From: Olaf Weber <o...@sgi.com>

Remove the Hangul decompositions from the utf8data trie, and do
algorithmic decomposition to calculate them on the fly. To store
the decomposition the caller of utf8lookup()/utf8nlookup() must
provide a 12-byte buffer, which is used to synthesize a leaf with
the decomposition. Trie size is reduced from 245kB to 90kB.

Signed-off-by: Olaf Weber <o...@sgi.com>
Signed-off-by: Gabriel Krisman Bertazi <kris...@collabora.co.uk>
  [Rebase to mainline]
  [Fix checkpatch errors]
  [Extract robustness fixes and merge back to original mkutf8data.c
  patch]
---
 fs/nls/nls_utf8n-norm.c | 191 +++++++++++++++++++++++---
 fs/nls/utf8n.h          |   4 +
 scripts/mkutf8data.c    | 295 +++++++++++++++++++++++++++++++++++-----
 3 files changed, 435 insertions(+), 55 deletions(-)

diff --git a/fs/nls/nls_utf8n-norm.c b/fs/nls/nls_utf8n-norm.c
index ca0bbf644b49..64c3cc74a2ca 100644
--- a/fs/nls/nls_utf8n-norm.c
+++ b/fs/nls/nls_utf8n-norm.c
@@ -98,6 +98,38 @@ static inline int utf8clen(const char *s)
        return 1 + (c >= 0xC0) + (c >= 0xE0) + (c >= 0xF0);
 }
 
+/*
+ * Decode a 3-byte UTF-8 sequence.
+ */
+static unsigned int
+utf8decode3(const char *str)
+{
+       unsigned int            uc;
+
+       uc = *str++ & 0x0F;
+       uc <<= 6;
+       uc |= *str++ & 0x3F;
+       uc <<= 6;
+       uc |= *str++ & 0x3F;
+
+       return uc;
+}
+
+/*
+ * Encode a 3-byte UTF-8 sequence.
+ */
+static int
+utf8encode3(char *str, unsigned int val)
+{
+       str[2] = (val & 0x3F) | 0x80;
+       val >>= 6;
+       str[1] = (val & 0x3F) | 0x80;
+       val >>= 6;
+       str[0] = val | 0xE0;
+
+       return 3;
+}
+
 /*
  * utf8trie_t
  *
@@ -159,7 +191,8 @@ typedef const unsigned char utf8trie_t;
  *          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.
+ * The decompositions in the trie have been fully expanded, with the
+ * exception of Hangul syllables, which are decomposed algorithmically.
  *
  * Casefolding, if applicable, is also done using decompositions.
  *
@@ -179,6 +212,105 @@ typedef const unsigned char utf8leaf_t;
 #define STOPPER                (0)
 #define        DECOMPOSE       (255)
 
