#define __PHYSICSFS_INTERNAL__

#include "physfs_internal.h"

/*

 * From rfc3629, the UTF-8 spec:

 *  https://www.ietf.org/rfc/rfc3629.txt

 *

 *   Char. number range  |        UTF-8 octet sequence

 *      (hexadecimal)    |              (binary)

 *   --------------------+---------------------------------------------

 *   0000 0000-0000 007F | 0xxxxxxx

 *   0000 0080-0000 07FF | 110xxxxx 10xxxxxx

 *   0000 0800-0000 FFFF | 1110xxxx 10xxxxxx 10xxxxxx

 *   0001 0000-0010 FFFF | 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx

 */

/*

 * This may not be the best value, but it's one that isn't represented

 *  in Unicode (0x10FFFF is the largest codepoint value). We return this

 *  value from utf8codepoint() if there's bogus bits in the

 *  stream. utf8codepoint() will turn this value into something

 *  reasonable (like a question mark), for text that wants to try to recover,

 *  whereas utf8valid() will use the value to determine if a string has bad

 *  bits.

 */

#define UNICODE_BOGUS_CHAR_VALUE 0xFFFFFFFF

/*

 * This is the codepoint we currently return when there was bogus bits in a

 *  UTF-8 string. May not fly in Asian locales?

 */

#define UNICODE_BOGUS_CHAR_CODEPOINT '?'

static PHYSFS_uint32 utf8codepoint(const char **_str)

{

    const char *str = *_str;

    PHYSFS_uint32 retval = 0;

    PHYSFS_uint32 octet = (PHYSFS_uint32) ((PHYSFS_uint8) *str);

    PHYSFS_uint32 octet2, octet3, octet4;

    if (octet == 0)  /* null terminator, end of string. */

        return 0;

    else if (octet < 128)  /* one octet char: 0 to 127 */

    {

        (*_str)++;  /* skip to next possible start of codepoint. */

        return octet;

    } /* else if */

    else if ((octet > 127) && (octet < 192))  /* bad (starts with 10xxxxxx). */

    {

        /*

         * Apparently each of these is supposed to be flagged as a bogus

         *  char, instead of just resyncing to the next valid codepoint.

         */

        (*_str)++;  /* skip to next possible start of codepoint. */

        return UNICODE_BOGUS_CHAR_VALUE;

    } /* else if */

    else if (octet < 224)  /* two octets */

    {

        (*_str)++;  /* advance at least one byte in case of an error */

        octet -= (128+64);

        octet2 = (PHYSFS_uint32) ((PHYSFS_uint8) *(++str));

        if ((octet2 & (128+64)) != 128)  /* Format isn't 10xxxxxx? */

            return UNICODE_BOGUS_CHAR_VALUE;

        *_str += 1;  /* skip to next possible start of codepoint. */

        retval = ((octet << 6) | (octet2 - 128));

        if ((retval >= 0x80) && (retval <= 0x7FF))

            return retval;

    } /* else if */

    else if (octet < 240)  /* three octets */

    {

        (*_str)++;  /* advance at least one byte in case of an error */

        octet -= (128+64+32);

        octet2 = (PHYSFS_uint32) ((PHYSFS_uint8) *(++str));

        if ((octet2 & (128+64)) != 128)  /* Format isn't 10xxxxxx? */

            return UNICODE_BOGUS_CHAR_VALUE;

        octet3 = (PHYSFS_uint32) ((PHYSFS_uint8) *(++str));

        if ((octet3 & (128+64)) != 128)  /* Format isn't 10xxxxxx? */

            return UNICODE_BOGUS_CHAR_VALUE;

        *_str += 2;  /* skip to next possible start of codepoint. */

        retval = ( ((octet << 12)) | ((octet2-128) << 6) | ((octet3-128)) );

        /* There are seven "UTF-16 surrogates" that are illegal in UTF-8. */

        switch (retval)

