/* SPDX-License-Identifier: LGPL-2.1-or-later */

/* Parts of this file are based on the GLIB utf8 validation functions. The

 * original license text follows. */

/* gutf8.c - Operations on UTF-8 strings.

 *

 * Copyright (C) 1999 Tom Tromey

 * Copyright (C) 2000 Red Hat, Inc.

 *

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

 * modify it under the terms of the GNU Library General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library 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

 * Library General Public License for more details.

 *

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

 * License along with this library; if not, write to the Free Software

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

 */

#include "nm-sd-adapt-shared.h"

#include <errno.h>

#include <stdbool.h>

#include <stdlib.h>

#include "alloc-util.h"

#include "gunicode.h"

#include "hexdecoct.h"

#include "macro.h"

#include "string-util.h"

#include "utf8.h"

bool unichar_is_valid(char32_t ch) {

        if (ch >= 0x110000) /* End of unicode space */

                return false;

        if ((ch & 0xFFFFF800) == 0xD800) /* Reserved area for UTF-16 */

                return false;

        if ((ch >= 0xFDD0) && (ch <= 0xFDEF)) /* Reserved */

                return false;

        if ((ch & 0xFFFE) == 0xFFFE) /* BOM (Byte Order Mark) */

                return false;

        return true;

}

static bool unichar_is_control(char32_t ch) {

        /*

          0 to ' '-1 is the C0 range.

          DEL=0x7F, and DEL+1 to 0x9F is C1 range.

          '\t' is in C0 range, but more or less harmless and commonly used.

        */

        return (ch < ' ' && !IN_SET(ch, '\t', '\n')) ||

                (0x7F <= ch && ch <= 0x9F);

}

/* count of characters used to encode one unicode char */

static size_t utf8_encoded_expected_len(uint8_t c) {

        if (c < 0x80)

                return 1;

        if ((c & 0xe0) == 0xc0)

                return 2;

        if ((c & 0xf0) == 0xe0)

                return 3;

        if ((c & 0xf8) == 0xf0)

                return 4;

        if ((c & 0xfc) == 0xf8)

                return 5;

        if ((c & 0xfe) == 0xfc)

                return 6;

        return 0;

}

/* decode one unicode char */

int utf8_encoded_to_unichar(const char *str, char32_t *ret_unichar) {

        char32_t unichar;

        size_t len, i;

        assert(str);

        len = utf8_encoded_expected_len(str[0]);

        switch (len) {

        case 1:

                *ret_unichar = (char32_t)str[0];

                return 0;

        case 2:

                unichar = str[0] & 0x1f;

                break;

        case 3:

                unichar = (char32_t)str[0] & 0x0f;

                break;

        case 4:

                unichar = (char32_t)str[0] & 0x07;

                break;

        case 5:

                unichar = (char32_t)str[0] & 0x03;

                break;

        case 6:

                unichar = (char32_t)str[0] & 0x01;

                break;

        default:

                return -EINVAL;

        }

        for (i = 1; i < len; i++) {

                if (((char32_t)str[i] & 0xc0) != 0x80)

                        return -EINVAL;

                unichar <<= 6;

                unichar |= (char32_t)str[i] & 0x3f;

        }

        *ret_unichar = unichar;

        return 0;

}

bool utf8_is_printable_newline(const char* str, size_t length, bool allow_newline) {

        const char *p;

        assert(str);

        for (p = str; length > 0;) {

                int encoded_len, r;

                char32_t val;

                encoded_len = utf8_encoded_valid_unichar(p, length);

                if (encoded_len < 0)

                        return false;

                assert(encoded_len > 0 && (size_t) encoded_len <= length);

                r = utf8_encoded_to_unichar(p, &val;;

                if (r < 0 ||

                    unichar_is_control(val) ||

                    (!allow_newline && val == '\n'))

                        return false;

                length -= encoded_len;

                p += encoded_len;

        }

        return true;

}

char *utf8_is_valid_n(const char *str, size_t len_bytes) {

        /* Check if the string is composed of valid utf8 characters. If length len_bytes is given, stop after

         * len_bytes. Otherwise, stop at NUL. */

        assert(str);

        for (const char *p = str; len_bytes != (size_t) -1 ? (size_t) (p - str) < len_bytes : *p != '\0'; ) {

                int len;

                if (_unlikely_(*p == '\0') && len_bytes != (size_t) -1)

                        return NULL; /* embedded NUL */

                len = utf8_encoded_valid_unichar(p,

                                                 len_bytes != (size_t) -1 ? len_bytes - (p - str) : (size_t) -1);

                if (_unlikely_(len < 0))

                        return NULL; /* invalid character */

                p += len;

        }

        return (char*) str;

}

char *utf8_escape_invalid(const char *str) {

        char *p, *s;

        assert(str);

        p = s = malloc(strlen(str) * 4 + 1);

        if (!p)

                return NULL;

        while (*str) {

                int len;

                len = utf8_encoded_valid_unichar(str, (size_t) -1);

                if (len > 0) {

                        s = mempcpy(s, str, len);

                        str += len;

