xref: /freebsd-10.1-release/contrib/expat/lib/xmltok.c

/* Copyright (c) 1998, 1999 Thai Open Source Software Center Ltd
   See the file COPYING for copying permission.
*/

#include <stddef.h>

#ifdef COMPILED_FROM_DSP
#include "winconfig.h"
#elif defined(MACOS_CLASSIC)
#include "macconfig.h"
#elif defined(__amigaos__)
#include "amigaconfig.h"
#elif defined(__WATCOMC__)
#include "watcomconfig.h"
#else
#ifdef HAVE_EXPAT_CONFIG_H
#include <expat_config.h>
#endif
#endif /* ndef COMPILED_FROM_DSP */

#include "expat_external.h"
#include "internal.h"
#include "xmltok.h"
#include "nametab.h"

#ifdef XML_DTD
#define IGNORE_SECTION_TOK_VTABLE , PREFIX(ignoreSectionTok)
#else
#define IGNORE_SECTION_TOK_VTABLE /* as nothing */
#endif

#define VTABLE1 \
  { PREFIX(prologTok), PREFIX(contentTok), \
    PREFIX(cdataSectionTok) IGNORE_SECTION_TOK_VTABLE }, \
  { PREFIX(attributeValueTok), PREFIX(entityValueTok) }, \
  PREFIX(sameName), \
  PREFIX(nameMatchesAscii), \
  PREFIX(nameLength), \
  PREFIX(skipS), \
  PREFIX(getAtts), \
  PREFIX(charRefNumber), \
  PREFIX(predefinedEntityName), \
  PREFIX(updatePosition), \
  PREFIX(isPublicId)

#define VTABLE VTABLE1, PREFIX(toUtf8), PREFIX(toUtf16)

#define UCS2_GET_NAMING(pages, hi, lo) \
   (namingBitmap[(pages[hi] << 3) + ((lo) >> 5)] & (1 << ((lo) & 0x1F)))

/* A 2 byte UTF-8 representation splits the characters 11 bits between
   the bottom 5 and 6 bits of the bytes.  We need 8 bits to index into
   pages, 3 bits to add to that index and 5 bits to generate the mask.
*/
#define UTF8_GET_NAMING2(pages, byte) \
    (namingBitmap[((pages)[(((byte)[0]) >> 2) & 7] << 3) \
                      + ((((byte)[0]) & 3) << 1) \
                      + ((((byte)[1]) >> 5) & 1)] \
         & (1 << (((byte)[1]) & 0x1F)))

/* A 3 byte UTF-8 representation splits the characters 16 bits between
   the bottom 4, 6 and 6 bits of the bytes.  We need 8 bits to index
   into pages, 3 bits to add to that index and 5 bits to generate the
   mask.
*/
#define UTF8_GET_NAMING3(pages, byte) \
  (namingBitmap[((pages)[((((byte)[0]) & 0xF) << 4) \
                             + ((((byte)[1]) >> 2) & 0xF)] \
                       << 3) \
                      + ((((byte)[1]) & 3) << 1) \
                      + ((((byte)[2]) >> 5) & 1)] \
         & (1 << (((byte)[2]) & 0x1F)))

#define UTF8_GET_NAMING(pages, p, n) \
  ((n) == 2 \
  ? UTF8_GET_NAMING2(pages, (const unsigned char *)(p)) \
  : ((n) == 3 \
     ? UTF8_GET_NAMING3(pages, (const unsigned char *)(p)) \
     : 0))

/* Detection of invalid UTF-8 sequences is based on Table 3.1B
   of Unicode 3.2: http://www.unicode.org/unicode/reports/tr28/
   with the additional restriction of not allowing the Unicode
   code points 0xFFFF and 0xFFFE (sequences EF,BF,BF and EF,BF,BE).
   Implementation details:
     (A & 0x80) == 0     means A < 0x80
   and
     (A & 0xC0) == 0xC0  means A > 0xBF
*/

#define UTF8_INVALID2(p) \
  ((*p) < 0xC2 || ((p)[1] & 0x80) == 0 || ((p)[1] & 0xC0) == 0xC0)

#define UTF8_INVALID3(p) \
  (((p)[2] & 0x80) == 0 \
  || \
  ((*p) == 0xEF && (p)[1] == 0xBF \
    ? \
    (p)[2] > 0xBD \
    : \
    ((p)[2] & 0xC0) == 0xC0) \
  || \
  ((*p) == 0xE0 \
    ? \
    (p)[1] < 0xA0 || ((p)[1] & 0xC0) == 0xC0 \
    : \
    ((p)[1] & 0x80) == 0 \
    || \
    ((*p) == 0xED ? (p)[1] > 0x9F : ((p)[1] & 0xC0) == 0xC0)))

#define UTF8_INVALID4(p) \
  (((p)[3] & 0x80) == 0 || ((p)[3] & 0xC0) == 0xC0 \
  || \
  ((p)[2] & 0x80) == 0 || ((p)[2] & 0xC0) == 0xC0 \
  || \
  ((*p) == 0xF0 \
    ? \
    (p)[1] < 0x90 || ((p)[1] & 0xC0) == 0xC0 \
    : \
    ((p)[1] & 0x80) == 0 \
    || \
    ((*p) == 0xF4 ? (p)[1] > 0x8F : ((p)[1] & 0xC0) == 0xC0)))

static int PTRFASTCALL
isNever(const ENCODING *enc, const char *p)
{
  return 0;
}

static int PTRFASTCALL
utf8_isName2(const ENCODING *enc, const char *p)
{
  return UTF8_GET_NAMING2(namePages, (const unsigned char *)p);
}

static int PTRFASTCALL
utf8_isName3(const ENCODING *enc, const char *p)
{
  return UTF8_GET_NAMING3(namePages, (const unsigned char *)p);
}

#define utf8_isName4 isNever

static int PTRFASTCALL
utf8_isNmstrt2(const ENCODING *enc, const char *p)
{
  return UTF8_GET_NAMING2(nmstrtPages, (const unsigned char *)p);
}

static int PTRFASTCALL
utf8_isNmstrt3(const ENCODING *enc, const char *p)
{
  return UTF8_GET_NAMING3(nmstrtPages, (const unsigned char *)p);
}

