/* dump.c
 * Copyright (c) 2011, Peter Ohler
 * All rights reserved.
 */

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#include "base64.h"
#include "cache8.h"
#include "ox.h"

#define USE_B64 0
#define MAX_DEPTH 1000

typedef unsigned long ulong;

typedef struct _str {
    const char *str;
    size_t      len;
} *Str;

typedef struct _element {
    struct _str   clas;
    struct _str   attr;
    unsigned long id;
    int           indent; /* < 0 indicates no \n */
    int           closed;
    char          type;
} *Element;

typedef struct _out {
    void (*w_start)(struct _out *out, Element e);
    void (*w_end)(struct _out *out, Element e);
    void (*w_time)(struct _out *out, VALUE obj);
    char         *buf;
    char         *end;
    char         *cur;
    Cache8        circ_cache;
    unsigned long circ_cnt;
    int           indent;
    int           depth; /* used by dumpHash */
    Options       opts;
    VALUE         obj;
} *Out;

static void dump_obj_to_xml(VALUE obj, Options copts, Out out);

static void dump_first_obj(VALUE obj, Out out);
static void dump_obj(ID aid, VALUE obj, int depth, Out out);
static void dump_gen_doc(VALUE obj, int depth, Out out);
static void dump_gen_element(VALUE obj, int depth, Out out);
static void dump_gen_instruct(VALUE obj, int depth, Out out);
static int  dump_gen_attr(VALUE key, VALUE value, VALUE ov);
static int  dump_gen_nodes(VALUE obj, int depth, Out out);
static void
dump_gen_val_node(VALUE obj, int depth, const char *pre, size_t plen, const char *suf, size_t slen, Out out);

static void dump_start(Out out, Element e);
static void dump_end(Out out, Element e);

static void grow(Out out, size_t len);

static void dump_value(Out out, const char *value, size_t size);
static void dump_str_value(Out out, const char *value, size_t size, const char *table);
static int  dump_var(ID key, VALUE value, VALUE ov);
static void dump_num(Out out, VALUE obj);
static void dump_date(Out out, VALUE obj);
static void dump_time_thin(Out out, VALUE obj);
static void dump_time_xsd(Out out, VALUE obj);
static int  dump_hash(VALUE key, VALUE value, VALUE ov);

static int is_xml_friendly(const uchar *str, int len, const char *table);

static const char hex_chars[17] = "0123456789abcdef";

// The : character is equivalent to 10. Used for replacement characters up to 10
// characters long such as '&#x10FFFF;'.
static const char xml_friendly_chars[257] = "\
:::::::::11::1::::::::::::::::::\
11611156111111111111111111114141\
11111111111111111111111111111111\
11111111111111111111111111111111\
11111111111111111111111111111111\
11111111111111111111111111111111\
11111111111111111111111111111111\
11111111111111111111111111111111";

static const char xml_quote_chars[257] = "\
:::::::::11::1::::::::::::::::::\
11611151111111111111111111114141\
11111111111111111111111111111111\
11111111111111111111111111111111\
11111111111111111111111111111111\
11111111111111111111111111111111\
11111111111111111111111111111111\
11111111111111111111111111111111";

static const char xml_element_chars[257] = "\
:::::::::11::1::::::::::::::::::\
11111151111111111111111111114141\
11111111111111111111111111111111\
11111111111111111111111111111111\
11111111111111111111111111111111\
11111111111111111111111111111111\
11111111111111111111111111111111\
11111111111111111111111111111111";

inline static int is_xml_friendly(const uchar *str, int len, const char *table) {
    for (; 0 < len; str++, len--) {
        if ('1' != table[*str]) {
            return 0;
        }
    }
    return 1;
}

inline static size_t xml_str_len(const uchar *str, size_t len, const char *table) {
    size_t size = 0;

    for (; 0 < len; str++, len--) {
        size += xml_friendly_chars[*str];
    }
    return size - len * (size_t)'0';
}

inline static void dump_hex(uchar c, Out out) {
    uchar d = (c >> 4) & 0x0F;

    *out->cur++ = hex_chars[d];
    d           = c & 0x0F;
    *out->cur++ = hex_chars[d];
}

static Type obj_class_code(VALUE obj) {
    VALUE clas = rb_obj_class(obj);

    switch (rb_type(obj)) {
    case T_NIL: return NilClassCode;
    case T_ARRAY: return ArrayCode;
    case T_HASH: return HashCode;
    case T_TRUE: return TrueClassCode;
    case T_FALSE: return FalseClassCode;
    case T_FIXNUM: return FixnumCode;
    case T_FLOAT: return FloatCode;
    case T_STRING:
        return (is_xml_friendly((uchar *)StringValuePtr(obj), (int)RSTRING_LEN(obj), xml_element_chars)) ? StringCode
                                                                                                         : String64Code;
    case T_SYMBOL: {
        const char *sym = rb_id2name(SYM2ID(obj));

