/*
* utf8.c
* Copyright (C) 2001-2004 A.J. van Os; Released under GPL
*
*====================================================================
* This part of the software is based on:
* An implementation of wcwidth() as defined in
* "The Single UNIX Specification, Version 2, The Open Group, 1997"
* <http://www.UNIX-systems.org/online.html>
* Markus Kuhn -- 2001-01-12 -- public domain
*====================================================================
* The credit should go to him, but all the bugs are mine.
*/

#include <stdlib.h>
#include <string.h>
#include "antiword.h"

struct interval {
       USHORT  first;
       USHORT  last;
};
/* Sorted list of non-overlapping intervals of non-spacing characters */
static const struct interval combining[] = {
       { 0x0300, 0x034E }, { 0x0360, 0x0362 }, { 0x0483, 0x0486 },
       { 0x0488, 0x0489 }, { 0x0591, 0x05A1 }, { 0x05A3, 0x05B9 },
       { 0x05BB, 0x05BD }, { 0x05BF, 0x05BF }, { 0x05C1, 0x05C2 },
       { 0x05C4, 0x05C4 }, { 0x064B, 0x0655 }, { 0x0670, 0x0670 },
       { 0x06D6, 0x06E4 }, { 0x06E7, 0x06E8 }, { 0x06EA, 0x06ED },
       { 0x070F, 0x070F }, { 0x0711, 0x0711 }, { 0x0730, 0x074A },
       { 0x07A6, 0x07B0 }, { 0x0901, 0x0902 }, { 0x093C, 0x093C },
       { 0x0941, 0x0948 }, { 0x094D, 0x094D }, { 0x0951, 0x0954 },
       { 0x0962, 0x0963 }, { 0x0981, 0x0981 }, { 0x09BC, 0x09BC },
       { 0x09C1, 0x09C4 }, { 0x09CD, 0x09CD }, { 0x09E2, 0x09E3 },
       { 0x0A02, 0x0A02 }, { 0x0A3C, 0x0A3C }, { 0x0A41, 0x0A42 },
       { 0x0A47, 0x0A48 }, { 0x0A4B, 0x0A4D }, { 0x0A70, 0x0A71 },
       { 0x0A81, 0x0A82 }, { 0x0ABC, 0x0ABC }, { 0x0AC1, 0x0AC5 },
       { 0x0AC7, 0x0AC8 }, { 0x0ACD, 0x0ACD }, { 0x0B01, 0x0B01 },
       { 0x0B3C, 0x0B3C }, { 0x0B3F, 0x0B3F }, { 0x0B41, 0x0B43 },
       { 0x0B4D, 0x0B4D }, { 0x0B56, 0x0B56 }, { 0x0B82, 0x0B82 },
       { 0x0BC0, 0x0BC0 }, { 0x0BCD, 0x0BCD }, { 0x0C3E, 0x0C40 },
       { 0x0C46, 0x0C48 }, { 0x0C4A, 0x0C4D }, { 0x0C55, 0x0C56 },
       { 0x0CBF, 0x0CBF }, { 0x0CC6, 0x0CC6 }, { 0x0CCC, 0x0CCD },
       { 0x0D41, 0x0D43 }, { 0x0D4D, 0x0D4D }, { 0x0DCA, 0x0DCA },
       { 0x0DD2, 0x0DD4 }, { 0x0DD6, 0x0DD6 }, { 0x0E31, 0x0E31 },
       { 0x0E34, 0x0E3A }, { 0x0E47, 0x0E4E }, { 0x0EB1, 0x0EB1 },
       { 0x0EB4, 0x0EB9 }, { 0x0EBB, 0x0EBC }, { 0x0EC8, 0x0ECD },
       { 0x0F18, 0x0F19 }, { 0x0F35, 0x0F35 }, { 0x0F37, 0x0F37 },
       { 0x0F39, 0x0F39 }, { 0x0F71, 0x0F7E }, { 0x0F80, 0x0F84 },
       { 0x0F86, 0x0F87 }, { 0x0F90, 0x0F97 }, { 0x0F99, 0x0FBC },
       { 0x0FC6, 0x0FC6 }, { 0x102D, 0x1030 }, { 0x1032, 0x1032 },
       { 0x1036, 0x1037 }, { 0x1039, 0x1039 }, { 0x1058, 0x1059 },
       { 0x1160, 0x11FF }, { 0x17B7, 0x17BD }, { 0x17C6, 0x17C6 },
       { 0x17C9, 0x17D3 }, { 0x180B, 0x180E }, { 0x18A9, 0x18A9 },
       { 0x200B, 0x200F }, { 0x202A, 0x202E }, { 0x206A, 0x206F },
       { 0x20D0, 0x20E3 }, { 0x302A, 0x302F }, { 0x3099, 0x309A },
       { 0xFB1E, 0xFB1E }, { 0xFE20, 0xFE23 }, { 0xFEFF, 0xFEFF },
       { 0xFFF9, 0xFFFB }
};

/* Auxiliary function for binary search in interval table */
static BOOL
bIsZeroWidthChar(ULONG ucs)
{
       int low = 0;
       int high = elementsof(combining) - 1;
       int mid;

       if (ucs < (ULONG)combining[low].first ||
           ucs > (ULONG)combining[high].last) {
               return FALSE;
       }

       while (high >= low) {
               mid = (low + high) / 2;
               if (ucs > (ULONG)combining[mid].last) {
                       low = mid + 1;
               } else if (ucs < (ULONG)combining[mid].first) {
                       high = mid - 1;
               } else {
                       return TRUE;
               }
       }
       return FALSE;
} /* end of bIsZeroWidthChar */

