_symbol(id, arg->arg);
    w_object(value, arg->arg, arg->limit);
    return ST_CONTINUE;
}

static void
w_ivar(tbl, arg)
    st_table *tbl;
    struct dump_call_arg *arg;
{
    if (tbl) {
        w_long(tbl->num_entries, arg->arg);
        st_foreach_safe(tbl, w_obj_each, (st_data_t)arg);
    }
    else {
        w_long(0, arg->arg);
    }
}

static void
w_object(obj, arg, limit)
    VALUE obj;
    struct dump_arg *arg;
    int limit;
{
    struct dump_call_arg c_arg;
    st_table *ivtbl = 0;
    st_data_t num;

    if (limit == 0) {
        rb_raise(rb_eArgError, "exceed depth limit");
    }

    limit--;
    c_arg.limit = limit;
    c_arg.arg = arg;

    if (st_lookup(arg->data, obj, &num)) {
        w_byte(TYPE_LINK, arg);
        w_long((long)num, arg);
        return;
    }

    if (ivtbl = rb_generic_ivar_table(obj)) {
        w_byte(TYPE_IVAR, arg);
    }
    if (obj == Qnil) {
        w_byte(TYPE_NIL, arg);
    }
    else if (obj == Qtrue) {
        w_byte(TYPE_TRUE, arg);
    }
    else if (obj == Qfalse) {
        w_byte(TYPE_FALSE, arg);
    }
    else if (FIXNUM_P(obj)) {
#if SIZEOF_LONG <= 4
        w_byte(TYPE_FIXNUM, arg);
        w_long(FIX2INT(obj), arg);
#else
        if (RSHIFT((long)obj, 31) == 0 || RSHIFT((long)obj, 31) == -1) {
            w_byte(TYPE_FIXNUM, arg);
            w_long(FIX2LONG(obj), arg);
        }
        else {
            w_object(rb_int2big(FIX2LONG(obj)), arg, limit);
        }
#endif
    }
    else if (SYMBOL_P(obj)) {
        w_symbol(SYM2ID(obj), arg);
    }
    else {
        if (OBJ_TAINTED(obj)) arg->taint = Qtrue;

        st_add_direct(arg->data, obj, arg->data->num_entries);
        if (rb_respond_to(obj, s_mdump)) {
            VALUE v;

            v = rb_funcall(obj, s_mdump, 0, 0);
            w_class(TYPE_USRMARSHAL, obj, arg, Qfalse);
            w_object(v, arg, limit);
            if (ivtbl) w_ivar(0, &c_arg);
            return;
        }
        if (rb_respond_to(obj, s_dump)) {
            VALUE v;

            v = rb_funcall(obj, s_dump, 1, INT2NUM(limit));
            if (TYPE(v) != T_STRING) {
                rb_raise(rb_eTypeError, "_dump() must return string");
            }
            if (!ivtbl && (ivtbl = rb_generic_ivar_table(v))) {
                w_byte(TYPE_IVAR, arg);
            }
            w_class(TYPE_USERDEF, obj, arg, Qfalse);
            w_bytes(RSTRING(v)->ptr, RSTRING(v)->len, arg);
            if (ivtbl) {
                w_ivar(ivtbl, &c_arg);
            }
            return;
        }

        switch (BUILTIN_TYPE(obj)) {
          case T_CLASS:
            if (FL_TEST(obj, FL_SINGLETON)) {
                rb_raise(rb_eTypeError, "singleton class can't be dumped");
            }
            w_byte(TYPE_CLASS, arg);
            {
                VALUE path = class2path(obj);
                w_bytes(RSTRING(path)->ptr, RSTRING(path)->len, arg);
            }
            break;

          case T_MODULE:
            w_byte(TYPE_MODULE, arg);
            {
                VALUE path = class2path(obj);
                w_bytes(RSTRING(path)->ptr, RSTRING(path)->len, arg);
            }
            break;

