path: root/src/utf8.c

#include <stdlib.h>
#include <stdint.h>
#include <assert.h>

#include "cmark_ctype.h"
#include "utf8.h"

static const int8_t utf8proc_utf8class[256] = {
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
    2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
    3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
    4, 4, 4, 4, 4, 4, 4, 4, 0, 0, 0, 0, 0, 0, 0, 0
};

static void encode_unknown(cmark_strbuf *buf)
{
    static const uint8_t repl[] = {239, 191, 189};
    cmark_strbuf_put(buf, repl, 3);
}

static int utf8proc_charlen(const uint8_t *str, int str_len)
{
    int length, i;

    if (!str_len)
        return 0;

    length = utf8proc_utf8class[str[0]];

    if (!length)
        return -1;

    if (str_len >= 0 && length > str_len)
        return -str_len;

    for (i = 1; i < length; i++) {
        if ((str[i] & 0xC0) != 0x80)
            return -i;
    }

    return length;
}

// Validate a single UTF-8 character according to RFC 3629.
static int utf8proc_valid(const uint8_t *str, int str_len)
{
    int length = utf8proc_charlen(str, str_len);

    if (length <= 0)
        return length;

    switch (length) {
    case 1:
        if (str[0] == 0x00) {
            // ASCII NUL is technically valid but rejected
            // for security reasons.
            return -length;
        }
        break;

    case 2:
        if (str[0] < 0xC2) {
            // Overlong
            return -length;
        }
        break;

    case 3:
        if (str[0] == 0xE0) {
            if (str[1] < 0xA0) {
                // Overlong
                return -length;
            }
        } else if (str[0] == 0xED) {
            if (str[1] >= 0xA0) {
                // Surrogate
                return -length;
            }
        }
        break;

    case 4:
        if (str[0] == 0xF0) {
            if (str[1] < 0x90) {
                // Overlong
                return -length;
            }
        } else if (str[0] >= 0xF4) {
            if (str[0] > 0xF4 || str[1] >= 0x90) {
                // Above 0x10FFFF
                return -length;
            }
        }
        break;
    }

    return length;
}

void utf8proc_detab(cmark_strbuf *ob, const uint8_t *line, size_t size)
{
    static const uint8_t whitespace[] = "    ";

    size_t i = 0, tab = 0;

    while (i < size) {
        size_t org = i;

        while (i < size && line[i] != '\t' && line[i] != '\0'
               && line[i] < 0x80) {
            i++;
            tab++;
        }

        if (i > org)
            cmark_strbuf_put(ob, line + org, i - org);

        if (i >= size)
            break;

        if (line[i] == '\t') {
            int numspaces = 4 - (tab % 4);
            cmark_strbuf_put(ob, whitespace, numspaces);
            i += 1;
            tab += numspaces;
        } else {
            int charlen = utf8proc_valid(line + i, size - i);

            if (charlen >= 0) {
                cmark_strbuf_put(ob, line + i, charlen);
            } else {
                encode_unknown(ob);
                charlen = -charlen;
            }

            i += charlen;
            tab += 1;
        }
    }
}

int utf8proc_iterate(const uint8_t *str, int str_len, int32_t *dst)
{
    int length;
    int32_t uc = -1;

    *dst = -1;
    length = utf8proc_charlen(str, str_len);
    if (length < 0)
        return -1;

    switch (length) {
    case 1:
        uc = str[0];
        break;
    case 2:
        uc = ((str[0] & 0x1F) <<  6) + (str[1] & 0x3F);
        if (uc < 0x80) uc = -1;
        break;
    case 3:
        uc = ((str[0] & 0x0F) << 12) + ((str[1] & 0x3F) <<  6)
             + (str[2] & 0x3F);
        if (uc < 0x800 || (uc >= 0xD800 && uc < 0xE000) ||
            (uc >= 0xFDD0 && uc < 0xFDF0)) uc = -1;
        break;
    case 4:
        uc = ((str[0] & 0x07) << 18) + ((str[1] & 0x3F) << 12)
             + ((str[2] & 0x3F) <<  6) + (str[3] & 0x3F);
        if (uc < 0x10000 || uc >= 0x110000) uc = -1;
        break;
    }

    if (uc < 0 || ((uc & 0xFFFF) >= 0xFFFE))
        return -1;