        return (is_xml_friendly((uchar *)sym, (int)strlen(sym), xml_element_chars)) ? SymbolCode : Symbol64Code;
    }
    case T_DATA: return (rb_cTime == clas) ? TimeCode : ((ox_date_class == clas) ? DateCode : 0);
    case T_STRUCT: return (rb_cRange == clas) ? RangeCode : StructCode;
    case T_OBJECT: return (ox_document_clas == clas || ox_element_clas == clas) ? RawCode : ObjectCode;
    case T_REGEXP: return RegexpCode;
    case T_BIGNUM: return BignumCode;
    case T_COMPLEX: return ComplexCode;
    case T_RATIONAL: return RationalCode;
    case T_CLASS: return ClassCode;
    default: return 0;
    }
}

inline static void fill_indent(Out out, int cnt) {
    if (0 <= cnt) {
        *out->cur++ = '\n';
        if (0 < out->opts->margin_len) {
            memcpy(out->cur, out->opts->margin, out->opts->margin_len);
            out->cur += out->opts->margin_len;
        }
        for (; 0 < cnt; cnt--) {
            *out->cur++ = ' ';
        }
    }
}

inline static void fill_value(Out out, const char *value, size_t len) {
    if (6 < len) {
        memcpy(out->cur, value, len);
        out->cur += len;
    } else {
        for (; 0 < len; len--, value++) {
            *out->cur++ = *value;
        }
    }
}

inline static void fill_attr(Out out, char name, const char *value, size_t len) {
    *out->cur++ = ' ';
    *out->cur++ = name;
    *out->cur++ = '=';
    *out->cur++ = '"';
    if (6 < len) {
        memcpy(out->cur, value, len);
        out->cur += len;
    } else {
        for (; 0 < len; len--, value++) {
            *out->cur++ = *value;
        }
    }
    *out->cur++ = '"';
}

inline static const char *ulong2str(ulong num, char *end) {
    char *b;

    *end-- = '\0';
    for (b = end; 0 < num || b == end; num /= 10, b--) {
        *b = (num % 10) + '0';
    }
    b++;

    return b;
}

static int check_circular(Out out, VALUE obj, Element e) {
    slot_t *slot;
    slot_t  id;
    int     result;

    if (0 == (id = ox_cache8_get(out->circ_cache, obj, &slot))) {
        out->circ_cnt++;
        id     = out->circ_cnt;
        *slot  = id;
        e->id  = id;
        result = 0;
    } else {
        e->type     = RefCode;
        e->clas.len = 0;
        e->clas.str = 0;
        e->closed   = 1;
        e->id       = id;
        out->w_start(out, e);
        result = 1;
    }
    return result;
}

static void grow(Out out, size_t len) {
    size_t size = out->end - out->buf;
    long   pos  = out->cur - out->buf;

    size *= 2;
    if (size <= len * 2 + pos) {
        size += len;
    }
    REALLOC_N(out->buf, char, size + 10); /* 10 extra for terminator character plus extra (paranoid) */
    out->end = out->buf + size;
    out->cur = out->buf + pos;
}

static void dump_start(Out out, Element e) {
    size_t size = e->indent + 4 + out->opts->margin_len;

    if (0 < e->attr.len) { /* a="attr" */
        size += e->attr.len + 5;
    }
    if (0 < e->clas.len) { /* c="class" */
        size += e->clas.len + 5;
    }
    if (0 < e->id) { /* i="id" */
        size += 24;  /* over estimate, 19 digits */
    }
    if (out->end - out->cur <= (long)size) {
        grow(out, size);
    }
    if (out->buf + out->opts->margin_len < out->cur) {
        fill_indent(out, e->indent);
    }
    *out->cur++ = '<';
    *out->cur++ = e->type;
    if (0 < e->attr.len) {
        fill_attr(out, 'a', e->attr.str, e->attr.len);
    }
    if ((ObjectCode == e->type || ExceptionCode == e->type || StructCode == e->type || ClassCode == e->type) &&
        0 < e->clas.len) {
        fill_attr(out, 'c', e->clas.str, e->clas.len);
    }
    if (0 < e->id) {
        char        buf[32];
        char       *end = buf + sizeof(buf) - 1;
        const char *s   = ulong2str(e->id, end);

        fill_attr(out, 'i', s, end - s);
    }
    if (e->closed) {
        if (out->opts->no_empty) {
            *out->cur++ = '>';
            *out->cur++ = '<';
            *out->cur++ = '/';
            *out->cur++ = e->type;
        } else {
            *out->cur++ = '/';
        }
    }
    *out->cur++ = '>';
    *out->cur   = '\0';
}

static void dump_end(Out out, Element e) {
    size_t size = e->indent + 5 + out->opts->margin_len;

    if (out->end - out->cur <= (long)size) {
        grow(out, size);
    }
    fill_indent(out, e->indent);
    *out->cur++ = '<';
    *out->cur++ = '/';
    *out->cur++ = e->type;
    *out->cur++ = '>';
    *out->cur   = '\0';
}

inline static void dump_value(Out out, const char *value, size_t size) {
    if (out->end - out->cur <= (long)size) {
        grow(out, size);
    }
    if (6 < size) {
        memcpy(out->cur, value, size);
        out->cur += size;
    } else {
        for (; 0 < size; size--, value++) {
            *out->cur++ = *value;
        }
    }
    *out->cur = '\0';
}

inline static void dump_str_value(Out out, const char *value, size_t size, const char *table) {
    size_t xsize = xml_str_len((const uchar *)value, size, table);

