terminal: Implement character set switching

Includes the 3 vt100 character sets.  Some of the graphic symbols don't
display because they are not included in the default font.  Apparantly
the cairo toy font API doesn't do font substitution.

Signed-off-by: Callum Lowcay <callum@callumscode.com>

diff --git a/clients/terminal.c b/clients/terminal.c
index 88864c3..a56f29b 100644 (file)
--- a/clients/terminal.c
+++ b/clients/terminal.c
@@ -166,6 +166,69 @@ utf8_next_char(struct utf8_state_machine *machine, char c)
        return machine->state;
 }
 
+struct char_sub {
+       union utf8_char match;
+       union utf8_char replace;
+};
+/* Set last char_sub match to NULL char */
+typedef struct char_sub *character_set;
+
+struct char_sub CS_US[] = {
+       {{{0, }}, {{0, }}}
+};
+static struct char_sub CS_UK[] = {
+       {{{'#', 0, }}, {{0xC2, 0xA3, 0, }}},
+       {{{0, }}, {{0, }}}
+};
+static struct char_sub CS_SPECIAL[] = {
+       {{{'`', 0, }}, {{0xE2, 0x99, 0xA6, 0}}}, /* diamond */
+       {{{'a', 0, }}, {{0xE2, 0x96, 0x92, 0}}}, /* 50% cell */
+       {{{'b', 0, }}, {{0xE2, 0x90, 0x89, 0}}}, /* HT */
+       {{{'c', 0, }}, {{0xE2, 0x90, 0x8C, 0}}}, /* FF */
+       {{{'d', 0, }}, {{0xE2, 0x90, 0x8D, 0}}}, /* CR */
+       {{{'e', 0, }}, {{0xE2, 0x90, 0x8A, 0}}}, /* LF */
+       {{{'f', 0, }}, {{0xC2, 0xB0, 0, }}}, /* Degree */
+       {{{'g', 0, }}, {{0xC2, 0xB1, 0, }}}, /* Plus/Minus */
+       {{{'h', 0, }}, {{0xE2, 0x90, 0xA4, 0}}}, /* NL */
+       {{{'i', 0, }}, {{0xE2, 0x90, 0x8B, 0}}}, /* VT */
+       {{{'j', 0, }}, {{0xE2, 0x94, 0x98, 0}}}, /* CN_RB */
+       {{{'k', 0, }}, {{0xE2, 0x94, 0x90, 0}}}, /* CN_RT */
+       {{{'l', 0, }}, {{0xE2, 0x94, 0x8C, 0}}}, /* CN_LT */
+       {{{'m', 0, }}, {{0xE2, 0x94, 0x94, 0}}}, /* CN_RB */
+       {{{'n', 0, }}, {{0xE2, 0x94, 0xBC, 0}}}, /* CROSS */
+       {{{'o', 0, }}, {{0xE2, 0x94, 0x80, 0}}}, /* H */
+       {{{'p', 0, }}, {{0xE2, 0x94, 0x80, 0}}}, /* H */
+       {{{'q', 0, }}, {{0xE2, 0x94, 0x80, 0}}}, /* H */
+       {{{'r', 0, }}, {{0xE2, 0x94, 0x80, 0}}}, /* H */
+       {{{'s', 0, }}, {{0xE2, 0x94, 0x80, 0}}}, /* H */
+       {{{'t', 0, }}, {{0xE2, 0x94, 0x9C, 0}}}, /* TR */
+       {{{'u', 0, }}, {{0xE2, 0x94, 0xA4, 0}}}, /* TL */
+       {{{'v', 0, }}, {{0xE2, 0x94, 0xB4, 0}}}, /* TU */
+       {{{'w', 0, }}, {{0xE2, 0x94, 0xAC, 0}}}, /* TD */
+       {{{'x', 0, }}, {{0xE2, 0x94, 0x82, 0}}}, /* V */
+       {{{'y', 0, }}, {{0xE2, 0x89, 0xA4, 0}}}, /* LE */
+       {{{'z', 0, }}, {{0xE2, 0x89, 0xA5, 0}}}, /* GE */
+       {{{'{', 0, }}, {{0xCF, 0x80, 0, }}}, /* PI */
+       {{{'|', 0, }}, {{0xE2, 0x89, 0xA0, 0}}}, /* NEQ */
+       {{{'}', 0, }}, {{0xC2, 0xA3, 0, }}}, /* POUND */
+       {{{'~', 0, }}, {{0xE2, 0x8B, 0x85, 0}}}, /* DOT */
+       {{{0, }}, {{0, }}}
+};
+
+static void
+apply_char_set(character_set cs, union utf8_char *utf8)
+{
+       int i = 0;
+       
+       while (cs[i].match.byte[0]) {
+               if ((*utf8).ch == cs[i].match.ch) {
+                       *utf8 = cs[i].replace;
+                       break;
+               }
+               i++;
+       }
+}
+
 struct terminal_color { double r, g, b, a; };
 struct attr {
        unsigned char fg, bg;
@@ -202,6 +265,8 @@ struct terminal {
        struct attr saved_attr;
        union utf8_char last_char;
        int margin_top, margin_bottom;
+       character_set cs, g0, g1;
+       character_set saved_cs, saved_g0, saved_g1;
        int data_pitch, attr_pitch;  /* The width in bytes of a line */
        int width, height, start, row, column;
        int saved_row, saved_column;
@@ -249,6 +314,14 @@ terminal_init(struct terminal *terminal)
        terminal->row = 0;
        terminal->column = 0;
 
