/*

 * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#include "precompiled.hpp"

#include "utilities/utf8.hpp"

// Assume the utf8 string is in legal form and has been

// checked in the class file parser/format checker.

char* UTF8::next(const char* str, jchar* value) {

  unsigned const char *ptr = (const unsigned char *)str;

  unsigned char ch, ch2, ch3;

  int length = -1;              /* bad length */

  jchar result;

  switch ((ch = ptr[0]) >> 4) {

    default:

    result = ch;

    length = 1;

    break;

  case 0x8: case 0x9: case 0xA: case 0xB: case 0xF:

    /* Shouldn't happen. */

    break;

  case 0xC: case 0xD:

    /* 110xxxxx  10xxxxxx */

    if (((ch2 = ptr[1]) & 0xC0) == 0x80) {

      unsigned char high_five = ch & 0x1F;

      unsigned char low_six = ch2 & 0x3F;

      result = (high_five << 6) + low_six;

      length = 2;

      break;

    }

    break;

  case 0xE:

    /* 1110xxxx 10xxxxxx 10xxxxxx */

    if (((ch2 = ptr[1]) & 0xC0) == 0x80) {

      if (((ch3 = ptr[2]) & 0xC0) == 0x80) {

        unsigned char high_four = ch & 0x0f;

        unsigned char mid_six = ch2 & 0x3f;

        unsigned char low_six = ch3 & 0x3f;

        result = (((high_four << 6) + mid_six) << 6) + low_six;

        length = 3;

      }

    }

    break;

  } /* end of switch */

  if (length <= 0) {

    *value = ptr[0];    /* default bad result; */

    return (char*)(ptr + 1); // make progress somehow

  }

  *value = result;

  // The assert is correct but the .class file is wrong

  // assert(UNICODE::utf8_size(result) == length, "checking reverse computation");

  return (char *)(ptr + length);

}

char* UTF8::next_character(const char* str, jint* value) {

  unsigned const char *ptr = (const unsigned char *)str;

  /* See if it's legal supplementary character:

     11101101 1010xxxx 10xxxxxx 11101101 1011xxxx 10xxxxxx */

  if (is_supplementary_character(ptr)) {

    *value = get_supplementary_character(ptr);

    return (char *)(ptr + 6);

  }

  jchar result;

  char* next_ch = next(str, &result);

  *value = result;

  return next_ch;

}

// Count bytes of the form 10xxxxxx and deduct this count

// from the total byte count.  The utf8 string must be in

// legal form which has been verified in the format checker.

int UTF8::unicode_length(const char* str, int len) {

  int num_chars = len;

  for (int i = 0; i < len; i++) {

    if ((str[i] & 0xC0) == 0x80) {

      --num_chars;

    }

  }

  return num_chars;

}

// Count bytes of the utf8 string except those in form

// 10xxxxxx which only appear in multibyte characters.

// The utf8 string must be in legal form and has been

// verified in the format checker.

int UTF8::unicode_length(const char* str) {

  int num_chars = 0;

  for (const char* p = str; *p; p++) {

    if (((*p) & 0xC0) != 0x80) {

      num_chars++;

    }

  }

  return num_chars;

}

// Writes a jchar a utf8 and returns the end

static u_char* utf8_write(u_char* base, jchar ch) {

  if ((ch != 0) && (ch <=0x7f)) {

    base[0] = (u_char) ch;

    return base + 1;

  }

  if (ch <= 0x7FF) {

    /* 11 bits or less. */

    unsigned char high_five = ch >> 6;

    unsigned char low_six = ch & 0x3F;

    base[0] = high_five | 0xC0; /* 110xxxxx */

    base[1] = low_six | 0x80;   /* 10xxxxxx */

    return base + 2;

