/*
* Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
*
* This is part of HarfBuzz, an OpenType Layout engine library.
*
* Permission is hereby granted, without written agreement and without
* license or royalty fees, to use, copy, modify, and distribute this
* software and its documentation for any purpose, provided that the
* above copyright notice and the following two paragraphs appear in
* all copies of this software.
*
* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*
* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
*/
#include "harfbuzz-shaper.h"
#include "harfbuzz-shaper-private.h"
#include <assert.h>
/*
// Hangul is a syllable based script. Unicode reserves a large range
// for precomposed hangul, where syllables are already precomposed to
// their final glyph shape. In addition, a so called jamo range is
// defined, that can be used to express old Hangul. Modern hangul
// syllables can also be expressed as jamo, and should be composed
// into syllables. The operation is rather simple and mathematical.
// Every hangul jamo is classified as being either a Leading consonant
// (L), and intermediat Vowel (V) or a trailing consonant (T). Modern
// hangul syllables (the ones in the precomposed area can be of type
// LV or LVT.
//
// Syllable breaks do _not_ occur between:
//
// L L, V or precomposed
// V, LV V, T
// LVT, T T
//
// A standard syllable is of the form L+V+T*. The above rules allow
// nonstandard syllables L*V*T*. To transform them into standard
// syllables fill characters L_f and V_f can be inserted.
*/
enum {
Hangul_SBase = 0xac00,
Hangul_LBase = 0x1100,
Hangul_VBase = 0x1161,
Hangul_TBase = 0x11a7,
Hangul_SCount = 11172,
Hangul_LCount = 19,
Hangul_VCount = 21,
Hangul_TCount = 28,
Hangul_NCount = 21*28
};
#define hangul_isPrecomposed(uc) \
(uc >= Hangul_SBase && uc < Hangul_SBase + Hangul_SCount)
#define hangul_isLV(uc) \
((uc - Hangul_SBase) % Hangul_TCount == 0)
typedef enum {
L,
V,
T,
LV,
LVT,
X
} HangulType;
static HangulType hangul_type(unsigned short uc) {
if (uc > Hangul_SBase && uc < Hangul_SBase + Hangul_SCount)
return hangul_isLV(uc) ? LV : LVT;
if (uc < Hangul_LBase || uc > 0x11ff)
return X;
if (uc < Hangul_VBase)
return L;
if (uc < Hangul_TBase)
return V;
return T;
}
static int hangul_nextSyllableBoundary(const HB_UChar16 *s, int start, int end)
{
const HB_UChar16 *uc = s + start;
HangulType state = hangul_type(*uc);
int pos = 1;
while (pos < end - start) {
HangulType newState = hangul_type(uc[pos]);
switch(newState) {
case X:
goto finish;
case L:
case V:
case T:
if (state > newState)
goto finish;
state = newState;
break;
case LV:
if (state > L)
goto finish;
state = V;
break;
case LVT:
if (state > L)
goto finish;
state = T;
}
++pos;
}
finish:
return start+pos;
}
#ifndef NO_OPENTYPE
static const HB_OpenTypeFeature hangul_features [] = {
{ HB_MAKE_TAG('c', 'c', 'm', 'p'), CcmpProperty },
{ HB_MAKE_TAG('l', 'j', 'm', 'o'), CcmpProperty },
{ HB_MAKE_TAG('v', 'j', 'm', 'o'), CcmpProperty },
{ HB_MAKE_TAG('t', 'j', 'm', 'o'), CcmpProperty },
{ 0, 0 }
};
#endif
static HB_Bool hangul_shape_syllable(HB_ShaperItem *item, HB_Bool openType)
{