          case T_FLOAT:
            w_byte(TYPE_FLOAT, arg);
            w_float(RFLOAT(obj)->value, arg);
            break;

          case T_BIGNUM:
            w_byte(TYPE_BIGNUM, arg);
            {
                char sign = RBIGNUM(obj)->sign ? '+' : '-';
                long len = RBIGNUM(obj)->len;
                BDIGIT *d = RBIGNUM(obj)->digits;

                w_byte(sign, arg);
                w_long(SHORTLEN(len), arg); /* w_short? */
                while (len--) {
#if SIZEOF_BDIGITS > SIZEOF_SHORT
                    BDIGIT num = *d;
                    int i;

                    for (i=0; i<SIZEOF_BDIGITS; i+=SIZEOF_SHORT) {
                        w_short(num & SHORTMASK, arg);
                        num = SHORTDN(num);
                        if (len == 0 && num == 0) break;
                    }
#else
                    w_short(*d, arg);
#endif
                    d++;
                }
            }
            break;

          case T_STRING:
            w_uclass(obj, rb_cString, arg);
            w_byte(TYPE_STRING, arg);
            w_bytes(RSTRING(obj)->ptr, RSTRING(obj)->len, arg);
            break;

          case T_REGEXP:
            w_uclass(obj, rb_cRegexp, arg);
            w_byte(TYPE_REGEXP, arg);
            w_bytes(RREGEXP(obj)->str, RREGEXP(obj)->len, arg);
            w_byte(rb_reg_options(obj), arg);
            break;

          case T_ARRAY:
            w_uclass(obj, rb_cArray, arg);
            w_byte(TYPE_ARRAY, arg);
            {
                long len = RARRAY(obj)->len;
                VALUE *ptr = RARRAY(obj)->ptr;

                w_long(len, arg);
                while (len--) {
                    w_object(*ptr, arg, limit);
                    ptr++;
                }
            }
            break;

          case T_HASH:
            w_uclass(obj, rb_cHash, arg);
            if (NIL_P(RHASH(obj)->ifnone)) {
                w_byte(TYPE_HASH, arg);
            }
            else if (FL_TEST(obj, FL_USER2)) {
                /* FL_USER2 means HASH_PROC_DEFAULT (see hash.c) */
                rb_raise(rb_eTypeError, "can't dump hash with default proc");
            }
            else {
                w_byte(TYPE_HASH_DEF, arg);
            }
            w_long(RHASH(obj)->tbl->num_entries, arg);
            rb_hash_foreach(obj, hash_each, (st_data_t)&c_arg);
            if (!NIL_P(RHASH(obj)->ifnone)) {
                w_object(RHASH(obj)->ifnone, arg, limit);
            }
            break;

          case T_STRUCT:
            w_class(TYPE_STRUCT, obj, arg, Qtrue);
            {
                long len = RSTRUCT(obj)->len;
                VALUE mem;
                long i;

                w_long(len, arg);
                mem = rb_struct_members(obj);
                for (i=0; i<len; i++) {
                    w_symbol(SYM2ID(RARRAY(mem)->ptr[i]), arg);
                    w_object(RSTRUCT(obj)->ptr[i], arg, limit);
                }
            }
            break;

          case T_OBJECT:
            w_class(TYPE_OBJECT, obj, arg, Qtrue);
            w_ivar(ROBJECT(obj)->iv_tbl, &c_arg);
            break;

          case T_DATA:
            {
                VALUE v;

                w_class(TYPE_DATA, obj, arg, Qtrue);
                if (!rb_respond_to(obj, s_dump_data)) {
                    rb_raise(rb_eTypeError,
                             "no marshal_dump is defined for class %s",
                             rb_obj_classname(obj));
                }
                v = rb_funcall(obj, s_dump_data, 0);
                w_object(v, arg, limit);
            }
            break;

          default:
            rb_raise(rb_eTypeError, "can't dump %s",
                     rb_obj_classname(obj));
            break;
        }
    }
    if (ivtbl) {
        w_ivar(ivtbl, &c_arg);
    }
}