#define utf8_isNmstrt4 isNever

static int PTRFASTCALL
utf8_isInvalid2(const ENCODING *enc, const char *p)
{
  return UTF8_INVALID2((const unsigned char *)p);
}

static int PTRFASTCALL
utf8_isInvalid3(const ENCODING *enc, const char *p)
{
  return UTF8_INVALID3((const unsigned char *)p);
}

static int PTRFASTCALL
utf8_isInvalid4(const ENCODING *enc, const char *p)
{
  return UTF8_INVALID4((const unsigned char *)p);
}

struct normal_encoding {
  ENCODING enc;
  unsigned char type[256];
#ifdef XML_MIN_SIZE
  int (PTRFASTCALL *byteType)(const ENCODING *, const char *);
  int (PTRFASTCALL *isNameMin)(const ENCODING *, const char *);
  int (PTRFASTCALL *isNmstrtMin)(const ENCODING *, const char *);
  int (PTRFASTCALL *byteToAscii)(const ENCODING *, const char *);
  int (PTRCALL *charMatches)(const ENCODING *, const char *, int);
#endif /* XML_MIN_SIZE */
  int (PTRFASTCALL *isName2)(const ENCODING *, const char *);
  int (PTRFASTCALL *isName3)(const ENCODING *, const char *);
  int (PTRFASTCALL *isName4)(const ENCODING *, const char *);
  int (PTRFASTCALL *isNmstrt2)(const ENCODING *, const char *);
  int (PTRFASTCALL *isNmstrt3)(const ENCODING *, const char *);
  int (PTRFASTCALL *isNmstrt4)(const ENCODING *, const char *);
  int (PTRFASTCALL *isInvalid2)(const ENCODING *, const char *);
  int (PTRFASTCALL *isInvalid3)(const ENCODING *, const char *);
  int (PTRFASTCALL *isInvalid4)(const ENCODING *, const char *);
};

#define AS_NORMAL_ENCODING(enc)   ((const struct normal_encoding *) (enc))

#ifdef XML_MIN_SIZE

#define STANDARD_VTABLE(E) \
 E ## byteType, \
 E ## isNameMin, \
 E ## isNmstrtMin, \
 E ## byteToAscii, \
 E ## charMatches,

#else

#define STANDARD_VTABLE(E) /* as nothing */

#endif

#define NORMAL_VTABLE(E) \
 E ## isName2, \
 E ## isName3, \
 E ## isName4, \
 E ## isNmstrt2, \
 E ## isNmstrt3, \
 E ## isNmstrt4, \
 E ## isInvalid2, \
 E ## isInvalid3, \
 E ## isInvalid4

static int FASTCALL checkCharRefNumber(int);

#include "xmltok_impl.h"
#include "ascii.h"

#ifdef XML_MIN_SIZE
#define sb_isNameMin isNever
#define sb_isNmstrtMin isNever
#endif

#ifdef XML_MIN_SIZE
#define MINBPC(enc) ((enc)->minBytesPerChar)
#else
/* minimum bytes per character */
#define MINBPC(enc) 1
#endif

#define SB_BYTE_TYPE(enc, p) \
  (((struct normal_encoding *)(enc))->type[(unsigned char)*(p)])

#ifdef XML_MIN_SIZE
static int PTRFASTCALL
sb_byteType(const ENCODING *enc, const char *p)
{
  return SB_BYTE_TYPE(enc, p);
}
#define BYTE_TYPE(enc, p) \
 (AS_NORMAL_ENCODING(enc)->byteType(enc, p))
#else
#define BYTE_TYPE(enc, p) SB_BYTE_TYPE(enc, p)
#endif

#ifdef XML_MIN_SIZE
#define BYTE_TO_ASCII(enc, p) \
 (AS_NORMAL_ENCODING(enc)->byteToAscii(enc, p))
static int PTRFASTCALL
sb_byteToAscii(const ENCODING *enc, const char *p)
{
  return *p;
}
#else
#define BYTE_TO_ASCII(enc, p) (*(p))
#endif

#define IS_NAME_CHAR(enc, p, n) \
 (AS_NORMAL_ENCODING(enc)->isName ## n(enc, p))
#define IS_NMSTRT_CHAR(enc, p, n) \
 (AS_NORMAL_ENCODING(enc)->isNmstrt ## n(enc, p))
#define IS_INVALID_CHAR(enc, p, n) \
 (AS_NORMAL_ENCODING(enc)->isInvalid ## n(enc, p))

#ifdef XML_MIN_SIZE
#define IS_NAME_CHAR_MINBPC(enc, p) \
 (AS_NORMAL_ENCODING(enc)->isNameMin(enc, p))
#define IS_NMSTRT_CHAR_MINBPC(enc, p) \
 (AS_NORMAL_ENCODING(enc)->isNmstrtMin(enc, p))
#else
#define IS_NAME_CHAR_MINBPC(enc, p) (0)
#define IS_NMSTRT_CHAR_MINBPC(enc, p) (0)
#endif

#ifdef XML_MIN_SIZE
#define CHAR_MATCHES(enc, p, c) \
 (AS_NORMAL_ENCODING(enc)->charMatches(enc, p, c))
static int PTRCALL
sb_charMatches(const ENCODING *enc, const char *p, int c)
{
  return *p == c;
}
#else
/* c is an ASCII character */
#define CHAR_MATCHES(enc, p, c) (*(p) == c)
#endif

#define PREFIX(ident) normal_ ## ident
#define XML_TOK_IMPL_C
#include "xmltok_impl.c"
#undef XML_TOK_IMPL_C

#undef MINBPC
#undef BYTE_TYPE
#undef BYTE_TO_ASCII
#undef CHAR_MATCHES
#undef IS_NAME_CHAR
#undef IS_NAME_CHAR_MINBPC
#undef IS_NMSTRT_CHAR
#undef IS_NMSTRT_CHAR_MINBPC
#undef IS_INVALID_CHAR

enum {  /* UTF8_cvalN is value of masked first byte of N byte sequence */
  UTF8_cval1 = 0x00,
  UTF8_cval2 = 0xc0,
  UTF8_cval3 = 0xe0,
  UTF8_cval4 = 0xf0
};

static void PTRCALL
utf8_toUtf8(const ENCODING *enc,
            const char **fromP, const char *fromLim,
            char **toP, const char *toLim)
{
  char *to;
  const char *from;
  if (fromLim - *fromP > toLim - *toP) {
    /* Avoid copying partial characters. */
    for (fromLim = *fromP + (toLim - *toP); fromLim > *fromP; fromLim--)
      if (((unsigned char)fromLim[-1] & 0xc0) != 0x80)
        break;
  }
  for (to = *toP, from = *fromP; from != fromLim; from++, to++)
    *to = *from;
  *fromP = from;
  *toP = to;
}

static void PTRCALL
utf8_toUtf16(const ENCODING *enc,
             const char **fromP, const char *fromLim,
             unsigned short **toP, const unsigned short *toLim)
{
  unsigned short *to = *toP;
  const char *from = *fromP;
  while (from != fromLim && to != toLim) {
    switch (((struct normal_encoding *)enc)->type[(unsigned char)*from]) {
    case BT_LEAD2:
      *to++ = (unsigned short)(((from[0] & 0x1f) << 6) | (from[1] & 0x3f));
      from += 2;
      break;
    case BT_LEAD3:
      *to++ = (unsigned short)(((from[0] & 0xf) << 12)
                               | ((from[1] & 0x3f) << 6) | (from[2] & 0x3f));
      from += 3;
      break;
    case BT_LEAD4:
      {
        unsigned long n;
        if (to + 1 == toLim)
          goto after;
        n = ((from[0] & 0x7) << 18) | ((from[1] & 0x3f) << 12)
            | ((from[2] & 0x3f) << 6) | (from[3] & 0x3f);
        n -= 0x10000;
        to[0] = (unsigned short)((n >> 10) | 0xD800);
        to[1] = (unsigned short)((n & 0x3FF) | 0xDC00);
        to += 2;
        from += 4;
      }
      break;
    default:
      *to++ = *from++;
      break;
    }
  }
after:
  *fromP = from;
  *toP = to;
}

