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Subject[PATCH v2 12/15] nls: utf8norm: Introduce code for UTF-8 normalization
Date
From: Olaf Weber <olaf@sgi.com>

Supporting functions for UTF-8 normalization are in utf8norm.c with the
header utf8norm.h. Two normalization forms are supported: nfkdi and
nfkdicf.

nfkdi:
- Apply unicode normalization form NFKD.
- Remove any Default_Ignorable_Code_Point.

nfkdicf:
- Apply unicode normalization form NFKD.
- Remove any Default_Ignorable_Code_Point.
- Apply a full casefold (C + F).

For the purposes of the code, a string is valid UTF-8 if:

- The values encoded are 0x1..0x10FFFF.
- The surrogate codepoints 0xD800..0xDFFFF are not encoded.
- The shortest possible encoding is used for all values.

The supporting functions work on null-terminated strings (utf8 prefix)
and on length-limited strings (utf8n prefix).

From the original SGI patch and for conformity with coding standards,
the utf8data_t typedef was dropped, since it was just masking the struct
keyword. On other occasions, namely utf8leaf_t and utf8trie_t, I
decided to keep it, since they are simple pointers to memory buffers,
and using uchars here wouldn't provide any more meaningful information.

Changes since RFC v2:
- Merge to NLS system

Changes since RFC v1:
- utf8_version_is_supported receives maj, min and rev as separate
arguments. (Olaf Weber)

Signed-off-by: Olaf Weber <olaf@sgi.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.co.uk>
[Rebase to Mainline]
[Fix up checkpatch.pl warnings]
[Drop typedefs]
[Merge with NLS subsystem]
---
fs/nls/Makefile | 4 +
fs/nls/nls_utf8n-norm.c | 640 ++++++++++++++++++++++++++++++++++++++++
fs/nls/utf8n.h | 112 +++++++
3 files changed, 756 insertions(+)
create mode 100644 fs/nls/nls_utf8n-norm.c
create mode 100644 fs/nls/utf8n.h

diff --git a/fs/nls/Makefile b/fs/nls/Makefile
index 9eff2f058c7a..6ff62c0fe436 100644
--- a/fs/nls/Makefile
+++ b/fs/nls/Makefile
@@ -56,6 +56,10 @@ obj-$(CONFIG_NLS_MAC_ROMANIAN) += mac-romanian.o
obj-$(CONFIG_NLS_MAC_ROMAN) += mac-roman.o
obj-$(CONFIG_NLS_MAC_TURKISH) += mac-turkish.o

+nls_utf8n-y += nls_utf8n-norm.o
+obj-$(CONFIG_NLS_UTF8_NORMALIZATION) += nls_utf8n.o
+
+$(obj)/nls_utf8n-norm.o: $(obj)/utf8data.h
$(obj)/utf8data.h: $(srctree)/$(src)/ucd/*.txt $(objtree)/scripts/mkutf8data FORCE
$(call cmd,mkutf8data)
quiet_cmd_mkutf8data = MKUTF8DATA $@
diff --git a/fs/nls/nls_utf8n-norm.c b/fs/nls/nls_utf8n-norm.c
new file mode 100644
index 000000000000..ca0bbf644b49
--- /dev/null
+++ b/fs/nls/nls_utf8n-norm.c
@@ -0,0 +1,640 @@
+/*
+ * Copyright (c) 2014 SGI.
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include "utf8n.h"
+
+struct utf8data {
+ unsigned int maxage;
+ unsigned int offset;
+};
+
+#define __INCLUDED_FROM_UTF8NORM_C__
+#include "utf8data.h"
+#undef __INCLUDED_FROM_UTF8NORM_C__
+
+int utf8version_is_supported(u8 maj, u8 min, u8 rev)
+{
+ int i = ARRAY_SIZE(utf8agetab) - 1;
+ unsigned int sb_utf8version = UNICODE_AGE(maj, min, rev);
+
+ while (i >= 0 && utf8agetab[i] != 0) {
+ if (sb_utf8version == utf8agetab[i])
+ return 1;
+ i--;
+ }
+ return 0;
+}
+EXPORT_SYMBOL(utf8version_is_supported);
+
+/*
+ * UTF-8 valid ranges.