static VALUE
dump(arg)
    struct dump_call_arg *arg;
{
    w_object(arg->obj, arg->arg, arg->limit);
    if (arg->arg->dest) {
        rb_io_write(arg->arg->dest, arg->arg->str);
        rb_str_resize(arg->arg->str, 0);
    }
    return 0;
}

static VALUE
dump_ensure(arg)
    struct dump_arg *arg;
{
    st_free_table(arg->symbols);
    st_free_table(arg->data);
    if (arg->taint) {
        OBJ_TAINT(arg->str);
    }
    return 0;
}

/*
 * call-seq:
 *      dump( obj [, anIO] , limit=--1 ) => anIO
 *
 * Serializes obj and all descendent objects. If anIO is
 * specified, the serialized data will be written to it, otherwise the
 * data will be returned as a String. If limit is specified, the
 * traversal of subobjects will be limited to that depth. If limit is
 * negative, no checking of depth will be performed.
 *
 *     class Klass
 *       def initialize(str)
 *         @str = str
 *       end
 *       def sayHello
 *         @str
 *       end
 *     end
 *
 * (produces no output)
 *
 *     o = Klass.new("hello\n")
 *     data = Marshal.dump(o)
 *     obj = Marshal.load(data)
 *     obj.sayHello   #=> "hello\n"
 */
static VALUE
marshal_dump(argc, argv)
    int argc;
    VALUE* argv;
{
    VALUE obj, port, a1, a2;
    int limit = -1;
    struct dump_arg arg;
    struct dump_call_arg c_arg;

    port = Qnil;
    rb_scan_args(argc, argv, "12", &obj, &a1, &a2);
    if (argc == 3) {
        if (!NIL_P(a2)) limit = NUM2INT(a2);
        if (NIL_P(a1)) goto type_error;
        port = a1;
    }
    else if (argc == 2) {
        if (FIXNUM_P(a1)) limit = FIX2INT(a1);
        else if (NIL_P(a1)) goto type_error;
        else port = a1;
    }
    arg.dest = 0;
    if (!NIL_P(port)) {
        if (!rb_respond_to(port, s_write)) {
          type_error:
            rb_raise(rb_eTypeError, "instance of IO needed");
        }
        arg.str = rb_str_buf_new(0);
        arg.dest = port;
        if (rb_respond_to(port, s_binmode)) {
            rb_funcall2(port, s_binmode, 0, 0);
        }
    }
    else {
        port = rb_str_buf_new(0);
        arg.str = port;
    }

    arg.symbols = st_init_numtable();
    arg.data    = st_init_numtable();
    arg.taint   = Qfalse;
    c_arg.obj   = obj;
    c_arg.arg   = &arg;
    c_arg.limit = limit;

    w_byte(MARSHAL_MAJOR, &arg);
    w_byte(MARSHAL_MINOR, &arg);

    rb_ensure(dump, (VALUE)&c_arg, dump_ensure, (VALUE)&arg);

    return port;
}

struct load_arg {
    VALUE src;
    long offset;
    st_table *symbols;
    VALUE data;
    VALUE proc;
    int taint;
};

static VALUE r_object (struct load_arg *arg);

static int
r_byte(arg)
    struct load_arg *arg;
{
    int c;

    if (TYPE(arg->src) == T_STRING) {
        if (RSTRING(arg->src)->len > arg->offset) {
            c = (unsigned char)RSTRING(arg->src)->ptr[arg->offset++];
        }
        else {
            rb_raise(rb_eArgError, "marshal data too short");
        }
    }
    else {
        VALUE src = arg->src;
        VALUE v = rb_funcall2(src, s_getc, 0, 0);
        if (NIL_P(v)) rb_eof_error();
        c = (unsigned char)FIX2INT(v);
    }
    return c;
}

static void
long_toobig(size)
    int size;
{
    rb_raise(rb_eTypeError, "long too big for this architecture (size %d, given %d)",
             sizeof(long), size);
}

