shared/utf8: merge implementations, remove cruft

This unifies the utf8 handling code which was previously duplicated in
udev and systemd.

3 files changed, 81 insertions, 210 deletions

diff --git a/src/shared/utf8.c b/src/shared/utf8.c
index 1a68394a53..732f0f00ca 100644
--- a/src/shared/utf8.c
+++ b/src/shared/utf8.c
@@ -51,8 +51,6 @@
 #include "utf8.h"
 #include "util.h"
 
-#define FILTER_CHAR '_'
-
 static inline bool is_unicode_valid(uint32_t ch) {
 
         if (ch >= 0x110000) /* End of unicode space */
@@ -67,17 +65,6 @@ 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) {
 
         /*
@@ -90,163 +77,97 @@ static bool is_unicode_control(uint32_t ch) {
                 (0x7F <= ch && ch <= 0x9F);
 }
 
-bool utf8_is_printable(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 = (unsigned char)str[0];
 
-        assert(str);
+        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;
+}
 
-        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
-                                return false;
-
-                        p++;
-                        length--;
-                        if (!length || !is_continuation_char(*p))
-                                return false;
-                        merge_continuation_char(&val, *p);
-
-                TWO_REMAINING:
-                        p++;
-                        length--;
-                        if (!is_continuation_char(*p))
-                                return false;
-                        merge_continuation_char(&val, *p);
-
-                ONE_REMAINING:
-                        p++;
-                        length--;
-                        if (!is_continuation_char(*p))
-                                return false;
-                        merge_continuation_char(&val, *p);
-
-                        if (val < min)
-                                return false;
-                }
+/* decode one unicode char */
+static int utf8_encoded_to_unichar(const char *str) {
+        int unichar;
+        int len;
+        int i;
 
-                if (is_unicode_control(val))
-                        return false;
+        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 -1;
         }
 
-        return true;
+        for (i = 1; i < len; i++) {
+                if (((int)str[i] & 0xc0) != 0x80)
+                        return -1;
+                unichar <<= 6;
+                unichar |= (int)str[i] & 0x3f;
+        }
+
+        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(const char* str, size_t length) {
+        const uint8_t *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;
-                        }
-
-                        continue;
-
-                error:
-                        if (o) {
-                                *o = FILTER_CHAR;
-                                p = last; /* We retry at the next character */
-                        } else
-                                goto failure;
-                }
+        for (p = (const uint8_t*) str; length; p++) {
+                int encoded_len = utf8_encoded_valid_unichar((const char *)p);
+                int32_t val = utf8_encoded_to_unichar((const char*)p);
 
-                if (o)
-                        o++;
-        }
+                if (encoded_len < 0 || val < 0 || is_unicode_control(val))
+                        return false;
 
-        if (o) {
-                *o = '\0';
-                return output;
+                length -= encoded_len;
         }
 
-        return (char*) str;
-
-failure:
-        return NULL;
-}
-
-char* utf8_is_valid (const char *str) {
-        return utf8_validate(str, NULL);
+        return true;
 }
 
-char* utf8_filter (const char *str) {
-        char *new_str;
+const char *utf8_is_valid(const char *str) {
+        const uint8_t *p;
 
         assert(str);
 
-        new_str = malloc(strlen(str) + 1);
-        if (!new_str)
-                return NULL;
+        for (p = (const uint8_t*) str; *p; ) {
+                int len = utf8_encoded_valid_unichar((const char *)p);
+
+                if (len < 0)
+                        return NULL;
+
+                p += len;
+        }
 
-        return utf8_validate(str, new_str);
+        return str;
 }
 
 char *ascii_is_valid(const char *str) {
@@ -318,64 +239,6 @@ char *utf16_to_utf8(const void *s, size_t length) {
         return r;
 }
 
-/* count of characters used to encode one unicode char */
-static int utf8_encoded_expected_len(const char *str) {
-        unsigned char 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;
-}
-
-/* decode one unicode char */
-static int utf8_encoded_to_unichar(const char *str) {
-        int unichar;
-        int len;
-        int i;
-
-        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 -1;
-        }
-
-        for (i = 1; i < len; i++) {
-                if (((int)str[i] & 0xc0) != 0x80)
-                        return -1;
-                unichar <<= 6;
-                unichar |= (int)str[i] & 0x3f;
-        }
-
-        return unichar;
-}
-
 /* expected size used to encode one unicode char */
 static int utf8_unichar_to_encoded_len(int unichar) {
         if (unichar < 0x80)
diff --git a/src/shared/utf8.h b/src/shared/utf8.h
index 7a5608c9ee..22e13461de 100644
--- a/src/shared/utf8.h
+++ b/src/shared/utf8.h
@@ -25,12 +25,11 @@
 
 #include "macro.h"
 
-char *utf8_is_valid(const char *s) _pure_;
+const char *utf8_is_valid(const char *s) _pure_;
 char *ascii_is_valid(const char *s) _pure_;
 
 bool utf8_is_printable(const char* str, size_t length) _pure_;
 
-char *utf8_filter(const char *s);
 char *ascii_filter(const char *s);
 
 char *utf16_to_utf8(const void *s, size_t length);
diff --git a/src/test/test-utf8.c b/src/test/test-utf8.c
index d2b9771f4b..26cc37bd6e 100644
--- a/src/test/test-utf8.c
+++ b/src/test/test-utf8.c
@@ -47,6 +47,12 @@ static void test_udev_encode_string(void) {
         assert_se(expect_encoded_as("s/ash/ng", "s\\x2fash\\x2fng"));
 }
 
+static void test_utf8_is_printable(void) {
+        assert_se(utf8_is_printable("ascii is valid\tunicode", 22));
+        assert_se(utf8_is_printable("\342\204\242", 3));
+        assert_se(!utf8_is_printable("\341\204", 2));
+}
+
 static void test_utf8_is_valid(void) {
         assert_se(utf8_is_valid("ascii is valid unicode"));
         assert_se(utf8_is_valid("\341\204\242"));
@@ -55,5 +61,8 @@ static void test_utf8_is_valid(void) {
 
 int main(int argc, char *argv[]) {
         test_utf8_is_valid();
+        test_utf8_is_printable();
         test_udev_encode_string();
+
+        return 0;
 }