new file mode 100644
--- /dev/null
+++ b/src/libvterm/src/state.c
@@ -0,0 +1,1851 @@
+#include "vterm_internal.h"
+
+#include <stdio.h>
+#include <string.h>
+
+#define strneq(a,b,n) (strncmp(a,b,n)==0)
+
+#if defined(DEBUG) && DEBUG > 1
+# define DEBUG_GLYPH_COMBINE
+#endif
+
+/* Some convenient wrappers to make callback functions easier */
+
+static void putglyph(VTermState *state, const uint32_t chars[], int width, VTermPos pos)
+{
+  VTermGlyphInfo info;
+  info.chars = chars;
+  info.width = width;
+  info.protected_cell = state->protected_cell;
+  info.dwl = state->lineinfo[pos.row].doublewidth;
+  info.dhl = state->lineinfo[pos.row].doubleheight;
+
+  if(state->callbacks && state->callbacks->putglyph)
+    if((*state->callbacks->putglyph)(&info, pos, state->cbdata))
+      return;
+
+  DEBUG_LOG3("libvterm: Unhandled putglyph U+%04x at (%d,%d)\n", chars[0], pos.col, pos.row);
+}
+
+static void updatecursor(VTermState *state, VTermPos *oldpos, int cancel_phantom)
+{
+  if(state->pos.col == oldpos->col && state->pos.row == oldpos->row)
+    return;
+
+  if(cancel_phantom)
+    state->at_phantom = 0;
+
+  if(state->callbacks && state->callbacks->movecursor)
+    if((*state->callbacks->movecursor)(state->pos, *oldpos, state->mode.cursor_visible, state->cbdata))
+      return;
+}
+
+static void erase(VTermState *state, VTermRect rect, int selective)
+{
+  if(state->callbacks && state->callbacks->erase)
+    if((*state->callbacks->erase)(rect, selective, state->cbdata))
+      return;
+}
+
+static VTermState *vterm_state_new(VTerm *vt)
+{
+  VTermState *state = vterm_allocator_malloc(vt, sizeof(VTermState));
+
+  state->vt = vt;
+
+  state->rows = vt->rows;
+  state->cols = vt->cols;
+
+  state->mouse_col     = 0;
+  state->mouse_row     = 0;
+  state->mouse_buttons = 0;
+
+  state->mouse_protocol = MOUSE_X10;
+
+  state->callbacks = NULL;
+  state->cbdata    = NULL;
+
+  vterm_state_newpen(state);
+
+  state->bold_is_highbright = 0;
+
+  return state;
+}
+
+INTERNAL void vterm_state_free(VTermState *state)
+{
+  vterm_allocator_free(state->vt, state->tabstops);
+  vterm_allocator_free(state->vt, state->lineinfo);
+  vterm_allocator_free(state->vt, state->combine_chars);
+  vterm_allocator_free(state->vt, state);
+}
+
+static void scroll(VTermState *state, VTermRect rect, int downward, int rightward)
+{
+  int rows;
+  int cols;
+  if(!downward && !rightward)
+    return;
+
+  rows = rect.end_row - rect.start_row;
+  if(downward > rows)
+    downward = rows;
+  else if(downward < -rows)
+    downward = -rows;
+
+  cols = rect.end_col - rect.start_col;
+  if(rightward > cols)
+    rightward = cols;
+  else if(rightward < -cols)
+    rightward = -cols;
+
+  /* Update lineinfo if full line */
+  if(rect.start_col == 0 && rect.end_col == state->cols && rightward == 0) {
+    int height = rect.end_row - rect.start_row - abs(downward);
+
+    if(downward > 0)
+      memmove(state->lineinfo + rect.start_row,
+              state->lineinfo + rect.start_row + downward,
+              height * sizeof(state->lineinfo[0]));
+    else
+      memmove(state->lineinfo + rect.start_row - downward,
+              state->lineinfo + rect.start_row,
+              height * sizeof(state->lineinfo[0]));
+  }
+
+  if(state->callbacks && state->callbacks->scrollrect)
+    if((*state->callbacks->scrollrect)(rect, downward, rightward, state->cbdata))
+      return;
+
+  if(state->callbacks)
+    vterm_scroll_rect(rect, downward, rightward,
+        state->callbacks->moverect, state->callbacks->erase, state->cbdata);
+}
+
+static void linefeed(VTermState *state)
+{
+  if(state->pos.row == SCROLLREGION_BOTTOM(state) - 1) {
+    VTermRect rect;
+    rect.start_row = state->scrollregion_top;
+    rect.end_row   = SCROLLREGION_BOTTOM(state);
+    rect.start_col = SCROLLREGION_LEFT(state);
+    rect.end_col   = SCROLLREGION_RIGHT(state);
+
+    scroll(state, rect, 1, 0);
+  }
+  else if(state->pos.row < state->rows-1)
+    state->pos.row++;
+}
+
+static void grow_combine_buffer(VTermState *state)
+{
+  size_t    new_size = state->combine_chars_size * 2;
+  uint32_t *new_chars = vterm_allocator_malloc(state->vt, new_size * sizeof(new_chars[0]));
+
+  memcpy(new_chars, state->combine_chars, state->combine_chars_size * sizeof(new_chars[0]));
+
+  vterm_allocator_free(state->vt, state->combine_chars);
+
+  state->combine_chars = new_chars;
+  state->combine_chars_size = new_size;
+}
+
+static void set_col_tabstop(VTermState *state, int col)
+{
+  unsigned char mask = 1 << (col & 7);
+  state->tabstops[col >> 3] |= mask;
+}
+
+static void clear_col_tabstop(VTermState *state, int col)
+{
+  unsigned char mask = 1 << (col & 7);
+  state->tabstops[col >> 3] &= ~mask;
+}
+
+static int is_col_tabstop(VTermState *state, int col)
+{
+  unsigned char mask = 1 << (col & 7);
+  return state->tabstops[col >> 3] & mask;
+}
+
+static int is_cursor_in_scrollregion(const VTermState *state)
+{
+  if(state->pos.row < state->scrollregion_top ||
+     state->pos.row >= SCROLLREGION_BOTTOM(state))
+    return 0;
+  if(state->pos.col < SCROLLREGION_LEFT(state) ||
+     state->pos.col >= SCROLLREGION_RIGHT(state))
+    return 0;
+
+  return 1;
+}
+
+static void tab(VTermState *state, int count, int direction)
+{
+  while(count > 0) {
+    if(direction > 0) {
+      if(state->pos.col >= THISROWWIDTH(state)-1)
+        return;
+
+      state->pos.col++;
+    }
+    else if(direction < 0) {
+      if(state->pos.col < 1)
+        return;
+
+      state->pos.col--;
+    }
+
+    if(is_col_tabstop(state, state->pos.col))
+      count--;
+  }
+}
+
+#define NO_FORCE 0
+#define FORCE    1
+
+#define DWL_OFF 0
+#define DWL_ON  1
+
+#define DHL_OFF    0
+#define DHL_TOP    1
+#define DHL_BOTTOM 2
+
+static void set_lineinfo(VTermState *state, int row, int force, int dwl, int dhl)
+{
+  VTermLineInfo info = state->lineinfo[row];