+/* Marker for hangul syllable decomposition. */
+#define HANGUL         ((char)(255))
+/* Size of the synthesized leaf used for Hangul syllable decomposition. */
+#define UTF8HANGULLEAF (12)
+
+/*
+ * Hangul decomposition (algorithm from Section 3.12 of Unicode 6.3.0)
+ *
+ * AC00;<Hangul Syllable, First>;Lo;0;L;;;;;N;;;;;
+ * D7A3;<Hangul Syllable, Last>;Lo;0;L;;;;;N;;;;;
+ *
+ * SBase = 0xAC00
+ * LBase = 0x1100
+ * VBase = 0x1161
+ * TBase = 0x11A7
+ * LCount = 19
+ * VCount = 21
+ * TCount = 28
+ * NCount = 588 (VCount * TCount)
+ * SCount = 11172 (LCount * NCount)
+ *
+ * Decomposition:
+ *   SIndex = s - SBase
+ *
+ * LV (Canonical/Full)
+ *   LIndex = SIndex / NCount
+ *   VIndex = (Sindex % NCount) / TCount
+ *   LPart = LBase + LIndex
+ *   VPart = VBase + VIndex
+ *
+ * LVT (Canonical)
+ *   LVIndex = (SIndex / TCount) * TCount
+ *   TIndex = (Sindex % TCount)
+ *   LVPart = SBase + LVIndex
+ *   TPart = TBase + TIndex
+ *
+ * LVT (Full)
+ *   LIndex = SIndex / NCount
+ *   VIndex = (Sindex % NCount) / TCount
+ *   TIndex = (Sindex % TCount)
+ *   LPart = LBase + LIndex
+ *   VPart = VBase + VIndex
+ *   if (TIndex == 0) {
+ *          d = <LPart, VPart>
+ *   } else {
+ *          TPart = TBase + TIndex
+ *          d = <LPart, TPart, VPart>
+ *   }
+ */
+
+/* Constants */
+#define SB     (0xAC00)
+#define LB     (0x1100)
+#define VB     (0x1161)
+#define TB     (0x11A7)
+#define LC     (19)
+#define VC     (21)
+#define TC     (28)
+#define NC     (VC * TC)
+#define SC     (LC * NC)
+
+/* Algorithmic decomposition of hangul syllable. */
+static utf8leaf_t *
+utf8hangul(const char *str, unsigned char *hangul)
+{
+       unsigned int    si;
+       unsigned int    li;
+       unsigned int    vi;
+       unsigned int    ti;
+       unsigned char   *h;
+
+       /* Calculate the SI, LI, VI, and TI values. */
+       si = utf8decode3(str) - SB;
+       li = si / NC;
+       vi = (si % NC) / TC;
+       ti = si % TC;
+
+       /* Fill in base of leaf. */
+       h = hangul;
+       LEAF_GEN(h) = 2;
+       LEAF_CCC(h) = DECOMPOSE;
+       h += 2;
+
+       /* Add LPart, a 3-byte UTF-8 sequence. */
+       h += utf8encode3((char *)h, li + LB);
+
+       /* Add VPart, a 3-byte UTF-8 sequence. */
+       h += utf8encode3((char *)h, vi + VB);
+
+       /* Add TPart if required, also a 3-byte UTF-8 sequence. */
+       if (ti)
+               h += utf8encode3((char *)h, ti + TB);
+
+       /* Terminate string. */
+       h[0] = '\0';
+
+       return hangul;
+}
+
 /*
  * Use trie to scan s, touching at most len bytes.
  * Returns the leaf if one exists, NULL otherwise.
@@ -187,8 +319,8 @@ typedef const unsigned char utf8leaf_t;
  * 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)
+static utf8leaf_t *utf8nlookup(const struct utf8data *data,
+                              unsigned char *hangul, const char *s, size_t len)
 {
        utf8trie_t      *trie = utf8data + data->offset;
        int             offlen;
@@ -226,8 +358,7 @@ static utf8leaf_t *utf8nlookup(const struct utf8data *data, 
const char *s,
                                trie++;
                        } else {
                                /* No right node. */
-                               node = 0;
-                               trie = NULL;
+                               return NULL;
                        }
                } else {
                        /* Left leg */
@@ -237,8 +368,7 @@ static utf8leaf_t *utf8nlookup(const struct utf8data *data, 
const char *s,
                                trie += offlen + 1;
                        } else if (*trie & RIGHTPATH) {
                                /* No left node. */
-                               node = 0;
-                               trie = NULL;
+                               return NULL;
                        } else {
                                /* Left node after this node */
                                node = (*trie & TRIENODE);
@@ -246,6 +376,14 @@ static utf8leaf_t *utf8nlookup(const struct utf8data 
*data, const char *s,
                        }
                }
        }
+       /*
+        * Hangul decomposition is done algorithmically. These are the
+        * codepoints >= 0xAC00 and <= 0xD7A3. Their UTF-8 encoding is
+        * always 3 bytes long, so s has been advanced twice, and the
+        * start of the sequence is at s-2.
+        */
+       if (LEAF_CCC(trie) == DECOMPOSE && LEAF_STR(trie)[0] == HANGUL)
+               trie = utf8hangul(s - 2, hangul);
        return trie;
 }
 
@@ -255,9 +393,10 @@ static utf8leaf_t *utf8nlookup(const struct utf8data 
*data, const char *s,
  *
  * Forwards to utf8nlookup().
  */
-static utf8leaf_t *utf8lookup(const struct utf8data *data, const char *s)
+static utf8leaf_t *utf8lookup(const struct utf8data *data,
+                             unsigned char *hangul, const char *s)
 {
-       return utf8nlookup(data, s, (size_t)-1);
+       return utf8nlookup(data, hangul, s, (size_t)-1);
 }
 
 /*
@@ -270,11 +409,13 @@ int utf8agemax(const struct utf8data *data, const char *s)
        utf8leaf_t      *leaf;
        int             age = 0;
        int             leaf_age;
+       unsigned char   hangul[UTF8HANGULLEAF];
 
        if (!data)
                return -1;
+
        while (*s) {
-               leaf = utf8lookup(data, s);
+               leaf = utf8lookup(data, hangul, s);
                if (!leaf)
                        return -1;
 