+ *
+ * The UTF-8 encoding spreads the bits of a 32bit word over several
+ * bytes. This table gives the ranges that can be held and how they'd
+ * be represented.
+ *
+ * 0x00000000 0x0000007F: 0xxxxxxx
+ * 0x00000000 0x000007FF: 110xxxxx 10xxxxxx
+ * 0x00000000 0x0000FFFF: 1110xxxx 10xxxxxx 10xxxxxx
+ * 0x00000000 0x001FFFFF: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
+ * 0x00000000 0x03FFFFFF: 111110xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
+ * 0x00000000 0x7FFFFFFF: 1111110x 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
+ *
+ * There is an additional requirement on UTF-8, in that only the
+ * shortest representation of a 32bit value is to be used. A decoder
+ * must not decode sequences that do not satisfy this requirement.
+ * Thus the allowed ranges have a lower bound.
+ *
+ * 0x00000000 0x0000007F: 0xxxxxxx
+ * 0x00000080 0x000007FF: 110xxxxx 10xxxxxx
+ * 0x00000800 0x0000FFFF: 1110xxxx 10xxxxxx 10xxxxxx
+ * 0x00010000 0x001FFFFF: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
+ * 0x00200000 0x03FFFFFF: 111110xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
+ * 0x04000000 0x7FFFFFFF: 1111110x 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
+ *
+ * Actual unicode characters are limited to the range 0x0 - 0x10FFFF,
+ * 17 planes of 65536 values. This limits the sequences actually seen
+ * even more, to just the following.
+ *
+ * 0 - 0x7F: 0 - 0x7F
+ * 0x80 - 0x7FF: 0xC2 0x80 - 0xDF 0xBF
+ * 0x800 - 0xFFFF: 0xE0 0xA0 0x80 - 0xEF 0xBF 0xBF
+ * 0x10000 - 0x10FFFF: 0xF0 0x90 0x80 0x80 - 0xF4 0x8F 0xBF 0xBF
+ *
+ * Within those ranges the surrogates 0xD800 - 0xDFFF are not allowed.
+ *
+ * Note that the longest sequence seen with valid usage is 4 bytes,
+ * the same a single UTF-32 character. This makes the UTF-8
+ * representation of Unicode strictly smaller than UTF-32.
+ *
+ * The shortest sequence requirement was introduced by:
+ * Corrigendum #1: UTF-8 Shortest Form
+ * It can be found here:
+ * http://www.unicode.org/versions/corrigendum1.html
+ *
+ */
+
+/*
+ * Return the number of bytes used by the current UTF-8 sequence.
+ * Assumes the input points to the first byte of a valid UTF-8
+ * sequence.
+ */
+static inline int utf8clen(const char *s)
+{
+ unsigned char c = *s;
+
+ return 1 + (c >= 0xC0) + (c >= 0xE0) + (c >= 0xF0);
+}
+
+/*
+ * utf8trie_t
+ *
+ * A compact binary tree, used to decode UTF-8 characters.
+ *
+ * Internal nodes are one byte for the node itself, and up to three
+ * bytes for an offset into the tree. The first byte contains the
+ * following information:
+ * NEXTBYTE - flag - advance to next byte if set
+ * BITNUM - 3 bit field - the bit number to tested
+ * OFFLEN - 2 bit field - number of bytes in the offset
+ * if offlen == 0 (non-branching node)
+ * RIGHTPATH - 1 bit field - set if the following node is for the
+ * right-hand path (tested bit is set)
+ * TRIENODE - 1 bit field - set if the following node is an internal
+ * node, otherwise it is a leaf node
+ * if offlen != 0 (branching node)
+ * LEFTNODE - 1 bit field - set if the left-hand node is internal
+ * RIGHTNODE - 1 bit field - set if the right-hand node is internal
+ *
+ * Due to the way utf8 works, there cannot be branching nodes with
+ * NEXTBYTE set, and moreover those nodes always have a righthand
+ * descendant.
+ */
+typedef const unsigned char utf8trie_t;
+#define BITNUM 0x07
+#define NEXTBYTE 0x08
+#define OFFLEN 0x30
+#define OFFLEN_SHIFT 4
+#define RIGHTPATH 0x40
+#define TRIENODE 0x80
+#define RIGHTNODE 0x40
+#define LEFTNODE 0x80
+
+/*
+ * utf8leaf_t
+ *
+ * The leaves of the trie are embedded in the trie, and so the same
+ * underlying datatype: unsigned char.