+
+  if(dwl == DWL_OFF)
+    info.doublewidth = DWL_OFF;
+  else if(dwl == DWL_ON)
+    info.doublewidth = DWL_ON;
+  /* else -1 to ignore */
+
+  if(dhl == DHL_OFF)
+    info.doubleheight = DHL_OFF;
+  else if(dhl == DHL_TOP)
+    info.doubleheight = DHL_TOP;
+  else if(dhl == DHL_BOTTOM)
+    info.doubleheight = DHL_BOTTOM;
+
+  if((state->callbacks &&
+      state->callbacks->setlineinfo &&
+      (*state->callbacks->setlineinfo)(row, &info, state->lineinfo + row, state->cbdata))
+      || force)
+    state->lineinfo[row] = info;
+}
+
+static int on_text(const char bytes[], size_t len, void *user)
+{
+  VTermState *state = user;
+  uint32_t *codepoints;
+  int npoints = 0;
+  size_t eaten = 0;
+  VTermEncodingInstance *encoding;
+  int i = 0;
+
+  VTermPos oldpos = state->pos;
+
+  /* We'll have at most len codepoints */
+  codepoints = vterm_allocator_malloc(state->vt, len * sizeof(uint32_t));
+
+  encoding =
+    state->gsingle_set     ? &state->encoding[state->gsingle_set] :
+    !(bytes[eaten] & 0x80) ? &state->encoding[state->gl_set] :
+    state->vt->mode.utf8   ? &state->encoding_utf8 :
+                             &state->encoding[state->gr_set];
+
+  (*encoding->enc->decode)(encoding->enc, encoding->data,
+      codepoints, &npoints, state->gsingle_set ? 1 : len,
+      bytes, &eaten, len);
+
+  /* There's a chance an encoding (e.g. UTF-8) hasn't found enough bytes yet
+   * for even a single codepoint
+   */
+  if(!npoints)
+  {
+    vterm_allocator_free(state->vt, codepoints);
+    return 0;
+  }
+
+  if(state->gsingle_set && npoints)
+    state->gsingle_set = 0;
+
+  /* This is a combining char. that needs to be merged with the previous
+   * glyph output */
+  if(vterm_unicode_is_combining(codepoints[i])) {
+    /* See if the cursor has moved since */
+    if(state->pos.row == state->combine_pos.row && state->pos.col == state->combine_pos.col + state->combine_width) {
+#ifdef DEBUG_GLYPH_COMBINE
+      int printpos;
+      printf("DEBUG: COMBINING SPLIT GLYPH of chars {");
+      for(printpos = 0; state->combine_chars[printpos]; printpos++)
+        printf("U+%04x ", state->combine_chars[printpos]);
+      printf("} + {");
+#endif
+
+      /* Find where we need to append these combining chars */
+      int saved_i = 0;
+      while(state->combine_chars[saved_i])
+        saved_i++;
+
+      /* Add extra ones */
+      while(i < npoints && vterm_unicode_is_combining(codepoints[i])) {
+        if(saved_i >= (int)state->combine_chars_size)
+          grow_combine_buffer(state);
+        state->combine_chars[saved_i++] = codepoints[i++];
+      }
+      if(saved_i >= (int)state->combine_chars_size)
+        grow_combine_buffer(state);
+      state->combine_chars[saved_i] = 0;
+
+#ifdef DEBUG_GLYPH_COMBINE
+      for(; state->combine_chars[printpos]; printpos++)
+        printf("U+%04x ", state->combine_chars[printpos]);
+      printf("}\n");
+#endif
+
+      /* Now render it */
+      putglyph(state, state->combine_chars, state->combine_width, state->combine_pos);
+    }
+    else {
+      DEBUG_LOG("libvterm: TODO: Skip over split char+combining\n");
+    }
+  }
+
+  for(; i < npoints; i++) {
+    /* Try to find combining characters following this */
+    int glyph_starts = i;
+    int glyph_ends;
+    int width = 0;
+    uint32_t *chars;
+
+    for(glyph_ends = i + 1; glyph_ends < npoints; glyph_ends++)
+      if(!vterm_unicode_is_combining(codepoints[glyph_ends]))
+        break;
+
+    chars = vterm_allocator_malloc(state->vt, (glyph_ends - glyph_starts + 1) * sizeof(uint32_t));
+
+    for( ; i < glyph_ends; i++) {
+      int this_width;
+      chars[i - glyph_starts] = codepoints[i];
+      this_width = vterm_unicode_width(codepoints[i]);
+#ifdef DEBUG
+      if(this_width < 0) {
+        fprintf(stderr, "Text with negative-width codepoint U+%04x\n", codepoints[i]);
+        abort();
+      }
+#endif
+      width += this_width;
+    }
+
+    chars[glyph_ends - glyph_starts] = 0;
+    i--;
+
+#ifdef DEBUG_GLYPH_COMBINE
+    int printpos;
+    printf("DEBUG: COMBINED GLYPH of %d chars {", glyph_ends - glyph_starts);
+    for(printpos = 0; printpos < glyph_ends - glyph_starts; printpos++)
+      printf("U+%04x ", chars[printpos]);
+    printf("}, onscreen width %d\n", width);
+#endif
+
+    if(state->at_phantom || state->pos.col + width > THISROWWIDTH(state)) {
+      linefeed(state);
+      state->pos.col = 0;
+      state->at_phantom = 0;
+    }
+
+    if(state->mode.insert) {
+      /* TODO: This will be a little inefficient for large bodies of text, as
+       * it'll have to 'ICH' effectively before every glyph. We should scan
+       * ahead and ICH as many times as required
+       */
+      VTermRect rect;
+      rect.start_row = state->pos.row;
+      rect.end_row   = state->pos.row + 1;
+      rect.start_col = state->pos.col;
+      rect.end_col   = THISROWWIDTH(state);
+      scroll(state, rect, 0, -1);
+    }
+
+    putglyph(state, chars, width, state->pos);
+
+    if(i == npoints - 1) {
+      /* End of the buffer. Save the chars in case we have to combine with
+       * more on the next call */
+      int save_i;
+      for(save_i = 0; chars[save_i]; save_i++) {
+        if(save_i >= (int)state->combine_chars_size)
+          grow_combine_buffer(state);
+        state->combine_chars[save_i] = chars[save_i];
+      }
+      if(save_i >= (int)state->combine_chars_size)
+        grow_combine_buffer(state);
+      state->combine_chars[save_i] = 0;
+      state->combine_width = width;
+      state->combine_pos = state->pos;
+    }
+
+    if(state->pos.col + width >= THISROWWIDTH(state)) {
+      if(state->mode.autowrap)
+        state->at_phantom = 1;
+    }
+    else {
+      state->pos.col += width;
+    }
+    vterm_allocator_free(state->vt, chars);
+  }
+
+  updatecursor(state, &oldpos, 0);
+
+#ifdef DEBUG