@@ -297,12 +438,13 @@ int utf8agemin(const struct utf8data *data, const char *s)
        utf8leaf_t      *leaf;
        int             age;
        int             leaf_age;
+       unsigned char   hangul[UTF8HANGULLEAF];
 
        if (!data)
                return -1;
        age = data->maxage;
        while (*s) {
-               leaf = utf8lookup(data, s);
+               leaf = utf8lookup(data, hangul, s);
                if (!leaf)
                        return -1;
                leaf_age = utf8agetab[LEAF_GEN(leaf)];
@@ -323,11 +465,13 @@ int utf8nagemax(const struct utf8data *data, const char 
*s, size_t len)
        utf8leaf_t      *leaf;
        int             age = 0;
        int             leaf_age;
+       unsigned char   hangul[UTF8HANGULLEAF];
 
        if (!data)
                return -1;
+
        while (len && *s) {
-               leaf = utf8nlookup(data, s, len);
+               leaf = utf8nlookup(data, hangul, s, len);
                if (!leaf)
                        return -1;
                leaf_age = utf8agetab[LEAF_GEN(leaf)];
@@ -349,12 +493,13 @@ int utf8nagemin(const struct utf8data *data, const char 
*s, size_t len)
        utf8leaf_t      *leaf;
        int             leaf_age;
        int             age;
+       unsigned char   hangul[UTF8HANGULLEAF];
 
        if (!data)
                return -1;
        age = data->maxage;
        while (len && *s) {
-               leaf = utf8nlookup(data, s, len);
+               leaf = utf8nlookup(data, hangul, s, len);
                if (!leaf)
                        return -1;
                leaf_age = utf8agetab[LEAF_GEN(leaf)];
@@ -377,11 +522,12 @@ ssize_t utf8len(const struct utf8data *data, const char 
*s)
 {
        utf8leaf_t      *leaf;
        size_t          ret = 0;
+       unsigned char   hangul[UTF8HANGULLEAF];
 
        if (!data)
                return -1;
        while (*s) {
-               leaf = utf8lookup(data, s);
+               leaf = utf8lookup(data, hangul, s);
                if (!leaf)
                        return -1;
                if (utf8agetab[LEAF_GEN(leaf)] > data->maxage)
@@ -404,11 +550,12 @@ ssize_t utf8nlen(const struct utf8data *data, const char 
*s, size_t len)
 {
        utf8leaf_t      *leaf;
        size_t          ret = 0;
+       unsigned char   hangul[UTF8HANGULLEAF];
 
        if (!data)
                return -1;
        while (len && *s) {
-               leaf = utf8nlookup(data, s, len);
+               leaf = utf8nlookup(data, hangul, s, len);
                if (!leaf)
                        return -1;
                if (utf8agetab[LEAF_GEN(leaf)] > data->maxage)
@@ -531,10 +678,12 @@ int utf8byte(struct utf8cursor *u8c)
                }
 
                /* 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);
+               if (u8c->p) {
+                       leaf = utf8lookup(u8c->data, u8c->hangul, u8c->s);
+               } else {
+                       leaf = utf8nlookup(u8c->data, u8c->hangul,
+                                          u8c->s, u8c->len);
+               }
 
                /* No leaf found implies that the input is a binary blob. */
                if (!leaf)
@@ -555,7 +704,9 @@ int utf8byte(struct utf8cursor *u8c)
                                ccc = STOPPER;
                                goto ccc_mismatch;
                        }
-                       leaf = utf8lookup(u8c->data, u8c->s);
+
+                       leaf = utf8lookup(u8c->data, u8c->hangul, u8c->s);
+                       ccc = LEAF_CCC(leaf);
                }
 
                /*
diff --git a/fs/nls/utf8n.h b/fs/nls/utf8n.h
index 0f5fc14d4fd2..f60827663503 100644
--- a/fs/nls/utf8n.h
+++ b/fs/nls/utf8n.h
@@ -76,6 +76,9 @@ extern int utf8nagemin(const struct utf8data *data, const 
char *s, size_t len);
 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);
 
+/* Needed in struct utf8cursor below. */
+#define UTF8HANGULLEAF (12)
+
 /*
  * Cursor structure used by the normalizer.
  */
@@ -89,6 +92,7 @@ struct utf8cursor {
        unsigned int    slen;
        short int       ccc;
        short int       nccc;
+       unsigned char   hangul[UTF8HANGULLEAF];
 };
 
 /*
diff --git a/scripts/mkutf8data.c b/scripts/mkutf8data.c
index 700b41c0cb66..69f3be92ba71 100644
--- a/scripts/mkutf8data.c
+++ b/scripts/mkutf8data.c
@@ -180,10 +180,14 @@ typedef unsigned char utf8leaf_t;
 #define MAXCCC         (254)
 #define STOPPER                (0)
 #define DECOMPOSE      (255)
+#define HANGUL         ((char)(255))
+
+#define UTF8HANGULLEAF (12)
 
 struct tree;
-static utf8leaf_t *utf8nlookup(struct tree *, const char *, size_t);
-static utf8leaf_t *utf8lookup(struct tree *, const char *);
+static utf8leaf_t *utf8nlookup(struct tree *, unsigned char *,
+                              const char *, size_t);
+static utf8leaf_t *utf8lookup(struct tree *, unsigned char *, const char *);
 
 unsigned char *utf8data;
 size_t utf8data_size;
@@ -334,6 +338,8 @@ utf32valid(unsigned int unichar)
        return unichar < 0x110000;
 }
 