+ *
+ * leaf[0]: The unicode version, stored as a generation number that is
+ * an index into utf8agetab[]. With this we can filter code
+ * points based on the unicode version in which they were
+ * defined. The CCC of a non-defined code point is 0.
+ * leaf[1]: Canonical Combining Class. During normalization, we need
+ * to do a stable sort into ascending order of all characters
+ * with a non-zero CCC that occur between two characters with
+ * a CCC of 0, or at the begin or end of a string.
+ * The unicode standard guarantees that all CCC values are
+ * between 0 and 254 inclusive, which leaves 255 available as
+ * a special value.
+ * Code points with CCC 0 are known as stoppers.
+ * leaf[2]: Decomposition. If leaf[1] == 255, then leaf[2] is the
+ * start of a NUL-terminated string that is the decomposition
+ * of the character.
+ * The CCC of a decomposable character is the same as the CCC
+ * of the first character of its decomposition.
+ * Some characters decompose as the empty string: these are
+ * characters with the Default_Ignorable_Code_Point property.
+ * These do affect normalization, as they all have CCC 0.
+ *
+ * The decompositions in the trie have been fully expanded.
+ *
+ * Casefolding, if applicable, is also done using decompositions.
+ *
+ * The trie is constructed in such a way that leaves exist for all
+ * UTF-8 sequences that match the criteria from the "UTF-8 valid
+ * ranges" comment above, and only for those sequences. Therefore a
+ * lookup in the trie can be used to validate the UTF-8 input.
+ */
+typedef const unsigned char utf8leaf_t;
+
+#define LEAF_GEN(LEAF) ((LEAF)[0])
+#define LEAF_CCC(LEAF) ((LEAF)[1])
+#define LEAF_STR(LEAF) ((const char *)((LEAF) + 2))
+
+#define MINCCC (0)
+#define MAXCCC (254)
+#define STOPPER (0)
+#define DECOMPOSE (255)
+
+/*
+ * Use trie to scan s, touching at most len bytes.
+ * Returns the leaf if one exists, NULL otherwise.
+ *
+ * A non-NULL return guarantees that the UTF-8 sequence starting at s
+ * is well-formed and corresponds to a known unicode code point. The
+ * shorthand for this will be "is valid UTF-8 unicode".
+ */
+static utf8leaf_t *utf8nlookup(const struct utf8data *data, const char *s,
+ size_t len)
+{
+ utf8trie_t *trie = utf8data + data->offset;
+ int offlen;
+ int offset;
+ int mask;
+ int node;
+
+ if (!data)
+ return NULL;
+ if (len == 0)
+ return NULL;
+ node = 1;
+ while (node) {
+ offlen = (*trie & OFFLEN) >> OFFLEN_SHIFT;
+ if (*trie & NEXTBYTE) {
+ if (--len == 0)
+ return NULL;
+ s++;
+ }
+ mask = 1 << (*trie & BITNUM);
+ if (*s & mask) {
+ /* Right leg */
+ if (offlen) {
+ /* Right node at offset of trie */
+ node = (*trie & RIGHTNODE);
+ offset = trie[offlen];
+ while (--offlen) {
+ offset <<= 8;
+ offset |= trie[offlen];
+ }
+ trie += offset;
+ } else if (*trie & RIGHTPATH) {
+ /* Right node after this node */
+ node = (*trie & TRIENODE);
+ trie++;
+ } else {
+ /* No right node. */
+ node = 0;
+ trie = NULL;
+ }
+ } else {
+ /* Left leg */
+ if (offlen) {
+ /* Left node after this node. */
+ node = (*trie & LEFTNODE);
+ trie += offlen + 1;
+ } else if (*trie & RIGHTPATH) {
+ /* No left node. */
+ node = 0;
+ trie = NULL;
+ } else {
+ /* Left node after this node */
+ node = (*trie & TRIENODE);
+ trie++;
+ }
+ }
+ }
+ return trie;
+}
+
+/*
+ * Use trie to scan s.
+ * Returns the leaf if one exists, NULL otherwise.
+ *
+ * Forwards to utf8nlookup().
