Implement tab setting/resetting.

protocols/ssh/include/terminal.h

@@ -47,6 +47,14 @@
 #include "display.h"
 #include "buffer.h"
 
+/**
+ * The maximum number of custom tab stops.
+ */
+#define GUAC_TERMINAL_MAX_TABS       16
+
+/**
+ * The number of rows to scroll per scroll wheel event.
+ */
 #define GUAC_SSH_WHEEL_SCROLL_AMOUNT 3
 
 typedef struct guac_terminal guac_terminal;
@@ -179,6 +187,18 @@ struct guac_terminal {
      */
     guac_terminal_buffer* buffer;
 
+    /**
+     * Automatically place a tabstop every N characters. If zero, then no
+     * tabstops exist automatically.
+     */
+    int tab_interval;
+
+    /**
+     * Array of all tabs set. Each entry is the column number of a tab + 1,
+     * or 0 if that tab cell is unset.
+     */
+    int custom_tabs[GUAC_TERMINAL_MAX_TABS];
+
     /**
      * Array of arrays of mapped characters, where the character N is located at the N-32
      * position within the array. Each element in a contained array is the corresponding Unicode
@@ -374,5 +394,26 @@ int guac_terminal_send_string(guac_terminal* term, const char* data);
  */
 int guac_terminal_sendf(guac_terminal* term, const char* format, ...);
 
+/**
+ * Sets a tabstop in the given column.
+ */
+void guac_terminal_set_tab(guac_terminal* term, int column);
+
+/**
+ * Removes the tabstop at the given column.
+ */
+void guac_terminal_unset_tab(guac_terminal* term, int column);
+
+/**
+ * Removes all tabstops.
+ */
+void guac_terminal_clear_tabs(guac_terminal* term);
+
+/**
+ * Given a column within the given terminal, returns the location of the
+ * next tabstop (or the rightmost character, if no more tabstops exist).
+ */
+int guac_terminal_next_tab(guac_terminal* term, int column);
+
 #endif
 

protocols/ssh/src/terminal.c

@@ -83,6 +83,10 @@ void guac_terminal_reset(guac_terminal* term) {
     term->automatic_carriage_return = false;
     term->insert_mode = false;
 
+    /* Reset tabs */
+    term->tab_interval = 8;
+    memset(term->custom_tabs, 0, sizeof(term->custom_tabs));
+
     /* Clear terminal */
     for (row=0; row<term->term_height; row++)
         guac_terminal_set_columns(term, row, 0, term->term_width, &(term->default_char));
@@ -787,4 +791,66 @@ int guac_terminal_sendf(guac_terminal* term, const char* format, ...) {
 
 }
 
+void guac_terminal_set_tab(guac_terminal* term, int column) {
+
+    int i;
+
+    /* Search for available space, set if available */
+    for (i=0; i<GUAC_TERMINAL_MAX_TABS; i++) {
+
+        /* Set tab if space free */
+        if (term->custom_tabs[i] == 0) {
+            term->custom_tabs[i] = column+1;
+            break;
+        }
+
+    }
+
+}
+
+void guac_terminal_unset_tab(guac_terminal* term, int column) {
+
+    int i;
+
+    /* Search for given tab, unset if found */
+    for (i=0; i<GUAC_TERMINAL_MAX_TABS; i++) {
+
+        /* Unset tab if found */
+        if (term->custom_tabs[i] == column+1) {
+            term->custom_tabs[i] = 0;
+            break;
+        }
+
+    }
+
+}
+
+void guac_terminal_clear_tabs(guac_terminal* term) {
+    term->tab_interval = 0;
+    memset(term->custom_tabs, 0, sizeof(term->custom_tabs));
+}
+
+int guac_terminal_next_tab(guac_terminal* term, int column) {
+
+    int i;
+
+    /* Determine tab stop from interval */
+    int tabstop;
+    if (term->tab_interval != 0)
+        tabstop = (column / term->tab_interval + 1) * term->tab_interval;
+    else
+        tabstop = term->term_width - 1;
+
+    /* Walk custom tabs, trying to find an earlier occurrence */
+    for (i=0; i<GUAC_TERMINAL_MAX_TABS; i++) {
+
+        int custom_tabstop = term->custom_tabs[i] - 1;
+        if (custom_tabstop != -1 && custom_tabstop > column && custom_tabstop < tabstop)
+            tabstop = custom_tabstop;
+
+    }
+
+    return tabstop;
+}
+
 

protocols/ssh/src/terminal_handlers.c

@@ -127,6 +127,11 @@ int guac_terminal_echo(guac_terminal* term, char c) {
                 term->cursor_col--;
             break;
 
+        /* Tab */
+        case 0x09:
+            term->cursor_col = guac_terminal_next_tab(term, term->cursor_col);
+            break;
+
         /* Line feed / VT / FF */
         case '\n':
         case 0x0B: /* VT */
@@ -304,6 +309,11 @@ int guac_terminal_escape(guac_terminal* term, char c) {
             term->char_handler = guac_terminal_echo; 
             break;
 
+        /* Set Tab (HTS) */
+        case 'H':
+            guac_terminal_set_tab(term, term->cursor_col);
+            break;
+
         /* Reverse Linefeed */
         case 'M':
 
@@ -685,6 +695,19 @@ int guac_terminal_csi(guac_terminal* term, char c) {
                 term->cursor_row = row;
                 break;
 
+            /* g: Clear tab */
+            case 'g':
+
+                /* Clear tab at current location */
+                if (argv[0] == 0)
+                    guac_terminal_unset_tab(term, term->cursor_col);
+
+                /* Clear all tabs */
+                else if (argv[0] == 3)
+                    guac_terminal_clear_tabs(term);
+
+                break;
+
             /* h: Set Mode */
             case 'h':