#undef SIGN_EXTEND_CHAR
#if __STDC__
# define SIGN_EXTEND_CHAR(c) ((signed char)(c))
#else  /* not __STDC__ */
/* As in Harbison and Steele.  */
# define SIGN_EXTEND_CHAR(c) ((((unsigned char)(c)) ^ 128) - 128)
#endif

static long
r_long(arg)
    struct load_arg *arg;
{
    register long x;
    int c = SIGN_EXTEND_CHAR(r_byte(arg));
    long i;

    if (c == 0) return 0;
    if (c > 0) {
        if (4 < c && c < 128) {
            return c - 5;
        }
        if (c > sizeof(long)) long_toobig(c);
        x = 0;
        for (i=0;i<c;i++) {
            x |= (long)r_byte(arg) << (8*i);
        }
    }
    else {
        if (-129 < c && c < -4) {
            return c + 5;
        }
        c = -c;
        if (c > sizeof(long)) long_toobig(c);
        x = -1;
        for (i=0;i<c;i++) {
            x &= ~((long)0xff << (8*i));
            x |= (long)r_byte(arg) << (8*i);
        }
    }
    return x;
}

#define r_bytes(arg) r_bytes0(r_long(arg), (arg))

static VALUE
r_bytes0(len, arg)
    long len;
    struct load_arg *arg;
{
    VALUE str;

    if (len == 0) return rb_str_new(0, 0);
    if (TYPE(arg->src) == T_STRING) {
        if (RSTRING(arg->src)->len > arg->offset) {
            str = rb_str_new(RSTRING(arg->src)->ptr+arg->offset, len);
            arg->offset += len;
        }
        else {
          too_short:
            rb_raise(rb_eArgError, "marshal data too short");
        }
    }
    else {
        VALUE src = arg->src;
        VALUE n = LONG2NUM(len);
        str = rb_funcall2(src, s_read, 1, &n);
        if (NIL_P(str)) goto too_short;
        StringValue(str);
        if (RSTRING(str)->len != len) goto too_short;
        if (OBJ_TAINTED(str)) arg->taint = Qtrue;
    }
    return str;
}

static ID
r_symlink(arg)
    struct load_arg *arg;
{
    ID id;
    long num = r_long(arg);

    if (st_lookup(arg->symbols, num, &id)) {
        return id;
    }
    rb_raise(rb_eArgError, "bad symbol");
}

static ID
r_symreal(arg)
    struct load_arg *arg;
{
    ID id;

    id = rb_intern(RSTRING(r_bytes(arg))->ptr);
    st_insert(arg->symbols, arg->symbols->num_entries, id);

    return id;
}

static ID
r_symbol(arg)
    struct load_arg *arg;
{
    if (r_byte(arg) == TYPE_SYMLINK) {
        return r_symlink(arg);
    }
    return r_symreal(arg);
}

static char*
r_unique(arg)
    struct load_arg *arg;
{
    return rb_id2name(r_symbol(arg));
}

static VALUE
r_string(arg)
    struct load_arg *arg;
{
    return r_bytes(arg);
}

static VALUE
r_entry(v, arg)
    VALUE v;
    struct load_arg *arg;
{
    rb_hash_aset(arg->data, INT2FIX(RHASH(arg->data)->tbl->num_entries), v);
    if (arg->taint) OBJ_TAINT(v);
    return v;
}

static void
r_ivar(obj, arg)
    VALUE obj;
    struct load_arg *arg;
{
    long len;

    len = r_long(arg);
    if (len > 0) {
        while (len--) {
            ID id = r_symbol(arg);
            VALUE val = r_object(arg);
            rb_ivar_set(obj, id, val);
        }
    }
}

static VALUE
path2class(path)
    char *path;
{
    VALUE v = rb_path2class(path);

    if (TYPE(v) != T_CLASS) {
        rb_raise(rb_eArgError, "%s does not refer class", path);
    }
    return v;
}