+ */
+static utf8leaf_t *utf8lookup(const struct utf8data *data, const char *s)
+{
+ return utf8nlookup(data, s, (size_t)-1);
+}
+
+/*
+ * Maximum age of any character in s.
+ * Return -1 if s is not valid UTF-8 unicode.
+ * Return 0 if only non-assigned code points are used.
+ */
+int utf8agemax(const struct utf8data *data, const char *s)
+{
+ utf8leaf_t *leaf;
+ int age = 0;
+ int leaf_age;
+
+ if (!data)
+ return -1;
+ while (*s) {
+ leaf = utf8lookup(data, s);
+ if (!leaf)
+ return -1;
+
+ leaf_age = utf8agetab[LEAF_GEN(leaf)];
+ if (leaf_age <= data->maxage && leaf_age > age)
+ age = leaf_age;
+ s += utf8clen(s);
+ }
+ return age;
+}
+EXPORT_SYMBOL(utf8agemax);
+
+/*
+ * Minimum age of any character in s.
+ * Return -1 if s is not valid UTF-8 unicode.
+ * Return 0 if non-assigned code points are used.
+ */
+int utf8agemin(const struct utf8data *data, const char *s)
+{
+ utf8leaf_t *leaf;
+ int age;
+ int leaf_age;
+
+ if (!data)
+ return -1;
+ age = data->maxage;
+ while (*s) {
+ leaf = utf8lookup(data, s);
+ if (!leaf)
+ return -1;
+ leaf_age = utf8agetab[LEAF_GEN(leaf)];
+ if (leaf_age <= data->maxage && leaf_age < age)
+ age = leaf_age;
+ s += utf8clen(s);
+ }
+ return age;
+}
+EXPORT_SYMBOL(utf8agemin);
+
+/*
+ * Maximum age of any character in s, touch at most len bytes.
+ * Return -1 if s is not valid UTF-8 unicode.
+ */
+int utf8nagemax(const struct utf8data *data, const char *s, size_t len)
+{
+ utf8leaf_t *leaf;
+ int age = 0;
+ int leaf_age;
+
+ if (!data)
+ return -1;
+ while (len && *s) {
+ leaf = utf8nlookup(data, s, len);
+ if (!leaf)
+ return -1;
+ leaf_age = utf8agetab[LEAF_GEN(leaf)];
+ if (leaf_age <= data->maxage && leaf_age > age)
+ age = leaf_age;
+ len -= utf8clen(s);
+ s += utf8clen(s);
+ }
+ return age;
+}
+EXPORT_SYMBOL(utf8nagemax);
+
+/*
+ * Maximum age of any character in s, touch at most len bytes.
+ * Return -1 if s is not valid UTF-8 unicode.
+ */
+int utf8nagemin(const struct utf8data *data, const char *s, size_t len)
+{
+ utf8leaf_t *leaf;
+ int leaf_age;
+ int age;
+
+ if (!data)
+ return -1;
+ age = data->maxage;
+ while (len && *s) {
+ leaf = utf8nlookup(data, s, len);
+ if (!leaf)
+ return -1;
+ leaf_age = utf8agetab[LEAF_GEN(leaf)];
+ if (leaf_age <= data->maxage && leaf_age < age)
+ age = leaf_age;
+ len -= utf8clen(s);
+ s += utf8clen(s);
+ }
+ return age;
+}
+EXPORT_SYMBOL(utf8nagemin);
+
+/*
+ * Length of the normalization of s.
+ * Return -1 if s is not valid UTF-8 unicode.
+ *
+ * A string of Default_Ignorable_Code_Point has length 0.
+ */
+ssize_t utf8len(const struct utf8data *data, const char *s)
+{
+ utf8leaf_t *leaf;
+ size_t ret = 0;
+
+ if (!data)
+ return -1;
+ while (*s) {
+ leaf = utf8lookup(data, s);
+ if (!leaf)
+ return -1;
+ if (utf8agetab[LEAF_GEN(leaf)] > data->maxage)
+ ret += utf8clen(s);
+ else if (LEAF_CCC(leaf) == DECOMPOSE)
+ ret += strlen(LEAF_STR(leaf));
+ else
+ ret += utf8clen(s);
+ s += utf8clen(s);
+ }
+ return ret;
+}
+EXPORT_SYMBOL(utf8len);
+
+/*
+ * Length of the normalization of s, touch at most len bytes.