+#define HANGUL_SYLLABLE(U)     ((U) >= 0xAC00 && (U) <= 0xD7A3)
+
 #define NODE 1
 #define LEAF 0
 
@@ -466,7 +472,7 @@ tree_walk(struct tree *tree)
                                                                 indent+1);
                                                leaves += 1;
                                        } else if (node->right) {
-                                               assert(node->rightnode==NODE);
+                                               assert(node->rightnode == NODE);
                                                indent += 1;
                                                node = node->right;
                                                break;
@@ -864,7 +870,7 @@ mark_nodes(struct tree *tree)
                                        }
                                }
                        } else if (node->right) {
-                               assert(node->rightnode==NODE);
+                               assert(node->rightnode == NODE);
                                node = node->right;
                                continue;
                        }
@@ -916,7 +922,7 @@ mark_nodes(struct tree *tree)
                                        }
                                }
                        } else if (node->right) {
-                               assert(node->rightnode==NODE);
+                               assert(node->rightnode == NODE);
                                node = node->right;
                                if (!node->mark && node->parent->mark &&
                                    !node->parent->left) {
@@ -1000,7 +1006,7 @@ index_nodes(struct tree *tree, int index)
                                        index += tree->leaf_size(node->right);
                                        count++;
                                } else if (node->right) {
-                                       assert(node->rightnode==NODE);
+                                       assert(node->rightnode == NODE);
                                        indent += 1;
                                        node = node->right;
                                        break;
@@ -1021,6 +1027,26 @@ index_nodes(struct tree *tree, int index)
        return index;
 }
 
+/*
+ * Mark the nodes in a subtree, helper for size_nodes().
+ */
+static int
+mark_subtree(struct node *node)
+{
+       int changed;
+
+       if (!node || node->mark)
+               return 0;
+       node->mark = 1;
+       node->index = node->parent->index;
+       changed = 1;
+       if (node->leftnode == NODE)
+               changed += mark_subtree(node->left);
+       if (node->rightnode == NODE)
+               changed += mark_subtree(node->right);
+       return changed;
+}
+
 /*
  * Compute the size of nodes and leaves. We start by assuming that
  * each node needs to store a three-byte offset. The indexes of the
@@ -1040,6 +1066,7 @@ size_nodes(struct tree *tree)
        unsigned int bitmask;
        unsigned int pathbits;
        unsigned int pathmask;
+       unsigned int nbit;
        int changed;
        int offset;
        int size;
@@ -1067,22 +1094,40 @@ size_nodes(struct tree *tree)
                        size = 1;
                } else {
                        if (node->rightnode == NODE) {
+                               /*
+                                * If the right node is not marked,
+                                * look for a corresponding node in
+                                * the next tree.  Such a node need
+                                * not exist.
+                                */
                                right = node->right;
                                next = tree->next;
                                while (!right->mark) {
                                        assert(next);
                                        n = next->root;
                                        while (n->bitnum != node->bitnum) {
-                                               if (pathbits & (1<<n->bitnum))
+                                               nbit = 1 << n->bitnum;
+                                               if (!(pathmask & nbit))
+                                                       break;
+                                               if (pathbits & nbit) {
+                                                       if (n->rightnode == 
LEAF)
+                                                               break;
                                                        n = n->right;
-                                               else
+                                               } else {
+                                                       if (n->leftnode == LEAF)
+                                                               break;
                                                        n = n->left;
+                                               }
                                        }
+                                       if (n->bitnum != node->bitnum)
+                                               break;
                                        n = n->right;
-                                       assert(right->bitnum == n->bitnum);
                                        right = n;
                                        next = next->next;
                                }
+                               /* Make sure the right node is marked. */
+                               if (!right->mark)
+                                       changed += mark_subtree(right);
                                offset = right->index - node->index;
                        } else {
                                offset = *tree->leaf_index(tree, node->right);
@@ -1124,7 +1169,7 @@ size_nodes(struct tree *tree)
                                if (node->rightnode == LEAF) {
                                        assert(node->right);
                                } else if (node->right) {
-                                       assert(node->rightnode==NODE);
+                                       assert(node->rightnode == NODE);
                                        indent += 1;
                                        node = node->right;
                                        break;
@@ -1158,8 +1203,15 @@ emit(struct tree *tree, unsigned char *data)
        int offset;
        int index;
        int indent;
+       int size;
+       int bytes;
+       int leaves;
+       int nodes[4];
        unsigned char byte;
 