#ifdef XML_NS
static const struct normal_encoding utf8_encoding_ns = {
  { VTABLE1, utf8_toUtf8, utf8_toUtf16, 1, 1, 0 },
  {
#include "asciitab.h"
#include "utf8tab.h"
  },
  STANDARD_VTABLE(sb_) NORMAL_VTABLE(utf8_)
};
#endif

static const struct normal_encoding utf8_encoding = {
  { VTABLE1, utf8_toUtf8, utf8_toUtf16, 1, 1, 0 },
  {
#define BT_COLON BT_NMSTRT
#include "asciitab.h"
#undef BT_COLON
#include "utf8tab.h"
  },
  STANDARD_VTABLE(sb_) NORMAL_VTABLE(utf8_)
};

#ifdef XML_NS

static const struct normal_encoding internal_utf8_encoding_ns = {
  { VTABLE1, utf8_toUtf8, utf8_toUtf16, 1, 1, 0 },
  {
#include "iasciitab.h"
#include "utf8tab.h"
  },
  STANDARD_VTABLE(sb_) NORMAL_VTABLE(utf8_)
};

#endif

static const struct normal_encoding internal_utf8_encoding = {
  { VTABLE1, utf8_toUtf8, utf8_toUtf16, 1, 1, 0 },
  {
#define BT_COLON BT_NMSTRT
#include "iasciitab.h"
#undef BT_COLON
#include "utf8tab.h"
  },
  STANDARD_VTABLE(sb_) NORMAL_VTABLE(utf8_)
};

static void PTRCALL
latin1_toUtf8(const ENCODING *enc,
              const char **fromP, const char *fromLim,
              char **toP, const char *toLim)
{
  for (;;) {
    unsigned char c;
    if (*fromP == fromLim)
      break;
    c = (unsigned char)**fromP;
    if (c & 0x80) {
      if (toLim - *toP < 2)
        break;
      *(*toP)++ = (char)((c >> 6) | UTF8_cval2);
      *(*toP)++ = (char)((c & 0x3f) | 0x80);
      (*fromP)++;
    }
    else {
      if (*toP == toLim)
        break;
      *(*toP)++ = *(*fromP)++;
    }
  }
}

static void PTRCALL
latin1_toUtf16(const ENCODING *enc,
               const char **fromP, const char *fromLim,
               unsigned short **toP, const unsigned short *toLim)
{
  while (*fromP != fromLim && *toP != toLim)
    *(*toP)++ = (unsigned char)*(*fromP)++;
}

#ifdef XML_NS

static const struct normal_encoding latin1_encoding_ns = {
  { VTABLE1, latin1_toUtf8, latin1_toUtf16, 1, 0, 0 },
  {
#include "asciitab.h"
#include "latin1tab.h"
  },
  STANDARD_VTABLE(sb_)
};

#endif

static const struct normal_encoding latin1_encoding = {
  { VTABLE1, latin1_toUtf8, latin1_toUtf16, 1, 0, 0 },
  {
#define BT_COLON BT_NMSTRT
#include "asciitab.h"
#undef BT_COLON
#include "latin1tab.h"
  },
  STANDARD_VTABLE(sb_)
};

static void PTRCALL
ascii_toUtf8(const ENCODING *enc,
             const char **fromP, const char *fromLim,
             char **toP, const char *toLim)
{
  while (*fromP != fromLim && *toP != toLim)
    *(*toP)++ = *(*fromP)++;
}

#ifdef XML_NS

static const struct normal_encoding ascii_encoding_ns = {
  { VTABLE1, ascii_toUtf8, latin1_toUtf16, 1, 1, 0 },
  {
#include "asciitab.h"
/* BT_NONXML == 0 */
  },
  STANDARD_VTABLE(sb_)
};

#endif

static const struct normal_encoding ascii_encoding = {
  { VTABLE1, ascii_toUtf8, latin1_toUtf16, 1, 1, 0 },
  {
#define BT_COLON BT_NMSTRT
#include "asciitab.h"
#undef BT_COLON
/* BT_NONXML == 0 */
  },
  STANDARD_VTABLE(sb_)
};

static int PTRFASTCALL
unicode_byte_type(char hi, char lo)
{
  switch ((unsigned char)hi) {
  case 0xD8: case 0xD9: case 0xDA: case 0xDB:
    return BT_LEAD4;
  case 0xDC: case 0xDD: case 0xDE: case 0xDF:
    return BT_TRAIL;
  case 0xFF:
    switch ((unsigned char)lo) {
    case 0xFF:
    case 0xFE:
      return BT_NONXML;
    }
    break;
  }
  return BT_NONASCII;
}

#define DEFINE_UTF16_TO_UTF8(E) \
static void  PTRCALL \
E ## toUtf8(const ENCODING *enc, \
            const char **fromP, const char *fromLim, \
            char **toP, const char *toLim) \
{ \
  const char *from; \
  for (from = *fromP; from != fromLim; from += 2) { \
    int plane; \
    unsigned char lo2; \
    unsigned char lo = GET_LO(from); \
    unsigned char hi = GET_HI(from); \
    switch (hi) { \
    case 0: \
      if (lo < 0x80) { \
        if (*toP == toLim) { \
          *fromP = from; \
          return; \
        } \
        *(*toP)++ = lo; \
        break; \
      } \
      /* fall through */ \
    case 0x1: case 0x2: case 0x3: \
    case 0x4: case 0x5: case 0x6: case 0x7: \
      if (toLim -  *toP < 2) { \
        *fromP = from; \
        return; \
      } \
      *(*toP)++ = ((lo >> 6) | (hi << 2) |  UTF8_cval2); \
      *(*toP)++ = ((lo & 0x3f) | 0x80); \
      break; \
    default: \
      if (toLim -  *toP < 3)  { \
        *fromP = from; \
        return; \
      } \
      /* 16 bits divided 4, 6, 6 amongst 3 bytes */ \
      *(*toP)++ = ((hi >> 4) | UTF8_cval3); \
      *(*toP)++ = (((hi & 0xf) << 2) | (lo >> 6) | 0x80); \
      *(*toP)++ = ((lo & 0x3f) | 0x80); \
      break; \
    case 0xD8: case 0xD9: case 0xDA: case 0xDB: \
      if (toLim -  *toP < 4) { \
        *fromP = from; \
        return; \
      } \
      plane = (((hi & 0x3) << 2) | ((lo >> 6) & 0x3)) + 1; \
      *(*toP)++ = ((plane >> 2) | UTF8_cval4); \
      *(*toP)++ = (((lo >> 2) & 0xF) | ((plane & 0x3) << 4) | 0x80); \
      from += 2; \
      lo2 = GET_LO(from); \
      *(*toP)++ = (((lo & 0x3) << 4) \
                   | ((GET_HI(from) & 0x3) << 2) \
                   | (lo2 >> 6) \
                   | 0x80); \
      *(*toP)++ = ((lo2 & 0x3f) | 0x80); \
      break; \
    } \
  } \
  *fromP = from; \
}