+ * Return -1 if s is not valid UTF-8 unicode.
+ */
+ssize_t utf8nlen(const struct utf8data *data, const char *s, size_t len)
+{
+ utf8leaf_t *leaf;
+ size_t ret = 0;
+
+ if (!data)
+ return -1;
+ while (len && *s) {
+ leaf = utf8nlookup(data, s, len);
+ if (!leaf)
+ return -1;
+ if (utf8agetab[LEAF_GEN(leaf)] > data->maxage)
+ ret += utf8clen(s);
+ else if (LEAF_CCC(leaf) == DECOMPOSE)
+ ret += strlen(LEAF_STR(leaf));
+ else
+ ret += utf8clen(s);
+ len -= utf8clen(s);
+ s += utf8clen(s);
+ }
+ return ret;
+}
+EXPORT_SYMBOL(utf8nlen);
+
+/*
+ * Set up an utf8cursor for use by utf8byte().
+ *
+ * u8c : pointer to cursor.
+ * data : const struct utf8data to use for normalization.
+ * s : string.
+ * len : length of s.
+ *
+ * Returns -1 on error, 0 on success.
+ */
+int utf8ncursor(struct utf8cursor *u8c, const struct utf8data *data,
+ const char *s, size_t len)
+{
+ if (!data)
+ return -1;
+ if (!s)
+ return -1;
+ u8c->data = data;
+ u8c->s = s;
+ u8c->p = NULL;
+ u8c->ss = NULL;
+ u8c->sp = NULL;
+ u8c->len = len;
+ u8c->slen = 0;
+ u8c->ccc = STOPPER;
+ u8c->nccc = STOPPER;
+ /* Check we didn't clobber the maximum length. */
+ if (u8c->len != len)
+ return -1;
+ /* The first byte of s may not be an utf8 continuation. */
+ if (len > 0 && (*s & 0xC0) == 0x80)
+ return -1;
+ return 0;
+}
+EXPORT_SYMBOL(utf8ncursor);
+
+/*
+ * Set up an utf8cursor for use by utf8byte().
+ *
+ * u8c : pointer to cursor.
+ * data : const struct utf8data to use for normalization.
+ * s : NUL-terminated string.
+ *
+ * Returns -1 on error, 0 on success.
+ */
+int utf8cursor(struct utf8cursor *u8c, const struct utf8data *data,
+ const char *s)
+{
+ return utf8ncursor(u8c, data, s, (unsigned int)-1);
+}
+EXPORT_SYMBOL(utf8cursor);
+
+/*
+ * Get one byte from the normalized form of the string described by u8c.
+ *
+ * Returns the byte cast to an unsigned char on succes, and -1 on failure.
+ *
+ * The cursor keeps track of the location in the string in u8c->s.
+ * When a character is decomposed, the current location is stored in
+ * u8c->p, and u8c->s is set to the start of the decomposition. Note
+ * that bytes from a decomposition do not count against u8c->len.
+ *
+ * Characters are emitted if they match the current CCC in u8c->ccc.
+ * Hitting end-of-string while u8c->ccc == STOPPER means we're done,
+ * and the function returns 0 in that case.
+ *
+ * Sorting by CCC is done by repeatedly scanning the string. The
+ * values of u8c->s and u8c->p are stored in u8c->ss and u8c->sp at
+ * the start of the scan. The first pass finds the lowest CCC to be
+ * emitted and stores it in u8c->nccc, the second pass emits the
+ * characters with this CCC and finds the next lowest CCC. This limits
+ * the number of passes to 1 + the number of different CCCs in the
+ * sequence being scanned.
+ *
+ * Therefore:
+ * u8c->p != NULL -> a decomposition is being scanned.
+ * u8c->ss != NULL -> this is a repeating scan.
+ * u8c->ccc == -1 -> this is the first scan of a repeating scan.