+       nodes[0] = nodes[1] = nodes[2] = nodes[3] = 0;
+       leaves = 0;
+       bytes = 0;
        index = tree->index;
        data += index;
        indent = 1;
@@ -1168,7 +1220,10 @@ emit(struct tree *tree, unsigned char *data)
        if (tree->childnode == LEAF) {
                assert(tree->root);
                tree->leaf_emit(tree->root, data);
-               return;
+               size = tree->leaf_size(tree->root);
+               index += size;
+               leaves++;
+               goto done;
        }
 
        assert(tree->childnode == NODE);
@@ -1195,6 +1250,7 @@ emit(struct tree *tree, unsigned char *data)
                                offlen = 2;
                        else
                                offlen = 3;
+                       nodes[offlen]++;
                        offset = node->offset;
                        byte |= offlen << OFFLEN_SHIFT;
                        *data++ = byte;
@@ -1207,12 +1263,14 @@ emit(struct tree *tree, unsigned char *data)
                } else if (node->left) {
                        if (node->leftnode == NODE)
                                byte |= TRIENODE;
+                       nodes[0]++;
                        *data++ = byte;
                        index++;
                } else if (node->right) {
                        byte |= RIGHTNODE;
                        if (node->rightnode == NODE)
                                byte |= TRIENODE;
+                       nodes[0]++;
                        *data++ = byte;
                        index++;
                } else {
@@ -1227,7 +1285,10 @@ emit(struct tree *tree, unsigned char *data)
                                        assert(node->left);
                                        data = tree->leaf_emit(node->left,
                                                               data);
-                                       index += tree->leaf_size(node->left);
+                                       size = tree->leaf_size(node->left);
+                                       index += size;
+                                       bytes += size;
+                                       leaves++;
                                } else if (node->left) {
                                        assert(node->leftnode == NODE);
                                        indent += 1;
@@ -1241,9 +1302,12 @@ emit(struct tree *tree, unsigned char *data)
                                        assert(node->right);
                                        data = tree->leaf_emit(node->right,
                                                               data);
-                                       index += tree->leaf_size(node->right);
+                                       size = tree->leaf_size(node->right);
+                                       index += size;
+                                       bytes += size;
+                                       leaves++;
                                } else if (node->right) {
-                                       assert(node->rightnode==NODE);
+                                       assert(node->rightnode == NODE);
                                        indent += 1;
                                        node = node->right;
                                        break;
@@ -1255,6 +1319,15 @@ emit(struct tree *tree, unsigned char *data)
                        indent -= 1;
                }
        }
+done:
+       if (verbose > 0) {
+               printf("Emitted %d (%d) leaves",
+                       leaves, bytes);
+               printf(" %d (%d+%d+%d+%d) nodes",
+                       nodes[0] + nodes[1] + nodes[2] + nodes[3],
+                       nodes[0], nodes[1], nodes[2], nodes[3]);
+               printf(" %d total\n", index - tree->index);
+       }
 }
 
 /* ------------------------------------------------------------------ */
@@ -1360,7 +1433,9 @@ nfkdi_print(void *l, int indent)
 
        printf("%*sleaf @ %p code %X ccc %d gen %d", indent, "", leaf,
                leaf->code, leaf->ccc, leaf->gen);
-       if (leaf->utf8nfkdi)
+       if (leaf->utf8nfkdi && leaf->utf8nfkdi[0] == HANGUL)
+               printf(" nfkdi \"%s\"", "HANGUL SYLLABLE");
+       else if (leaf->utf8nfkdi)
                printf(" nfkdi \"%s\"", (const char*)leaf->utf8nfkdi);
        printf("\n");
 }
@@ -1374,6 +1449,8 @@ nfkdicf_print(void *l, int indent)
                leaf->code, leaf->ccc, leaf->gen);
        if (leaf->utf8nfkdicf)
                printf(" nfkdicf \"%s\"", (const char*)leaf->utf8nfkdicf);
+       else if (leaf->utf8nfkdi && leaf->utf8nfkdi[0] == HANGUL)
+               printf(" nfkdi \"%s\"", "HANGUL SYLLABLE");
        else if (leaf->utf8nfkdi)
                printf(" nfkdi \"%s\"", (const char*)leaf->utf8nfkdi);
        printf("\n");
@@ -1409,7 +1486,9 @@ nfkdi_size(void *l)
        struct unicode_data *leaf = l;
 
        int size = 2;
-       if (leaf->utf8nfkdi)
+       if (HANGUL_SYLLABLE(leaf->code))
+               size += 1;
+       else if (leaf->utf8nfkdi)
                size += strlen(leaf->utf8nfkdi) + 1;
        return size;
 }
@@ -1420,7 +1499,9 @@ nfkdicf_size(void *l)
        struct unicode_data *leaf = l;
 
        int size = 2;
-       if (leaf->utf8nfkdicf)
+       if (HANGUL_SYLLABLE(leaf->code))
+               size += 1;
+       else if (leaf->utf8nfkdicf)
                size += strlen(leaf->utf8nfkdicf) + 1;
        else if (leaf->utf8nfkdi)
                size += strlen(leaf->utf8nfkdi) + 1;
@@ -1450,7 +1531,10 @@ nfkdi_emit(void *l, unsigned char *data)
        unsigned char *s;
 