    if (out->end - out->cur <= (long)xsize) {
        grow(out, xsize);
    }
    for (; 0 < size; size--, value++) {
        if ('1' == table[(uchar)*value]) {
            *out->cur++ = *value;
        } else {
            switch (*value) {
            case '"':
                *out->cur++ = '&';
                *out->cur++ = 'q';
                *out->cur++ = 'u';
                *out->cur++ = 'o';
                *out->cur++ = 't';
                *out->cur++ = ';';
                break;
            case '&':
                *out->cur++ = '&';
                *out->cur++ = 'a';
                *out->cur++ = 'm';
                *out->cur++ = 'p';
                *out->cur++ = ';';
                break;
            case '\'':
                *out->cur++ = '&';
                *out->cur++ = 'a';
                *out->cur++ = 'p';
                *out->cur++ = 'o';
                *out->cur++ = 's';
                *out->cur++ = ';';
                break;
            case '<':
                *out->cur++ = '&';
                *out->cur++ = 'l';
                *out->cur++ = 't';
                *out->cur++ = ';';
                break;
            case '>':
                *out->cur++ = '&';
                *out->cur++ = 'g';
                *out->cur++ = 't';
                *out->cur++ = ';';
                break;
            default:
                // Must be one of the invalid characters.
                if (StrictEffort == out->opts->effort) {
                    rb_raise(ox_syntax_error_class, "'\\#x%02x' is not a valid XML character.", *value);
                }
                if (Yes == out->opts->allow_invalid) {
                    *out->cur++ = '&';
                    *out->cur++ = '#';
                    *out->cur++ = 'x';
                    *out->cur++ = '0';
                    *out->cur++ = '0';
                    dump_hex(*value, out);
                    *out->cur++ = ';';
                } else if ('\0' != *out->opts->inv_repl) {
                    // If the empty string then ignore. The first character of
                    // the replacement is the length.
                    memcpy(out->cur, out->opts->inv_repl + 1, (size_t)*out->opts->inv_repl);
                    out->cur += *out->opts->inv_repl;
                }
                break;
            }
        }
    }
    *out->cur = '\0';
}

inline static void dump_num(Out out, VALUE obj) {
    char  buf[32];
    char *b   = buf + sizeof(buf) - 1;
    long  num = NUM2LONG(obj);
    int   neg = 0;

    if (0 > num) {
        neg = 1;
        num = -num;
    }
    *b-- = '\0';
    if (0 < num) {
        for (; 0 < num; num /= 10, b--) {
            *b = (num % 10) + '0';
        }
        if (neg) {
            *b = '-';
        } else {
            b++;
        }
    } else {
        *b = '0';
    }
    if (out->end - out->cur <= (long)(sizeof(buf) - (b - buf))) {
        grow(out, sizeof(buf) - (b - buf));
    }
    for (; '\0' != *b; b++) {
        *out->cur++ = *b;
    }
    *out->cur = '\0';
}

static void dump_time_thin(Out out, VALUE obj) {
    char            buf[64];
    char           *b    = buf + sizeof(buf) - 1;
    struct timespec ts   = rb_time_timespec(obj);
    time_t          sec  = ts.tv_sec;
    long            nsec = ts.tv_nsec;
    char           *dot  = b - 10;
    long            size;

    *b-- = '\0';
    for (; dot < b; b--, nsec /= 10) {
        *b = '0' + (nsec % 10);
    }
    *b-- = '.';
    for (; 0 < sec; b--, sec /= 10) {
        *b = '0' + (sec % 10);
    }
    b++;
    size = sizeof(buf) - (b - buf) - 1;
    if (out->end - out->cur <= size) {
        grow(out, size);
    }
    memcpy(out->cur, b, size);
    out->cur += size;
}

static void dump_date(Out out, VALUE obj) {
    char  buf[64];
    char *b  = buf + sizeof(buf) - 1;
    long  jd = NUM2LONG(rb_funcall2(obj, ox_jd_id, 0, 0));
    long  size;

    *b-- = '\0';
    for (; 0 < jd; b--, jd /= 10) {
        *b = '0' + (jd % 10);
    }
    b++;
    if ('\0' == *b) {
        b--;
        *b = '0';
    }
    size = sizeof(buf) - (b - buf) - 1;
    if (out->end - out->cur <= size) {
        grow(out, size);
    }
    memcpy(out->cur, b, size);
    out->cur += size;
}

static void dump_time_xsd(Out out, VALUE obj) {
    struct tm      *tm;
    struct timespec ts   = rb_time_timespec(obj);
    time_t          sec  = ts.tv_sec;
    long            nsec = ts.tv_nsec;
    int             tzhour, tzmin;
    char            tzsign = '+';