static VALUE
path2module(path)
    char *path;
{
    VALUE v = rb_path2class(path);

    if (TYPE(v) != T_MODULE) {
        rb_raise(rb_eArgError, "%s does not refer module", path);
    }
    return v;
}

static VALUE
r_object0(arg, proc, ivp, extmod)
    struct load_arg *arg;
    VALUE proc;
    int *ivp;
    VALUE extmod;
{
    VALUE v = Qnil;
    int type = r_byte(arg);
    long id;

    switch (type) {
      case TYPE_LINK:
        id = r_long(arg);
        v = rb_hash_aref(arg->data, LONG2FIX(id));
        if (NIL_P(v)) {
            rb_raise(rb_eArgError, "dump format error (unlinked)");
        }
        return v;

      case TYPE_IVAR:
        {
            int ivar = Qtrue;

            v = r_object0(arg, 0, &ivar, extmod);
            if (ivar) r_ivar(v, arg);
        }
        break;

      case TYPE_EXTENDED:
        {
            VALUE m = path2module(r_unique(arg));

            if (NIL_P(extmod)) extmod = rb_ary_new2(0);
            rb_ary_push(extmod, m);

            v = r_object0(arg, 0, 0, extmod);
            while (RARRAY(extmod)->len > 0) {
                m = rb_ary_pop(extmod);
                rb_extend_object(v, m);
            }
        }
        break;

      case TYPE_UCLASS:
        {
            VALUE c = path2class(r_unique(arg));

            if (FL_TEST(c, FL_SINGLETON)) {
                rb_raise(rb_eTypeError, "singleton can't be loaded");
            }
            v = r_object0(arg, 0, 0, extmod);
            if (rb_special_const_p(v) || TYPE(v) == T_OBJECT || TYPE(v) == T_CLASS) {
              format_error:
                rb_raise(rb_eArgError, "dump format error (user class)");
            }
            if (TYPE(v) == T_MODULE || !RTEST(rb_class_inherited_p(c, RBASIC(v)->klass))) {
                VALUE tmp = rb_obj_alloc(c);

                if (TYPE(v) != TYPE(tmp)) goto format_error;
            }
            RBASIC(v)->klass = c;
        }
        break;

      case TYPE_NIL:
        v = Qnil;
        break;

      case TYPE_TRUE:
        v = Qtrue;
        break;

      case TYPE_FALSE:
        v = Qfalse;
        break;

      case TYPE_FIXNUM:
        {
            long i = r_long(arg);
            v = LONG2FIX(i);
        }
        break;

      case TYPE_FLOAT:
        {
            double d, t = 0.0;
            VALUE str = r_bytes(arg);
            const char *ptr = RSTRING(str)->ptr;

            if (strcmp(ptr, "nan") == 0) {
                d = t / t;
            }
            else if (strcmp(ptr, "inf") == 0) {
                d = 1.0 / t;
            }
            else if (strcmp(ptr, "-inf") == 0) {
                d = -1.0 / t;
            }
            else {
                char *e;
                d = strtod(ptr, &e);
                d = load_mantissa(d, e, RSTRING(str)->len - (e - ptr));
            }
            v = rb_float_new(d);
            r_entry(v, arg);
        }
        break;

      case TYPE_BIGNUM:
        {
            long len;
            BDIGIT *digits;
            volatile VALUE data;

            NEWOBJ(big, struct RBignum);
            OBJSETUP(big, rb_cBignum, T_BIGNUM);
            big->sign = (r_byte(arg) == '+');
            len = r_long(arg);
            data = r_bytes0(len * 2, arg);
#if SIZEOF_BDIGITS == SIZEOF_SHORT
            big->len = len;
#else
            big->len = (len + 1) * 2 / sizeof(BDIGIT);
#endif
            big->digits = digits = ALLOC_N(BDIGIT, big->len);
            MEMCPY(digits, RSTRING(data)->ptr, char, len * 2);
#if SIZEOF_BDIGITS > SIZEOF_SHORT
            MEMZERO((char *)digits + len * 2, char,
                    big->len * sizeof(BDIGIT) - len * 2);
#endif
            len = big->len;
            while (len > 0) {
                unsigned char *p = (unsigned char *)digits;
                BDIGIT num = 0;
#if SIZEOF_BDIGITS > SIZEOF_SHORT
                int shift = 0;
                int i;