#define DEFINE_UTF16_TO_UTF16(E) \
static void  PTRCALL \
E ## toUtf16(const ENCODING *enc, \
             const char **fromP, const char *fromLim, \
             unsigned short **toP, const unsigned short *toLim) \
{ \
  /* Avoid copying first half only of surrogate */ \
  if (fromLim - *fromP > ((toLim - *toP) << 1) \
      && (GET_HI(fromLim - 2) & 0xF8) == 0xD8) \
    fromLim -= 2; \
  for (; *fromP != fromLim && *toP != toLim; *fromP += 2) \
    *(*toP)++ = (GET_HI(*fromP) << 8) | GET_LO(*fromP); \
}

#define SET2(ptr, ch) \
  (((ptr)[0] = ((ch) & 0xff)), ((ptr)[1] = ((ch) >> 8)))
#define GET_LO(ptr) ((unsigned char)(ptr)[0])
#define GET_HI(ptr) ((unsigned char)(ptr)[1])

DEFINE_UTF16_TO_UTF8(little2_)
DEFINE_UTF16_TO_UTF16(little2_)

#undef SET2
#undef GET_LO
#undef GET_HI

#define SET2(ptr, ch) \
  (((ptr)[0] = ((ch) >> 8)), ((ptr)[1] = ((ch) & 0xFF)))
#define GET_LO(ptr) ((unsigned char)(ptr)[1])
#define GET_HI(ptr) ((unsigned char)(ptr)[0])

DEFINE_UTF16_TO_UTF8(big2_)
DEFINE_UTF16_TO_UTF16(big2_)

#undef SET2
#undef GET_LO
#undef GET_HI

#define LITTLE2_BYTE_TYPE(enc, p) \
 ((p)[1] == 0 \
  ? ((struct normal_encoding *)(enc))->type[(unsigned char)*(p)] \
  : unicode_byte_type((p)[1], (p)[0]))
#define LITTLE2_BYTE_TO_ASCII(enc, p) ((p)[1] == 0 ? (p)[0] : -1)
#define LITTLE2_CHAR_MATCHES(enc, p, c) ((p)[1] == 0 && (p)[0] == c)
#define LITTLE2_IS_NAME_CHAR_MINBPC(enc, p) \
  UCS2_GET_NAMING(namePages, (unsigned char)p[1], (unsigned char)p[0])
#define LITTLE2_IS_NMSTRT_CHAR_MINBPC(enc, p) \
  UCS2_GET_NAMING(nmstrtPages, (unsigned char)p[1], (unsigned char)p[0])

#ifdef XML_MIN_SIZE

static int PTRFASTCALL
little2_byteType(const ENCODING *enc, const char *p)
{
  return LITTLE2_BYTE_TYPE(enc, p);
}

static int PTRFASTCALL
little2_byteToAscii(const ENCODING *enc, const char *p)
{
  return LITTLE2_BYTE_TO_ASCII(enc, p);
}

static int PTRCALL
little2_charMatches(const ENCODING *enc, const char *p, int c)
{
  return LITTLE2_CHAR_MATCHES(enc, p, c);
}

static int PTRFASTCALL
little2_isNameMin(const ENCODING *enc, const char *p)
{
  return LITTLE2_IS_NAME_CHAR_MINBPC(enc, p);
}

static int PTRFASTCALL
little2_isNmstrtMin(const ENCODING *enc, const char *p)
{
  return LITTLE2_IS_NMSTRT_CHAR_MINBPC(enc, p);
}

#undef VTABLE
#define VTABLE VTABLE1, little2_toUtf8, little2_toUtf16

#else /* not XML_MIN_SIZE */

#undef PREFIX
#define PREFIX(ident) little2_ ## ident
#define MINBPC(enc) 2
/* CHAR_MATCHES is guaranteed to have MINBPC bytes available. */
#define BYTE_TYPE(enc, p) LITTLE2_BYTE_TYPE(enc, p)
#define BYTE_TO_ASCII(enc, p) LITTLE2_BYTE_TO_ASCII(enc, p)
#define CHAR_MATCHES(enc, p, c) LITTLE2_CHAR_MATCHES(enc, p, c)
#define IS_NAME_CHAR(enc, p, n) 0
#define IS_NAME_CHAR_MINBPC(enc, p) LITTLE2_IS_NAME_CHAR_MINBPC(enc, p)
#define IS_NMSTRT_CHAR(enc, p, n) (0)
#define IS_NMSTRT_CHAR_MINBPC(enc, p) LITTLE2_IS_NMSTRT_CHAR_MINBPC(enc, p)

#define XML_TOK_IMPL_C
#include "xmltok_impl.c"
#undef XML_TOK_IMPL_C

#undef MINBPC
#undef BYTE_TYPE
#undef BYTE_TO_ASCII
#undef CHAR_MATCHES
#undef IS_NAME_CHAR
#undef IS_NAME_CHAR_MINBPC
#undef IS_NMSTRT_CHAR
#undef IS_NMSTRT_CHAR_MINBPC
#undef IS_INVALID_CHAR

#endif /* not XML_MIN_SIZE */

#ifdef XML_NS

static const struct normal_encoding little2_encoding_ns = {
  { VTABLE, 2, 0,
#if BYTEORDER == 1234
    1
#else
    0
#endif
  },
  {
#include "asciitab.h"
#include "latin1tab.h"
  },
  STANDARD_VTABLE(little2_)
};

#endif

static const struct normal_encoding little2_encoding = {
  { VTABLE, 2, 0,
#if BYTEORDER == 1234
    1
#else
    0
#endif
  },
  {
#define BT_COLON BT_NMSTRT
#include "asciitab.h"
#undef BT_COLON
#include "latin1tab.h"
  },
  STANDARD_VTABLE(little2_)
};

#if BYTEORDER != 4321

#ifdef XML_NS

static const struct normal_encoding internal_little2_encoding_ns = {
  { VTABLE, 2, 0, 1 },
  {
#include "iasciitab.h"
#include "latin1tab.h"
  },
  STANDARD_VTABLE(little2_)
};

#endif

static const struct normal_encoding internal_little2_encoding = {
  { VTABLE, 2, 0, 1 },
  {
#define BT_COLON BT_NMSTRT
#include "iasciitab.h"
#undef BT_COLON
#include "latin1tab.h"
  },
  STANDARD_VTABLE(little2_)
};

#endif


#define BIG2_BYTE_TYPE(enc, p) \
 ((p)[0] == 0 \
  ? ((struct normal_encoding *)(enc))->type[(unsigned char)(p)[1]] \
  : unicode_byte_type((p)[0], (p)[1]))
#define BIG2_BYTE_TO_ASCII(enc, p) ((p)[0] == 0 ? (p)[1] : -1)
#define BIG2_CHAR_MATCHES(enc, p, c) ((p)[0] == 0 && (p)[1] == c)
#define BIG2_IS_NAME_CHAR_MINBPC(enc, p) \
  UCS2_GET_NAMING(namePages, (unsigned char)p[0], (unsigned char)p[1])
#define BIG2_IS_NMSTRT_CHAR_MINBPC(enc, p) \
  UCS2_GET_NAMING(nmstrtPages, (unsigned char)p[0], (unsigned char)p[1])