        {

            case 0xD800:

            case 0xDB7F:

            case 0xDB80:

            case 0xDBFF:

            case 0xDC00:

            case 0xDF80:

            case 0xDFFF:

                return UNICODE_BOGUS_CHAR_VALUE;

        } /* switch */

        /* 0xFFFE and 0xFFFF are illegal, too, so we check them at the edge. */

        if ((retval >= 0x800) && (retval <= 0xFFFD))

            return retval;

    } /* else if */

    else if (octet < 248)  /* four octets */

    {

        (*_str)++;  /* advance at least one byte in case of an error */

        octet -= (128+64+32+16);

        octet2 = (PHYSFS_uint32) ((PHYSFS_uint8) *(++str));

        if ((octet2 & (128+64)) != 128)  /* Format isn't 10xxxxxx? */

            return UNICODE_BOGUS_CHAR_VALUE;

        octet3 = (PHYSFS_uint32) ((PHYSFS_uint8) *(++str));

        if ((octet3 & (128+64)) != 128)  /* Format isn't 10xxxxxx? */

            return UNICODE_BOGUS_CHAR_VALUE;

        octet4 = (PHYSFS_uint32) ((PHYSFS_uint8) *(++str));

        if ((octet4 & (128+64)) != 128)  /* Format isn't 10xxxxxx? */

            return UNICODE_BOGUS_CHAR_VALUE;

        *_str += 3;  /* skip to next possible start of codepoint. */

        retval = ( ((octet << 18)) | ((octet2 - 128) << 12) |

                   ((octet3 - 128) << 6) | ((octet4 - 128)) );

        if ((retval >= 0x10000) && (retval <= 0x10FFFF))

            return retval;

    } /* else if */

    /*

     * Five and six octet sequences became illegal in rfc3629.

     *  We throw the codepoint away, but parse them to make sure we move

     *  ahead the right number of bytes and don't overflow the buffer.

     */

    else if (octet < 252)  /* five octets */

    {

        (*_str)++;  /* advance at least one byte in case of an error */

        octet = (PHYSFS_uint32) ((PHYSFS_uint8) *(++str));

        if ((octet & (128+64)) != 128)  /* Format isn't 10xxxxxx? */

            return UNICODE_BOGUS_CHAR_VALUE;

        octet = (PHYSFS_uint32) ((PHYSFS_uint8) *(++str));

        if ((octet & (128+64)) != 128)  /* Format isn't 10xxxxxx? */

            return UNICODE_BOGUS_CHAR_VALUE;

        octet = (PHYSFS_uint32) ((PHYSFS_uint8) *(++str));

        if ((octet & (128+64)) != 128)  /* Format isn't 10xxxxxx? */

            return UNICODE_BOGUS_CHAR_VALUE;

        octet = (PHYSFS_uint32) ((PHYSFS_uint8) *(++str));

        if ((octet & (128+64)) != 128)  /* Format isn't 10xxxxxx? */

            return UNICODE_BOGUS_CHAR_VALUE;

        *_str += 4;  /* skip to next possible start of codepoint. */

        return UNICODE_BOGUS_CHAR_VALUE;

    } /* else if */

    else  /* six octets */

    {

        (*_str)++;  /* advance at least one byte in case of an error */

        octet = (PHYSFS_uint32) ((PHYSFS_uint8) *(++str));

        if ((octet & (128+64)) != 128)  /* Format isn't 10xxxxxx? */

            return UNICODE_BOGUS_CHAR_VALUE;

        octet = (PHYSFS_uint32) ((PHYSFS_uint8) *(++str));

        if ((octet & (128+64)) != 128)  /* Format isn't 10xxxxxx? */

            return UNICODE_BOGUS_CHAR_VALUE;

        octet = (PHYSFS_uint32) ((PHYSFS_uint8) *(++str));

        if ((octet & (128+64)) != 128)  /* Format isn't 10xxxxxx? */

            return UNICODE_BOGUS_CHAR_VALUE;

        octet = (PHYSFS_uint32) ((PHYSFS_uint8) *(++str));

        if ((octet & (128+64)) != 128)  /* Format isn't 10xxxxxx? */

            return UNICODE_BOGUS_CHAR_VALUE;

        octet = (PHYSFS_uint32) ((PHYSFS_uint8) *(++str));

        if ((octet & (128+64)) != 128)  /* Format isn't 10xxxxxx? */

            return UNICODE_BOGUS_CHAR_VALUE;