    if (out->end - out->cur <= 33) {
        grow(out, 33);
    }
    /* 2010-07-09T10:47:45.895826+09:00 */
    tm = localtime(&sec);
#if HAVE_ST_TM_GMTOFF
    if (0 > tm->tm_gmtoff) {
        tzsign = '-';
        tzhour = (int)(tm->tm_gmtoff / -3600);
        tzmin  = (int)(tm->tm_gmtoff / -60) - (tzhour * 60);
    } else {
        tzhour = (int)(tm->tm_gmtoff / 3600);
        tzmin  = (int)(tm->tm_gmtoff / 60) - (tzhour * 60);
    }
#else
    tzhour = 0;
    tzmin  = 0;
#endif
    /* TBD replace with more efficient printer */
    out->cur += sprintf(out->cur,
                        "%04d-%02d-%02dT%02d:%02d:%02d.%06ld%c%02d:%02d",
                        tm->tm_year + 1900,
                        tm->tm_mon + 1,
                        tm->tm_mday,
                        tm->tm_hour,
                        tm->tm_min,
                        tm->tm_sec,
                        nsec / 1000,
                        tzsign,
                        tzhour,
                        tzmin);
}

static void dump_first_obj(VALUE obj, Out out) {
    char    buf[128];
    Options copts = out->opts;
    int     cnt;

    if (Yes == copts->with_xml) {
        if (0 < copts->margin_len) {
            dump_value(out, copts->margin, copts->margin_len);
        }
        if ('\0' == *copts->encoding) {
            dump_value(out, "<?xml version=\"1.0\"?>", 21);
        } else {
            cnt = snprintf(buf, sizeof(buf), "<?xml version=\"1.0\" encoding=\"%s\"?>", copts->encoding);
            dump_value(out, buf, cnt);
        }
    }
    if (Yes == copts->with_instruct) {
        if (out->buf < out->cur) {
            dump_value(out, "\n", 1);
        }
        if (0 < copts->margin_len) {
            dump_value(out, copts->margin, copts->margin_len);
        }
        cnt = snprintf(
            buf,
            sizeof(buf),
            "<?ox version=\"1.0\" mode=\"object\"%s%s?>",
            (Yes == copts->circular) ? " circular=\"yes\"" : ((No == copts->circular) ? " circular=\"no\"" : ""),
            (Yes == copts->xsd_date) ? " xsd_date=\"yes\"" : ((No == copts->xsd_date) ? " xsd_date=\"no\"" : ""));
        dump_value(out, buf, cnt);
    }
    if (Yes == copts->with_dtd) {
        if (0 < copts->margin_len) {
            dump_value(out, copts->margin, copts->margin_len);
        }
        cnt = snprintf(buf,
                       sizeof(buf),
                       "%s<!DOCTYPE %c SYSTEM \"ox.dtd\">",
                       (out->buf < out->cur) ? "\n" : "",
                       obj_class_code(obj));
        dump_value(out, buf, cnt);
    }
    if (0 < copts->margin_len) {
        dump_value(out, copts->margin, copts->margin_len);
    }
    dump_obj(0, obj, 0, out);
}

static void dump_obj(ID aid, VALUE obj, int depth, Out out) {
    struct _element e;
    VALUE           prev_obj = out->obj;
    char            value_buf[64];
    int             cnt;

    if (MAX_DEPTH < depth) {
        rb_raise(rb_eSysStackError, "maximum depth exceeded");
    }
    out->obj = obj;
    if (0 == aid) {
        e.attr.str = 0;
        e.attr.len = 0;
    } else {
        e.attr.str = rb_id2name(aid);
        // Ruby 2.3 started to return NULL for some IDs so check for
        // NULL. Ignore if NULL aid.
        if (NULL == e.attr.str) {
            return;
        }
        e.attr.len = strlen(e.attr.str);
    }
    e.closed = 0;
    if (0 == depth) {
        e.indent = (0 <= out->indent) ? 0 : -1;
    } else if (0 > out->indent) {
        e.indent = -1;
    } else if (0 == out->indent) {
        e.indent = 0;
    } else {
        e.indent = depth * out->indent;
    }
    e.id       = 0;
    e.clas.len = 0;
    e.clas.str = 0;
    switch (rb_type(obj)) {
    case T_NIL:
        e.type   = NilClassCode;
        e.closed = 1;
        out->w_start(out, &e);
        break;
    case T_ARRAY:
        if (0 != out->circ_cache && check_circular(out, obj, &e)) {
            break;
        }
        cnt      = (int)RARRAY_LEN(obj);
        e.type   = ArrayCode;
        e.closed = (0 >= cnt);
        out->w_start(out, &e);
        if (!e.closed) {
            const VALUE *np = RARRAY_PTR(obj);
            int          i;
            int          d2 = depth + 1;

            for (i = cnt; 0 < i; i--, np++) {
                dump_obj(0, *np, d2, out);
            }
            out->w_end(out, &e);
        }
        break;
    case T_HASH:
        if (0 != out->circ_cache && check_circular(out, obj, &e)) {
            break;
        }
        cnt      = (int)RHASH_SIZE(obj);
        e.type   = HashCode;
        e.closed = (0 >= cnt);
        out->w_start(out, &e);
        if (0 < cnt) {
            unsigned int od = out->depth;

            out->depth = depth + 1;
            rb_hash_foreach(obj, dump_hash, (VALUE)out);
            out->depth = od;
            out->w_end(out, &e);
        }
        break;
    case T_TRUE:
        e.type   = TrueClassCode;
        e.closed = 1;
        out->w_start(out, &e);
        break;
    case T_FALSE:
        e.type   = FalseClassCode;
        e.closed = 1;
        out->w_start(out, &e);
        break;
    case T_FIXNUM:
        e.type = FixnumCode;
        out->w_start(out, &e);
        dump_num(out, obj);
        e.indent = -1;
        out->w_end(out, &e);
        break;
    case T_FLOAT:
        e.type = FloatCode;
        cnt    = snprintf(value_buf, sizeof(value_buf), "%0.16g", rb_num2dbl(obj));
        out->w_start(out, &e);
        dump_value(out, value_buf, cnt);
        e.indent = -1;
        out->w_end(out, &e);
        break;
    case T_STRING: {
        const char *str;