+  if(state->pos.row < 0 || state->pos.row >= state->rows ||
+     state->pos.col < 0 || state->pos.col >= state->cols) {
+    fprintf(stderr, "Position out of bounds after text: (%d,%d)\n",
+        state->pos.row, state->pos.col);
+    abort();
+  }
+#endif
+
+  vterm_allocator_free(state->vt, codepoints);
+  return eaten;
+}
+
+static int on_control(unsigned char control, void *user)
+{
+  VTermState *state = user;
+
+  VTermPos oldpos = state->pos;
+
+  switch(control) {
+  case 0x07: /* BEL - ECMA-48 8.3.3 */
+    if(state->callbacks && state->callbacks->bell)
+      (*state->callbacks->bell)(state->cbdata);
+    break;
+
+  case 0x08: /* BS - ECMA-48 8.3.5 */
+    if(state->pos.col > 0)
+      state->pos.col--;
+    break;
+
+  case 0x09: /* HT - ECMA-48 8.3.60 */
+    tab(state, 1, +1);
+    break;
+
+  case 0x0a: /* LF - ECMA-48 8.3.74 */
+  case 0x0b: /* VT */
+  case 0x0c: /* FF */
+    linefeed(state);
+    if(state->mode.newline)
+      state->pos.col = 0;
+    break;
+
+  case 0x0d: /* CR - ECMA-48 8.3.15 */
+    state->pos.col = 0;
+    break;
+
+  case 0x0e: /* LS1 - ECMA-48 8.3.76 */
+    state->gl_set = 1;
+    break;
+
+  case 0x0f: /* LS0 - ECMA-48 8.3.75 */
+    state->gl_set = 0;
+    break;
+
+  case 0x84: /* IND - DEPRECATED but implemented for completeness */
+    linefeed(state);
+    break;
+
+  case 0x85: /* NEL - ECMA-48 8.3.86 */
+    linefeed(state);
+    state->pos.col = 0;
+    break;
+
+  case 0x88: /* HTS - ECMA-48 8.3.62 */
+    set_col_tabstop(state, state->pos.col);
+    break;
+
+  case 0x8d: /* RI - ECMA-48 8.3.104 */
+    if(state->pos.row == state->scrollregion_top) {
+      VTermRect rect;
+      rect.start_row = state->scrollregion_top;
+      rect.end_row   = SCROLLREGION_BOTTOM(state);
+      rect.start_col = SCROLLREGION_LEFT(state);
+      rect.end_col   = SCROLLREGION_RIGHT(state);
+
+      scroll(state, rect, -1, 0);
+    }
+    else if(state->pos.row > 0)
+        state->pos.row--;
+    break;
+
+  case 0x8e: /* SS2 - ECMA-48 8.3.141 */
+    state->gsingle_set = 2;
+    break;
+
+  case 0x8f: /* SS3 - ECMA-48 8.3.142 */
+    state->gsingle_set = 3;
+    break;
+
+  default:
+    if(state->fallbacks && state->fallbacks->control)
+      if((*state->fallbacks->control)(control, state->fbdata))
+        return 1;
+
+    return 0;
+  }
+
+  updatecursor(state, &oldpos, 1);
+
+#ifdef DEBUG
+  if(state->pos.row < 0 || state->pos.row >= state->rows ||
+     state->pos.col < 0 || state->pos.col >= state->cols) {
+    fprintf(stderr, "Position out of bounds after Ctrl %02x: (%d,%d)\n",
+        control, state->pos.row, state->pos.col);
+    abort();
+  }
+#endif
+
+  return 1;
+}
+
+static int settermprop_bool(VTermState *state, VTermProp prop, int v)
+{
+  VTermValue val;
+  val.boolean = v;
+  return vterm_state_set_termprop(state, prop, &val);
+}
+
+static int settermprop_int(VTermState *state, VTermProp prop, int v)
+{
+  VTermValue val;
+  val.number = v;
+  return vterm_state_set_termprop(state, prop, &val);
+}
+
+static int settermprop_string(VTermState *state, VTermProp prop, const char *str, size_t len)
+{
+  char *strvalue;
+  int r;
+  VTermValue val;
+  strvalue = vterm_allocator_malloc(state->vt, (len+1) * sizeof(char));
+  strncpy(strvalue, str, len);
+  strvalue[len] = 0;
+
+  val.string = strvalue;
+  r = vterm_state_set_termprop(state, prop, &val);
+  vterm_allocator_free(state->vt, strvalue);
+  return r;
+}
+
+static void savecursor(VTermState *state, int save)
+{
+  if(save) {
+    state->saved.pos = state->pos;
+    state->saved.mode.cursor_visible = state->mode.cursor_visible;
+    state->saved.mode.cursor_blink   = state->mode.cursor_blink;
+    state->saved.mode.cursor_shape   = state->mode.cursor_shape;
+
+    vterm_state_savepen(state, 1);
+  }
+  else {
+    VTermPos oldpos = state->pos;
+
+    state->pos = state->saved.pos;
+
+    settermprop_bool(state, VTERM_PROP_CURSORVISIBLE, state->saved.mode.cursor_visible);
+    settermprop_bool(state, VTERM_PROP_CURSORBLINK,   state->saved.mode.cursor_blink);
+    settermprop_int (state, VTERM_PROP_CURSORSHAPE,   state->saved.mode.cursor_shape);
+
+    vterm_state_savepen(state, 0);
+
+    updatecursor(state, &oldpos, 1);
+  }
+}
+
+static int on_escape(const char *bytes, size_t len, void *user)
+{
+  VTermState *state = user;
+
+  /* Easier to decode this from the first byte, even though the final
+   * byte terminates it
+   */
+  switch(bytes[0]) {
+  case ' ':
+    if(len != 2)
+      return 0;
+
+    switch(bytes[1]) {
+      case 'F': /* S7C1T */
+        state->vt->mode.ctrl8bit = 0;
+        break;
+
+      case 'G': /* S8C1T */
+        state->vt->mode.ctrl8bit = 1;
+        break;
+
+      default:
+        return 0;
+    }
+    return 2;
+
+  case '#':
+    if(len != 2)
+      return 0;
+
+    switch(bytes[1]) {
+      case '3': /* DECDHL top */
+        if(state->mode.leftrightmargin)
+          break;
+        set_lineinfo(state, state->pos.row, NO_FORCE, DWL_ON, DHL_TOP);
+        break;
+
+      case '4': /* DECDHL bottom */
+        if(state->mode.leftrightmargin)
+          break;
+        set_lineinfo(state, state->pos.row, NO_FORCE, DWL_ON, DHL_BOTTOM);
+        break;
+
+      case '5': /* DECSWL */
+        if(state->mode.leftrightmargin)
+          break;
+        set_lineinfo(state, state->pos.row, NO_FORCE, DWL_OFF, DHL_OFF);
+        break;
+
+      case '6': /* DECDWL */
+        if(state->mode.leftrightmargin)
+          break;
+        set_lineinfo(state, state->pos.row, NO_FORCE, DWL_ON, DHL_OFF);
+        break;
+
+      case '8': /* DECALN */
+      {
+        VTermPos pos;
+        uint32_t E[] = { 'E', 0 };
+        for(pos.row = 0; pos.row < state->rows; pos.row++)
+          for(pos.col = 0; pos.col < ROWWIDTH(state, pos.row); pos.col++)
+            putglyph(state, E, 1, pos);
+        break;