        *_str += 6;  /* skip to next possible start of codepoint. */

        return UNICODE_BOGUS_CHAR_VALUE;

    } /* else if */

    return UNICODE_BOGUS_CHAR_VALUE;

} /* utf8codepoint */

void PHYSFS_utf8ToUcs4(const char *src, PHYSFS_uint32 *dst, PHYSFS_uint64 len)

{

    len -= sizeof (PHYSFS_uint32);   /* save room for null char. */

    while (len >= sizeof (PHYSFS_uint32))

    {

        PHYSFS_uint32 cp = utf8codepoint(&src);

        if (cp == 0)

            break;

        else if (cp == UNICODE_BOGUS_CHAR_VALUE)

            cp = UNICODE_BOGUS_CHAR_CODEPOINT;

        *(dst++) = cp;

        len -= sizeof (PHYSFS_uint32);

    } /* while */

    *dst = 0;

} /* PHYSFS_utf8ToUcs4 */

void PHYSFS_utf8ToUcs2(const char *src, PHYSFS_uint16 *dst, PHYSFS_uint64 len)

{

    len -= sizeof (PHYSFS_uint16);   /* save room for null char. */

    while (len >= sizeof (PHYSFS_uint16))

    {

        PHYSFS_uint32 cp = utf8codepoint(&src);

        if (cp == 0)

            break;

        else if (cp == UNICODE_BOGUS_CHAR_VALUE)

            cp = UNICODE_BOGUS_CHAR_CODEPOINT;

        if (cp > 0xFFFF)  /* UTF-16 surrogates (bogus chars in UCS-2) */

            cp = UNICODE_BOGUS_CHAR_CODEPOINT;

        *(dst++) = cp;

        len -= sizeof (PHYSFS_uint16);

    } /* while */

    *dst = 0;

} /* PHYSFS_utf8ToUcs2 */

void PHYSFS_utf8ToUtf16(const char *src, PHYSFS_uint16 *dst, PHYSFS_uint64 len)

{

    len -= sizeof (PHYSFS_uint16);   /* save room for null char. */

    while (len >= sizeof (PHYSFS_uint16))

    {

        PHYSFS_uint32 cp = utf8codepoint(&src);

        if (cp == 0)

            break;

        else if (cp == UNICODE_BOGUS_CHAR_VALUE)

            cp = UNICODE_BOGUS_CHAR_CODEPOINT;

        if (cp > 0xFFFF)  /* encode as surrogate pair */

        {

            if (len < (sizeof (PHYSFS_uint16) * 2))

                break;  /* not enough room for the pair, stop now. */

            cp -= 0x10000;  /* Make this a 20-bit value */

            *(dst++) = 0xD800 + ((cp >> 10) & 0x3FF);

            len -= sizeof (PHYSFS_uint16);

            cp = 0xDC00 + (cp & 0x3FF);

        } /* if */

        *(dst++) = cp;

        len -= sizeof (PHYSFS_uint16);

    } /* while */

    *dst = 0;

} /* PHYSFS_utf8ToUtf16 */

static void utf8fromcodepoint(PHYSFS_uint32 cp, char **_dst, PHYSFS_uint64 *_len)

{

    char *dst = *_dst;

    PHYSFS_uint64 len = *_len;

    if (len == 0)

        return;

    if (cp > 0x10FFFF)

        cp = UNICODE_BOGUS_CHAR_CODEPOINT;

    else if ((cp == 0xFFFE) || (cp == 0xFFFF))  /* illegal values. */

        cp = UNICODE_BOGUS_CHAR_CODEPOINT;

    else

    {

        /* There are seven "UTF-16 surrogates" that are illegal in UTF-8. */

        switch (cp)

