1 files changed, 19 insertions, 3 deletions

diff --git a/st.c b/st.c
index 4fc4d3d..d169ddf 100644
--- a/st.c
+++ b/st.c
@@ -164,7 +164,7 @@ typedef struct {
         int col;        /* nb col */
         Line* line;     /* screen */
         Line* alt;      /* alternate screen */
-        bool* dirty; /* dirtyness of lines */
+        bool* dirty;    /* dirtyness of lines */
         TCursor c;      /* cursor */
         int top;        /* top    scroll limit */
         int bot;        /* bottom scroll limit */
@@ -172,6 +172,7 @@ typedef struct {
         int esc;        /* escape state flags */
         char title[ESC_TITLE_SIZ];
         int titlelen;
+        bool *tabs;
 } Term;
 
 /* Purely graphic info */
@@ -847,12 +848,16 @@ tcursor(int mode) {
 
 void
 treset(void) {
+        unsigned i;
         term.c = (TCursor){{
                 .mode = ATTR_NULL,
                 .fg = DefaultFG,
                 .bg = DefaultBG
         }, .x = 0, .y = 0, .state = CURSOR_DEFAULT};
-        
+
+        memset(term.tabs, 0, term.col * sizeof(*term.tabs));
+        for (i = TAB; i < term.col; i += TAB)
+                term.tabs[i] = 1;
         term.top = 0, term.bot = term.row - 1;
         term.mode = MODE_WRAP;
         tclearregion(0, 0, term.col-1, term.row-1);
@@ -865,12 +870,14 @@ tnew(int col, int row) {
         term.line = malloc(term.row * sizeof(Line));
         term.alt  = malloc(term.row * sizeof(Line));
         term.dirty = malloc(term.row * sizeof(*term.dirty));
+        term.tabs = malloc(term.col * sizeof(*term.tabs));
 
         for(row = 0; row < term.row; row++) {
                 term.line[row] = malloc(term.col * sizeof(Glyph));
                 term.alt [row] = malloc(term.col * sizeof(Glyph));
                 term.dirty[row] = 0;
         }
+        memset(term.tabs, 0, term.col * sizeof(*term.tabs));
         /* setup screen */
         treset();
 }
@@ -1588,6 +1595,7 @@ tresize(int col, int row) {
         term.line = realloc(term.line, row * sizeof(Line));
         term.alt  = realloc(term.alt,  row * sizeof(Line));
         term.dirty = realloc(term.dirty, row * sizeof(*term.dirty));
+        term.tabs = realloc(term.tabs, col * sizeof(*term.tabs));
 
         /* resize each row to new width, zero-pad if needed */
         for(i = 0; i < minrow; i++) {
@@ -1606,7 +1614,15 @@ tresize(int col, int row) {
                 term.line[i] = calloc(col, sizeof(Glyph));
                 term.alt [i] = calloc(col, sizeof(Glyph));
         }
-        
+        if (col > term.col) {
+                bool *bp = term.tabs + term.col;
+
+                memset(bp, 0, sizeof(*term.tabs) * (col - term.col));
+                while (--bp > term.tabs && !*bp)
+                        /* nothing */ ;
+                for (bp += TAB; bp < term.tabs + col; bp += TAB)
+                        *bp = 1;
+        }
         /* update terminal size */
         term.col = col, term.row = row;
         /* make use of the LIMIT in tmoveto */