  }

  /* possibly full 16 bits. */

  char high_four = ch >> 12;

  char mid_six = (ch >> 6) & 0x3F;

  char low_six = ch & 0x3f;

  base[0] = high_four | 0xE0; /* 1110xxxx */

  base[1] = mid_six | 0x80;   /* 10xxxxxx */

  base[2] = low_six | 0x80;   /* 10xxxxxx */

  return base + 3;

}

void UTF8::convert_to_unicode(const char* utf8_str, jchar* unicode_str, int unicode_length) {

  unsigned char ch;

  const char *ptr = (const char *)utf8_str;

  int index = 0;

  /* ASCII case loop optimization */

  for (; index < unicode_length; index++) {

    if((ch = ptr[0]) > 0x7F) { break; }

    unicode_str[index] = ch;

    ptr = (const char *)(ptr + 1);

  }

  for (; index < unicode_length; index++) {

    ptr = UTF8::next(ptr, &unicode_str[index]);

  }

}

// Returns NULL if 'c' it not found. This only works as long

// as 'c' is an ASCII character

jbyte* UTF8::strrchr(jbyte* base, int length, jbyte c) {

  assert(length >= 0, "sanity check");

  assert(c >= 0, "does not work for non-ASCII characters");

  // Skip backwards in string until 'c' is found or end is reached

  while(--length >= 0 && base[length] != c);

  return (length < 0) ? NULL : &base[length];

}

bool UTF8::equal(jbyte* base1, int length1, jbyte* base2, int length2) {

  // Length must be the same

  if (length1 != length2) return false;

  for (int i = 0; i < length1; i++) {

    if (base1[i] != base2[i]) return false;

  }

  return true;

}

bool UTF8::is_supplementary_character(const unsigned char* str) {

  return ((str[0] & 0xFF) == 0xED) && ((str[1] & 0xF0) == 0xA0) && ((str[2] & 0xC0) == 0x80)

      && ((str[3] & 0xFF) == 0xED) && ((str[4] & 0xF0) == 0xB0) && ((str[5] & 0xC0) == 0x80);

}

jint UTF8::get_supplementary_character(const unsigned char* str) {

  return 0x10000 + ((str[1] & 0x0f) << 16) + ((str[2] & 0x3f) << 10)

                 + ((str[4] & 0x0f) << 6)  + (str[5] & 0x3f);

}

//-------------------------------------------------------------------------------------

int UNICODE::utf8_size(jchar c) {

  if ((0x0001 <= c) && (c <= 0x007F)) return 1;

  if (c <= 0x07FF) return 2;

  return 3;

}

int UNICODE::utf8_length(jchar* base, int length) {

  int result = 0;

  for (int index = 0; index < length; index++) {

    jchar c = base[index];

    if ((0x0001 <= c) && (c <= 0x007F)) result += 1;

    else if (c <= 0x07FF) result += 2;

    else result += 3;

  }

  return result;

}

char* UNICODE::as_utf8(jchar* base, int length) {

  int utf8_len = utf8_length(base, length);

  u_char* result = NEW_RESOURCE_ARRAY(u_char, utf8_len + 1);

  u_char* p = result;

  for (int index = 0; index < length; index++) {

    p = utf8_write(p, base[index]);

  }

  *p = '\0';

  assert(p == &result[utf8_len], "length prediction must be correct");

  return (char*) result;

}

char* UNICODE::as_utf8(jchar* base, int length, char* buf, int buflen) {

  u_char* p = (u_char*)buf;

  u_char* end = (u_char*)buf + buflen;

  for (int index = 0; index < length; index++) {

    jchar c = base[index];

    if (p + utf8_size(c) >= end) break;      // string is truncated

    p = utf8_write(p, base[index]);

  }

  *p = '\0';

  return buf;

}

void UNICODE::convert_to_utf8(const jchar* base, int length, char* utf8_buffer) {

  for(int index = 0; index < length; index++) {

    utf8_buffer = (char*)utf8_write((u_char*)utf8_buffer, base[index]);

  }

  *utf8_buffer = '\0';

}