#ifdef XML_MIN_SIZE

static int PTRFASTCALL
big2_byteType(const ENCODING *enc, const char *p)
{
  return BIG2_BYTE_TYPE(enc, p);
}

static int PTRFASTCALL
big2_byteToAscii(const ENCODING *enc, const char *p)
{
  return BIG2_BYTE_TO_ASCII(enc, p);
}

static int PTRCALL
big2_charMatches(const ENCODING *enc, const char *p, int c)
{
  return BIG2_CHAR_MATCHES(enc, p, c);
}

static int PTRFASTCALL
big2_isNameMin(const ENCODING *enc, const char *p)
{
  return BIG2_IS_NAME_CHAR_MINBPC(enc, p);
}

static int PTRFASTCALL
big2_isNmstrtMin(const ENCODING *enc, const char *p)
{
  return BIG2_IS_NMSTRT_CHAR_MINBPC(enc, p);
}

#undef VTABLE
#define VTABLE VTABLE1, big2_toUtf8, big2_toUtf16

#else /* not XML_MIN_SIZE */

#undef PREFIX
#define PREFIX(ident) big2_ ## ident
#define MINBPC(enc) 2
/* CHAR_MATCHES is guaranteed to have MINBPC bytes available. */
#define BYTE_TYPE(enc, p) BIG2_BYTE_TYPE(enc, p)
#define BYTE_TO_ASCII(enc, p) BIG2_BYTE_TO_ASCII(enc, p)
#define CHAR_MATCHES(enc, p, c) BIG2_CHAR_MATCHES(enc, p, c)
#define IS_NAME_CHAR(enc, p, n) 0
#define IS_NAME_CHAR_MINBPC(enc, p) BIG2_IS_NAME_CHAR_MINBPC(enc, p)
#define IS_NMSTRT_CHAR(enc, p, n) (0)
#define IS_NMSTRT_CHAR_MINBPC(enc, p) BIG2_IS_NMSTRT_CHAR_MINBPC(enc, p)

#define XML_TOK_IMPL_C
#include "xmltok_impl.c"
#undef XML_TOK_IMPL_C

#undef MINBPC
#undef BYTE_TYPE
#undef BYTE_TO_ASCII
#undef CHAR_MATCHES
#undef IS_NAME_CHAR
#undef IS_NAME_CHAR_MINBPC
#undef IS_NMSTRT_CHAR
#undef IS_NMSTRT_CHAR_MINBPC
#undef IS_INVALID_CHAR

#endif /* not XML_MIN_SIZE */

#ifdef XML_NS

static const struct normal_encoding big2_encoding_ns = {
  { VTABLE, 2, 0,
#if BYTEORDER == 4321
  1
#else
  0
#endif
  },
  {
#include "asciitab.h"
#include "latin1tab.h"
  },
  STANDARD_VTABLE(big2_)
};

#endif

static const struct normal_encoding big2_encoding = {
  { VTABLE, 2, 0,
#if BYTEORDER == 4321
  1
#else
  0
#endif
  },
  {
#define BT_COLON BT_NMSTRT
#include "asciitab.h"
#undef BT_COLON
#include "latin1tab.h"
  },
  STANDARD_VTABLE(big2_)
};

#if BYTEORDER != 1234

#ifdef XML_NS

static const struct normal_encoding internal_big2_encoding_ns = {
  { VTABLE, 2, 0, 1 },
  {
#include "iasciitab.h"
#include "latin1tab.h"
  },
  STANDARD_VTABLE(big2_)
};

#endif

static const struct normal_encoding internal_big2_encoding = {
  { VTABLE, 2, 0, 1 },
  {
#define BT_COLON BT_NMSTRT
#include "iasciitab.h"
#undef BT_COLON
#include "latin1tab.h"
  },
  STANDARD_VTABLE(big2_)
};

#endif

#undef PREFIX

static int FASTCALL
streqci(const char *s1, const char *s2)
{
  for (;;) {
    char c1 = *s1++;
    char c2 = *s2++;
    if (ASCII_a <= c1 && c1 <= ASCII_z)
      c1 += ASCII_A - ASCII_a;
    if (ASCII_a <= c2 && c2 <= ASCII_z)
      c2 += ASCII_A - ASCII_a;
    if (c1 != c2)
      return 0;
    if (!c1)
      break;
  }
  return 1;
}

static void PTRCALL
initUpdatePosition(const ENCODING *enc, const char *ptr,
                   const char *end, POSITION *pos)
{
  normal_updatePosition(&utf8_encoding.enc, ptr, end, pos);
}

static int
toAscii(const ENCODING *enc, const char *ptr, const char *end)
{
  char buf[1];
  char *p = buf;
  XmlUtf8Convert(enc, &ptr, end, &p, p + 1);
  if (p == buf)
    return -1;
  else
    return buf[0];
}

static int FASTCALL
isSpace(int c)
{
  switch (c) {
  case 0x20:
  case 0xD:
  case 0xA:
  case 0x9:
    return 1;
  }
  return 0;
}

/* Return 1 if there's just optional white space or there's an S
   followed by name=val.
*/
static int
parsePseudoAttribute(const ENCODING *enc,
                     const char *ptr,
                     const char *end,
                     const char **namePtr,
                     const char **nameEndPtr,
                     const char **valPtr,
                     const char **nextTokPtr)
{
  int c;
  char open;
  if (ptr == end) {
    *namePtr = NULL;
    return 1;
  }
  if (!isSpace(toAscii(enc, ptr, end))) {
    *nextTokPtr = ptr;
    return 0;
  }
  do {
    ptr += enc->minBytesPerChar;
  } while (isSpace(toAscii(enc, ptr, end)));
  if (ptr == end) {
    *namePtr = NULL;
    return 1;
  }
  *namePtr = ptr;
  for (;;) {
    c = toAscii(enc, ptr, end);
    if (c == -1) {
      *nextTokPtr = ptr;
      return 0;
    }
    if (c == ASCII_EQUALS) {
      *nameEndPtr = ptr;
      break;
    }
    if (isSpace(c)) {
      *nameEndPtr = ptr;
      do {
        ptr += enc->minBytesPerChar;
      } while (isSpace(c = toAscii(enc, ptr, end)));
      if (c != ASCII_EQUALS) {
        *nextTokPtr = ptr;
        return 0;
      }
      break;
    }
    ptr += enc->minBytesPerChar;
  }
  if (ptr == *namePtr) {
    *nextTokPtr = ptr;
    return 0;
  }
  ptr += enc->minBytesPerChar;
  c = toAscii(enc, ptr, end);
  while (isSpace(c)) {
    ptr += enc->minBytesPerChar;
    c = toAscii(enc, ptr, end);
  }
  if (c != ASCII_QUOT && c != ASCII_APOS) {
    *nextTokPtr = ptr;
    return 0;
  }
  open = (char)c;
  ptr += enc->minBytesPerChar;
  *valPtr = ptr;
  for (;; ptr += enc->minBytesPerChar) {
    c = toAscii(enc, ptr, end);
    if (c == open)
      break;
    if (!(ASCII_a <= c && c <= ASCII_z)
        && !(ASCII_A <= c && c <= ASCII_Z)
        && !(ASCII_0 <= c && c <= ASCII_9)
        && c != ASCII_PERIOD
        && c != ASCII_MINUS
        && c != ASCII_UNDERSCORE) {
      *nextTokPtr = ptr;
      return 0;
    }
  }
  *nextTokPtr = ptr + enc->minBytesPerChar;
  return 1;
}