    *dst = uc;
    return length;
}

void utf8proc_encode_char(int32_t uc, cmark_strbuf *buf)
{
    uint8_t dst[4];
    int len = 0;

    assert(uc >= 0);

    if (uc < 0x80) {
        dst[0] = uc;
        len = 1;
    } else if (uc < 0x800) {
        dst[0] = 0xC0 + (uc >> 6);
        dst[1] = 0x80 + (uc & 0x3F);
        len = 2;
    } else if (uc == 0xFFFF) {
        dst[0] = 0xFF;
        len = 1;
    } else if (uc == 0xFFFE) {
        dst[0] = 0xFE;
        len = 1;
    } else if (uc < 0x10000) {
        dst[0] = 0xE0 + (uc >> 12);
        dst[1] = 0x80 + ((uc >> 6) & 0x3F);
        dst[2] = 0x80 + (uc & 0x3F);
        len = 3;
    } else if (uc < 0x110000) {
        dst[0] = 0xF0 + (uc >> 18);
        dst[1] = 0x80 + ((uc >> 12) & 0x3F);
        dst[2] = 0x80 + ((uc >> 6) & 0x3F);
        dst[3] = 0x80 + (uc & 0x3F);
        len = 4;
    } else {
        encode_unknown(buf);
        return;
    }

    cmark_strbuf_put(buf, dst, len);
}

void utf8proc_case_fold(cmark_strbuf *dest, const uint8_t *str, int len)
{
    int32_t c;

#define bufpush(x)              \
    utf8proc_encode_char(x, dest)

    while (len > 0) {
        int char_len = utf8proc_iterate(str, len, &c);

        if (char_len >= 0) {
#include "case_fold_switch.inc"
        } else {
            encode_unknown(dest);
            char_len = -char_len;
        }

        str += char_len;
        len -= char_len;
    }
}

// matches anything in the Zs class, plus LF, CR, TAB, FF.
int utf8proc_is_space(int32_t uc)
{
    return (uc == 9 ||
            uc == 10 ||
            uc == 12 ||
            uc == 13 ||
            uc == 32 ||
            uc == 160 ||
            uc == 5760 ||
            (uc >= 8192 && uc <= 8202) ||
            uc == 8239 ||
            uc == 8287 ||
            uc == 12288);
}

