/* Thai / Lao shaper */
+
+/* PUA shaping */
+
+
+enum thai_consonant_type_t
+{
+ NC,
+ AC,
+ RC,
+ DC,
+ NOT_CONSONANT,
+ NUM_CONSONANT_TYPES = NOT_CONSONANT
+};
+
+static thai_consonant_type_t
+get_consonant_type (hb_codepoint_t u)
+{
+ if (u == 0x0E1B || u == 0x0E1D || u == 0x0E1F || u == 0x0E2C)
+ return AC;
+ if (u == 0x0E0D || u == 0x0E10)
+ return RC;
+ if (u == 0x0E0E || u == 0x0E0F)
+ return DC;
+ if (hb_in_range<hb_codepoint_t> (u, 0x0E01, 0x0E2E))
+ return NC;
+ return NOT_CONSONANT;
+}
+
+
+enum thai_mark_type_t
+{
+ AV,
+ BV,
+ T,
+ NOT_MARK,
+ NUM_MARK_TYPES = NOT_MARK
+};
+
+static thai_mark_type_t
+get_mark_type (hb_codepoint_t u)
+{
+ if (u == 0x0E31 || hb_in_range<hb_codepoint_t> (u, 0x0E34, 0x0E37) ||
+ u == 0x0E47 || hb_in_range<hb_codepoint_t> (u, 0x0E4D, 0x0E4E))
+ return AV;
+ if (hb_in_range<hb_codepoint_t> (u, 0x0E38, 0x0E3A))
+ return BV;
+ if (hb_in_range<hb_codepoint_t> (u, 0x0E48, 0x0E4C))
+ return T;
+ return NOT_MARK;
+}
+
+
+enum thai_action_t
+{
+ NOP,
+ SD, /* Shift combining-mark down */
+ SL, /* Shift combining-mark left */
+ SDL, /* Shift combining-mark down-left */
+ RD /* Remove descender from base */
+};
+
+static hb_codepoint_t
+thai_pua_shape (hb_codepoint_t u, thai_action_t action, hb_font_t *font)
+{
+ struct thai_pua_mapping_t {
+ hb_codepoint_t u;
+ hb_codepoint_t win_pua;
+ hb_codepoint_t mac_pua;
+ } const *pua_mappings = NULL;
+ static const thai_pua_mapping_t SD_mappings[] = {
+ {0x0E48, 0xF70A, 0xF88B}, /* MAI EK */
+ {0x0E49, 0xF70B, 0xF88E}, /* MAI THO */
+ {0x0E4A, 0xF70C, 0xF891}, /* MAI TRI */
+ {0x0E4B, 0xF70D, 0xF894}, /* MAI CHATTAWA */
+ {0x0E4C, 0xF70E, 0xF897}, /* THANTHAKHAT */
+ {0x0E38, 0xF718, 0xF89B}, /* SARA U */
+ {0x0E39, 0xF719, 0xF89C}, /* SARA UU */
+ {0x0E3A, 0xF71A, 0xF89D}, /* PHINTHU */
+ {0x0000, 0x0000, 0x0000}
+ };
+ static const thai_pua_mapping_t SDL_mappings[] = {
+ {0x0E48, 0xF705, 0xF88C}, /* MAI EK */
+ {0x0E49, 0xF706, 0xF88F}, /* MAI THO */
+ {0x0E4A, 0xF707, 0xF892}, /* MAI TRI */
+ {0x0E4B, 0xF708, 0xF895}, /* MAI CHATTAWA */
+ {0x0E4C, 0xF709, 0xF898}, /* THANTHAKHAT */
+ {0x0000, 0x0000, 0x0000}
+ };
+ static const thai_pua_mapping_t SL_mappings[] = {
+ {0x0E48, 0xF713, 0xF88A}, /* MAI EK */
+ {0x0E49, 0xF714, 0xF88D}, /* MAI THO */
+ {0x0E4A, 0xF715, 0xF890}, /* MAI TRI */
+ {0x0E4B, 0xF716, 0xF893}, /* MAI CHATTAWA */
+ {0x0E4C, 0xF717, 0xF896}, /* THANTHAKHAT */
+ {0x0E31, 0xF710, 0xF884}, /* MAI HAN-AKAT */
+ {0x0E34, 0xF701, 0xF885}, /* SARA I */
+ {0x0E35, 0xF702, 0xF886}, /* SARA II */
+ {0x0E36, 0xF703, 0xF887}, /* SARA UE */
+ {0x0E37, 0xF704, 0xF888}, /* SARA UEE */
+ {0x0E47, 0xF712, 0xF889}, /* MAITAIKHU */
+ {0x0E4D, 0xF711, 0xF899}, /* NIKHAHIT */
+ {0x0000, 0x0000, 0x0000}
+ };
+ static const thai_pua_mapping_t RD_mappings[] = {
+ {0x0E0D, 0xF70F, 0xF89A}, /* YO YING */
+ {0x0E10, 0xF700, 0xF89E}, /* THO THAN */
+ {0x0000, 0x0000, 0x0000}
+ };
+
+ switch (action) {
+ default: assert (false); /* Fallthrough */
+ case NOP: return u;
+ case SD: pua_mappings = SD_mappings; break;
+ case SDL: pua_mappings = SDL_mappings; break;