static const char KW_version[] = {
  ASCII_v, ASCII_e, ASCII_r, ASCII_s, ASCII_i, ASCII_o, ASCII_n, '\0'
};

static const char KW_encoding[] = {
  ASCII_e, ASCII_n, ASCII_c, ASCII_o, ASCII_d, ASCII_i, ASCII_n, ASCII_g, '\0'
};

static const char KW_standalone[] = {
  ASCII_s, ASCII_t, ASCII_a, ASCII_n, ASCII_d, ASCII_a, ASCII_l, ASCII_o,
  ASCII_n, ASCII_e, '\0'
};

static const char KW_yes[] = {
  ASCII_y, ASCII_e, ASCII_s,  '\0'
};

static const char KW_no[] = {
  ASCII_n, ASCII_o,  '\0'
};

static int
doParseXmlDecl(const ENCODING *(*encodingFinder)(const ENCODING *,
                                                 const char *,
                                                 const char *),
               int isGeneralTextEntity,
               const ENCODING *enc,
               const char *ptr,
               const char *end,
               const char **badPtr,
               const char **versionPtr,
               const char **versionEndPtr,
               const char **encodingName,
               const ENCODING **encoding,
               int *standalone)
{
  const char *val = NULL;
  const char *name = NULL;
  const char *nameEnd = NULL;
  ptr += 5 * enc->minBytesPerChar;
  end -= 2 * enc->minBytesPerChar;
  if (!parsePseudoAttribute(enc, ptr, end, &name, &nameEnd, &val, &ptr)
      || !name) {
    *badPtr = ptr;
    return 0;
  }
  if (!XmlNameMatchesAscii(enc, name, nameEnd, KW_version)) {
    if (!isGeneralTextEntity) {
      *badPtr = name;
      return 0;
    }
  }
  else {
    if (versionPtr)
      *versionPtr = val;
    if (versionEndPtr)
      *versionEndPtr = ptr;
    if (!parsePseudoAttribute(enc, ptr, end, &name, &nameEnd, &val, &ptr)) {
      *badPtr = ptr;
      return 0;
    }
    if (!name) {
      if (isGeneralTextEntity) {
        /* a TextDecl must have an EncodingDecl */
        *badPtr = ptr;
        return 0;
      }
      return 1;
    }
  }
  if (XmlNameMatchesAscii(enc, name, nameEnd, KW_encoding)) {
    int c = toAscii(enc, val, end);
    if (!(ASCII_a <= c && c <= ASCII_z) && !(ASCII_A <= c && c <= ASCII_Z)) {
      *badPtr = val;
      return 0;
    }
    if (encodingName)
      *encodingName = val;
    if (encoding)
      *encoding = encodingFinder(enc, val, ptr - enc->minBytesPerChar);
    if (!parsePseudoAttribute(enc, ptr, end, &name, &nameEnd, &val, &ptr)) {
      *badPtr = ptr;
      return 0;
    }
    if (!name)
      return 1;
  }
  if (!XmlNameMatchesAscii(enc, name, nameEnd, KW_standalone)
      || isGeneralTextEntity) {
    *badPtr = name;
    return 0;
  }
  if (XmlNameMatchesAscii(enc, val, ptr - enc->minBytesPerChar, KW_yes)) {
    if (standalone)
      *standalone = 1;
  }
  else if (XmlNameMatchesAscii(enc, val, ptr - enc->minBytesPerChar, KW_no)) {
    if (standalone)
      *standalone = 0;
  }
  else {
    *badPtr = val;
    return 0;
  }
  while (isSpace(toAscii(enc, ptr, end)))
    ptr += enc->minBytesPerChar;
  if (ptr != end) {
    *badPtr = ptr;
    return 0;
  }
  return 1;
}

static int FASTCALL
checkCharRefNumber(int result)
{
  switch (result >> 8) {
  case 0xD8: case 0xD9: case 0xDA: case 0xDB:
  case 0xDC: case 0xDD: case 0xDE: case 0xDF:
    return -1;
  case 0:
    if (latin1_encoding.type[result] == BT_NONXML)
      return -1;
    break;
  case 0xFF:
    if (result == 0xFFFE || result == 0xFFFF)
      return -1;
    break;
  }
  return result;
}

int FASTCALL
XmlUtf8Encode(int c, char *buf)
{
  enum {
    /* minN is minimum legal resulting value for N byte sequence */
    min2 = 0x80,
    min3 = 0x800,
    min4 = 0x10000
  };

  if (c < 0)
    return 0;
  if (c < min2) {
    buf[0] = (char)(c | UTF8_cval1);
    return 1;
  }
  if (c < min3) {
    buf[0] = (char)((c >> 6) | UTF8_cval2);
    buf[1] = (char)((c & 0x3f) | 0x80);
    return 2;
  }
  if (c < min4) {
    buf[0] = (char)((c >> 12) | UTF8_cval3);
    buf[1] = (char)(((c >> 6) & 0x3f) | 0x80);
    buf[2] = (char)((c & 0x3f) | 0x80);
    return 3;
  }
  if (c < 0x110000) {
    buf[0] = (char)((c >> 18) | UTF8_cval4);
    buf[1] = (char)(((c >> 12) & 0x3f) | 0x80);
    buf[2] = (char)(((c >> 6) & 0x3f) | 0x80);
    buf[3] = (char)((c & 0x3f) | 0x80);
    return 4;
  }
  return 0;
}

int FASTCALL
XmlUtf16Encode(int charNum, unsigned short *buf)
{
  if (charNum < 0)
    return 0;
  if (charNum < 0x10000) {
    buf[0] = (unsigned short)charNum;
    return 1;
  }
  if (charNum < 0x110000) {
    charNum -= 0x10000;
    buf[0] = (unsigned short)((charNum >> 10) + 0xD800);
    buf[1] = (unsigned short)((charNum & 0x3FF) + 0xDC00);
    return 2;
  }
  return 0;
}

struct unknown_encoding {
  struct normal_encoding normal;
  CONVERTER convert;
  void *userData;
  unsigned short utf16[256];
  char utf8[256][4];
};