/* The following functions define the column width of an ISO 10646
* character as follows:
*
*    - The null character (U+0000) has a column width of 0.
*
*    - Other C0/C1 control characters and DEL will lead to a return
*      value of -1.
*
*    - Non-spacing and enclosing combining characters (general
*      category code Mn or Me in the Unicode database) have a
*      column width of 0.
*
*    - Other format characters (general category code Cf in the Unicode
*      database) and ZERO WIDTH SPACE (U+200B) have a column width of 0.
*
*    - Hangul Jamo medial vowels and final consonants (U+1160-U+11FF)
*      have a column width of 0.
*
*    - Spacing characters in the East Asian Wide (W) or East Asian
*      FullWidth (F) category as defined in Unicode Technical
*      Report #11 have a column width of 2.
*
*    - All remaining characters (including all printable
*      ISO 8859-1 and WGL4 characters, Unicode control characters,
*      etc.) have a column width of 1.
*
* This implementation assumes that all characters are encoded
* in ISO 10646.
*
* This function is not named wcwidth() to prevent name clashes
*/
static int
iWcWidth(ULONG ucs)
{
       /* Test for 8-bit control characters */
       if (ucs == 0) {
               return 0;
       }
       if (ucs < 0x20 || (ucs >= 0x7f && ucs < 0xa0)) {
               NO_DBG_HEX(ucs);
               return -1;
       }

       /* Binary search in table of non-spacing characters */
       if (bIsZeroWidthChar(ucs)) {
               return 0;
       }

       /* Ucs is not a combining or C0/C1 control character */

       return 1 +
       (ucs >= 0x1100 &&
        (ucs <= 0x115f ||                    /* Hangul Jamo init. consonants */
         (ucs >= 0x2e80 && ucs <= 0xa4cf && (ucs & ~0x0011) != 0x300a &&
          ucs != 0x303f) ||                  /* CJK ... Yi */
         (ucs >= 0xac00 && ucs <= 0xd7a3) || /* Hangul Syllables */
         (ucs >= 0xf900 && ucs <= 0xfaff) || /* CJK Compatibility Ideographs */
         (ucs >= 0xfe30 && ucs <= 0xfe6f) || /* CJK Compatibility Forms */
         (ucs >= 0xff00 && ucs <= 0xff5f) || /* Fullwidth Forms */
         (ucs >= 0xffe0 && ucs <= 0xffe6) ||
         (ucs >= 0x20000 && ucs <= 0x2ffff)));
} /* end of iWcWidth */

/*
* utf8_to_ucs - convert from UTF-8 to UCS
*
* Returns the UCS character,
* Fills in the number of bytes in the UTF-8 character
*/
static ULONG
utf8_to_ucs(const char *p, int iStrLen, int *piUtfLen)
{
       ULONG   ulUcs;
       int     iIndex, iCharLen;

       fail(p == NULL || piUtfLen == NULL);
       fail(iStrLen < 1);

       ulUcs = (ULONG)(UCHAR)p[0];

       if (ulUcs < 0x80) {
               *piUtfLen = 1;
               return ulUcs;
       }

       if (ulUcs < 0xe0){
               iCharLen = 2;
               ulUcs &= 0x1f;
       } else if (ulUcs < 0xf0){
               iCharLen = 3;
               ulUcs &= 0x0f;
       } else if (ulUcs < 0xf8){
               iCharLen = 4;
               ulUcs &= 0x07;
       } else if (ulUcs < 0xfc){
               iCharLen = 5;
               ulUcs &= 0x03;
       } else {
               iCharLen = 6;
               ulUcs &= 0x01;
       }
       for (iIndex = 1; iIndex < iCharLen; iIndex++) {
               ulUcs <<= 6;
               if (iIndex < iStrLen) {
                       ulUcs |= (ULONG)(UCHAR)p[iIndex] & 0x3f;
               }
       }
       *piUtfLen = iCharLen;
       return ulUcs;
} /* end of utf8_to_ucs */

/*
* utf8_strwidth - compute the string width of an UTF-8 string
*
* Returns the string width in columns
*/
long
utf8_strwidth(const char *pcString, size_t tNumchars)
{
       ULONG   ulUcs;
       long    lTotal;
       int     iToGo, iWidth, iUtflen;

       fail(pcString == NULL || tNumchars > (size_t)INT_MAX);

       lTotal = 0;
       iToGo = (int)tNumchars;

       while (iToGo > 0 && *pcString != '\0') {
               ulUcs = utf8_to_ucs(pcString, iToGo, &iUtflen);
               iWidth = iWcWidth(ulUcs);
               if (iWidth > 0) {
                       lTotal += iWidth;
               }
               pcString += iUtflen;
               iToGo -= iUtflen;
       }
       NO_DBG_DEC(lTotal);
       return lTotal;
} /* end of utf8_strwidth */

/*
* utf8_chrlength - get the number of bytes in an UTF-8 character
*
* Returns the number of bytes
*/
int
utf8_chrlength(const char *p)
{
       int     iUtflen;

       fail(p == NULL);

       iUtflen = -1;           /* Just to make sure */
       (void)utf8_to_ucs(p, INT_MAX, &iUtflen);
       NO_DBG_DEC(iUtflen);
       return iUtflen;
} /* end of utf8_chrlength */

/*
* is_locale_utf8 - return TRUE if the locale is UTF-8
*/
BOOL
is_locale_utf8(void)
{
       char    szCodeset[20];

       szCodeset[0] = '\0';
       if (!bGetNormalizedCodeset(szCodeset, sizeof(szCodeset), NULL)) {
               return FALSE;
       }
       DBG_MSG(szCodeset);
       return STREQ(szCodeset, "utf8");
} /* end of is_locale_utf8 */