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/* This file is taken from the FreeType (1) tree. It's been reindented
* to roughly match Pango guidelines (in anticipation of future changes),
* but not otherwise much altered.
*/
/****************************************************************************/
/* */
/* The FreeType project -- a free and portable quality TrueType renderer. */
/* */
/* Copyright 1996-2000 by */
/* D. Turner, R.Wilhelm, and W. Lemberg */
/* */
/* arabic -- An implementation of the contextual algorithm given in the */
/* Unicode 2.0 book to assign the `isolated', `initial', `medial', and */
/* `final' properties to an input string of character codes for the Arabic */
/* script. */
/* */
/****************************************************************************/
#include "arabic-ot.h"
/*
*
* Here a table of the joining classes for characters in the range
* U+0620 - U+06FF.
*
* The following character also has a joining class:
*
* U+200C ZERO WIDTH NON-JOINER -> causing
*
* All other characters are given the joining class `none'.
*
*/
joining_class arabic[] =
{
/* U+0620 */
none, none, right, right,
right, right, dual, right,
dual, right, dual, dual,
dual, dual, dual, right,
/* U+0630 */
right, right, right, dual,
dual, dual, dual, dual,
dual, dual, dual, none,
none, none, none, none,
/* U+0640 */
causing, dual, dual, dual,
dual, dual, dual, dual,
right, dual, dual, transparent,
transparent, transparent, transparent, transparent,
/* U+0650 */
transparent, transparent, transparent, none,
none, none, none, none,
none, none, none, none,
none, none, none, none,
/* U+0660 */
none, none, none, none,
none, none, none, none,
none, none, none, none,
none, none, dual, dual,
/* U+0670 */
transparent, right, right, right,
none, right, right, right,
dual, dual, dual, dual,
dual, dual, dual, dual,
/* U+0680 */
dual, dual, dual, dual,
dual, dual, dual, dual,
right, right, right, right,
right, right, right, right,
/* U+0690 */
right, right, right, right,
right, right, right, right,
right, right, dual, dual,
dual, dual, dual, dual,
/* U+06A0 */
dual, dual, dual, dual,
dual, dual, dual, dual,
dual, dual, dual, dual,
dual, dual, dual, dual,
/* U+06B0 */
dual, dual, dual, dual,
dual, dual, dual, dual,
dual, dual, dual, dual,
dual, dual, dual, dual,
/* U+06C0 */
right, dual, right, right,
right, right, right, right,
right, right, right, right,
dual, right, dual, right,
/* U+06D0 */
dual, dual, right, right,
none, right, none, transparent,
transparent, transparent, transparent, transparent,
transparent, transparent, transparent, transparent,
/* U+06E0 */
transparent, transparent, transparent, transparent,
transparent, none, none, transparent,
transparent, none, transparent, transparent,
transparent, transparent, none, none,
/* U+06F0 */
none, none, none, none,
none, none, none, none,
none, none, dual, dual,
dual, none, none, none
};
#if 0
struct cgc_
{
FT_UShort char_code;
FT_UShort glyph_index;
FT_UShort class;
};
typedef struct cgc_ cgc;
int compare_cgc (const void* a,
const void* b)
{
return (((cgc*)a)->glyph_index > ((cgc*)b)->glyph_index) ?
1 : ((((cgc*)a)->glyph_index == ((cgc*)b)->glyph_index) ?
0 : -1);
}
TT_Error Build_Arabic_Glyph_Properties (TT_CharMap char_map,
TT_UShort max_glyphs,
TTO_GDEFHeader** gdef)
{
TT_UShort i, j, num_glyphs;
cgc Arabic[0x0700 - 0x0620];
TT_UShort glyph_indices[0x700 - 0x0620];
TT_UShort classes[0x700 - 0x0620];
if (!gdef)
return TT_Err_Invalid_Argument;
j = 0;
for (i = 0x0620; i < 0x0700; i++)
{
Arabic[j].char_code = i;
Arabic[j].class = (arabic[i - 0x0620] == transparent) ?
