/* SPDX-License-Identifier: LGPL-2.1+ */ /* 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 #include #include #include #include "alloc-util.h" #include "gunicode.h" #include "hexdecoct.h" #include "macro.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 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) || (!newline && val == '\n')) return false; length -= encoded_len; p += encoded_len; } return true; } char *utf8_is_valid(const char *str) { const char *p; assert(str); p = str; while (*p) { int len; len = utf8_encoded_valid_unichar(p, (size_t) -1); if (len < 0) return NULL; 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'; return p; } char *utf8_escape_non_printable(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) { if (utf8_is_printable(str, len)) { s = mempcpy(s, str, len); str += len; } else { while (len > 0) { *(s++) = '\\'; *(s++) = 'x'; *(s++) = hexchar((int) *str >> 4); *(s++) = hexchar((int) *str); str += 1; len--; } } } else { s = stpcpy(s, UTF8_REPLACEMENT_CHARACTER); str += 1; } } *s = '\0'; return p; } 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; } 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; } /** * 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; } 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; } /* 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; } 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 != 0) { char32_t c; if (utf8_encoded_to_unichar(str, &c) < 0) return (size_t) -1; str = utf8_next_char(str); n += unichar_iswide(c) ? 2 : 1; } return n; }