                } else {

                        s = stpcpy(s, UTF8_REPLACEMENT_CHARACTER);

                        str += 1;

                }

        }

        *s = '\0';

        (void) str_realloc(&p);

        return p;

}

#if 0 /* NM_IGNORED */

static int utf8_char_console_width(const char *str) {

        char32_t c;

        int r;

        r = utf8_encoded_to_unichar(str, &c);

        if (r < 0)

                return r;

        /* TODO: we should detect combining characters */

        return unichar_iswide(c) ? 2 : 1;

}

char *utf8_escape_non_printable_full(const char *str, size_t console_width) {

        char *p, *s, *prev_s;

        size_t n = 0; /* estimated print width */

        assert(str);

        if (console_width == 0)

                return strdup("");

        p = s = prev_s = malloc(strlen(str) * 4 + 1);

        if (!p)

                return NULL;

        for (;;) {

                int len;

                char *saved_s = s;

                if (!*str) /* done! */

                        goto finish;

                len = utf8_encoded_valid_unichar(str, (size_t) -1);

                if (len > 0) {

                        if (utf8_is_printable(str, len)) {

                                int w;

                                w = utf8_char_console_width(str);

                                assert(w >= 0);

                                if (n + w > console_width)

                                        goto truncation;

                                s = mempcpy(s, str, len);

                                str += len;

                                n += w;

                        } else {

                                for (; len > 0; len--) {

                                        if (n + 4 > console_width)

                                                goto truncation;

                                        *(s++) = '\\';

                                        *(s++) = 'x';

                                        *(s++) = hexchar((int) *str >> 4);

                                        *(s++) = hexchar((int) *str);

                                        str += 1;

                                        n += 4;

                                }

                        }

                } else {

                        if (n + 1 > console_width)

                                goto truncation;

                        s = mempcpy(s, UTF8_REPLACEMENT_CHARACTER, strlen(UTF8_REPLACEMENT_CHARACTER));

                        str += 1;

                        n += 1;

                }

                prev_s = saved_s;

        }

 truncation:

        /* Try to go back one if we don't have enough space for the ellipsis */

        if (n + 1 >= console_width)

                s = prev_s;

        s = mempcpy(s, "…", strlen("…"));

 finish:

        *s = '\0';

        (void) str_realloc(&p);

        return p;

}

#endif /* NM_IGNORED */

char *ascii_is_valid(const char *str) {

        const char *p;

        /* Check whether the string consists of valid ASCII bytes,

         * i.e values between 0 and 127, inclusive. */

        assert(str);

        for (p = str; *p; p++)

                if ((unsigned char) *p >= 128)

                        return NULL;

        return (char*) str;

}

#if 0 /* NM_IGNORED */

char *ascii_is_valid_n(const char *str, size_t len) {

        size_t i;

        /* Very similar to ascii_is_valid(), but checks exactly len

         * bytes and rejects any NULs in that range. */

        assert(str);

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

                if ((unsigned char) str[i] >= 128 || str[i] == 0)

                        return NULL;

        return (char*) str;

}

#endif /* NM_IGNORED */

/**

 * utf8_encode_unichar() - Encode single UCS-4 character as UTF-8

 * @out_utf8: output buffer of at least 4 bytes or NULL

 * @g: UCS-4 character to encode

 *

 * This encodes a single UCS-4 character as UTF-8 and writes it into @out_utf8.

 * The length of the character is returned. It is not zero-terminated! If the

 * output buffer is NULL, only the length is returned.

 *

 * Returns: The length in bytes that the UTF-8 representation does or would

 *          occupy.

 */

size_t utf8_encode_unichar(char *out_utf8, char32_t g) {

        if (g < (1 << 7)) {

                if (out_utf8)

                        out_utf8[0] = g & 0x7f;

                return 1;

        } else if (g < (1 << 11)) {

                if (out_utf8) {

                        out_utf8[0] = 0xc0 | ((g >> 6) & 0x1f);

                        out_utf8[1] = 0x80 | (g & 0x3f);

                }

                return 2;

        } else if (g < (1 << 16)) {

                if (out_utf8) {

                        out_utf8[0] = 0xe0 | ((g >> 12) & 0x0f);

                        out_utf8[1] = 0x80 | ((g >> 6) & 0x3f);

                        out_utf8[2] = 0x80 | (g & 0x3f);

                }

                return 3;

        } else if (g < (1 << 21)) {

                if (out_utf8) {

                        out_utf8[0] = 0xf0 | ((g >> 18) & 0x07);

                        out_utf8[1] = 0x80 | ((g >> 12) & 0x3f);

                        out_utf8[2] = 0x80 | ((g >> 6) & 0x3f);

                        out_utf8[3] = 0x80 | (g & 0x3f);

                }

                return 4;

        }

        return 0;

}

#if 0 /* NM_IGNORED */

char *utf16_to_utf8(const char16_t *s, size_t length /* bytes! */) {

        const uint8_t *f;

        char *r, *t;

        assert(s);

        /* Input length is in bytes, i.e. the shortest possible character takes 2 bytes. Each unicode character may