        *data++ = leaf->gen;
-       if (leaf->utf8nfkdi) {
+       if (HANGUL_SYLLABLE(leaf->code)) {
+               *data++ = DECOMPOSE;
+               *data++ = HANGUL;
+       } else if (leaf->utf8nfkdi) {
                *data++ = DECOMPOSE;
                s = (unsigned char*)leaf->utf8nfkdi;
                while ((*data++ = *s++) != 0)
@@ -1468,7 +1552,10 @@ nfkdicf_emit(void *l, unsigned char *data)
        unsigned char *s;
 
        *data++ = leaf->gen;
-       if (leaf->utf8nfkdicf) {
+       if (HANGUL_SYLLABLE(leaf->code)) {
+               *data++ = DECOMPOSE;
+               *data++ = HANGUL;
+       } else if (leaf->utf8nfkdicf) {
                *data++ = DECOMPOSE;
                s = (unsigned char*)leaf->utf8nfkdicf;
                while ((*data++ = *s++) != 0)
@@ -1492,6 +1579,11 @@ utf8_create(struct unicode_data *data)
        unsigned int *um;
        int i;
 
+       if (data->utf8nfkdi) {
+               assert(data->utf8nfkdi[0] == HANGUL);
+               return;
+       }
+
        u = utf;
        um = data->utf32nfkdi;
        if (um) {
@@ -1682,6 +1774,7 @@ verify(struct tree *tree)
        utf8leaf_t      *leaf;
        unsigned int    unichar;
        char            key[4];
+       unsigned char   hangul[UTF8HANGULLEAF];
        int             report;
        int             nocf;
 
@@ -1695,7 +1788,8 @@ verify(struct tree *tree)
                if (data->correction <= tree->maxage)
                        data = &unicode_data[unichar];
                utf8encode(key,unichar);
-               leaf = utf8lookup(tree, key);
+               leaf = utf8lookup(tree, hangul, key);
+
                if (!leaf) {
                        if (data->gen != -1)
                                report++;
@@ -1709,7 +1803,10 @@ verify(struct tree *tree)
                        if (data->gen != LEAF_GEN(leaf))
                                report++;
                        if (LEAF_CCC(leaf) == DECOMPOSE) {
-                               if (nocf) {
+                               if (HANGUL_SYLLABLE(data->code)) {
+                                       if (data->utf8nfkdi[0] != HANGUL)
+                                               report++;
+                               } else if (nocf) {
                                        if (!data->utf8nfkdi) {
                                                report++;
                                        } else if (strcmp(data->utf8nfkdi,
@@ -2394,6 +2491,15 @@ hangul_decompose(void)
                memcpy(um, mapping, i * sizeof(unsigned int));
                unicode_data[unichar].utf32nfkdicf = um;
 
+               /*
+                * Add a cookie as a reminder that the hangul syllable
+                * decompositions must not be stored in the generated
+                * trie.
+                */
+               unicode_data[unichar].utf8nfkdi = malloc(2);
+               unicode_data[unichar].utf8nfkdi[0] = HANGUL;
+               unicode_data[unichar].utf8nfkdi[1] = '\0';
+
                if (verbose > 1)
                        print_utf32nfkdi(unichar);
 
@@ -2521,6 +2627,100 @@ int utf8cursor(struct utf8cursor *, struct tree *, 
const char *);
 int utf8ncursor(struct utf8cursor *, struct tree *, const char *, size_t);
 int utf8byte(struct utf8cursor *);
 