                for (i=0; i<SIZEOF_BDIGITS; i++) {
                    num |= (int)p[i] << shift;
                    shift += 8;
                }
#else
                num = p[0] | (p[1] << 8);
#endif
                *digits++ = num;
                len--;
            }
            v = rb_big_norm((VALUE)big);
            r_entry(v, arg);
        }
        break;

      case TYPE_STRING:
        v = r_entry(r_string(arg), arg);
        break;

      case TYPE_REGEXP:
        {
            volatile VALUE str = r_bytes(arg);
            int options = r_byte(arg);
            v = r_entry(rb_reg_new(RSTRING(str)->ptr, RSTRING(str)->len, options), arg);
        }
        break;

      case TYPE_ARRAY:
        {
            volatile long len = r_long(arg); /* gcc 2.7.2.3 -O2 bug?? */

            v = rb_ary_new2(len);
            r_entry(v, arg);
            while (len--) {
                rb_ary_push(v, r_object(arg));
            }
        }
        break;

      case TYPE_HASH:
      case TYPE_HASH_DEF:
        {
            long len = r_long(arg);

            v = rb_hash_new();
            r_entry(v, arg);
            while (len--) {
                VALUE key = r_object(arg);
                VALUE value = r_object(arg);
                rb_hash_aset(v, key, value);
            }
            if (type == TYPE_HASH_DEF) {
                RHASH(v)->ifnone = r_object(arg);
            }
        }
        break;

      case TYPE_STRUCT:
        {
            VALUE klass, mem, values;
            volatile long i;    /* gcc 2.7.2.3 -O2 bug?? */
            long len;
            ID slot;

            klass = path2class(r_unique(arg));
            mem = rb_struct_s_members(klass);
            if (mem == Qnil) {
                rb_raise(rb_eTypeError, "uninitialized struct");
            }
            len = r_long(arg);

            values = rb_ary_new2(len);
            for (i=0; i<len; i++) {
                rb_ary_push(values, Qnil);
            }
            v = rb_struct_alloc(klass, values);
            r_entry(v, arg);
            for (i=0; i<len; i++) {
                slot = r_symbol(arg);

                if (RARRAY(mem)->ptr[i] != ID2SYM(slot)) {
                    rb_raise(rb_eTypeError, "struct %s not compatible (:%s for :%s)",
                             rb_class2name(klass),
                             rb_id2name(slot),
                             rb_id2name(SYM2ID(RARRAY(mem)->ptr[i])));
                }
                rb_struct_aset(v, LONG2FIX(i), r_object(arg));
            }
        }
        break;

      case TYPE_USERDEF:
        {
            VALUE klass = path2class(r_unique(arg));
            VALUE data;

            if (!rb_respond_to(klass, s_load)) {
                rb_raise(rb_eTypeError, "class %s needs to have method `_load'",
                         rb_class2name(klass));
            }
            data = r_string(arg);
            if (ivp) {
                r_ivar(data, arg);
                *ivp = Qfalse;
            }
            v = rb_funcall(klass, s_load, 1, data);
            r_entry(v, arg);
        }
        break;

      case TYPE_USRMARSHAL:
        {
            VALUE klass = path2class(r_unique(arg));
            VALUE data;

            v = rb_obj_alloc(klass);
            if (! NIL_P(extmod)) {
                while (RARRAY(extmod)->len > 0) {
                    VALUE m = rb_ary_pop(extmod);
                    rb_extend_object(v, m);
                }
            }
            if (!rb_respond_to(v, s_mload)) {
                rb_raise(rb_eTypeError, "instance of %s needs to have method `marshal_load'",
                         rb_class2name(klass));
            }
            r_entry(v, arg);
            data = r_object(arg);
            rb_funcall(v, s_mload, 1, data);
        }
        break;