+ case SL: pua_mappings = SL_mappings; break;
+ case RD: pua_mappings = RD_mappings; break;
+ }
+ for (; pua_mappings->u; pua_mappings++)
+ if (pua_mappings->u == u)
+ {
+ hb_codepoint_t glyph;
+ if (hb_font_get_glyph (font, pua_mappings->win_pua, 0, &glyph))
+ return pua_mappings->win_pua;
+ if (hb_font_get_glyph (font, pua_mappings->mac_pua, 0, &glyph))
+ return pua_mappings->mac_pua;
+ break;
+ }
+ return u;
+}
+
+
+static enum thai_above_state_t
+{ /* Cluster above looks like: */
+ T0, /* ⣤ */
+ T1, /* ⣼ */
+ T2, /* ⣾ */
+ T3, /* ⣿ */
+ NUM_ABOVE_STATES
+} thai_above_start_state[NUM_CONSONANT_TYPES + 1/* For NOT_CONSONANT */] =
+{
+ T0, /* NC */
+ T1, /* AC */
+ T0, /* RC */
+ T0, /* DC */
+ T3, /* NOT_CONSONANT */
+};
+
+static const struct thai_above_state_machine_edge_t {
+ thai_action_t action;
+ thai_above_state_t next_state;
+} thai_above_state_machine[NUM_ABOVE_STATES][NUM_MARK_TYPES] =
+{ /*AV*/ /*BV*/ /*T*/
+/*T0*/ {{NOP,T3}, {NOP,T0}, {SD, T3}},
+/*T1*/ {{SL, T2}, {NOP,T1}, {SDL,T2}},
+/*T2*/ {{NOP,T3}, {NOP,T2}, {SL, T3}},
+/*T3*/ {{NOP,T3}, {NOP,T3}, {NOP,T3}},
+};
+
+
+static enum thai_below_state_t
+{
+ B0, /* No descender */
+ B1, /* Removable descender */
+ B2, /* Strict descender */
+ NUM_BELOW_STATES
+} thai_below_start_state[NUM_CONSONANT_TYPES + 1/* For NOT_CONSONANT */] =
+{
+ B0, /* NC */
+ B0, /* AC */
+ B1, /* RC */
+ B2, /* DC */
+ B2, /* NOT_CONSONANT */
+};
+
+static const struct thai_below_state_machine_edge_t {
+ thai_action_t action;
+ thai_below_state_t next_state;
+} thai_below_state_machine[NUM_BELOW_STATES][NUM_MARK_TYPES] =
+{ /*AV*/ /*BV*/ /*T*/
+/*B0*/ {{NOP,B0}, {NOP,B2}, {NOP, B0}},
+/*B1*/ {{NOP,B1}, {RD, B2}, {NOP, B1}},
+/*B2*/ {{NOP,B2}, {SD, B2}, {NOP, B2}},
+};
+
+
static void
do_thai_pua_shaping (const hb_ot_shape_plan_t *plan,
hb_buffer_t *buffer,
hb_font_t *font)
{
+ thai_above_state_t above_state = thai_above_start_state[NOT_CONSONANT];
+ thai_below_state_t below_state = thai_below_start_state[NOT_CONSONANT];
+ unsigned int base = 0;
+
+ hb_glyph_info_t *info = buffer->info;
+ unsigned int count = buffer->len;
+ for (unsigned int i = 0; i < count; i++)
+ {
+ thai_mark_type_t mt = get_mark_type (info[i].codepoint);
+
+ if (mt == NOT_MARK) {
+ thai_consonant_type_t ct = get_consonant_type (info[i].codepoint);
+ above_state = thai_above_start_state[ct];
+ below_state = thai_below_start_state[ct];
+ base = i;
+ continue;
+ }
+
+ const thai_above_state_machine_edge_t &above_edge = thai_above_state_machine[above_state][mt];
+ const thai_below_state_machine_edge_t &below_edge = thai_below_state_machine[below_state][mt];
+ above_state = above_edge.next_state;
+ below_state = below_edge.next_state;
+
+ /* At least one of the above/below actions is NOP. */
+ thai_action_t action = above_edge.action != NOP ? above_edge.action : below_edge.action;
+
+ if (action == RD)
+ info[base].codepoint = thai_pua_shape (info[base].codepoint, action, font);
+ else
+ info[i].codepoint = thai_pua_shape (info[i].codepoint, action, font);
+ }
}
+
static void
preprocess_text_thai (const hb_ot_shape_plan_t *plan,
hb_buffer_t *buffer,