+      }
+
+      default:
+        return 0;
+    }
+    return 2;
+
+  case '(': case ')': case '*': case '+': /* SCS */
+    if(len != 2)
+      return 0;
+
+    {
+      int setnum = bytes[0] - 0x28;
+      VTermEncoding *newenc = vterm_lookup_encoding(ENC_SINGLE_94, bytes[1]);
+
+      if(newenc) {
+        state->encoding[setnum].enc = newenc;
+
+        if(newenc->init)
+          (*newenc->init)(newenc, state->encoding[setnum].data);
+      }
+    }
+
+    return 2;
+
+  case '7': /* DECSC */
+    savecursor(state, 1);
+    return 1;
+
+  case '8': /* DECRC */
+    savecursor(state, 0);
+    return 1;
+
+  case '<': /* Ignored by VT100. Used in VT52 mode to switch up to VT100 */
+    return 1;
+
+  case '=': /* DECKPAM */
+    state->mode.keypad = 1;
+    return 1;
+
+  case '>': /* DECKPNM */
+    state->mode.keypad = 0;
+    return 1;
+
+  case 'c': /* RIS - ECMA-48 8.3.105 */
+  {
+    VTermPos oldpos = state->pos;
+    vterm_state_reset(state, 1);
+    if(state->callbacks && state->callbacks->movecursor)
+      (*state->callbacks->movecursor)(state->pos, oldpos, state->mode.cursor_visible, state->cbdata);
+    return 1;
+  }
+
+  case 'n': /* LS2 - ECMA-48 8.3.78 */
+    state->gl_set = 2;
+    return 1;
+
+  case 'o': /* LS3 - ECMA-48 8.3.80 */
+    state->gl_set = 3;
+    return 1;
+
+  case '~': /* LS1R - ECMA-48 8.3.77 */
+    state->gr_set = 1;
+    return 1;
+
+  case '}': /* LS2R - ECMA-48 8.3.79 */
+    state->gr_set = 2;
+    return 1;
+
+  case '|': /* LS3R - ECMA-48 8.3.81 */
+    state->gr_set = 3;
+    return 1;
+
+  default:
+    return 0;
+  }
+}
+
+static void set_mode(VTermState *state, int num, int val)
+{
+  switch(num) {
+  case 4: /* IRM - ECMA-48 7.2.10 */
+    state->mode.insert = val;
+    break;
+
+  case 20: /* LNM - ANSI X3.4-1977 */
+    state->mode.newline = val;
+    break;
+
+  default:
+    DEBUG_LOG1("libvterm: Unknown mode %d\n", num);
+    return;
+  }
+}
+
+static void set_dec_mode(VTermState *state, int num, int val)
+{
+  switch(num) {
+  case 1:
+    state->mode.cursor = val;
+    break;
+
+  case 5: /* DECSCNM - screen mode */
+    settermprop_bool(state, VTERM_PROP_REVERSE, val);
+    break;
+
+  case 6: /* DECOM - origin mode */
+    {
+      VTermPos oldpos = state->pos;
+      state->mode.origin = val;
+      state->pos.row = state->mode.origin ? state->scrollregion_top : 0;
+      state->pos.col = state->mode.origin ? SCROLLREGION_LEFT(state) : 0;
+      updatecursor(state, &oldpos, 1);
+    }
+    break;
+
+  case 7:
+    state->mode.autowrap = val;
+    break;
+
+  case 12:
+    settermprop_bool(state, VTERM_PROP_CURSORBLINK, val);
+    break;
+
+  case 25:
+    settermprop_bool(state, VTERM_PROP_CURSORVISIBLE, val);
+    break;
+
+  case 69: /* DECVSSM - vertical split screen mode */
+           /* DECLRMM - left/right margin mode */
+    state->mode.leftrightmargin = val;
+    if(val) {
+      int row;
+
+      /* Setting DECVSSM must clear doublewidth/doubleheight state of every line */
+      for(row = 0; row < state->rows; row++)
+        set_lineinfo(state, row, FORCE, DWL_OFF, DHL_OFF);
+    }
+
+    break;
+
+  case 1000:
+  case 1002:
+  case 1003:
+    settermprop_int(state, VTERM_PROP_MOUSE,
+        !val          ? VTERM_PROP_MOUSE_NONE  :
+        (num == 1000) ? VTERM_PROP_MOUSE_CLICK :
+        (num == 1002) ? VTERM_PROP_MOUSE_DRAG  :
+                        VTERM_PROP_MOUSE_MOVE);
+    break;
+
+  case 1005:
+    state->mouse_protocol = val ? MOUSE_UTF8 : MOUSE_X10;
+    break;
+
+  case 1006:
+    state->mouse_protocol = val ? MOUSE_SGR : MOUSE_X10;
+    break;
+
+  case 1015:
+    state->mouse_protocol = val ? MOUSE_RXVT : MOUSE_X10;
+    break;
+
+  case 1047:
+    settermprop_bool(state, VTERM_PROP_ALTSCREEN, val);
+    break;
+
+  case 1048:
+    savecursor(state, val);
+    break;
+
+  case 1049:
+    settermprop_bool(state, VTERM_PROP_ALTSCREEN, val);
+    savecursor(state, val);
+    break;
+
+  case 2004:
+    state->mode.bracketpaste = val;
+    break;
+
+  default:
+    DEBUG_LOG1("libvterm: Unknown DEC mode %d\n", num);
+    return;
+  }
+}
+
+static void request_dec_mode(VTermState *state, int num)
+{
+  int reply;
+
+  switch(num) {
+    case 1:
+      reply = state->mode.cursor;
+      break;
+
+    case 5:
+      reply = state->mode.screen;
+      break;
+
+    case 6:
+      reply = state->mode.origin;
+      break;
+
+    case 7:
+      reply = state->mode.autowrap;
+      break;
+
+    case 12:
+      reply = state->mode.cursor_blink;
+      break;
+
+    case 25:
+      reply = state->mode.cursor_visible;
+      break;
+
+    case 69:
+      reply = state->mode.leftrightmargin;
+      break;
+
+    case 1000:
+      reply = state->mouse_flags == MOUSE_WANT_CLICK;
+      break;
+
+    case 1002:
+      reply = state->mouse_flags == (MOUSE_WANT_CLICK|MOUSE_WANT_DRAG);
+      break;
+
+    case 1003:
+      reply = state->mouse_flags == (MOUSE_WANT_CLICK|MOUSE_WANT_MOVE);
+      break;
+
+    case 1005:
+      reply = state->mouse_protocol == MOUSE_UTF8;
+      break;
+
+    case 1006:
+      reply = state->mouse_protocol == MOUSE_SGR;
+      break;
+
+    case 1015:
+      reply = state->mouse_protocol == MOUSE_RXVT;
+      break;
+
+    case 1047:
+      reply = state->mode.alt_screen;
+      break;
+
+    case 2004:
+      reply = state->mode.bracketpaste;
+
+    default:
+      vterm_push_output_sprintf_ctrl(state->vt, C1_CSI, "?%d;%d$y", num, 0);
+      return;
+  }
+
+  vterm_push_output_sprintf_ctrl(state->vt, C1_CSI, "?%d;%d$y", num, reply ? 1 : 2);
+}
+
+static int on_csi(const char *leader, const long args[], int argcount, const char *intermed, char command, void *user)
+{
+  VTermState *state = user;
+  int leader_byte = 0;
+  int intermed_byte = 0;
+  VTermPos oldpos = state->pos;
+
+  /* Some temporaries for later code */
+  int count, val;