+       terminal->g0 = CS_US;
+       terminal->g1 = CS_US;
+       terminal->cs = terminal->g0;
+
+       terminal->saved_g0 = terminal->g0;
+       terminal->saved_g1 = terminal->g1;
+       terminal->saved_cs = terminal->cs;
+
        terminal->saved_attr = terminal->curr_attr;
        terminal->saved_origin_mode = terminal->origin_mode;
        terminal->saved_row = terminal->row;
@@ -714,6 +787,12 @@ handle_term_parameter(struct terminal *terminal, int code, int sr)
 
        if (terminal->qmark_flag) {
                switch(code) {
+               case 2:  /* DECANM */
+                       /* No VT52 support yet */
+                       terminal->g0 = CS_US;
+                       terminal->g1 = CS_US;
+                       terminal->cs = terminal->g0;
+                       break;
                case 3:  /* DECCOLM */
                        if (sr)
                                terminal_resize(terminal, 132, 24);
@@ -1147,12 +1226,18 @@ handle_non_csi_escape(struct terminal *terminal, char code)
                terminal->saved_column = terminal->column;
                terminal->saved_attr = terminal->curr_attr;
                terminal->saved_origin_mode = terminal->origin_mode;
+               terminal->saved_cs = terminal->cs;
+               terminal->saved_g0 = terminal->g0;
+               terminal->saved_g1 = terminal->g1;
                break;
        case '8':    /* DECRC */
                terminal->row = terminal->saved_row;
                terminal->column = terminal->saved_column;
                terminal->curr_attr = terminal->saved_attr;
                terminal->origin_mode = terminal->saved_origin_mode;
+               terminal->cs = terminal->saved_cs;
+               terminal->g0 = terminal->saved_g0;
+               terminal->g1 = terminal->saved_g1;
                break;
        default:
                fprintf(stderr, "Unknown escape code: %c\n", code);
@@ -1179,6 +1264,30 @@ handle_special_escape(struct terminal *terminal, char special, char code)
                        fprintf(stderr, "Unknown HASH escape #%c\n", code);
                        break;
                }
+       } else if (special == '(' || special == ')') {
+               switch(code) {
+               case '0':
+                       if (special == '(')
+                               terminal->g0 = CS_SPECIAL;
+                       else
+                               terminal->g1 = CS_SPECIAL;
+                       break;
+               case 'A':
+                       if (special == '(')
+                               terminal->g0 = CS_UK;
+                       else
+                               terminal->g1 = CS_UK;
+                       break;
+               case 'B':
+                       if (special == '(')
+                               terminal->g0 = CS_US;
+                       else
+                               terminal->g1 = CS_US;
+                       break;
+               default:
+                       fprintf(stderr, "Unknown character set %c\n", code);
+                       break;
+               }
        } else {
                fprintf(stderr, "Unknown special escape %c%c\n", special, code);
        }
@@ -1307,6 +1416,12 @@ handle_special_char(struct terminal *terminal, char c)
        case '\a':
                /* Bell */
                break;
+       case '\x0E': /* SO */
+               terminal->cs = terminal->g1;
+               break;
+       case '\x0F': /* SI */
+               terminal->cs = terminal->g0;
+               break;
        default:
                return 0;
        }
@@ -1321,6 +1436,8 @@ handle_char(struct terminal *terminal, union utf8_char utf8)
        struct attr *attr_row;
        
        if (handle_special_char(terminal, utf8.byte[0])) return;
+
+       apply_char_set(terminal->cs, &utf8);
        
        /* There are a whole lot of non-characters, control codes,
         * and formatting codes that should probably be ignored,