#define AS_UNKNOWN_ENCODING(enc)  ((const struct unknown_encoding *) (enc))

int
XmlSizeOfUnknownEncoding(void)
{
  return sizeof(struct unknown_encoding);
}

static int PTRFASTCALL
unknown_isName(const ENCODING *enc, const char *p)
{
  const struct unknown_encoding *uenc = AS_UNKNOWN_ENCODING(enc);
  int c = uenc->convert(uenc->userData, p);
  if (c & ~0xFFFF)
    return 0;
  return UCS2_GET_NAMING(namePages, c >> 8, c & 0xFF);
}

static int PTRFASTCALL
unknown_isNmstrt(const ENCODING *enc, const char *p)
{
  const struct unknown_encoding *uenc = AS_UNKNOWN_ENCODING(enc);
  int c = uenc->convert(uenc->userData, p);
  if (c & ~0xFFFF)
    return 0;
  return UCS2_GET_NAMING(nmstrtPages, c >> 8, c & 0xFF);
}

static int PTRFASTCALL
unknown_isInvalid(const ENCODING *enc, const char *p)
{
  const struct unknown_encoding *uenc = AS_UNKNOWN_ENCODING(enc);
  int c = uenc->convert(uenc->userData, p);
  return (c & ~0xFFFF) || checkCharRefNumber(c) < 0;
}

static void PTRCALL
unknown_toUtf8(const ENCODING *enc,
               const char **fromP, const char *fromLim,
               char **toP, const char *toLim)
{
  const struct unknown_encoding *uenc = AS_UNKNOWN_ENCODING(enc);
  char buf[XML_UTF8_ENCODE_MAX];
  for (;;) {
    const char *utf8;
    int n;
    if (*fromP == fromLim)
      break;
    utf8 = uenc->utf8[(unsigned char)**fromP];
    n = *utf8++;
    if (n == 0) {
      int c = uenc->convert(uenc->userData, *fromP);
      n = XmlUtf8Encode(c, buf);
      if (n > toLim - *toP)
        break;
      utf8 = buf;
      *fromP += (AS_NORMAL_ENCODING(enc)->type[(unsigned char)**fromP]
                 - (BT_LEAD2 - 2));
    }
    else {
      if (n > toLim - *toP)
        break;
      (*fromP)++;
    }
    do {
      *(*toP)++ = *utf8++;
    } while (--n != 0);
  }
}

static void PTRCALL
unknown_toUtf16(const ENCODING *enc,
                const char **fromP, const char *fromLim,
                unsigned short **toP, const unsigned short *toLim)
{
  const struct unknown_encoding *uenc = AS_UNKNOWN_ENCODING(enc);
  while (*fromP != fromLim && *toP != toLim) {
    unsigned short c = uenc->utf16[(unsigned char)**fromP];
    if (c == 0) {
      c = (unsigned short)
          uenc->convert(uenc->userData, *fromP);
      *fromP += (AS_NORMAL_ENCODING(enc)->type[(unsigned char)**fromP]
                 - (BT_LEAD2 - 2));
    }
    else
      (*fromP)++;
    *(*toP)++ = c;
  }
}

ENCODING *
XmlInitUnknownEncoding(void *mem,
                       int *table,
                       CONVERTER convert,
                       void *userData)
{
  int i;
  struct unknown_encoding *e = (struct unknown_encoding *)mem;
  for (i = 0; i < (int)sizeof(struct normal_encoding); i++)
    ((char *)mem)[i] = ((char *)&latin1_encoding)[i];
  for (i = 0; i < 128; i++)
    if (latin1_encoding.type[i] != BT_OTHER
        && latin1_encoding.type[i] != BT_NONXML
        && table[i] != i)
      return 0;
  for (i = 0; i < 256; i++) {
    int c = table[i];
    if (c == -1) {
      e->normal.type[i] = BT_MALFORM;
      /* This shouldn't really get used. */
      e->utf16[i] = 0xFFFF;
      e->utf8[i][0] = 1;
      e->utf8[i][1] = 0;
    }
    else if (c < 0) {
      if (c < -4)
        return 0;
      e->normal.type[i] = (unsigned char)(BT_LEAD2 - (c + 2));
      e->utf8[i][0] = 0;
      e->utf16[i] = 0;
    }
    else if (c < 0x80) {
      if (latin1_encoding.type[c] != BT_OTHER
          && latin1_encoding.type[c] != BT_NONXML
          && c != i)
        return 0;
      e->normal.type[i] = latin1_encoding.type[c];
      e->utf8[i][0] = 1;
      e->utf8[i][1] = (char)c;
      e->utf16[i] = (unsigned short)(c == 0 ? 0xFFFF : c);
    }
    else if (checkCharRefNumber(c) < 0) {
      e->normal.type[i] = BT_NONXML;
      /* This shouldn't really get used. */
      e->utf16[i] = 0xFFFF;
      e->utf8[i][0] = 1;
      e->utf8[i][1] = 0;
    }
    else {
      if (c > 0xFFFF)
        return 0;
      if (UCS2_GET_NAMING(nmstrtPages, c >> 8, c & 0xff))
        e->normal.type[i] = BT_NMSTRT;
      else if (UCS2_GET_NAMING(namePages, c >> 8, c & 0xff))
        e->normal.type[i] = BT_NAME;
      else
        e->normal.type[i] = BT_OTHER;
      e->utf8[i][0] = (char)XmlUtf8Encode(c, e->utf8[i] + 1);
      e->utf16[i] = (unsigned short)c;
    }
  }
  e->userData = userData;
  e->convert = convert;
  if (convert) {
    e->normal.isName2 = unknown_isName;
    e->normal.isName3 = unknown_isName;
    e->normal.isName4 = unknown_isName;
    e->normal.isNmstrt2 = unknown_isNmstrt;
    e->normal.isNmstrt3 = unknown_isNmstrt;
    e->normal.isNmstrt4 = unknown_isNmstrt;
    e->normal.isInvalid2 = unknown_isInvalid;
    e->normal.isInvalid3 = unknown_isInvalid;
    e->normal.isInvalid4 = unknown_isInvalid;
  }
  e->normal.enc.utf8Convert = unknown_toUtf8;
  e->normal.enc.utf16Convert = unknown_toUtf16;
  return &(e->normal.enc);
}

/* If this enumeration is changed, getEncodingIndex and encodings
must also be changed. */
enum {
  UNKNOWN_ENC = -1,
  ISO_8859_1_ENC = 0,
  US_ASCII_ENC,
  UTF_8_ENC,
  UTF_16_ENC,
  UTF_16BE_ENC,
  UTF_16LE_ENC,
  /* must match encodingNames up to here */
  NO_ENC
};

static const char KW_ISO_8859_1[] = {
  ASCII_I, ASCII_S, ASCII_O, ASCII_MINUS, ASCII_8, ASCII_8, ASCII_5, ASCII_9,
  ASCII_MINUS, ASCII_1, '\0'
};
static const char KW_US_ASCII[] = {
  ASCII_U, ASCII_S, ASCII_MINUS, ASCII_A, ASCII_S, ASCII_C, ASCII_I, ASCII_I,
  '\0'
};
static const char KW_UTF_8[] =  {
  ASCII_U, ASCII_T, ASCII_F, ASCII_MINUS, ASCII_8, '\0'
};
static const char KW_UTF_16[] = {
  ASCII_U, ASCII_T, ASCII_F, ASCII_MINUS, ASCII_1, ASCII_6, '\0'
};
static const char KW_UTF_16BE[] = {
  ASCII_U, ASCII_T, ASCII_F, ASCII_MINUS, ASCII_1, ASCII_6, ASCII_B, ASCII_E,
  '\0'
};
static const char KW_UTF_16LE[] = {
  ASCII_U, ASCII_T, ASCII_F, ASCII_MINUS, ASCII_1, ASCII_6, ASCII_L, ASCII_E,
  '\0'
};

static int FASTCALL
getEncodingIndex(const char *name)
{
  static const char * const encodingNames[] = {
    KW_ISO_8859_1,
    KW_US_ASCII,
    KW_UTF_8,
    KW_UTF_16,
    KW_UTF_16BE,
    KW_UTF_16LE,
  };
  int i;
  if (name == NULL)
    return NO_ENC;
  for (i = 0; i < (int)(sizeof(encodingNames)/sizeof(encodingNames[0])); i++)
    if (streqci(name, encodingNames[i]))
      return i;
  return UNKNOWN_ENC;
}