+  int row, col;
+  VTermRect rect;
+  int selective;
+
+  if(leader && leader[0]) {
+    if(leader[1]) /* longer than 1 char */
+      return 0;
+
+    switch(leader[0]) {
+    case '?':
+    case '>':
+      leader_byte = leader[0];
+      break;
+    default:
+      return 0;
+    }
+  }
+
+  if(intermed && intermed[0]) {
+    if(intermed[1]) /* longer than 1 char */
+      return 0;
+
+    switch(intermed[0]) {
+    case ' ':
+    case '"':
+    case '$':
+    case '\'':
+      intermed_byte = intermed[0];
+      break;
+    default:
+      return 0;
+    }
+  }
+
+  oldpos = state->pos;
+
+#define LBOUND(v,min) if((v) < (min)) (v) = (min)
+#define UBOUND(v,max) if((v) > (max)) (v) = (max)
+
+#define LEADER(l,b) ((l << 8) | b)
+#define INTERMED(i,b) ((i << 16) | b)
+
+  switch(intermed_byte << 16 | leader_byte << 8 | command) {
+  case 0x40: /* ICH - ECMA-48 8.3.64 */
+    count = CSI_ARG_COUNT(args[0]);
+
+    if(!is_cursor_in_scrollregion(state))
+      break;
+
+    rect.start_row = state->pos.row;
+    rect.end_row   = state->pos.row + 1;
+    rect.start_col = state->pos.col;
+    if(state->mode.leftrightmargin)
+      rect.end_col = SCROLLREGION_RIGHT(state);
+    else
+      rect.end_col = THISROWWIDTH(state);
+
+    scroll(state, rect, 0, -count);
+
+    break;
+
+  case 0x41: /* CUU - ECMA-48 8.3.22 */
+    count = CSI_ARG_COUNT(args[0]);
+    state->pos.row -= count;
+    state->at_phantom = 0;
+    break;
+
+  case 0x42: /* CUD - ECMA-48 8.3.19 */
+    count = CSI_ARG_COUNT(args[0]);
+    state->pos.row += count;
+    state->at_phantom = 0;
+    break;
+
+  case 0x43: /* CUF - ECMA-48 8.3.20 */
+    count = CSI_ARG_COUNT(args[0]);
+    state->pos.col += count;
+    state->at_phantom = 0;
+    break;
+
+  case 0x44: /* CUB - ECMA-48 8.3.18 */
+    count = CSI_ARG_COUNT(args[0]);
+    state->pos.col -= count;
+    state->at_phantom = 0;
+    break;
+
+  case 0x45: /* CNL - ECMA-48 8.3.12 */
+    count = CSI_ARG_COUNT(args[0]);
+    state->pos.col = 0;
+    state->pos.row += count;
+    state->at_phantom = 0;
+    break;
+
+  case 0x46: /* CPL - ECMA-48 8.3.13 */
+    count = CSI_ARG_COUNT(args[0]);
+    state->pos.col = 0;
+    state->pos.row -= count;
+    state->at_phantom = 0;
+    break;
+
+  case 0x47: /* CHA - ECMA-48 8.3.9 */
+    val = CSI_ARG_OR(args[0], 1);
+    state->pos.col = val-1;
+    state->at_phantom = 0;
+    break;
+
+  case 0x48: /* CUP - ECMA-48 8.3.21 */
+    row = CSI_ARG_OR(args[0], 1);
+    col = argcount < 2 || CSI_ARG_IS_MISSING(args[1]) ? 1 : CSI_ARG(args[1]);
+    /* zero-based */
+    state->pos.row = row-1;
+    state->pos.col = col-1;
+    if(state->mode.origin) {
+      state->pos.row += state->scrollregion_top;
+      state->pos.col += SCROLLREGION_LEFT(state);
+    }
+    state->at_phantom = 0;
+    break;
+
+  case 0x49: /* CHT - ECMA-48 8.3.10 */
+    count = CSI_ARG_COUNT(args[0]);
+    tab(state, count, +1);
+    break;
+
+  case 0x4a: /* ED - ECMA-48 8.3.39 */
+  case LEADER('?', 0x4a): /* DECSED - Selective Erase in Display */
+    selective = (leader_byte == '?');
+    switch(CSI_ARG(args[0])) {
+    case CSI_ARG_MISSING:
+    case 0:
+      rect.start_row = state->pos.row; rect.end_row = state->pos.row + 1;
+      rect.start_col = state->pos.col; rect.end_col = state->cols;
+      if(rect.end_col > rect.start_col)
+        erase(state, rect, selective);
+
+      rect.start_row = state->pos.row + 1; rect.end_row = state->rows;
+      rect.start_col = 0;
+      for(row = rect.start_row; row < rect.end_row; row++)
+	set_lineinfo(state, row, FORCE, DWL_OFF, DHL_OFF);
+      if(rect.end_row > rect.start_row)
+        erase(state, rect, selective);
+      break;
+
+    case 1:
+      rect.start_row = 0; rect.end_row = state->pos.row;
+      rect.start_col = 0; rect.end_col = state->cols;
+      for(row = rect.start_row; row < rect.end_row; row++)
+	set_lineinfo(state, row, FORCE, DWL_OFF, DHL_OFF);
+      if(rect.end_col > rect.start_col)
+        erase(state, rect, selective);
+
+      rect.start_row = state->pos.row; rect.end_row = state->pos.row + 1;
+                          rect.end_col = state->pos.col + 1;
+      if(rect.end_row > rect.start_row)
+        erase(state, rect, selective);
+      break;
+
+    case 2:
+      rect.start_row = 0; rect.end_row = state->rows;
+      rect.start_col = 0; rect.end_col = state->cols;
+      for(row = rect.start_row; row < rect.end_row; row++)
+	set_lineinfo(state, row, FORCE, DWL_OFF, DHL_OFF);
+      erase(state, rect, selective);
+      break;
+    }
+    break;
+
+  case 0x4b: /* EL - ECMA-48 8.3.41 */
+  case LEADER('?', 0x4b): /* DECSEL - Selective Erase in Line */
+    selective = (leader_byte == '?');
+    rect.start_row = state->pos.row;
+    rect.end_row   = state->pos.row + 1;
+
+    switch(CSI_ARG(args[0])) {
+    case CSI_ARG_MISSING:
+    case 0:
+      rect.start_col = state->pos.col; rect.end_col = THISROWWIDTH(state); break;
+    case 1:
+      rect.start_col = 0; rect.end_col = state->pos.col + 1; break;
+    case 2:
+      rect.start_col = 0; rect.end_col = THISROWWIDTH(state); break;
+    default:
+      return 0;
+    }
+
+    if(rect.end_col > rect.start_col)
+      erase(state, rect, selective);
+
+    break;
+
+  case 0x4c: /* IL - ECMA-48 8.3.67 */
+    count = CSI_ARG_COUNT(args[0]);
+
+    if(!is_cursor_in_scrollregion(state))
+      break;
+
+    rect.start_row = state->pos.row;
+    rect.end_row   = SCROLLREGION_BOTTOM(state);
+    rect.start_col = SCROLLREGION_LEFT(state);
+    rect.end_col   = SCROLLREGION_RIGHT(state);
+
+    scroll(state, rect, -count, 0);
+
+    break;
+
+  case 0x4d: /* DL - ECMA-48 8.3.32 */
+    count = CSI_ARG_COUNT(args[0]);
+
+    if(!is_cursor_in_scrollregion(state))
+      break;
+
+    rect.start_row = state->pos.row;
+    rect.end_row   = SCROLLREGION_BOTTOM(state);