+ */
+int utf8byte(struct utf8cursor *u8c)
+{
+ utf8leaf_t *leaf;
+ int ccc;
+
+ for (;;) {
+ /* Check for the end of a decomposed character. */
+ if (u8c->p && *u8c->s == '\0') {
+ u8c->s = u8c->p;
+ u8c->p = NULL;
+ }
+
+ /* Check for end-of-string. */
+ if (!u8c->p && (u8c->len == 0 || *u8c->s == '\0')) {
+ /* There is no next byte. */
+ if (u8c->ccc == STOPPER)
+ return 0;
+ /* End-of-string during a scan counts as a stopper. */
+ ccc = STOPPER;
+ goto ccc_mismatch;
+ } else if ((*u8c->s & 0xC0) == 0x80) {
+ /* This is a continuation of the current character. */
+ if (!u8c->p)
+ u8c->len--;
+ return (unsigned char)*u8c->s++;
+ }
+
+ /* Look up the data for the current character. */
+ if (u8c->p)
+ leaf = utf8lookup(u8c->data, u8c->s);
+ else
+ leaf = utf8nlookup(u8c->data, u8c->s, u8c->len);
+
+ /* No leaf found implies that the input is a binary blob. */
+ if (!leaf)
+ return -1;
+
+ ccc = LEAF_CCC(leaf);
+ /* Characters that are too new have CCC 0. */
+ if (utf8agetab[LEAF_GEN(leaf)] > u8c->data->maxage) {
+ ccc = STOPPER;
+ } else if (ccc == DECOMPOSE) {
+ u8c->len -= utf8clen(u8c->s);
+ u8c->p = u8c->s + utf8clen(u8c->s);
+ u8c->s = LEAF_STR(leaf);
+ /* Empty decomposition implies CCC 0. */
+ if (*u8c->s == '\0') {
+ if (u8c->ccc == STOPPER)
+ continue;
+ ccc = STOPPER;
+ goto ccc_mismatch;
+ }
+ leaf = utf8lookup(u8c->data, u8c->s);
+ }
+
+ /*
+ * If this is not a stopper, then see if it updates
+ * the next canonical class to be emitted.
+ */
+ if (ccc != STOPPER && u8c->ccc < ccc && ccc < u8c->nccc)
+ u8c->nccc = ccc;
+
+ /*
+ * Return the current byte if this is the current
+ * combining class.
+ */
+ if (ccc == u8c->ccc) {
+ if (!u8c->p)
+ u8c->len--;
+ return (unsigned char)*u8c->s++;
+ }
+
+ /* Current combining class mismatch. */
+ccc_mismatch:
+ if (u8c->nccc == STOPPER) {
+ /*
+ * Scan forward for the first canonical class
+ * to be emitted. Save the position from
+ * which to restart.
+ */
+ u8c->ccc = MINCCC - 1;
+ u8c->nccc = ccc;
+ u8c->sp = u8c->p;
+ u8c->ss = u8c->s;
+ u8c->slen = u8c->len;
+ if (!u8c->p)
+ u8c->len -= utf8clen(u8c->s);
+ u8c->s += utf8clen(u8c->s);
+ } else if (ccc != STOPPER) {
+ /* Not a stopper, and not the ccc we're emitting. */
+ if (!u8c->p)
+ u8c->len -= utf8clen(u8c->s);
+ u8c->s += utf8clen(u8c->s);
+ } else if (u8c->nccc != MAXCCC + 1) {
+ /* At a stopper, restart for next ccc. */
+ u8c->ccc = u8c->nccc;
+ u8c->nccc = MAXCCC + 1;
+ u8c->s = u8c->ss;
+ u8c->p = u8c->sp;
+ u8c->len = u8c->slen;
+ } else {
+ /* All done, proceed from here. */
+ u8c->ccc = STOPPER;
+ u8c->nccc = STOPPER;
+ u8c->sp = NULL;
+ u8c->ss = NULL;
+ u8c->slen = 0;
+ }
+ }
+}
+EXPORT_SYMBOL(utf8byte);
+
+const struct utf8data *utf8nfkdi(unsigned int maxage)
+{
+ int i = ARRAY_SIZE(utf8nfkdidata) - 1;
+
+ while (maxage < utf8nfkdidata[i].maxage)
+ i--;
+ if (maxage > utf8nfkdidata[i].maxage)
+ return NULL;
+ return &utf8nfkdidata[i];
+}
+EXPORT_SYMBOL(utf8nfkdi);
+
+const struct utf8data *utf8nfkdicf(unsigned int maxage)
+{
+ int i = ARRAY_SIZE(utf8nfkdicfdata) - 1;
+
+ while (maxage < utf8nfkdicfdata[i].maxage)
+ i--;
+ if (maxage > utf8nfkdicfdata[i].maxage)
+ return NULL;
+ return &utf8nfkdicfdata[i];
+}
+EXPORT_SYMBOL(utf8nfkdicf);
diff --git a/fs/nls/utf8n.h b/fs/nls/utf8n.h
new file mode 100644
index 000000000000..0f5fc14d4fd2
--- /dev/null
+++ b/fs/nls/utf8n.h
@@ -0,0 +1,112 @@
+/*
+ * Copyright (c) 2014 SGI.
