chiark / gitweb /
util: when unescaping C escape sequences support C++11 \u and \U unicode literals
[elogind.git] / src / shared / utf8.c
index a6f5b3f9e5dff38fc28efd4eb1d47943a2f49a87..800884ffee99c77b36c6c16f35015a70442409fa 100644 (file)
@@ -3,6 +3,7 @@
 /***
   This file is part of systemd.
 
+  Copyright 2008-2011 Kay Sievers
   Copyright 2012 Lennart Poettering
 
   systemd is free software; you can redistribute it and/or modify it
@@ -19,7 +20,7 @@
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 ***/
 
-/* This file is based on the GLIB utf8 validation functions. The
+/* 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) 2000 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
+ * 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
- * Lesser General Public License for more details.
+ * 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 Lesser General Public
- * License along with this library; if not, write to the
- * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- * Boston, MA 02111-1307, USA.
+ * 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 "utf8.h"
+#include "util.h"
 
-#define FILTER_CHAR '_'
-
-static inline bool is_unicode_valid(uint32_t ch) {
+bool unichar_is_valid(uint32_t ch) {
 
         if (ch >= 0x110000) /* End of unicode space */
                 return false;
@@ -67,18 +66,7 @@ static inline bool is_unicode_valid(uint32_t ch) {
         return true;
 }
 
-static inline bool is_continuation_char(uint8_t ch) {
-        if ((ch & 0xc0) != 0x80) /* 10xxxxxx */
-                return false;
-        return true;
-}
-
-static inline void merge_continuation_char(uint32_t *u_ch, uint8_t ch) {
-        *u_ch <<= 6;
-        *u_ch |= ch & 0x3f;
-}
-
-static bool is_unicode_control(uint32_t ch) {
+static bool unichar_is_control(uint32_t ch) {
 
         /*
           0 to ' '-1 is the C0 range.
@@ -86,170 +74,181 @@ static bool is_unicode_control(uint32_t ch) {
           '\t' is in C0 range, but more or less harmless and commonly used.
         */
 
-        return (ch < ' ' && ch != '\t') ||
+        return (ch < ' ' && ch != '\t' && ch != '\n') ||
                 (0x7F <= ch && ch <= 0x9F);
 }
 
-char* utf8_is_printable_n(const char* str, size_t length) {
-        uint32_t val = 0;
-        uint32_t min = 0;
-        const uint8_t *p;
+/* count of characters used to encode one unicode char */
+static int utf8_encoded_expected_len(const char *str) {
+        unsigned char c;
 
         assert(str);
 
-        for (p = (const uint8_t*) str; length; p++, length--) {
-                if (*p < 128) {
-                        val = *p;
-                } else {
-                        if ((*p & 0xe0) == 0xc0) { /* 110xxxxx two-char seq. */
-                                min = 128;
-                                val = (uint32_t) (*p & 0x1e);
-                                goto ONE_REMAINING;
-                        } else if ((*p & 0xf0) == 0xe0) { /* 1110xxxx three-char seq.*/
-                                min = (1 << 11);
-                                val = (uint32_t) (*p & 0x0f);
-                                goto TWO_REMAINING;
-                        } else if ((*p & 0xf8) == 0xf0) { /* 11110xxx four-char seq */
-                                min = (1 << 16);
-                                val = (uint32_t) (*p & 0x07);
-                        } else
-                                goto error;
-
-                        p++;
-                        length--;
-                        if (!length || !is_continuation_char(*p))
-                                goto error;
-                        merge_continuation_char(&val, *p);
-
-                TWO_REMAINING:
-                        p++;
-                        length--;
-                        if (!is_continuation_char(*p))
-                                goto error;
-                        merge_continuation_char(&val, *p);
-
-                ONE_REMAINING:
-                        p++;
-                        length--;
-                        if (!is_continuation_char(*p))
-                                goto error;
-                        merge_continuation_char(&val, *p);
-
-                        if (val < min)
-                                goto error;
-                }
+        c = (unsigned char) 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;
+}
 
-                if (is_unicode_control(val))
-                        goto error;
+/* decode one unicode char */
+int utf8_encoded_to_unichar(const char *str) {
+        int unichar, len, i;
+
+        assert(str);
+
+        len = utf8_encoded_expected_len(str);
+
+        switch (len) {
+        case 1:
+                return (int)str[0];
+        case 2:
+                unichar = str[0] & 0x1f;
+                break;
+        case 3:
+                unichar = (int)str[0] & 0x0f;
+                break;
+        case 4:
+                unichar = (int)str[0] & 0x07;
+                break;
+        case 5:
+                unichar = (int)str[0] & 0x03;
+                break;
+        case 6:
+                unichar = (int)str[0] & 0x01;
+                break;
+        default:
+                return -EINVAL;
         }
 
-        return (char*) str;
+        for (i = 1; i < len; i++) {
+                if (((int)str[i] & 0xc0) != 0x80)
+                        return -EINVAL;
+                unichar <<= 6;
+                unichar |= (int)str[i] & 0x3f;
+        }
 
-error:
-        return NULL;
+        return unichar;
 }
 
-static char* utf8_validate(const char *str, char *output) {
-        uint32_t val = 0;
-        uint32_t min = 0;
-        const uint8_t *p, *last;
-        int size;
-        uint8_t *o;
+bool utf8_is_printable_newline(const char* str, size_t length, bool newline) {
+        const char *p;
 
         assert(str);
 