        if (0 != out->circ_cache && check_circular(out, obj, &e)) {
            break;
        }
        str = StringValuePtr(obj);
        cnt = (int)RSTRING_LEN(obj);
#if USE_B64
        if (is_xml_friendly((uchar *)str, cnt)) {
            e.type = StringCode;
            out->w_start(out, &e);
            dump_str_value(out, str, cnt, '<');
            e.indent = -1;
            out->w_end(out, &e);
        } else {
            ulong size = b64_size(cnt);
            char *b64  = ALLOCA_N(char, size + 1);

            e.type = String64Code;
            to_base64((uchar *)str, cnt, b64);
            out->w_start(out, &e);
            dump_value(out, b64, size);
            e.indent = -1;
            out->w_end(out, &e);
        }
#else
        e.type = StringCode;
        out->w_start(out, &e);
        dump_str_value(out, str, cnt, xml_element_chars);
        e.indent = -1;
        out->w_end(out, &e);
#endif
        break;
    }
    case T_SYMBOL: {
        const char *sym = rb_id2name(SYM2ID(obj));

        cnt = (int)strlen(sym);
#if USE_B64
        if (is_xml_friendly((uchar *)sym, cnt)) {
            e.type = SymbolCode;
            out->w_start(out, &e);
            dump_str_value(out, sym, cnt, '<');
            e.indent = -1;
            out->w_end(out, &e);
        } else {
            ulong size = b64_size(cnt);
            char *b64  = ALLOCA_N(char, size + 1);

            e.type = Symbol64Code;
            to_base64((uchar *)sym, cnt, b64);
            out->w_start(out, &e);
            dump_value(out, b64, size);
            e.indent = -1;
            out->w_end(out, &e);
        }
#else
        e.type = SymbolCode;
        out->w_start(out, &e);
        dump_str_value(out, sym, cnt, xml_element_chars);
        e.indent = -1;
        out->w_end(out, &e);
#endif
        break;
    }
    case T_DATA: {
        VALUE clas;

        clas = rb_obj_class(obj);
        if (rb_cTime == clas) {
            e.type = TimeCode;
            out->w_start(out, &e);
            out->w_time(out, obj);
            e.indent = -1;
            out->w_end(out, &e);
        } else {
            const char *classname = rb_class2name(clas);

            if (0 == strcmp("Date", classname)) {
                e.type = DateCode;
                out->w_start(out, &e);
                dump_date(out, obj);
                e.indent = -1;
                out->w_end(out, &e);
            } else if (0 == strcmp("BigDecimal", classname)) {
                volatile VALUE rs = rb_String(obj);

                e.type = BigDecimalCode;
                out->w_start(out, &e);
                dump_value(out, StringValuePtr(rs), RSTRING_LEN(rs));
                e.indent = -1;
                out->w_end(out, &e);
            } else {
                if (StrictEffort == out->opts->effort) {
                    rb_raise(rb_eNotImpError, "Failed to dump T_DATA %s\n", classname);
                } else {
                    e.type   = NilClassCode;
                    e.closed = 1;
                    out->w_start(out, &e);
                }
            }
        }
        break;
    }
    case T_STRUCT: {
#ifdef RSTRUCT_GET
        VALUE clas;

        if (0 != out->circ_cache && check_circular(out, obj, &e)) {
            break;
        }
        clas = rb_obj_class(obj);
        if (rb_cRange == clas) {
            VALUE beg  = RSTRUCT_GET(obj, 0);
            VALUE end  = RSTRUCT_GET(obj, 1);
            VALUE excl = RSTRUCT_GET(obj, 2);
            int   d2   = depth + 1;

            e.type     = RangeCode;
            e.clas.len = 5;
            e.clas.str = "Range";
            out->w_start(out, &e);
            dump_obj(ox_beg_id, beg, d2, out);
            dump_obj(ox_end_id, end, d2, out);
            dump_obj(ox_excl_id, excl, d2, out);
            out->w_end(out, &e);
        } else {
            char num_buf[16];
            int  d2 = depth + 1;
            long i;
            long cnt   = NUM2LONG(rb_struct_size(obj));
            e.type     = StructCode;
            e.clas.str = rb_class2name(clas);
            e.clas.len = strlen(e.clas.str);
            out->w_start(out, &e);

            for (i = 0; i < cnt; i++) {
                VALUE v = RSTRUCT_GET(obj, (int)(i));
                dump_obj(rb_intern(ulong2str(i, num_buf + sizeof(num_buf) - 1)), v, d2, out);
            }
            out->w_end(out, &e);
        }
#else
        e.type   = NilClassCode;
        e.closed = 1;
        out->w_start(out, &e);
#endif
        break;
    }
    case T_OBJECT: {
        VALUE clas;