+    rect.start_col = SCROLLREGION_LEFT(state);
+    rect.end_col   = SCROLLREGION_RIGHT(state);
+
+    scroll(state, rect, count, 0);
+
+    break;
+
+  case 0x50: /* DCH - ECMA-48 8.3.26 */
+    count = CSI_ARG_COUNT(args[0]);
+
+    if(!is_cursor_in_scrollregion(state))
+      break;
+
+    rect.start_row = state->pos.row;
+    rect.end_row   = state->pos.row + 1;
+    rect.start_col = state->pos.col;
+    if(state->mode.leftrightmargin)
+      rect.end_col = SCROLLREGION_RIGHT(state);
+    else
+      rect.end_col = THISROWWIDTH(state);
+
+    scroll(state, rect, 0, count);
+
+    break;
+
+  case 0x53: /* SU - ECMA-48 8.3.147 */
+    count = CSI_ARG_COUNT(args[0]);
+
+    rect.start_row = state->scrollregion_top;
+    rect.end_row   = SCROLLREGION_BOTTOM(state);
+    rect.start_col = SCROLLREGION_LEFT(state);
+    rect.end_col   = SCROLLREGION_RIGHT(state);
+
+    scroll(state, rect, count, 0);
+
+    break;
+
+  case 0x54: /* SD - ECMA-48 8.3.113 */
+    count = CSI_ARG_COUNT(args[0]);
+
+    rect.start_row = state->scrollregion_top;
+    rect.end_row   = SCROLLREGION_BOTTOM(state);
+    rect.start_col = SCROLLREGION_LEFT(state);
+    rect.end_col   = SCROLLREGION_RIGHT(state);
+
+    scroll(state, rect, -count, 0);
+
+    break;
+
+  case 0x58: /* ECH - ECMA-48 8.3.38 */
+    count = CSI_ARG_COUNT(args[0]);
+
+    rect.start_row = state->pos.row;
+    rect.end_row   = state->pos.row + 1;
+    rect.start_col = state->pos.col;
+    rect.end_col   = state->pos.col + count;
+    UBOUND(rect.end_col, THISROWWIDTH(state));
+
+    erase(state, rect, 0);
+    break;
+
+  case 0x5a: /* CBT - ECMA-48 8.3.7 */
+    count = CSI_ARG_COUNT(args[0]);
+    tab(state, count, -1);
+    break;
+
+  case 0x60: /* HPA - ECMA-48 8.3.57 */
+    col = CSI_ARG_OR(args[0], 1);
+    state->pos.col = col-1;
+    state->at_phantom = 0;
+    break;
+
+  case 0x61: /* HPR - ECMA-48 8.3.59 */
+    count = CSI_ARG_COUNT(args[0]);
+    state->pos.col += count;
+    state->at_phantom = 0;
+    break;
+
+  case 0x63: /* DA - ECMA-48 8.3.24 */
+    val = CSI_ARG_OR(args[0], 0);
+    if(val == 0)
+      /* DEC VT100 response */
+      vterm_push_output_sprintf_ctrl(state->vt, C1_CSI, "?1;2c");
+    break;
+
+  case LEADER('>', 0x63): /* DEC secondary Device Attributes */
+    vterm_push_output_sprintf_ctrl(state->vt, C1_CSI, ">%d;%d;%dc", 0, 100, 0);
+    break;
+
+  case 0x64: /* VPA - ECMA-48 8.3.158 */
+    row = CSI_ARG_OR(args[0], 1);
+    state->pos.row = row-1;
+    if(state->mode.origin)
+      state->pos.row += state->scrollregion_top;
+    state->at_phantom = 0;
+    break;
+
+  case 0x65: /* VPR - ECMA-48 8.3.160 */
+    count = CSI_ARG_COUNT(args[0]);
+    state->pos.row += count;
+    state->at_phantom = 0;
+    break;
+
+  case 0x66: /* HVP - ECMA-48 8.3.63 */
+    row = CSI_ARG_OR(args[0], 1);
+    col = argcount < 2 || CSI_ARG_IS_MISSING(args[1]) ? 1 : CSI_ARG(args[1]);
+    /* zero-based */
+    state->pos.row = row-1;
+    state->pos.col = col-1;
+    if(state->mode.origin) {
+      state->pos.row += state->scrollregion_top;
+      state->pos.col += SCROLLREGION_LEFT(state);
+    }
+    state->at_phantom = 0;
+    break;
+
+  case 0x67: /* TBC - ECMA-48 8.3.154 */
+    val = CSI_ARG_OR(args[0], 0);
+
+    switch(val) {
+    case 0:
+      clear_col_tabstop(state, state->pos.col);
+      break;
+    case 3:
+    case 5:
+      for(col = 0; col < state->cols; col++)
+        clear_col_tabstop(state, col);
+      break;
+    case 1:
+    case 2:
+    case 4:
+      break;
+    /* TODO: 1, 2 and 4 aren't meaningful yet without line tab stops */
+    default:
+      return 0;
+    }
+    break;
+
+  case 0x68: /* SM - ECMA-48 8.3.125 */
+    if(!CSI_ARG_IS_MISSING(args[0]))
+      set_mode(state, CSI_ARG(args[0]), 1);
+    break;
+
+  case LEADER('?', 0x68): /* DEC private mode set */
+    if(!CSI_ARG_IS_MISSING(args[0]))
+      set_dec_mode(state, CSI_ARG(args[0]), 1);
+    break;
+
+  case 0x6a: /* HPB - ECMA-48 8.3.58 */
+    count = CSI_ARG_COUNT(args[0]);
+    state->pos.col -= count;
+    state->at_phantom = 0;
+    break;
+
+  case 0x6b: /* VPB - ECMA-48 8.3.159 */
+    count = CSI_ARG_COUNT(args[0]);
+    state->pos.row -= count;
+    state->at_phantom = 0;
+    break;
+
+  case 0x6c: /* RM - ECMA-48 8.3.106 */
+    if(!CSI_ARG_IS_MISSING(args[0]))
+      set_mode(state, CSI_ARG(args[0]), 0);
+    break;
+
+  case LEADER('?', 0x6c): /* DEC private mode reset */
+    if(!CSI_ARG_IS_MISSING(args[0]))
+      set_dec_mode(state, CSI_ARG(args[0]), 0);
+    break;
+
+  case 0x6d: /* SGR - ECMA-48 8.3.117 */
+    vterm_state_setpen(state, args, argcount);
+    break;
+
+  case 0x6e: /* DSR - ECMA-48 8.3.35 */
+  case LEADER('?', 0x6e): /* DECDSR */
+    val = CSI_ARG_OR(args[0], 0);
+
+    {
+      char *qmark = (leader_byte == '?') ? "?" : "";
+
+      switch(val) {
+      case 0: case 1: case 2: case 3: case 4:
+        /* ignore - these are replies */
+        break;
+      case 5:
+        vterm_push_output_sprintf_ctrl(state->vt, C1_CSI, "%s0n", qmark);
+        break;
+      case 6: /* CPR - cursor position report */
+        vterm_push_output_sprintf_ctrl(state->vt, C1_CSI, "%s%d;%dR", qmark, state->pos.row + 1, state->pos.col + 1);
+        break;
+      }
+    }
+    break;
+
+
+  case LEADER('!', 0x70): /* DECSTR - DEC soft terminal reset */
+    vterm_state_reset(state, 0);
+    break;
+
+  case LEADER('?', INTERMED('$', 0x70)):
+    request_dec_mode(state, CSI_ARG(args[0]));
+    break;
+
+  case INTERMED(' ', 0x71): /* DECSCUSR - DEC set cursor shape */
+    val = CSI_ARG_OR(args[0], 1);
+
+    switch(val) {
+    case 0: case 1:
+      settermprop_bool(state, VTERM_PROP_CURSORBLINK, 1);
+      settermprop_int (state, VTERM_PROP_CURSORSHAPE, VTERM_PROP_CURSORSHAPE_BLOCK);
+      break;
+    case 2:
+      settermprop_bool(state, VTERM_PROP_CURSORBLINK, 0);