/* For binary compatibility, we store the index of the encoding
   specified at initialization in the isUtf16 member.
*/

#define INIT_ENC_INDEX(enc) ((int)(enc)->initEnc.isUtf16)
#define SET_INIT_ENC_INDEX(enc, i) ((enc)->initEnc.isUtf16 = (char)i)

/* This is what detects the encoding.  encodingTable maps from
   encoding indices to encodings; INIT_ENC_INDEX(enc) is the index of
   the external (protocol) specified encoding; state is
   XML_CONTENT_STATE if we're parsing an external text entity, and
   XML_PROLOG_STATE otherwise.
*/


static int
initScan(const ENCODING * const *encodingTable,
         const INIT_ENCODING *enc,
         int state,
         const char *ptr,
         const char *end,
         const char **nextTokPtr)
{
  const ENCODING **encPtr;

  if (ptr == end)
    return XML_TOK_NONE;
  encPtr = enc->encPtr;
  if (ptr + 1 == end) {
    /* only a single byte available for auto-detection */
#ifndef XML_DTD /* FIXME */
    /* a well-formed document entity must have more than one byte */
    if (state != XML_CONTENT_STATE)
      return XML_TOK_PARTIAL;
#endif
    /* so we're parsing an external text entity... */
    /* if UTF-16 was externally specified, then we need at least 2 bytes */
    switch (INIT_ENC_INDEX(enc)) {
    case UTF_16_ENC:
    case UTF_16LE_ENC:
    case UTF_16BE_ENC:
      return XML_TOK_PARTIAL;
    }
    switch ((unsigned char)*ptr) {
    case 0xFE:
    case 0xFF:
    case 0xEF: /* possibly first byte of UTF-8 BOM */
      if (INIT_ENC_INDEX(enc) == ISO_8859_1_ENC
          && state == XML_CONTENT_STATE)
        break;
      /* fall through */
    case 0x00:
    case 0x3C:
      return XML_TOK_PARTIAL;
    }
  }
  else {
    switch (((unsigned char)ptr[0] << 8) | (unsigned char)ptr[1]) {
    case 0xFEFF:
      if (INIT_ENC_INDEX(enc) == ISO_8859_1_ENC
          && state == XML_CONTENT_STATE)
        break;
      *nextTokPtr = ptr + 2;
      *encPtr = encodingTable[UTF_16BE_ENC];
      return XML_TOK_BOM;
    /* 00 3C is handled in the default case */
    case 0x3C00:
      if ((INIT_ENC_INDEX(enc) == UTF_16BE_ENC
           || INIT_ENC_INDEX(enc) == UTF_16_ENC)
          && state == XML_CONTENT_STATE)
        break;
      *encPtr = encodingTable[UTF_16LE_ENC];
      return XmlTok(*encPtr, state, ptr, end, nextTokPtr);
    case 0xFFFE:
      if (INIT_ENC_INDEX(enc) == ISO_8859_1_ENC
          && state == XML_CONTENT_STATE)
        break;
      *nextTokPtr = ptr + 2;
      *encPtr = encodingTable[UTF_16LE_ENC];
      return XML_TOK_BOM;
    case 0xEFBB:
      /* Maybe a UTF-8 BOM (EF BB BF) */
      /* If there's an explicitly specified (external) encoding
         of ISO-8859-1 or some flavour of UTF-16
         and this is an external text entity,
         don't look for the BOM,
         because it might be a legal data.
      */
      if (state == XML_CONTENT_STATE) {
        int e = INIT_ENC_INDEX(enc);
        if (e == ISO_8859_1_ENC || e == UTF_16BE_ENC
            || e == UTF_16LE_ENC || e == UTF_16_ENC)
          break;
      }
      if (ptr + 2 == end)
        return XML_TOK_PARTIAL;
      if ((unsigned char)ptr[2] == 0xBF) {
        *nextTokPtr = ptr + 3;
        *encPtr = encodingTable[UTF_8_ENC];
        return XML_TOK_BOM;
      }
      break;
    default:
      if (ptr[0] == '\0') {
        /* 0 isn't a legal data character. Furthermore a document
           entity can only start with ASCII characters.  So the only
           way this can fail to be big-endian UTF-16 if it it's an
           external parsed general entity that's labelled as
           UTF-16LE.
        */
        if (state == XML_CONTENT_STATE && INIT_ENC_INDEX(enc) == UTF_16LE_ENC)
          break;
        *encPtr = encodingTable[UTF_16BE_ENC];
        return XmlTok(*encPtr, state, ptr, end, nextTokPtr);
      }
      else if (ptr[1] == '\0') {
        /* We could recover here in the case:
            - parsing an external entity
            - second byte is 0
            - no externally specified encoding
            - no encoding declaration
           by assuming UTF-16LE.  But we don't, because this would mean when
           presented just with a single byte, we couldn't reliably determine
           whether we needed further bytes.
        */
        if (state == XML_CONTENT_STATE)
          break;
        *encPtr = encodingTable[UTF_16LE_ENC];
        return XmlTok(*encPtr, state, ptr, end, nextTokPtr);
      }
      break;
    }
  }
  *encPtr = encodingTable[INIT_ENC_INDEX(enc)];
  return XmlTok(*encPtr, state, ptr, end, nextTokPtr);
}


#define NS(x) x
#define ns(x) x
#define XML_TOK_NS_C
#include "xmltok_ns.c"
#undef XML_TOK_NS_C
#undef NS
#undef ns

#ifdef XML_NS

#define NS(x) x ## NS
#define ns(x) x ## _ns

#define XML_TOK_NS_C
#include "xmltok_ns.c"
#undef XML_TOK_NS_C

#undef NS
#undef ns

ENCODING *
XmlInitUnknownEncodingNS(void *mem,
                         int *table,
                         CONVERTER convert,
                         void *userData)
{
  ENCODING *enc = XmlInitUnknownEncoding(mem, table, convert, userData);
  if (enc)
    ((struct normal_encoding *)enc)->type[ASCII_COLON] = BT_COLON;
  return enc;
}

#endif /* XML_NS */