#include "xmltok.h"
#include "nametab.h"

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

#define VTABLE2 \
  PREFIX(encode), \
  { PREFIX(toUtf8) }

#define VTABLE VTABLE1, VTABLE2

#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))

struct normal_encoding {
  ENCODING enc;
  unsigned char type[256];
};

static int checkCharRefNumber(int);

#include "xmltok_impl.h"

/* minimum bytes per character */
#define MINBPC 1
#define BYTE_TYPE(enc, p) \
  (((struct normal_encoding *)(enc))->type[(unsigned char)*(p)])
#define BYTE_TO_ASCII(enc, p) (*p)
#define IS_NAME_CHAR(enc, p, n) UTF8_GET_NAMING(namePages, p, n)
#define IS_NMSTRT_CHAR(enc, p, n) UTF8_GET_NAMING(nmstrtPages, p, n)

/* c is an ASCII character */
#define CHAR_MATCHES(enc, p, c) (*(p) == c)

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

#undef MINBPC
#undef BYTE_TYPE
#undef BYTE_TO_ASCII
#undef CHAR_MATCHES
#undef IS_NAME_CHAR
#undef IS_NMSTRT_CHAR

enum {
  // cvalN is value of masked first byte of N byte sequence
  cval1 = 0x00,
  cval2 = 0xc0,
  cval3 = 0xe0,
  cval4 = 0xf0,
  // minN is minimum legal resulting value for N byte sequence
  min2 = 0x80,
  min3 = 0x800,
  min4 = 0x10000
};

static
int utf8_encode(const ENCODING *enc, int c, char *buf)
{
  if (c < 0)
    return 0;
  if (c < min2) {
    buf[0] = (c | cval1);
    return 1;
  }
  if (c < min3) {
    buf[0] = ((c >> 6) | cval2);
    buf[1] = ((c & 0x3f) | 0x80);
    return 2;
  }
  if (c < min4) {
    buf[0] = ((c >> 12) | cval3);
    buf[1] = (((c >> 6) & 0x3f) | 0x80);
    buf[2] = ((c & 0x3f) | 0x80);
    return 3;
  }
  if (c < 0x110000) {
    buf[0] = ((c >> 18) | cval4);
    buf[1] = (((c >> 12) & 0x3f) | 0x80);
    buf[2] = (((c >> 6) & 0x3f) | 0x80);
    buf[3] = ((c & 0x3f) | 0x80);
    return 4;
  }
  return 0;
}

static
void 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 const struct normal_encoding utf8_encoding = {
  { VTABLE1, utf8_encode, { utf8_toUtf8 }, 1 },
  {
#include "asciitab.h"
#include "utf8tab.h"
  }
};

static const struct normal_encoding internal_utf8_encoding = {
  { VTABLE1, utf8_encode, { utf8_toUtf8 }, 1 },
  {
#include "iasciitab.h"
#include "utf8tab.h"
  }
};

static
int latin1_encode(const ENCODING *enc, int c, char *buf)
{
  if (c < 0)
    return 0;
  if (c <= 0xFF) {
    buf[0] = (char)c;
    return 1;
  }
  return 0;
}

static
void 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)++ = ((c >> 6) | cval2);
      *(*toP)++ = ((c & 0x3f) | 0x80);
    }
    else {
      if (*toP == toLim)
	break;
      *(*toP)++ = *(*fromP)++;
    }
  }
}

static const struct normal_encoding latin1_encoding = {
  { VTABLE1, latin1_encode, { latin1_toUtf8 }, 1 },
  {
#include "asciitab.h"
#include "latin1tab.h"
  }
};

#define latin1tab (latin1_encoding.type)

#undef PREFIX

static int 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_ENCODE \
static \
int PREFIX(encode)(const ENCODING *enc, int charNum, char *buf) \
{ \
  if (charNum < 0) \
    return 0; \
  if (charNum < 0x10000) { \
    SET2(buf, charNum); \
    return 2; \
  } \
  if (charNum < 0x110000) { \
    charNum -= 0x10000; \
    SET2(buf, (charNum >> 10) + 0xD800); \
    SET2(buf + 2, (charNum & 0x3FF) + 0xDC00); \
    return 4; \
  } \
  return 0; \
}

#define DEFINE_UTF16_TO_UTF8 \
static \
void PREFIX(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) |  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) | 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) | 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 PREFIX(ident) little2_ ## ident
#define MINBPC 2
#define BYTE_TYPE(enc, p) \
 ((p)[1] == 0 ? latin1tab[(unsigned char)*(p)] : unicode_byte_type((p)[1], (p)[0]))
#define BYTE_TO_ASCII(enc, p) ((p)[1] == 0 ? (p)[0] : -1)
#define CHAR_MATCHES(enc, p, c) ((p)[1] == 0 && (p)[0] == c)
#define IS_NAME_CHAR(enc, p, n) \
  UCS2_GET_NAMING(namePages, (unsigned char)p[1], (unsigned char)p[0])
#define IS_NMSTRT_CHAR(enc, p, n) \
  UCS2_GET_NAMING(nmstrtPages, (unsigned char)p[1], (unsigned char)p[0])

