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-rw-r--r--src/basic/utf8.c532
1 files changed, 532 insertions, 0 deletions
diff --git a/src/basic/utf8.c b/src/basic/utf8.c
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--- /dev/null
+++ b/src/basic/utf8.c
@@ -0,0 +1,532 @@
+/* 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 <errno.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+
+#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(const char *str) {
+ uint8_t c;
+
+ assert(str);
+
+ c = (uint8_t) str[0];
+ 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);
+
+ 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;) {
+ int encoded_len, r;
+ char32_t val;
+
+ encoded_len = utf8_encoded_valid_unichar(p);
+ if (encoded_len < 0 ||
+ (size_t) encoded_len > length)
+ return false;
+
+ 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);
+ 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);
+ 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);
+ 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) {
+ char32_t unichar;
+ size_t len, i;
+ int r;
+
+ assert(str);
+
+ len = utf8_encoded_expected_len(str);
+ if (len == 0)
+ 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);
+ 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;
+}
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