        if (0 != out->circ_cache && check_circular(out, obj, &e)) {
            break;
        }
        clas       = rb_obj_class(obj);
        e.clas.str = rb_class2name(clas);
        e.clas.len = strlen(e.clas.str);
        if (ox_document_clas == clas) {
            e.type = RawCode;
            out->w_start(out, &e);
            dump_gen_doc(obj, depth + 1, out);
            out->w_end(out, &e);
        } else if (ox_element_clas == clas) {
            e.type = RawCode;
            out->w_start(out, &e);
            dump_gen_element(obj, depth + 1, out);
            out->w_end(out, &e);
        } else { /* Object */
            e.type   = (Qtrue == rb_obj_is_kind_of(obj, rb_eException)) ? ExceptionCode : ObjectCode;
            cnt      = (int)rb_ivar_count(obj);
            e.closed = (0 >= cnt);
            out->w_start(out, &e);
            if (0 < cnt) {
                unsigned int od = out->depth;

                out->depth = depth + 1;
                rb_ivar_foreach(obj, dump_var, (VALUE)out);
                out->depth = od;
                out->w_end(out, &e);
            }
        }
        break;
    }
    case T_REGEXP: {
        volatile VALUE rs = rb_funcall2(obj, ox_inspect_id, 0, 0);
        const char    *s  = StringValuePtr(rs);

        cnt    = (int)RSTRING_LEN(rs);
        e.type = RegexpCode;
        out->w_start(out, &e);
#if USE_B64
        if (is_xml_friendly((uchar *)s, cnt)) {
            /*dump_value(out, "/", 1); */
            dump_str_value(out, s, cnt, '<');
        } else {
            ulong size = b64_size(cnt);
            char *b64  = ALLOCA_N(char, size + 1);

            to_base64((uchar *)s, cnt, b64);
            dump_value(out, b64, size);
        }
#else
        dump_str_value(out, s, cnt, xml_element_chars);
#endif
        e.indent = -1;
        out->w_end(out, &e);
        break;
    }
    case T_BIGNUM: {
        volatile VALUE rs = rb_big2str(obj, 10);

        e.type = BignumCode;
        out->w_start(out, &e);
        dump_value(out, StringValuePtr(rs), RSTRING_LEN(rs));
        e.indent = -1;
        out->w_end(out, &e);
        break;
    }
    case T_COMPLEX: e.type = ComplexCode; out->w_start(out, &e);
#ifdef RCOMPLEX
        dump_obj(0, RCOMPLEX(obj)->real, depth + 1, out);
        dump_obj(0, RCOMPLEX(obj)->imag, depth + 1, out);
#else
        dump_obj(0, rb_funcall2(obj, rb_intern("real"), 0, 0), depth + 1, out);
        dump_obj(0, rb_funcall2(obj, rb_intern("imag"), 0, 0), depth + 1, out);
#endif
        out->w_end(out, &e);
        break;
    case T_RATIONAL: e.type = RationalCode; out->w_start(out, &e);
#ifdef RRATIONAL
        dump_obj(0, RRATIONAL(obj)->num, depth + 1, out);
        dump_obj(0, RRATIONAL(obj)->den, depth + 1, out);
#else
        dump_obj(0, rb_funcall2(obj, rb_intern("numerator"), 0, 0), depth + 1, out);
        dump_obj(0, rb_funcall2(obj, rb_intern("denominator"), 0, 0), depth + 1, out);
#endif
        out->w_end(out, &e);
        break;
    case T_CLASS: {
        e.type     = ClassCode;
        e.clas.str = rb_class2name(obj);
        e.clas.len = strlen(e.clas.str);
        e.closed   = 1;
        out->w_start(out, &e);
        break;
    }
    default:
        if (StrictEffort == out->opts->effort) {
            rb_raise(rb_eNotImpError, "Failed to dump %s Object (%02x)\n", rb_obj_classname(obj), rb_type(obj));
        } else {
            e.type   = NilClassCode;
            e.closed = 1;
            out->w_start(out, &e);
        }
        break;
    }
    out->obj = prev_obj;
}

static int dump_var(ID key, VALUE value, VALUE ov) {
    Out out = (Out)ov;

    if (T_DATA == rb_type(value) && key == ox_mesg_id) {
        /* There is a secret recipe that keeps Exception mesg attributes as a
         * T_DATA until it is needed. The safe way around this hack is to call
         * the message() method and use the returned string as the
         * message. Not pretty but it solves the most common use of this
         * hack. If there are others they will have to be handled one at a
         * time.
         */
        value = rb_funcall(out->obj, ox_message_id, 0);
    }
    dump_obj(key, value, out->depth, out);

    return ST_CONTINUE;
}

static int dump_hash(VALUE key, VALUE value, VALUE ov) {
    Out out = (Out)ov;

    dump_obj(0, key, out->depth, out);
    dump_obj(0, value, out->depth, out);

    return ST_CONTINUE;
}

static void dump_gen_doc(VALUE obj, int depth, Out out) {
    volatile VALUE attrs = rb_attr_get(obj, ox_attributes_id);
    volatile VALUE nodes = rb_attr_get(obj, ox_nodes_id);

    if ('\0' == *out->opts->encoding && Qnil != attrs) {
        volatile VALUE renc = rb_hash_lookup(attrs, ox_encoding_sym);