#include "xmltok_impl.c"

#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_ENCODE
DEFINE_UTF16_TO_UTF8

#undef SET2
#undef GET_LO
#undef GET_HI
#undef MINBPC
#undef BYTE_TYPE
#undef BYTE_TO_ASCII
#undef CHAR_MATCHES
#undef IS_NAME_CHAR
#undef IS_NMSTRT_CHAR

static const struct encoding little2_encoding = { VTABLE, 2 };

#undef PREFIX

#define PREFIX(ident) big2_ ## ident
#define MINBPC 2
/* CHAR_MATCHES is guaranteed to have MINBPC bytes available. */
#define BYTE_TYPE(enc, p) \
 ((p)[0] == 0 ? latin1tab[(unsigned char)(p)[1]] : unicode_byte_type((p)[0], (p)[1]))
#define BYTE_TO_ASCII(enc, p) ((p)[0] == 0 ? (p)[1] : -1)
#define CHAR_MATCHES(enc, p, c) ((p)[0] == 0 && (p)[1] == c)
#define IS_NAME_CHAR(enc, p, n) \
  UCS2_GET_NAMING(namePages, (unsigned char)p[0], (unsigned char)p[1])
#define IS_NMSTRT_CHAR(enc, p, n) \
  UCS2_GET_NAMING(nmstrtPages, (unsigned char)p[0], (unsigned char)p[1])

#include "xmltok_impl.c"

#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_ENCODE
DEFINE_UTF16_TO_UTF8

#undef SET2
#undef GET_LO
#undef GET_HI
#undef MINBPC
#undef BYTE_TYPE
#undef BYTE_TO_ASCII
#undef CHAR_MATCHES
#undef IS_NAME_CHAR
#undef IS_NMSTRT_CHAR

static const struct encoding big2_encoding = { VTABLE, 2 };

#undef PREFIX

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

  if (ptr == end)
    return XML_TOK_NONE;
  encPtr = ((const INIT_ENCODING *)enc)->encPtr;
  if (ptr + 1 == end) {
    switch ((unsigned char)*ptr) {
    case 0xFE:
    case 0xFF:
    case 0x00:
    case 0x3C:
      return XML_TOK_PARTIAL;
    }
  }
  else {
    switch (((unsigned char)ptr[0] << 8) | (unsigned char)ptr[1]) {
    case 0x003C:
      *encPtr = &big2_encoding;
      return XmlTok(*encPtr, state, ptr, end, nextTokPtr);
    case 0xFEFF:
      *nextTokPtr = ptr + 2;
      *encPtr = &big2_encoding;
      return XML_TOK_BOM;
    case 0x3C00:
      *encPtr = &little2_encoding;
      return XmlTok(*encPtr, state, ptr, end, nextTokPtr);
    case 0xFFFE:
      *nextTokPtr = ptr + 2;
      *encPtr = &little2_encoding;
      return XML_TOK_BOM;
    }
  }
  *encPtr = &utf8_encoding.enc;
  return XmlTok(*encPtr, state, ptr, end, nextTokPtr);
}

static
int initScanProlog(const ENCODING *enc, const char *ptr, const char *end,
		   const char **nextTokPtr)
{
  return initScan(enc, XML_PROLOG_STATE, ptr, end, nextTokPtr);
}

static
int initScanContent(const ENCODING *enc, const char *ptr, const char *end,
		    const char **nextTokPtr)
{
  return initScan(enc, XML_CONTENT_STATE, ptr, end, nextTokPtr);
}

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

const ENCODING *XmlGetInternalEncoding(int e)
{
  switch (e) {
  case XML_UTF8_ENCODING:
    return &internal_utf8_encoding.enc;
  }
  return 0;
}

void XmlInitEncoding(INIT_ENCODING *p, const ENCODING **encPtr)
{
  p->initEnc.scanners[XML_PROLOG_STATE] = initScanProlog;
  p->initEnc.scanners[XML_CONTENT_STATE] = initScanContent;
  p->initEnc.updatePosition = initUpdatePosition;
  p->initEnc.minBytesPerChar = 1;
  p->encPtr = encPtr;
  *encPtr = &(p->initEnc);
}