        {

            case 0xD800:

            case 0xDB7F:

            case 0xDB80:

            case 0xDBFF:

            case 0xDC00:

            case 0xDF80:

            case 0xDFFF:

                cp = UNICODE_BOGUS_CHAR_CODEPOINT;

        } /* switch */

    } /* else */

    /* Do the encoding... */

    if (cp < 0x80)

    {

        *(dst++) = (char) cp;

        len--;

    } /* if */

    else if (cp < 0x800)

    {

        if (len < 2)

            len = 0;

        else

        {

            *(dst++) = (char) ((cp >> 6) | 128 | 64);

            *(dst++) = (char) (cp & 0x3F) | 128;

            len -= 2;

        } /* else */

    } /* else if */

    else if (cp < 0x10000)

    {

        if (len < 3)

            len = 0;

        else

        {

            *(dst++) = (char) ((cp >> 12) | 128 | 64 | 32);

            *(dst++) = (char) ((cp >> 6) & 0x3F) | 128;

            *(dst++) = (char) (cp & 0x3F) | 128;

            len -= 3;

        } /* else */

    } /* else if */

    else

    {

        if (len < 4)

            len = 0;

        else

        {

            *(dst++) = (char) ((cp >> 18) | 128 | 64 | 32 | 16);

            *(dst++) = (char) ((cp >> 12) & 0x3F) | 128;

            *(dst++) = (char) ((cp >> 6) & 0x3F) | 128;

            *(dst++) = (char) (cp & 0x3F) | 128;

            len -= 4;

        } /* else if */

    } /* else */

    *_dst = dst;

    *_len = len;

} /* utf8fromcodepoint */

#define UTF8FROMTYPE(typ, src, dst, len) \

    if (len == 0) return; \

    len--;  \

    while (len) \

    { \

        const PHYSFS_uint32 cp = (PHYSFS_uint32) ((typ) (*(src++))); \

        if (cp == 0) break; \

        utf8fromcodepoint(cp, &dst, &len); \

    } \

    *dst = '\0'; \

void PHYSFS_utf8FromUcs4(const PHYSFS_uint32 *src, char *dst, PHYSFS_uint64 len)

{

    UTF8FROMTYPE(PHYSFS_uint32, src, dst, len);

} /* PHYSFS_utf8FromUcs4 */

void PHYSFS_utf8FromUcs2(const PHYSFS_uint16 *src, char *dst, PHYSFS_uint64 len)

{

    UTF8FROMTYPE(PHYSFS_uint64, src, dst, len);

} /* PHYSFS_utf8FromUcs2 */

/* latin1 maps to unicode codepoints directly, we just utf-8 encode it. */

void PHYSFS_utf8FromLatin1(const char *src, char *dst, PHYSFS_uint64 len)

{

    UTF8FROMTYPE(PHYSFS_uint8, src, dst, len);

} /* PHYSFS_utf8FromLatin1 */

#undef UTF8FROMTYPE

void PHYSFS_utf8FromUtf16(const PHYSFS_uint16 *src, char *dst, PHYSFS_uint64 len)

{

    if (len == 0)

        return;

    len--;

    while (len)

    {

        PHYSFS_uint32 cp = (PHYSFS_uint32) *(src++);

        if (cp == 0)

            break;

        /* Orphaned second half of surrogate pair? */

        if ((cp >= 0xDC00) && (cp <= 0xDFFF))

            cp = UNICODE_BOGUS_CHAR_CODEPOINT;

        else if ((cp >= 0xD800) && (cp <= 0xDBFF))  /* start surrogate pair! */

        {

            const PHYSFS_uint32 pair = (PHYSFS_uint32) *src;

            if ((pair < 0xDC00) || (pair > 0xDFFF))

                cp = UNICODE_BOGUS_CHAR_CODEPOINT;

            else

            {

                src++;  /* eat the other surrogate. */

                cp = (((cp - 0xD800) << 10) | (pair - 0xDC00));