+/*
+ * Hangul decomposition (algorithm from Section 3.12 of Unicode 6.3.0)
+ *
+ * AC00;<Hangul Syllable, First>;Lo;0;L;;;;;N;;;;;
+ * D7A3;<Hangul Syllable, Last>;Lo;0;L;;;;;N;;;;;
+ *
+ * SBase = 0xAC00
+ * LBase = 0x1100
+ * VBase = 0x1161
+ * TBase = 0x11A7
+ * LCount = 19
+ * VCount = 21
+ * TCount = 28
+ * NCount = 588 (VCount * TCount)
+ * SCount = 11172 (LCount * NCount)
+ *
+ * Decomposition:
+ *   SIndex = s - SBase
+ *
+ * LV (Canonical/Full)
+ *   LIndex = SIndex / NCount
+ *   VIndex = (Sindex % NCount) / TCount
+ *   LPart = LBase + LIndex
+ *   VPart = VBase + VIndex
+ *
+ * LVT (Canonical)
+ *   LVIndex = (SIndex / TCount) * TCount
+ *   TIndex = (Sindex % TCount)
+ *   LVPart = SBase + LVIndex
+ *   TPart = TBase + TIndex
+ *
+ * LVT (Full)
+ *   LIndex = SIndex / NCount
+ *   VIndex = (Sindex % NCount) / TCount
+ *   TIndex = (Sindex % TCount)
+ *   LPart = LBase + LIndex
+ *   VPart = VBase + VIndex
+ *   if (TIndex == 0) {
+ *          d = <LPart, VPart>
+ *   } else {
+ *          TPart = TBase + TIndex
+ *          d = <LPart, VPart, TPart>
+ *   }
+ */
+
+/* Constants */
+#define SB     (0xAC00)
+#define LB     (0x1100)
+#define VB     (0x1161)
+#define TB     (0x11A7)
+#define LC     (19)
+#define VC     (21)
+#define TC     (28)
+#define NC     (VC * TC)
+#define SC     (LC * NC)
+
+/* Algorithmic decomposition of hangul syllable. */
+static utf8leaf_t *
+utf8hangul(const char *str, unsigned char *hangul)
+{
+       unsigned int    si;
+       unsigned int    li;
+       unsigned int    vi;
+       unsigned int    ti;
+       unsigned char   *h;
+
+       /* Calculate the SI, LI, VI, and TI values. */
+       si = utf8decode(str) - SB;
+       li = si / NC;
+       vi = (si % NC) / TC;
+       ti = si % TC;
+
+       /* Fill in base of leaf. */
+       h = hangul;
+       LEAF_GEN(h) = 2;
+       LEAF_CCC(h) = DECOMPOSE;
+       h += 2;
+
+       /* Add LPart, a 3-byte UTF-8 sequence. */
+       h += utf8encode((char *)h, li + LB);
+
+       /* Add VPart, a 3-byte UTF-8 sequence. */
+       h += utf8encode((char *)h, vi + VB);
+
+       /* Add TPart if required, also a 3-byte UTF-8 sequence. */
+       if (ti)
+               h += utf8encode((char *)h, ti + TB);
+
+       /* Terminate string. */
+       h[0] = '\0';
+
+       return hangul;
+}
+
 /*
  * Use trie to scan s, touching at most len bytes.
  * Returns the leaf if one exists, NULL otherwise.
@@ -2530,7 +2730,7 @@ int utf8byte(struct utf8cursor *);
  * shorthand for this will be "is valid UTF-8 unicode".
  */
 static utf8leaf_t *
-utf8nlookup(struct tree *tree, const char *s, size_t len)
+utf8nlookup(struct tree *tree, unsigned char *hangul, const char *s, size_t 
len)
 {
        utf8trie_t      *trie = utf8data + tree->index;
        int             offlen;
@@ -2586,6 +2786,14 @@ utf8nlookup(struct tree *tree, const char *s, size_t len)
                        }
                }
        }
+       /*
+        * Hangul decomposition is done algorithmically. These are the
+        * codepoints >= 0xAC00 and <= 0xD7A3. Their UTF-8 encoding is
+        * always 3 bytes long, so s has been advanced twice, and the
+        * start of the sequence is at s-2.
+        */
+       if (LEAF_CCC(trie) == DECOMPOSE && LEAF_STR(trie)[0] == HANGUL)
+               trie = utf8hangul(s - 2, hangul);
        return trie;
 }
 
@@ -2596,9 +2804,9 @@ utf8nlookup(struct tree *tree, const char *s, size_t len)
  * Forwards to trie_nlookup().
  */
 static utf8leaf_t *
-utf8lookup(struct tree *tree, const char *s)
+utf8lookup(struct tree *tree, unsigned char *hangul, const char *s)
 {
-       return utf8nlookup(tree, s, (size_t)-1);
+       return utf8nlookup(tree, hangul, s, (size_t)-1);
 }
 