      case TYPE_OBJECT:
        {
            VALUE klass = path2class(r_unique(arg));

            v = rb_obj_alloc(klass);
            if (TYPE(v) != T_OBJECT) {
                rb_raise(rb_eArgError, "dump format error");
            }
            r_entry(v, arg);
            r_ivar(v, arg);
        }
        break;

      case TYPE_DATA:
       {
           VALUE klass = path2class(r_unique(arg));
           if (rb_respond_to(klass, s_alloc)) {
               static int warn = Qtrue;
               if (warn) {
                   rb_warn("define `allocate' instead of `_alloc'");
                   warn = Qfalse;
               }
               v = rb_funcall(klass, s_alloc, 0);
           }
           else {
               v = rb_obj_alloc(klass);
           }
           if (TYPE(v) != T_DATA) {
               rb_raise(rb_eArgError, "dump format error");
           }
           r_entry(v, arg);
           if (!rb_respond_to(v, s_load_data)) {
               rb_raise(rb_eTypeError,
                        "class %s needs to have instance method `_load_data'",
                        rb_class2name(klass));
           }
           rb_funcall(v, s_load_data, 1, r_object0(arg, 0, 0, extmod));
       }
       break;

      case TYPE_MODULE_OLD:
        {
            volatile VALUE str = r_bytes(arg);

            v = rb_path2class(RSTRING(str)->ptr);
            r_entry(v, arg);
        }
        break;

      case TYPE_CLASS:
        {
            volatile VALUE str = r_bytes(arg);

            v = path2class(RSTRING(str)->ptr);
            r_entry(v, arg);
        }
        break;

      case TYPE_MODULE:
        {
            volatile VALUE str = r_bytes(arg);

            v = path2module(RSTRING(str)->ptr);
            r_entry(v, arg);
        }
        break;

      case TYPE_SYMBOL:
        v = ID2SYM(r_symreal(arg));
        break;

      case TYPE_SYMLINK:
        return ID2SYM(r_symlink(arg));

      default:
        rb_raise(rb_eArgError, "dump format error(0x%x)", type);
        break;
    }
    if (proc) {
        rb_funcall(proc, rb_intern("call"), 1, v);
    }
    return v;
}

static VALUE
r_object(arg)
    struct load_arg *arg;
{
    return r_object0(arg, arg->proc, 0, Qnil);
}

static VALUE
load(arg)
    struct load_arg *arg;
{
    return r_object(arg);
}

static VALUE
load_ensure(arg)
    struct load_arg *arg;
{
    st_free_table(arg->symbols);
    return 0;
}

/*
 * call-seq:
 *     load( source [, proc] ) => obj
 *     restore( source [, proc] ) => obj
 * 
 * Returns the result of converting the serialized data in source into a
 * Ruby object (possibly with associated subordinate objects). source
 * may be either an instance of IO or an object that responds to
 * to_str. If proc is specified, it will be passed each object as it
 * is deserialized.
 */
static VALUE
marshal_load(argc, argv)
    int argc;
    VALUE *argv;
{
    VALUE port, proc;
    int major, minor;
    VALUE v;
    struct load_arg arg;

    rb_scan_args(argc, argv, "11", &port, &proc);
    if (rb_respond_to(port, rb_intern("to_str"))) {
        arg.taint = OBJ_TAINTED(port); /* original taintedness */
        StringValue(port);             /* possible conversion */
    }
    else if (rb_respond_to(port, s_getc) && rb_respond_to(port, s_read)) {
        if (rb_respond_to(port, s_binmode)) {
            rb_funcall2(port, s_binmode, 0, 0);
        }
        arg.taint = Qtrue;
    }
    else {
        rb_raise(rb_eTypeError, "instance of IO needed");
    }
    arg.src = port;
    arg.offset = 0;