        if (Qnil != renc) {
            const char *enc = StringValuePtr(renc);

            strncpy(out->opts->encoding, enc, sizeof(out->opts->encoding) - 1);
        }
    }
    if (Yes == out->opts->with_xml) {
        if (0 < out->opts->margin_len) {
            dump_value(out, out->opts->margin, out->opts->margin_len);
        }
        dump_value(out, "<?xml", 5);
        if (Qnil != attrs) {
            rb_hash_foreach(attrs, dump_gen_attr, (VALUE)out);
        }
        dump_value(out, "?>", 2);
    }
    if (Yes == out->opts->with_instruct) {
        if (out->buf < out->cur) {
            dump_value(out, "\n", 1);
        }
        if (0 < out->opts->margin_len) {
            dump_value(out, out->opts->margin, out->opts->margin_len);
        }
        dump_value(out, "<?ox version=\"1.0\" mode=\"generic\"?>", 35);
    }
    if (Qnil != nodes) {
        dump_gen_nodes(nodes, depth, out);
    }
}

static void dump_gen_element(VALUE obj, int depth, Out out) {
    volatile VALUE rname = rb_attr_get(obj, ox_at_value_id);
    volatile VALUE attrs = rb_attr_get(obj, ox_attributes_id);
    volatile VALUE nodes = rb_attr_get(obj, ox_nodes_id);
    const char    *name  = StringValuePtr(rname);
    long           nlen  = RSTRING_LEN(rname);
    size_t         size;
    int            indent;

    if (0 > out->indent) {
        indent = -1;
    } else if (0 == out->indent) {
        indent = 0;
    } else {
        indent = depth * out->indent;
    }
    size = indent + 4 + nlen + out->opts->margin_len;
    if (out->end - out->cur <= (long)size) {
        grow(out, size);
    }
    if (0 == depth && 0 < out->opts->margin_len && 0 < out->indent) {
        memcpy(out->cur, out->opts->margin, out->opts->margin_len);
        out->cur += out->opts->margin_len;
    }
    fill_indent(out, indent);
    *out->cur++ = '<';
    fill_value(out, name, nlen);
    if (Qnil != attrs) {
        rb_hash_foreach(attrs, dump_gen_attr, (VALUE)out);
    }
    if (Qnil != nodes && 0 < RARRAY_LEN(nodes)) {
        int do_indent;

        *out->cur++ = '>';
        do_indent   = dump_gen_nodes(nodes, depth, out);
        if (out->end - out->cur <= (long)size) {
            grow(out, size);
        }
        if (do_indent) {
            fill_indent(out, indent);
        }
        *out->cur++ = '<';
        *out->cur++ = '/';
        fill_value(out, name, nlen);
    } else if (out->opts->no_empty) {
        *out->cur++ = '>';
        *out->cur++ = '<';
        *out->cur++ = '/';
        fill_value(out, name, nlen);
    } else {
        *out->cur++ = '/';
    }
    *out->cur++ = '>';
    *out->cur   = '\0';
}

static void dump_gen_instruct(VALUE obj, int depth, Out out) {
    volatile VALUE rname    = rb_attr_get(obj, ox_at_value_id);
    volatile VALUE attrs    = rb_attr_get(obj, ox_attributes_id);
    volatile VALUE rcontent = rb_attr_get(obj, ox_at_content_id);
    const char    *name     = StringValuePtr(rname);
    const char    *content  = 0;
    long           nlen     = RSTRING_LEN(rname);
    long           clen     = 0;
    size_t         size;

    if (T_STRING == rb_type(rcontent)) {
        content = StringValuePtr(rcontent);
        clen    = RSTRING_LEN(rcontent);
        size    = 4 + nlen + clen;
    } else {
        size = 4 + nlen;
    }
    if (out->end - out->cur <= (long)size) {
        grow(out, size);
    }
    *out->cur++ = '<';
    *out->cur++ = '?';
    fill_value(out, name, nlen);
    if (0 != content) {
        if (' ' != *content) {
            dump_value(out, " ", 1);
        }
        fill_value(out, content, clen);
    } else if (Qnil != attrs) {
        rb_hash_foreach(attrs, dump_gen_attr, (VALUE)out);
    }
    *out->cur++ = '?';
    *out->cur++ = '>';
    *out->cur   = '\0';
}

static int dump_gen_nodes(VALUE obj, int depth, Out out) {
    long cnt           = RARRAY_LEN(obj);
    int  indent_needed = 1;

    if (0 < cnt) {
        const VALUE *np = RARRAY_PTR(obj);
        VALUE        clas;
        int          d2 = depth + 1;