+      settermprop_int (state, VTERM_PROP_CURSORSHAPE, VTERM_PROP_CURSORSHAPE_BLOCK);
+      break;
+    case 3:
+      settermprop_bool(state, VTERM_PROP_CURSORBLINK, 1);
+      settermprop_int (state, VTERM_PROP_CURSORSHAPE, VTERM_PROP_CURSORSHAPE_UNDERLINE);
+      break;
+    case 4:
+      settermprop_bool(state, VTERM_PROP_CURSORBLINK, 0);
+      settermprop_int (state, VTERM_PROP_CURSORSHAPE, VTERM_PROP_CURSORSHAPE_UNDERLINE);
+      break;
+    case 5:
+      settermprop_bool(state, VTERM_PROP_CURSORBLINK, 1);
+      settermprop_int (state, VTERM_PROP_CURSORSHAPE, VTERM_PROP_CURSORSHAPE_BAR_LEFT);
+      break;
+    case 6:
+      settermprop_bool(state, VTERM_PROP_CURSORBLINK, 0);
+      settermprop_int (state, VTERM_PROP_CURSORSHAPE, VTERM_PROP_CURSORSHAPE_BAR_LEFT);
+      break;
+    }
+
+    break;
+
+  case INTERMED('"', 0x71): /* DECSCA - DEC select character protection attribute */
+    val = CSI_ARG_OR(args[0], 0);
+
+    switch(val) {
+    case 0: case 2:
+      state->protected_cell = 0;
+      break;
+    case 1:
+      state->protected_cell = 1;
+      break;
+    }
+
+    break;
+
+  case 0x72: /* DECSTBM - DEC custom */
+    state->scrollregion_top = CSI_ARG_OR(args[0], 1) - 1;
+    state->scrollregion_bottom = argcount < 2 || CSI_ARG_IS_MISSING(args[1]) ? -1 : CSI_ARG(args[1]);
+    LBOUND(state->scrollregion_top, 0);
+    UBOUND(state->scrollregion_top, state->rows);
+    LBOUND(state->scrollregion_bottom, -1);
+    if(state->scrollregion_top == 0 && state->scrollregion_bottom == state->rows)
+      state->scrollregion_bottom = -1;
+    else
+      UBOUND(state->scrollregion_bottom, state->rows);
+
+    if(SCROLLREGION_BOTTOM(state) <= state->scrollregion_top) {
+      /* Invalid */
+      state->scrollregion_top    = 0;
+      state->scrollregion_bottom = -1;
+    }
+
+    break;
+
+  case 0x73: /* DECSLRM - DEC custom */
+    /* Always allow setting these margins, just they won't take effect without DECVSSM */
+    state->scrollregion_left = CSI_ARG_OR(args[0], 1) - 1;
+    state->scrollregion_right = argcount < 2 || CSI_ARG_IS_MISSING(args[1]) ? -1 : CSI_ARG(args[1]);
+    LBOUND(state->scrollregion_left, 0);
+    UBOUND(state->scrollregion_left, state->cols);
+    LBOUND(state->scrollregion_right, -1);
+    if(state->scrollregion_left == 0 && state->scrollregion_right == state->cols)
+      state->scrollregion_right = -1;
+    else
+      UBOUND(state->scrollregion_right, state->cols);
+
+    if(state->scrollregion_right > -1 &&
+       state->scrollregion_right <= state->scrollregion_left) {
+      /* Invalid */
+      state->scrollregion_left  = 0;
+      state->scrollregion_right = -1;
+    }
+
+    break;
+
+  case INTERMED('\'', 0x7D): /* DECIC */
+    count = CSI_ARG_COUNT(args[0]);
+
+    if(!is_cursor_in_scrollregion(state))
+      break;
+
+    rect.start_row = state->scrollregion_top;
+    rect.end_row   = SCROLLREGION_BOTTOM(state);
+    rect.start_col = state->pos.col;
+    rect.end_col   = SCROLLREGION_RIGHT(state);
+
+    scroll(state, rect, 0, -count);
+
+    break;
+
+  case INTERMED('\'', 0x7E): /* DECDC */
+    count = CSI_ARG_COUNT(args[0]);
+
+    if(!is_cursor_in_scrollregion(state))
+      break;
+
+    rect.start_row = state->scrollregion_top;
+    rect.end_row   = SCROLLREGION_BOTTOM(state);
+    rect.start_col = state->pos.col;
+    rect.end_col   = SCROLLREGION_RIGHT(state);
+
+    scroll(state, rect, 0, count);
+
+    break;
+
+  default:
+    if(state->fallbacks && state->fallbacks->csi)
+      if((*state->fallbacks->csi)(leader, args, argcount, intermed, command, state->fbdata))
+        return 1;
+
+    return 0;
+  }
+
+  if(state->mode.origin) {
+    LBOUND(state->pos.row, state->scrollregion_top);
+    UBOUND(state->pos.row, SCROLLREGION_BOTTOM(state)-1);
+    LBOUND(state->pos.col, SCROLLREGION_LEFT(state));
+    UBOUND(state->pos.col, SCROLLREGION_RIGHT(state)-1);
+  }
+  else {
+    LBOUND(state->pos.row, 0);
+    UBOUND(state->pos.row, state->rows-1);
+    LBOUND(state->pos.col, 0);
+    UBOUND(state->pos.col, THISROWWIDTH(state)-1);
+  }
+
+  updatecursor(state, &oldpos, 1);
+
+#ifdef DEBUG
+  if(state->pos.row < 0 || state->pos.row >= state->rows ||
+     state->pos.col < 0 || state->pos.col >= state->cols) {
+    fprintf(stderr, "Position out of bounds after CSI %c: (%d,%d)\n",
+        command, state->pos.row, state->pos.col);
+    abort();
+  }
+
+  if(SCROLLREGION_BOTTOM(state) <= state->scrollregion_top) {
+    fprintf(stderr, "Scroll region height out of bounds after CSI %c: %d <= %d\n",
+        command, SCROLLREGION_BOTTOM(state), state->scrollregion_top);
+    abort();
+  }
+
+  if(SCROLLREGION_RIGHT(state) <= SCROLLREGION_LEFT(state)) {
+    fprintf(stderr, "Scroll region width out of bounds after CSI %c: %d <= %d\n",
+        command, SCROLLREGION_RIGHT(state), SCROLLREGION_LEFT(state));
+    abort();
+  }
+#endif
+
+  return 1;
+}
+
+static int on_osc(const char *command, size_t cmdlen, void *user)
+{
+  VTermState *state = user;
+
+  if(cmdlen < 2)
+    return 0;
+
+  if(strneq(command, "0;", 2)) {
+    settermprop_string(state, VTERM_PROP_ICONNAME, command + 2, cmdlen - 2);
+    settermprop_string(state, VTERM_PROP_TITLE, command + 2, cmdlen - 2);
+    return 1;
+  }
+  else if(strneq(command, "1;", 2)) {
+    settermprop_string(state, VTERM_PROP_ICONNAME, command + 2, cmdlen - 2);
+    return 1;
+  }
+  else if(strneq(command, "2;", 2)) {
+    settermprop_string(state, VTERM_PROP_TITLE, command + 2, cmdlen - 2);
+    return 1;
+  }
+  else if(state->fallbacks && state->fallbacks->osc)
+    if((*state->fallbacks->osc)(command, cmdlen, state->fbdata))
+      return 1;
+
+  return 0;
+}
+
+static void request_status_string(VTermState *state, const char *command, size_t cmdlen)
+{
+  if(cmdlen == 1)
+    switch(command[0]) {
+      case 'm': /* Query SGR */
+        {