const HB_UChar16 *ch = item->string + item->item.pos;
int len = item->item.length;
#ifndef NO_OPENTYPE
const int availableGlyphs = item->num_glyphs;
#endif
int i;
HB_UChar16 composed = 0;
/* see if we can compose the syllable into a modern hangul */
if (item->item.length == 2) {
int LIndex = ch[0] - Hangul_LBase;
int VIndex = ch[1] - Hangul_VBase;
if (LIndex >= 0 && LIndex < Hangul_LCount &&
VIndex >= 0 && VIndex < Hangul_VCount)
composed = (LIndex * Hangul_VCount + VIndex) * Hangul_TCount + Hangul_SBase;
} else if (item->item.length == 3) {
int LIndex = ch[0] - Hangul_LBase;
int VIndex = ch[1] - Hangul_VBase;
int TIndex = ch[2] - Hangul_TBase;
if (LIndex >= 0 && LIndex < Hangul_LCount &&
VIndex >= 0 && VIndex < Hangul_VCount &&
TIndex >= 0 && TIndex < Hangul_TCount)
composed = (LIndex * Hangul_VCount + VIndex) * Hangul_TCount + TIndex + Hangul_SBase;
}
/* if we have a modern hangul use the composed form */
if (composed) {
ch = &composed;
len = 1;
}
if (!item->font->klass->convertStringToGlyphIndices(item->font,
ch, len,
item->glyphs, &item->num_glyphs,
item->item.bidiLevel % 2))
return FALSE;
for (i = 0; i < len; i++) {
item->attributes[i].mark = FALSE;
item->attributes[i].clusterStart = FALSE;
item->attributes[i].justification = 0;
item->attributes[i].zeroWidth = FALSE;
/*IDEBUG(" %d: %4x", i, ch[i].unicode()); */
}
#ifndef NO_OPENTYPE
if (!composed && openType) {
HB_Bool positioned;
HB_STACKARRAY(unsigned short, logClusters, len);
for (i = 0; i < len; ++i)
logClusters[i] = i;
item->log_clusters = logClusters;
HB_OpenTypeShape(item, /*properties*/0);
positioned = HB_OpenTypePosition(item, availableGlyphs, /*doLogClusters*/FALSE);
HB_FREE_STACKARRAY(logClusters);
if (!positioned)
return FALSE;
} else {
HB_HeuristicPosition(item);
}
#endif
item->attributes[0].clusterStart = TRUE;
return TRUE;
}
HB_Bool HB_HangulShape(HB_ShaperItem *item)
{
const HB_UChar16 *uc = item->string + item->item.pos;
HB_Bool allPrecomposed = TRUE;
int i;
assert(item->item.script == HB_Script_Hangul);
for (i = 0; i < (int)item->item.length; ++i) {
if (!hangul_isPrecomposed(uc[i])) {
allPrecomposed = FALSE;
break;
}
}
if (!allPrecomposed) {
HB_Bool openType = FALSE;
unsigned short *logClusters = item->log_clusters;
HB_ShaperItem syllable;
int first_glyph = 0;
int sstart = item->item.pos;
int end = sstart + item->item.length;
#ifndef NO_OPENTYPE
openType = HB_SelectScript(item, hangul_features);
#endif
syllable = *item;
while (sstart < end) {
int send = hangul_nextSyllableBoundary(item->string, sstart, end);
syllable.item.pos = sstart;
syllable.item.length = send-sstart;
syllable.glyphs = item->glyphs + first_glyph;
syllable.attributes = item->attributes + first_glyph;
syllable.offsets = item->offsets + first_glyph;
syllable.advances = item->advances + first_glyph;
syllable.num_glyphs = item->num_glyphs - first_glyph;
if (!hangul_shape_syllable(&syllable, openType)) {
item->num_glyphs += syllable.num_glyphs;
return FALSE;
}
/* fix logcluster array */
for (i = sstart; i < send; ++i)
logClusters[i-item->item.pos] = first_glyph;
sstart = send;
first_glyph += syllable.num_glyphs;
}
item->num_glyphs = first_glyph;
return TRUE;
}
return HB_BasicShape(item);
}