MARK_GLYPH : SIMPLE_GLYPH;
Arabic[j].glyph_index = TT_Char_Index (char_map, i);
if (Arabic[j].glyph_index)
j++;
}
num_glyphs = j;
if (!num_glyphs)
{
/* no Arabic font */
*gdef = NULL;
return TT_Err_Ok;
}
/* sort it */
qsort (Arabic, num_glyphs, sizeof (cgc), compare_cgc);
/* write it to the arrays, removing duplicates */
glyph_indices[0] = Arabic[0].glyph_index;
classes[0] = Arabic[0].class;
j = 1;
for (i = 1; i < num_glyphs; i++)
{
glyph_indices[j] = Arabic[i].glyph_index;
classes[j] = Arabic[i].class;
if (glyph_indices[j - 1] != glyph_indices[j])
j++;
}
num_glyphs = j;
TT_GDEF_Build_ClassDefinition (*gdef, max_glyphs, num_glyphs,
glyph_indices, classes);
return TT_Err_Ok;
}
#endif
/* The joining rules as given in the Unicode 2.0 book (characters are
* here specified as appearing in the byte stream, i.e. *not* in
* visual order). Joining classes are given in angle brackets, glyph
* forms in square brackets. Glyphs affected by a specific rule are
* enclosed with vertical bars.
*
* Note: The description of the joining algorithm in the book is
* severely broken. You can get a corrected version from
* www.unicode.org (as of 29-Jun-1999, this hasn't appeared).
*
* R1: <anything1> <transparent> <anything2>
*
* apply joining rules for
* <anything1> <anything2> -> [shape1] [shape2]
*
* -> [shape1] [isolated] [shape2]
*
* R2: <causing|left|dual> |<right>|
*
* -> [final]
*
* R3: |<left>| <causing|right|dual>
*
* -> [initial]
*
* R4: <causing|left|dual> |<dual>| <causing|right|dual>
*
* -> [medial]
*
* R5: <causing|left|dual> |<dual>| <!(causing|right|dual)>
*
* -> [final]
*
* R6: <!(causing|left|dual)> |<dual>| <causing|right|dual>
*
* -> [initial]
*
* R7: If R1-R6 fail:
*
* <anything> -> [isolated]
*/
/* `direction' can be -1, 0, or 1 to indicate the last non-transparent
* glyph, the current glyph, and the next non-transparent glyph,
* respectively.
*/
static joining_class Get_Joining_Class (gunichar* string,
int pos,
int length,
int direction)
{
joining_class j;
while (1)
{
if (pos == 0 && direction < 0)
return none;
pos += direction;
if (pos >= length)
return none;
if (string[pos] < 0x0620 ||
string[pos] >= 0x0700)
{
if (string[pos] == 0x200C)
return causing;
else
return none;
}
else
j = arabic[string[pos] - 0x0620];
if (!direction || j != transparent)
return j;
}
}
FT_Error Arabic_Assign_Properties (gunichar *string,
gulong *properties,
int length)
{
joining_class previous, current, next;
int i;
if (!string || !properties || length == 0)
return FT_Err_Invalid_Argument;
for (i = 0; i < length; i++)
{
previous = Get_Joining_Class (string, i, length, -1);
current = Get_Joining_Class (string, i, length, 0);
next = Get_Joining_Class (string, i, length, 1);
/* R1 */
if (current == transparent)
{
properties[i] |= isolated_p;
continue;
}
/* R2 */
if (previous == causing ||
previous == left ||
previous == dual )
if (current == right)
{
properties[i] |= final_p;
continue;
}
/* R3 */
if (current == left)
if (next == causing ||
next == right ||
next == dual )
{
properties[i] |= initial_p;
continue;
}
/* R4 */
if (previous == causing ||
previous == left ||
previous == dual )
if (current == dual)
if (next == causing ||
next == right ||
next == dual )
{
properties[i] |= medial_p;
continue;
}
/* R5 */
if (previous == causing ||
previous == left ||
previous == dual )
if (current == dual)
if (!(next == causing ||
next == right ||
next == dual ))
{
properties[i] |= final_p;
continue;
}
/* R6 */
if (!(previous == causing ||
previous == left ||
previous == dual ))
if (current == dual)
if (next == causing ||
next == right ||
next == dual )
{
properties[i] |= initial_p;
continue;
}
/* R7 */
properties[i] |= isolated_p;
}
return FT_Err_Ok;
}
/* End */
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