static
int toAscii(const ENCODING *enc, const char *ptr, const char *end)
{
  char buf[1];
  char *p = buf;
  XmlConvert(enc, XML_UTF8_ENCODING, &ptr, end, &p, p + 1);
  if (p == buf)
    return -1;
  else
    return buf[0];
}

static
int isSpace(int c)
{
  switch (c) {
  case ' ':
  case '\r':
  case '\n':
  case '\t':
    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 **valPtr,
			 const char **nextTokPtr)
{
  int c;
  char open;
  if (ptr == end) {
    *namePtr = 0;
    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 = 0;
    return 1;
  }
  *namePtr = ptr;
  for (;;) {
    c = toAscii(enc, ptr, end);
    if (c == -1) {
      *nextTokPtr = ptr;
      return 0;
    }
    if (c == '=')
      break;
    if (isSpace(c)) {
      do {
	ptr += enc->minBytesPerChar;
      } while (isSpace(c = toAscii(enc, ptr, end)));
      if (c != '=') {
	*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 != '"' && c != '\'') {
    *nextTokPtr = ptr;
    return 0;
  }
  open = c;
  ptr += enc->minBytesPerChar;
  *valPtr = ptr;
  for (;; ptr += enc->minBytesPerChar) {
    c = toAscii(enc, ptr, end);
    if (c == open)
      break;
    if (!('a' <= c && c <= 'z')
	&& !('A' <= c && c <= 'Z')
	&& !('0' <= c && c <= '9')
	&& c != '.'
	&& c != '-'
	&& c != '_') {
      *nextTokPtr = ptr;
      return 0;
    }
  }
  *nextTokPtr = ptr + enc->minBytesPerChar;
  return 1;
}

static
int streq(const char *s1, const char *s2)
{
  for (; *s1 == *s2; s1++, s2++)
    if (!*s1)
      return 1;
  return 0;
}

static
const ENCODING *findEncoding(const ENCODING *enc, const char *ptr, const char *end)
{
#define ENCODING_MAX 128
  char buf[ENCODING_MAX];
  char *p = buf;
  int i;
  XmlConvert(enc, XML_UTF8_ENCODING, &ptr, end, &p, p + ENCODING_MAX - 1);
  if (ptr != end)
    return 0;
  *p = 0;
  for (i = 0; buf[i]; i++) {
    if ('a' <= buf[i] && buf[i] <= 'z')
      buf[i] +=  'A' - 'a';
  }
  if (streq(buf, "UTF-8"))
    return &utf8_encoding.enc;
  if (streq(buf, "ISO-8859-1"))
    return &latin1_encoding.enc;
  if (streq(buf, "UTF-16")) {
    static const unsigned short n = 1;
    if (enc->minBytesPerChar == 2)
      return enc;
    if (*(const char *)&n)
      return &little2_encoding;
    else
      return &big2_encoding;
  }
  return 0;  
}

int XmlParseXmlDecl(int isGeneralTextEntity,
		    const ENCODING *enc,
		    const char *ptr,
		    const char *end,
		    const char **badPtr,
		    const char **versionPtr,
		    const char **encodingName,
		    const ENCODING **encoding,
		    int *standalone)
{
  const char *val = 0;
  const char *name = 0;
  ptr += 5 * enc->minBytesPerChar;
  end -= 2 * enc->minBytesPerChar;
  if (!parsePseudoAttribute(enc, ptr, end, &name, &val, &ptr) || !name) {
    *badPtr = ptr;
    return 0;
  }
  if (!XmlNameMatchesAscii(enc, name, "version")) {
    if (!isGeneralTextEntity) {
      *badPtr = name;
      return 0;
    }
  }
  else {
    if (versionPtr)
      *versionPtr = val;
    if (!parsePseudoAttribute(enc, ptr, end, &name, &val, &ptr)) {
      *badPtr = ptr;
      return 0;
    }
    if (!name)
      return 1;
  }
  if (XmlNameMatchesAscii(enc, name, "encoding")) {
    int c = toAscii(enc, val, end);
    if (!('a' <= c && c <= 'z') && !('A' <= c && c <= 'Z')) {
      *badPtr = val;
      return 0;
    }
    if (encodingName)
      *encodingName = val;
    if (encoding)
      *encoding = findEncoding(enc, val, ptr - enc->minBytesPerChar);
    if (!parsePseudoAttribute(enc, ptr, end, &name, &val, &ptr)) {
      *badPtr = ptr;
      return 0;
    }
    if (!name)
      return 1;
  }
  if (!XmlNameMatchesAscii(enc, name, "standalone") || isGeneralTextEntity) {
    *badPtr = name;
    return 0;
  }
  if (XmlNameMatchesAscii(enc, val, "yes")) {
    if (standalone)
      *standalone = 1;
  }
  else if (XmlNameMatchesAscii(enc, val, "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 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;
}