        if (MAX_DEPTH < depth) {
            rb_raise(rb_eSysStackError, "maximum depth exceeded");
        }
        for (; 0 < cnt; cnt--, np++) {
            clas = rb_obj_class(*np);
            if (ox_element_clas == clas) {
                dump_gen_element(*np, d2, out);
            } else if (ox_instruct_clas == clas) {
                dump_gen_instruct(*np, d2, out);
                indent_needed = (1 == cnt) ? 0 : 1;
            } else if (rb_cString == clas) {
                dump_str_value(out, StringValuePtr(*(VALUE *)np), RSTRING_LEN(*np), xml_element_chars);
                indent_needed = (1 == cnt) ? 0 : 1;
            } else if (ox_comment_clas == clas) {
                dump_gen_val_node(*np, d2, "<!--", 4, "-->", 3, out);
            } else if (ox_raw_clas == clas) {
                dump_gen_val_node(*np, d2, "", 0, "", 0, out);
            } else if (ox_cdata_clas == clas) {
                dump_gen_val_node(*np, d2, "<![CDATA[", 9, "]]>", 3, out);
            } else if (ox_doctype_clas == clas) {
                dump_gen_val_node(*np, d2, "<!DOCTYPE ", 10, ">", 1, out);
            } else {
                rb_raise(rb_eTypeError, "Unexpected class, %s, while dumping generic XML\n", rb_class2name(clas));
            }
        }
    }
    return indent_needed;
}

static int dump_gen_attr(VALUE key, VALUE value, VALUE ov) {
    Out out = (Out)ov;

    const char *ks;
    size_t      klen;
    size_t      size;

    switch (rb_type(key)) {
    case T_SYMBOL: ks = rb_id2name(SYM2ID(key)); break;
    case T_STRING: ks = StringValuePtr(key); break;
    default:
        key = rb_String(key);
        ks  = StringValuePtr(key);
        break;
    }
    klen  = strlen(ks);
    value = rb_String(value);
    size  = 4 + klen + RSTRING_LEN(value);
    if (out->end - out->cur <= (long)size) {
        grow(out, size);
    }
    *out->cur++ = ' ';
    fill_value(out, ks, klen);
    *out->cur++ = '=';
    *out->cur++ = '"';
    dump_str_value(out, StringValuePtr(value), RSTRING_LEN(value), xml_quote_chars);
    *out->cur++ = '"';

    return ST_CONTINUE;
}

static void
dump_gen_val_node(VALUE obj, int depth, const char *pre, size_t plen, const char *suf, size_t slen, Out out) {
    volatile VALUE v = rb_attr_get(obj, ox_at_value_id);
    const char    *val;
    size_t         vlen;
    size_t         size;
    int            indent;

    if (T_STRING != rb_type(v)) {
        return;
    }
    val  = StringValuePtr(v);
    vlen = RSTRING_LEN(v);
    if (0 > out->indent) {
        indent = -1;
    } else if (0 == out->indent) {
        indent = 0;
    } else {
        indent = depth * out->indent;
    }
    size = indent + plen + slen + vlen + out->opts->margin_len;
    if (out->end - out->cur <= (long)size) {
        grow(out, size);
    }
    fill_indent(out, indent);
    fill_value(out, pre, plen);
    fill_value(out, val, vlen);
    fill_value(out, suf, slen);
    *out->cur = '\0';
}

static void dump_obj_to_xml(VALUE obj, Options copts, Out out) {
    VALUE clas = rb_obj_class(obj);

    out->w_time     = (Yes == copts->xsd_date) ? dump_time_xsd : dump_time_thin;
    out->buf        = ALLOC_N(char, 65336);
    out->end        = out->buf + 65325; /* 10 less than end plus extra for possible errors */
    out->cur        = out->buf;
    out->circ_cache = 0;
    out->circ_cnt   = 0;
    out->opts       = copts;
    out->obj        = obj;
    *out->cur       = '\0';
    if (Yes == copts->circular) {
        ox_cache8_new(&out->circ_cache);
    }
    out->indent = copts->indent;

    if (ox_document_clas == clas) {
        dump_gen_doc(obj, -1, out);
    } else if (ox_element_clas == clas) {
        dump_gen_element(obj, 0, out);
    } else if (ox_cdata_clas == clas) {
        dump_gen_val_node(obj, 0, "<![CDATA[", 9, "]]>", 3, out);
    } else if (ox_instruct_clas == clas) {
        dump_gen_instruct(obj, 0, out);
    } else if (ox_comment_clas == clas) {
        dump_gen_val_node(obj, 0, "<!--", 4, "-->", 3, out);
    } else if (ox_doctype_clas == clas) {
        dump_gen_val_node(obj, 0, "<!DOCTYPE ", 10, ">", 1, out);
    } else {
        out->w_start = dump_start;
        out->w_end   = dump_end;
        dump_first_obj(obj, out);
    }
    if (0 <= out->indent) {
        dump_value(out, "\n", 1);
    }
    if (Yes == copts->circular) {
        ox_cache8_delete(out->circ_cache);
    }
}

char *ox_write_obj_to_str(VALUE obj, Options copts) {
    struct _out out;

    dump_obj_to_xml(obj, copts, &out);
    return out.buf;
}

void ox_write_obj_to_file(VALUE obj, const char *path, Options copts) {
    struct _out out;
    size_t      size;
    FILE       *f;

    dump_obj_to_xml(obj, copts, &out);
    size = out.cur - out.buf;
    if (0 == (f = fopen(path, "w"))) {
        rb_raise(rb_eIOError, "%s\n", strerror(errno));
    }
    if (size != fwrite(out.buf, 1, size, f)) {
        int err = ferror(f);
        rb_raise(rb_eIOError, "Write failed. [%d:%s]\n", err, strerror(err));
    }
    xfree(out.buf);
    fclose(f);
}