         * take up to 4 bytes in UTF-8. Let's also account for a trailing NUL byte. */

        if (length * 2 < length)

                return NULL; /* overflow */

        r = new(char, length * 2 + 1);

        if (!r)

                return NULL;

        f = (const uint8_t*) s;

        t = r;

        while (f + 1 < (const uint8_t*) s + length) {

                char16_t w1, w2;

                /* see RFC 2781 section 2.2 */

                w1 = f[1] << 8 | f[0];

                f += 2;

                if (!utf16_is_surrogate(w1)) {

                        t += utf8_encode_unichar(t, w1);

                        continue;

                }

                if (utf16_is_trailing_surrogate(w1))

                        continue; /* spurious trailing surrogate, ignore */

                if (f + 1 >= (const uint8_t*) s + length)

                        break;

                w2 = f[1] << 8 | f[0];

                f += 2;

                if (!utf16_is_trailing_surrogate(w2)) {

                        f -= 2;

                        continue; /* surrogate missing its trailing surrogate, ignore */

                }

                t += utf8_encode_unichar(t, utf16_surrogate_pair_to_unichar(w1, w2));

        }

        *t = 0;

        return r;

}

size_t utf16_encode_unichar(char16_t *out, char32_t c) {

        /* Note that this encodes as little-endian. */

        switch (c) {

        case 0 ... 0xd7ffU:

        case 0xe000U ... 0xffffU:

                out[0] = htole16(c);

                return 1;

        case 0x10000U ... 0x10ffffU:

                c -= 0x10000U;

                out[0] = htole16((c >> 10) + 0xd800U);

                out[1] = htole16((c & 0x3ffU) + 0xdc00U);

                return 2;

        default: /* A surrogate (invalid) */

                return 0;

        }

}

char16_t *utf8_to_utf16(const char *s, size_t length) {

        char16_t *n, *p;

        size_t i;

        int r;

        assert(s);

        n = new(char16_t, length + 1);

        if (!n)

                return NULL;

        p = n;

        for (i = 0; i < length;) {

                char32_t unichar;

                size_t e;

                e = utf8_encoded_expected_len(s[i]);

                if (e <= 1) /* Invalid and single byte characters are copied as they are */

                        goto copy;

                if (i + e > length) /* sequence longer than input buffer, then copy as-is */

                        goto copy;

                r = utf8_encoded_to_unichar(s + i, &unichar);

                if (r < 0) /* sequence invalid, then copy as-is */

                        goto copy;

                p += utf16_encode_unichar(p, unichar);

                i += e;

                continue;

        copy:

                *(p++) = htole16(s[i++]);

        }

        *p = 0;

        return n;

}

size_t char16_strlen(const char16_t *s) {

        size_t n = 0;

        assert(s);

        while (*s != 0)

                n++, s++;

        return n;

}

#endif /* NM_IGNORED */

/* expected size used to encode one unicode char */

static int utf8_unichar_to_encoded_len(char32_t unichar) {

        if (unichar < 0x80)

                return 1;

        if (unichar < 0x800)

                return 2;

        if (unichar < 0x10000)

                return 3;

        if (unichar < 0x200000)

                return 4;

        if (unichar < 0x4000000)

                return 5;

        return 6;

}

/* validate one encoded unicode char and return its length */

int utf8_encoded_valid_unichar(const char *str, size_t length /* bytes */) {

        char32_t unichar;

        size_t len, i;

        int r;

        assert(str);

        assert(length > 0);

        /* We read until NUL, at most length bytes. (size_t) -1 may be used to disable the length check. */

        len = utf8_encoded_expected_len(str[0]);

        if (len == 0)

                return -EINVAL;

        /* Do we have a truncated multi-byte character? */

        if (len > length)

                return -EINVAL;

        /* ascii is valid */

        if (len == 1)

                return 1;

        /* check if expected encoded chars are available */

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

                if ((str[i] & 0x80) != 0x80)

                        return -EINVAL;

        r = utf8_encoded_to_unichar(str, &unichar);

        if (r < 0)

                return r;

        /* check if encoded length matches encoded value */

        if (utf8_unichar_to_encoded_len(unichar) != (int) len)

                return -EINVAL;

        /* check if value has valid range */

        if (!unichar_is_valid(unichar))

                return -EINVAL;

        return (int) len;

}

#if 0 /* NM_IGNORED */

size_t utf8_n_codepoints(const char *str) {

        size_t n = 0;

        /* Returns the number of UTF-8 codepoints in this string, or (size_t) -1 if the string is not valid UTF-8. */

        while (*str != 0) {

                int k;

                k = utf8_encoded_valid_unichar(str, (size_t) -1);

                if (k < 0)

                        return (size_t) -1;

                str += k;

                n++;

        }

        return n;

}

size_t utf8_console_width(const char *str) {

        size_t n = 0;

        /* Returns the approximate width a string will take on screen when printed on a character cell

         * terminal/console. */

        while (*str) {

                int w;

                w = utf8_char_console_width(str);

                if (w < 0)

                        return (size_t) -1;

                n += w;

                str = utf8_next_char(str);

        }

        return n;

}

#endif /* NM_IGNORED */