-        o = (uint8_t*) output;
-        for (p = (const uint8_t*) str; *p; p++) {
-                if (*p < 128) {
-                        if (o)
-                                *o = *p;
-                } else {
-                        last = p;
-
-                        if ((*p & 0xe0) == 0xc0) { /* 110xxxxx two-char seq. */
-                                size = 2;
-                                min = 128;
-                                val = (uint32_t) (*p & 0x1e);
-                                goto ONE_REMAINING;
-                        } else if ((*p & 0xf0) == 0xe0) { /* 1110xxxx three-char seq.*/
-                                size = 3;
-                                min = (1 << 11);
-                                val = (uint32_t) (*p & 0x0f);
-                                goto TWO_REMAINING;
-                        } else if ((*p & 0xf8) == 0xf0) { /* 11110xxx four-char seq */
-                                size = 4;
-                                min = (1 << 16);
-                                val = (uint32_t) (*p & 0x07);
-                        } else
-                                goto error;
-
-                        p++;
-                        if (!is_continuation_char(*p))
-                                goto error;
-                        merge_continuation_char(&val, *p);
-
-                TWO_REMAINING:
-                        p++;
-                        if (!is_continuation_char(*p))
-                                goto error;
-                        merge_continuation_char(&val, *p);
-
-                ONE_REMAINING:
-                        p++;
-                        if (!is_continuation_char(*p))
-                                goto error;
-                        merge_continuation_char(&val, *p);
-
-                        if (val < min)
-                                goto error;
-
-                        if (!is_unicode_valid(val))
-                                goto error;
-
-                        if (o) {
-                                memcpy(o, last, (size_t) size);
-                                o += size;
-                        }
+        for (p = str; length;) {
+                int encoded_len, val;
 
-                        continue;
+                encoded_len = utf8_encoded_valid_unichar(p);
+                if (encoded_len < 0 ||
+                    (size_t) encoded_len > length)
+                        return false;
 
-                error:
-                        if (o) {
-                                *o = FILTER_CHAR;
-                                p = last; /* We retry at the next character */
-                        } else
-                                goto failure;
-                }
+                val = utf8_encoded_to_unichar(p);
+                if (val < 0 ||
+                    unichar_is_control(val) ||
+                    (!newline && val == '\n'))
+                        return false;
 
-                if (o)
-                        o++;
+                length -= encoded_len;
+                p += encoded_len;
         }
 
-        if (o) {
-                *o = '\0';
-                return output;
-        }
+        return true;
+}
 
-        return (char*) str;
+const char *utf8_is_valid(const char *str) {
+        const uint8_t *p;
+
+        assert(str);
+
+        for (p = (const uint8_t*) str; *p; ) {
+                int len;
+
+                len = utf8_encoded_valid_unichar((const char *)p);
+                if (len < 0)
+                        return NULL;
+
+                p += len;
+        }
 
-failure:
-        return NULL;
+        return str;
 }
 
-char* utf8_is_valid (const char *str) {
-        return utf8_validate(str, NULL);
+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_filter (const char *str) {
-        char *new_str;
+char *utf8_escape_non_printable(const char *str) {
+        char *p, *s;
 
         assert(str);
 
-        new_str = malloc(strlen(str) + 1);
-        if (!new_str)
+        p = s = malloc(strlen(str) * 4 + 1);
+        if (!p)
                 return NULL;
 
-        return utf8_validate(str, new_str);
+        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) {
@@ -264,22 +263,140 @@ char *ascii_is_valid(const char *str) {
         return (char*) str;
 }
 
-char *ascii_filter(const char *str) {
-        char *r, *s, *d;
-        size_t l;
+/**
+ * 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, uint32_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;
+}
 
-        assert(str);
+char *utf16_to_utf8(const void *s, size_t length) {
+        const uint8_t *f;
+        char *r, *t;
 
-        l = strlen(str);
-        r = malloc(l + 1);
+        r = new(char, (length * 4 + 1) / 2 + 1);
         if (!r)
                 return NULL;
 
-        for (s = r, d = r; *s; s++)
-                if ((unsigned char) *s < 128)
-                        *(d++) = *s;
+        f = s;
+        t = r;
+
+        while (f < (const uint8_t*) s + length) {
+                uint16_t w1, w2;
 
-        *d = 0;
+                /* 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;
+                else if (f >= (const uint8_t*) s + length)
+                        break;
+
+                w2 = f[1] << 8 | f[0];
+                f += 2;
+
+                if (!utf16_is_trailing_surrogate(w2)) {
+                        f -= 2;
+                        continue;
+                }
+
+                t += utf8_encode_unichar(t, utf16_surrogate_pair_to_unichar(w1, w2));
+        }
+
+        *t = 0;
         return r;
 }
+
+/* expected size used to encode one unicode char */
+static int utf8_unichar_to_encoded_len(int 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) {
+        int len, unichar, i;
+
+        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;
+
+        unichar = utf8_encoded_to_unichar(str);
+
+        /* check if encoded length matches encoded value */
+        if (utf8_unichar_to_encoded_len(unichar) != len)
+                return -EINVAL;
+
+        /* check if value has valid range */
+        if (!unichar_is_valid(unichar))
+                return -EINVAL;
+
+        return len;
+}