    major = r_byte(&arg);
    minor = r_byte(&arg);
    if (major != MARSHAL_MAJOR || minor > MARSHAL_MINOR) {
        rb_raise(rb_eTypeError, "incompatible marshal file format (can't be read)\n\
\tformat version %d.%d required; %d.%d given",
                 MARSHAL_MAJOR, MARSHAL_MINOR, major, minor);
    }
    if (RTEST(ruby_verbose) && minor != MARSHAL_MINOR) {
        rb_warn("incompatible marshal file format (can be read)\n\
\tformat version %d.%d required; %d.%d given",
                MARSHAL_MAJOR, MARSHAL_MINOR, major, minor);
    }

    arg.symbols = st_init_numtable();
    arg.data   = rb_hash_new();
    if (NIL_P(proc)) arg.proc = 0;
    else             arg.proc = proc;
    v = rb_ensure(load, (VALUE)&arg, load_ensure, (VALUE)&arg);

    return v;
}

/*
 * The marshaling library converts collections of Ruby objects into a
 * byte stream, allowing them to be stored outside the currently
 * active script. This data may subsequently be read and the original
 * objects reconstituted.
 * Marshaled data has major and minor version numbers stored along
 * with the object information. In normal use, marshaling can only
 * load data written with the same major version number and an equal
 * or lower minor version number. If Ruby's ``verbose'' flag is set
 * (normally using -d, -v, -w, or --verbose) the major and minor
 * numbers must match exactly. Marshal versioning is independent of
 * Ruby's version numbers. You can extract the version by reading the
 * first two bytes of marshaled data.
 *
 *     str = Marshal.dump("thing")
 *     RUBY_VERSION   #=> "1.8.0"
 *     str[0]         #=> 4
 *     str[1]         #=> 8
 *
 * Some objects cannot be dumped: if the objects to be dumped include
 * bindings, procedure or method objects, instances of class IO, or
 * singleton objects, a TypeError will be raised.
 * If your class has special serialization needs (for example, if you
 * want to serialize in some specific format), or if it contains
 * objects that would otherwise not be serializable, you can implement
 * your own serialization strategy by defining two methods, _dump and
 * _load:
 * The instance method _dump should return a String object containing
 * all the information necessary to reconstitute objects of this class
 * and all referenced objects up to a maximum depth given as an integer
 * parameter (a value of -1 implies that you should disable depth checking).
 * The class method _load should take a String and return an object of this class.
 */
void
Init_marshal()
{
    VALUE rb_mMarshal = rb_define_module("Marshal");

    s_dump = rb_intern("_dump");
    s_load = rb_intern("_load");
    s_mdump = rb_intern("marshal_dump");
    s_mload = rb_intern("marshal_load");
    s_dump_data = rb_intern("_dump_data");
    s_load_data = rb_intern("_load_data");
    s_alloc = rb_intern("_alloc");
    s_getc = rb_intern("getc");
    s_read = rb_intern("read");
    s_write = rb_intern("write");
    s_binmode = rb_intern("binmode");

    rb_define_module_function(rb_mMarshal, "dump", marshal_dump, -1);
    rb_define_module_function(rb_mMarshal, "load", marshal_load, -1);
    rb_define_module_function(rb_mMarshal, "restore", marshal_load, -1);

    rb_define_const(rb_mMarshal, "MAJOR_VERSION", INT2FIX(MARSHAL_MAJOR));
    rb_define_const(rb_mMarshal, "MINOR_VERSION", INT2FIX(MARSHAL_MINOR));
}

VALUE
rb_marshal_dump(obj, port)
    VALUE obj, port;
{
    int argc = 1;
    VALUE argv[2];

    argv[0] = obj;
    argv[1] = port;
    if (!NIL_P(port)) argc = 2;
    return marshal_dump(argc, argv);
}

VALUE
rb_marshal_load(port)
    VALUE port;
{
    return marshal_load(1, &port);
}

---