            } /* else */

        } /* else if */

        utf8fromcodepoint(cp, &dst, &len);

    } /* while */

    *dst = '\0';

} /* PHYSFS_utf8FromUtf16 */

typedef struct CaseFoldMapping

{

    PHYSFS_uint32 from;

    PHYSFS_uint32 to0;

    PHYSFS_uint32 to1;

    PHYSFS_uint32 to2;

} CaseFoldMapping;

typedef struct CaseFoldHashBucket

{

    const PHYSFS_uint8 count;

    const CaseFoldMapping *list;

} CaseFoldHashBucket;

#include "physfs_casefolding.h"

static void locate_case_fold_mapping(const PHYSFS_uint32 from,

                                     PHYSFS_uint32 *to)

{

    PHYSFS_uint32 i;

    const PHYSFS_uint8 hashed = ((from ^ (from >> 8)) & 0xFF);

    const CaseFoldHashBucket *bucket = &case_fold_hash[hashed];

    const CaseFoldMapping *mapping = bucket->list;

    for (i = 0; i < bucket->count; i++, mapping++)

    {

        if (mapping->from == from)

        {

            to[0] = mapping->to0;

            to[1] = mapping->to1;

            to[2] = mapping->to2;

            return;

        } /* if */

    } /* for */

    /* Not found...there's no remapping for this codepoint. */

    to[0] = from;

    to[1] = 0;

    to[2] = 0;

} /* locate_case_fold_mapping */

static int utf8codepointcmp(const PHYSFS_uint32 cp1, const PHYSFS_uint32 cp2)

{

    PHYSFS_uint32 folded1[3], folded2[3];

    if (cp1 == cp2)

        return 0;  /* obviously matches. */

    locate_case_fold_mapping(cp1, folded1);

    locate_case_fold_mapping(cp2, folded2);

    if (folded1[0] < folded2[0])

        return -1;

    else if (folded1[0] > folded2[0])

        return 1;

    else if (folded1[1] < folded2[1])

        return -1;

    else if (folded1[1] > folded2[1])

        return 1;

    else if (folded1[2] < folded2[2])

        return -1;

    else if (folded1[2] > folded2[2])

        return 1;

    return 0;  /* complete match. */

} /* utf8codepointcmp */

int __PHYSFS_utf8stricmp(const char *str1, const char *str2)

{

    while (1)

    {

        const PHYSFS_uint32 cp1 = utf8codepoint(&str1);

        const PHYSFS_uint32 cp2 = utf8codepoint(&str2);

        const int rc = utf8codepointcmp(cp1, cp2);

        if (rc != 0)

            return rc;

        else if (cp1 == 0)

            break;  /* complete match. */

    } /* while */

    return 0;

} /* __PHYSFS_utf8stricmp */

int __PHYSFS_utf8strnicmp(const char *str1, const char *str2, PHYSFS_uint32 n)

{

    while (n > 0)

    {

        const PHYSFS_uint32 cp1 = utf8codepoint(&str1);

        const PHYSFS_uint32 cp2 = utf8codepoint(&str2);

        const int rc = utf8codepointcmp(cp1, cp2);

        if (rc != 0)

            return rc;

        else if (cp1 == 0)

            return 0;

        n--;

    } /* while */

    return 0;  /* matched to n chars. */

} /* __PHYSFS_utf8strnicmp */

int __PHYSFS_stricmpASCII(const char *str1, const char *str2)

{

    while (1)

    {

        const char ch1 = *(str1++);

        const char ch2 = *(str2++);

        const char cp1 = ((ch1 >= 'A') && (ch1 <= 'Z')) ? (ch1+32) : ch1;

        const char cp2 = ((ch2 >= 'A') && (ch2 <= 'Z')) ? (ch2+32) : ch2;

        if (cp1 < cp2)

            return -1;

        else if (cp1 > cp2)

            return 1;

        else if (cp1 == 0)  /* they're both null chars? */

            break;

    } /* while */

    return 0;

} /* __PHYSFS_stricmpASCII */