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef UTF8NORM_H
+#define UTF8NORM_H
+
+#include <linux/types.h>
+#include <linux/export.h>
+#include <linux/string.h>
+#include <linux/module.h>
+
+/* Encoding a unicode version number as a single unsigned int. */
+#define UNICODE_MAJ_SHIFT (16)
+#define UNICODE_MIN_SHIFT (8)
+
+#define UNICODE_AGE(MAJ, MIN, REV) \
+ (((unsigned int)(MAJ) << UNICODE_MAJ_SHIFT) | \
+ ((unsigned int)(MIN) << UNICODE_MIN_SHIFT) | \
+ ((unsigned int)(REV)))
+
+/* Highest unicode version supported by the data tables. */
+extern int utf8version_is_supported(u8 maj, u8 min, u8 rev);
+
+/*
+ * Look for the correct const struct utf8data for a unicode version.
+ * Returns NULL if the version requested is too new.
+ *
+ * Two normalization forms are supported: nfkdi and nfkdicf.
+ *
+ * nfkdi:
+ * - Apply unicode normalization form NFKD.
+ * - Remove any Default_Ignorable_Code_Point.
+ *
+ * nfkdicf:
+ * - Apply unicode normalization form NFKD.
+ * - Remove any Default_Ignorable_Code_Point.
+ * - Apply a full casefold (C + F).
+ */
+extern const struct utf8data *utf8nfkdi(unsigned int maxage);
+extern const struct utf8data *utf8nfkdicf(unsigned int maxage);
+
+/*
+ * Determine the maximum age of any unicode character in the string.
+ * Returns 0 if only unassigned code points are present.
+ * Returns -1 if the input is not valid UTF-8.
+ */
+extern int utf8agemax(const struct utf8data *data, const char *s);
+extern int utf8nagemax(const struct utf8data *data, const char *s, size_t len);
+
+/*
+ * Determine the minimum age of any unicode character in the string.
+ * Returns 0 if any unassigned code points are present.
+ * Returns -1 if the input is not valid UTF-8.
+ */
+extern int utf8agemin(const struct utf8data *data, const char *s);
+extern int utf8nagemin(const struct utf8data *data, const char *s, size_t len);
+
+/*
+ * Determine the length of the normalized from of the string,
+ * excluding any terminating NULL byte.
+ * Returns 0 if only ignorable code points are present.
+ * Returns -1 if the input is not valid UTF-8.
+ */
+extern ssize_t utf8len(const struct utf8data *data, const char *s);
+extern ssize_t utf8nlen(const struct utf8data *data, const char *s, size_t len);
+
+/*
+ * Cursor structure used by the normalizer.
+ */
+struct utf8cursor {
+ const struct utf8data *data;
+ const char *s;
+ const char *p;
+ const char *ss;
+ const char *sp;
+ unsigned int len;
+ unsigned int slen;
+ short int ccc;
+ short int nccc;
+};
+
+/*
+ * Initialize a utf8cursor to normalize a string.
+ * Returns 0 on success.
+ * Returns -1 on failure.
+ */
+extern int utf8cursor(struct utf8cursor *u8c, const struct utf8data *data,
+ const char *s);
+extern int utf8ncursor(struct utf8cursor *u8c, const struct utf8data *data,
+ const char *s, size_t len);
+
+/*
+ * Get the next byte in the normalization.
+ * Returns a value > 0 && < 256 on success.
+ * Returns 0 when the end of the normalization is reached.
+ * Returns -1 if the string being normalized is not valid UTF-8.
+ */
+extern int utf8byte(struct utf8cursor *u8c);
+
+#endif /* UTF8NORM_H */
--
2.17.0
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