// matches anything in the P[cdefios] classes.
int utf8proc_is_punctuation(int32_t uc)
{
    return ((uc < 128 && cmark_ispunct((char)uc)) ||
            uc == 161 ||
            uc == 167 ||
            uc == 171 ||
            uc == 182 ||
            uc == 183 ||
            uc == 187 ||
            uc == 191 ||
            uc == 894 ||
            uc == 903 ||
            (uc >= 1370 && uc <= 1375) ||
            uc == 1417 ||
            uc == 1418 ||
            uc == 1470 ||
            uc == 1472 ||
            uc == 1475 ||
            uc == 1478 ||
            uc == 1523 ||
            uc == 1524 ||
            uc == 1545 ||
            uc == 1546 ||
            uc == 1548 ||
            uc == 1549 ||
            uc == 1563 ||
            uc == 1566 ||
            uc == 1567 ||
            (uc >= 1642 && uc <= 1645) ||
            uc == 1748 ||
            (uc >= 1792 && uc <= 1805) ||
            (uc >= 2039 && uc <= 2041) ||
            (uc >= 2096 && uc <= 2110) ||
            uc == 2142 ||
            uc == 2404 ||
            uc == 2405 ||
            uc == 2416 ||
            uc == 2800 ||
            uc == 3572 ||
            uc == 3663 ||
            uc == 3674 ||
            uc == 3675 ||
            (uc >= 3844 && uc <= 3858) ||
            uc == 3860 ||
            (uc >= 3898 && uc <= 3901) ||
            uc == 3973 ||
            (uc >= 4048 && uc <= 4052) ||
            uc == 4057 ||
            uc == 4058 ||
            (uc >= 4170 && uc <= 4175) ||
            uc == 4347 ||
            (uc >= 4960 && uc <= 4968) ||
            uc == 5120 ||
            uc == 5741 ||
            uc == 5742 ||
            uc == 5787 ||
            uc == 5788 ||
            (uc >= 5867 && uc <= 5869) ||
            uc == 5941 ||
            uc == 5942 ||
            (uc >= 6100 && uc <= 6102) ||
            (uc >= 6104 && uc <= 6106) ||
            (uc >= 6144 && uc <= 6154) ||
            uc == 6468 ||
            uc == 6469 ||
            uc == 6686 ||
            uc == 6687 ||
            (uc >= 6816 && uc <= 6822) ||
            (uc >= 6824 && uc <= 6829) ||
            (uc >= 7002 && uc <= 7008) ||
            (uc >= 7164 && uc <= 7167) ||
            (uc >= 7227 && uc <= 7231) ||
            uc == 7294 ||
            uc == 7295 ||
            (uc >= 7360 && uc <= 7367) ||
            uc == 7379 ||
            (uc >= 8208 && uc <= 8231) ||
            (uc >= 8240 && uc <= 8259) ||
            (uc >= 8261 && uc <= 8273) ||
            (uc >= 8275 && uc <= 8286) ||
            uc == 8317 ||
            uc == 8318 ||
            uc == 8333 ||
            uc == 8334 ||
            (uc >= 8968 && uc <= 8971) ||
            uc == 9001 ||
            uc == 9002 ||
            (uc >= 10088 && uc <= 10101) ||
            uc == 10181 ||
            uc == 10182 ||
            (uc >= 10214 && uc <= 10223) ||
            (uc >= 10627 && uc <= 10648) ||
            (uc >= 10712 && uc <= 10715) ||
            uc == 10748 ||
            uc == 10749 ||
            (uc >= 11513 && uc <= 11516) ||
            uc == 11518 ||
            uc == 11519 ||
            uc == 11632 ||
            (uc >= 11776 && uc <= 11822) ||
            (uc >= 11824 && uc <= 11842) ||
            (uc >= 12289 && uc <= 12291) ||
            (uc >= 12296 && uc <= 12305) ||
            (uc >= 12308 && uc <= 12319) ||
            uc == 12336 ||
            uc == 12349 ||
            uc == 12448 ||
            uc == 12539 ||
            uc == 42238 ||
            uc == 42239 ||
            (uc >= 42509 && uc <= 42511) ||
            uc == 42611 ||
            uc == 42622 ||
            (uc >= 42738 && uc <= 42743) ||
            (uc >= 43124 && uc <= 43127) ||
            uc == 43214 ||
            uc == 43215 ||
            (uc >= 43256 && uc <= 43258) ||
            uc == 43310 ||
            uc == 43311 ||
            uc == 43359 ||
            (uc >= 43457 && uc <= 43469) ||
            uc == 43486 ||
            uc == 43487 ||
            (uc >= 43612 && uc <= 43615) ||
            uc == 43742 ||
            uc == 43743 ||
            uc == 43760 ||
            uc == 43761 ||
            uc == 44011 ||
            uc == 64830 ||
            uc == 64831 ||
            (uc >= 65040 && uc <= 65049) ||
            (uc >= 65072 && uc <= 65106) ||
            (uc >= 65108 && uc <= 65121) ||
            uc == 65123 ||
            uc == 65128 ||
            uc == 65130 ||
            uc == 65131 ||
            (uc >= 65281 && uc <= 65283) ||
            (uc >= 65285 && uc <= 65290) ||
            (uc >= 65292 && uc <= 65295) ||
            uc == 65306 ||
            uc == 65307 ||
            uc == 65311 ||
            uc == 65312 ||
            (uc >= 65339 && uc <= 65341) ||
            uc == 65343 ||
            uc == 65371 ||
            uc == 65373 ||
            (uc >= 65375 && uc <= 65381) ||
            (uc >= 65792 && uc <= 65794) ||
            uc == 66463 ||
            uc == 66512 ||
            uc == 66927 ||
            uc == 67671 ||
            uc == 67871 ||
            uc == 67903 ||
            (uc >= 68176 && uc <= 68184) ||
            uc == 68223 ||
            (uc >= 68336 && uc <= 68342) ||
            (uc >= 68409 && uc <= 68415) ||
            (uc >= 68505 && uc <= 68508) ||
            (uc >= 69703 && uc <= 69709) ||
            uc == 69819 ||
            uc == 69820 ||
            (uc >= 69822 && uc <= 69825) ||
            (uc >= 69952 && uc <= 69955) ||
            uc == 70004 ||
            uc == 70005 ||
            (uc >= 70085 && uc <= 70088) ||
            uc == 70093 ||
            (uc >= 70200 && uc <= 70205) ||
            uc == 70854 ||
            (uc >= 71105 && uc <= 71113) ||
            (uc >= 71233 && uc <= 71235) ||
            (uc >= 74864 && uc <= 74868) ||
            uc == 92782 ||
            uc == 92783 ||
            uc == 92917 ||
            (uc >= 92983 && uc <= 92987) ||
            uc == 92996 ||
            uc == 113823);
}