 /*
@@ -2624,11 +2832,14 @@ utf8agemax(struct tree *tree, const char *s)
        utf8leaf_t      *leaf;
        int             age = 0;
        int             leaf_age;
+       unsigned char   hangul[UTF8HANGULLEAF];
 
        if (!tree)
                return -1;
+
        while (*s) {
-               if (!(leaf = utf8lookup(tree, s)))
+               leaf = utf8lookup(tree, hangul, s);
+               if (!leaf)
                        return -1;
                leaf_age = ages[LEAF_GEN(leaf)];
                if (leaf_age <= tree->maxage && leaf_age > age)
@@ -2649,12 +2860,14 @@ utf8agemin(struct tree *tree, const char *s)
        utf8leaf_t      *leaf;
        int             age;
        int             leaf_age;
+       unsigned char   hangul[UTF8HANGULLEAF];
 
        if (!tree)
                return -1;
        age = tree->maxage;
        while (*s) {
-               if (!(leaf = utf8lookup(tree, s)))
+               leaf = utf8lookup(tree, hangul, s);
+               if (!leaf)
                        return -1;
                leaf_age = ages[LEAF_GEN(leaf)];
                if (leaf_age <= tree->maxage && leaf_age < age)
@@ -2674,11 +2887,14 @@ utf8nagemax(struct tree *tree, const char *s, size_t 
len)
        utf8leaf_t      *leaf;
        int             age = 0;
        int             leaf_age;
+       unsigned char   hangul[UTF8HANGULLEAF];
 
        if (!tree)
                return -1;
+
         while (len && *s) {
-               if (!(leaf = utf8nlookup(tree, s, len)))
+               leaf = utf8nlookup(tree, hangul, s, len);
+               if (!leaf)
                        return -1;
                leaf_age = ages[LEAF_GEN(leaf)];
                if (leaf_age <= tree->maxage && leaf_age > age)
@@ -2699,12 +2915,14 @@ utf8nagemin(struct tree *tree, const char *s, size_t 
len)
        utf8leaf_t      *leaf;
        int             leaf_age;
        int             age;
+       unsigned char   hangul[UTF8HANGULLEAF];
 
        if (!tree)
                return -1;
        age = tree->maxage;
         while (len && *s) {
-               if (!(leaf = utf8nlookup(tree, s, len)))
+               leaf = utf8nlookup(tree, hangul, s, len);
+               if (!leaf)
                        return -1;
                leaf_age = ages[LEAF_GEN(leaf)];
                if (leaf_age <= tree->maxage && leaf_age < age)
@@ -2726,11 +2944,13 @@ utf8len(struct tree *tree, const char *s)
 {
        utf8leaf_t      *leaf;
        size_t          ret = 0;
+       unsigned char   hangul[UTF8HANGULLEAF];
 
        if (!tree)
                return -1;
        while (*s) {
-               if (!(leaf = utf8lookup(tree, s)))
+               leaf = utf8lookup(tree, hangul, s);
+               if (!leaf)
                        return -1;
                if (ages[LEAF_GEN(leaf)] > tree->maxage)
                        ret += utf8clen(s);
@@ -2752,11 +2972,13 @@ utf8nlen(struct tree *tree, const char *s, size_t len)
 {
        utf8leaf_t      *leaf;
        size_t          ret = 0;
+       unsigned char   hangul[UTF8HANGULLEAF];
 
        if (!tree)
                return -1;
        while (len && *s) {
-               if (!(leaf = utf8nlookup(tree, s, len)))
+               leaf = utf8nlookup(tree, hangul, s, len);
+               if (!leaf)
                        return -1;
                if (ages[LEAF_GEN(leaf)] > tree->maxage)
                        ret += utf8clen(s);
@@ -2784,6 +3006,7 @@ struct utf8cursor {
        short int       ccc;
        short int       nccc;
        unsigned int    unichar;
+       unsigned char   hangul[UTF8HANGULLEAF];
 };
 
 /*
@@ -2900,10 +3123,12 @@ utf8byte(struct utf8cursor *u8c)
                }
 
                /* Look up the data for the current character. */
-               if (u8c->p)
-                       leaf = utf8lookup(u8c->tree, u8c->s);
-               else
-                       leaf = utf8nlookup(u8c->tree, u8c->s, u8c->len);
+               if (u8c->p) {
+                       leaf = utf8lookup(u8c->tree, u8c->hangul, u8c->s);
+               } else {
+                       leaf = utf8nlookup(u8c->tree, u8c->hangul,
+                                          u8c->s, u8c->len);
+               }
 
                /* No leaf found implies that the input is a binary blob. */
                if (!leaf)
@@ -2923,7 +3148,7 @@ utf8byte(struct utf8cursor *u8c)
                                ccc = STOPPER;
                                goto ccc_mismatch;
                        }
-                       leaf = utf8lookup(u8c->tree, u8c->s);
+                       leaf = utf8lookup(u8c->tree, u8c->hangul, u8c->s);
                        ccc = LEAF_CCC(leaf);
                }
                u8c->unichar = utf8decode(u8c->s);
-- 
2.17.0

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