+          long args[20];
+          int argc = vterm_state_getpen(state, args, sizeof(args)/sizeof(args[0]));
+	  int argi;
+          vterm_push_output_sprintf_ctrl(state->vt, C1_DCS, "1$r");
+          for(argi = 0; argi < argc; argi++)
+            vterm_push_output_sprintf(state->vt,
+                argi == argc - 1             ? "%d" :
+                CSI_ARG_HAS_MORE(args[argi]) ? "%d:" :
+                                               "%d;",
+                CSI_ARG(args[argi]));
+          vterm_push_output_sprintf(state->vt, "m");
+          vterm_push_output_sprintf_ctrl(state->vt, C1_ST, "");
+        }
+        return;
+      case 'r': /* Query DECSTBM */
+        vterm_push_output_sprintf_dcs(state->vt, "1$r%d;%dr", state->scrollregion_top+1, SCROLLREGION_BOTTOM(state));
+        return;
+      case 's': /* Query DECSLRM */
+        vterm_push_output_sprintf_dcs(state->vt, "1$r%d;%ds", SCROLLREGION_LEFT(state)+1, SCROLLREGION_RIGHT(state));
+        return;
+    }
+
+  if(cmdlen == 2) {
+    if(strneq(command, " q", 2)) {
+      int reply;
+      switch(state->mode.cursor_shape) {
+        case VTERM_PROP_CURSORSHAPE_BLOCK:     reply = 2; break;
+        case VTERM_PROP_CURSORSHAPE_UNDERLINE: reply = 4; break;
+        case VTERM_PROP_CURSORSHAPE_BAR_LEFT:  reply = 6; break;
+      }
+      if(state->mode.cursor_blink)
+        reply--;
+      vterm_push_output_sprintf_dcs(state->vt, "1$r%d q", reply);
+      return;
+    }
+    else if(strneq(command, "\"q", 2)) {
+      vterm_push_output_sprintf_dcs(state->vt, "1$r%d\"q", state->protected_cell ? 1 : 2);
+      return;
+    }
+  }
+
+  vterm_push_output_sprintf_dcs(state->vt, "0$r%.s", (int)cmdlen, command);
+}
+
+static int on_dcs(const char *command, size_t cmdlen, void *user)
+{
+  VTermState *state = user;
+
+  if(cmdlen >= 2 && strneq(command, "$q", 2)) {
+    request_status_string(state, command+2, cmdlen-2);
+    return 1;
+  }
+  else if(state->fallbacks && state->fallbacks->dcs)
+    if((*state->fallbacks->dcs)(command, cmdlen, state->fbdata))
+      return 1;
+
+  return 0;
+}
+
+static int on_resize(int rows, int cols, void *user)
+{
+  VTermState *state = user;
+  VTermPos oldpos = state->pos;
+  VTermPos delta = { 0, 0 };
+
+  if(cols != state->cols) {
+    unsigned char *newtabstops = vterm_allocator_malloc(state->vt, (cols + 7) / 8);
+
+    /* TODO: This can all be done much more efficiently bytewise */
+    int col;
+    for(col = 0; col < state->cols && col < cols; col++) {
+      unsigned char mask = 1 << (col & 7);
+      if(state->tabstops[col >> 3] & mask)
+        newtabstops[col >> 3] |= mask;
+      else
+        newtabstops[col >> 3] &= ~mask;
+      }
+
+    for( ; col < cols; col++) {
+      unsigned char mask = 1 << (col & 7);
+      if(col % 8 == 0)
+        newtabstops[col >> 3] |= mask;
+      else
+        newtabstops[col >> 3] &= ~mask;
+    }
+
+    vterm_allocator_free(state->vt, state->tabstops);
+    state->tabstops = newtabstops;
+  }
+
+  if(rows != state->rows) {
+    VTermLineInfo *newlineinfo = vterm_allocator_malloc(state->vt, rows * sizeof(VTermLineInfo));
+
+    int row;
+    for(row = 0; row < state->rows && row < rows; row++) {
+      newlineinfo[row] = state->lineinfo[row];
+    }
+
+    for( ; row < rows; row++) {
+      newlineinfo[row].doublewidth = 0;
+      newlineinfo[row].doubleheight = 0;
+    }
+
+    vterm_allocator_free(state->vt, state->lineinfo);
+    state->lineinfo = newlineinfo;
+  }
+
+  state->rows = rows;
+  state->cols = cols;
+
+  if(state->scrollregion_bottom > -1)
+    UBOUND(state->scrollregion_bottom, state->rows);
+  if(state->scrollregion_right > -1)
+    UBOUND(state->scrollregion_right, state->cols);
+
+  if(state->callbacks && state->callbacks->resize)
+    (*state->callbacks->resize)(rows, cols, &delta, state->cbdata);
+
+  if(state->at_phantom && state->pos.col < cols-1) {
+    state->at_phantom = 0;
+    state->pos.col++;
+  }
+
+  state->pos.row += delta.row;
+  state->pos.col += delta.col;
+
+  if(state->pos.row >= rows)
+    state->pos.row = rows - 1;
+  if(state->pos.col >= cols)
+    state->pos.col = cols - 1;
+
+  updatecursor(state, &oldpos, 1);
+
+  return 1;
+}
+
+static const VTermParserCallbacks parser_callbacks = {
+  on_text, /* text */
+  on_control, /* control */
+  on_escape, /* escape */
+  on_csi, /* csi */
+  on_osc, /* osc */
+  on_dcs, /* dcs */
+  on_resize /* resize */
+};
+
+VTermState *vterm_obtain_state(VTerm *vt)
+{
+  VTermState *state;
+  if(vt->state)
+    return vt->state;
+
+  state = vterm_state_new(vt);
+  vt->state = state;
+
+  state->combine_chars_size = 16;
+  state->combine_chars = vterm_allocator_malloc(state->vt, state->combine_chars_size * sizeof(state->combine_chars[0]));
+
+  state->tabstops = vterm_allocator_malloc(state->vt, (state->cols + 7) / 8);
+
+  state->lineinfo = vterm_allocator_malloc(state->vt, state->rows * sizeof(VTermLineInfo));
+
+  state->encoding_utf8.enc = vterm_lookup_encoding(ENC_UTF8, 'u');
+  if(*state->encoding_utf8.enc->init)
+    (*state->encoding_utf8.enc->init)(state->encoding_utf8.enc, state->encoding_utf8.data);
+
+  vterm_parser_set_callbacks(vt, &parser_callbacks, state);
+
+  return state;
+}
+
+void vterm_state_reset(VTermState *state, int hard)
+{
+  VTermEncoding *default_enc;
+
+  state->scrollregion_top = 0;
+  state->scrollregion_bottom = -1;
+  state->scrollregion_left = 0;
+  state->scrollregion_right = -1;
+
+  state->mode.keypad          = 0;
+  state->mode.cursor          = 0;
+  state->mode.autowrap        = 1;
+  state->mode.insert          = 0;
+  state->mode.newline         = 0;
+  state->mode.alt_screen      = 0;
+  state->mode.origin          = 0;
+  state->mode.leftrightmargin = 0;
+  state->mode.bracketpaste    = 0;
+
+  state->vt->mode.ctrl8bit   = 0;
+
+  {
+    int col;
+    for(col = 0; col < state->cols; col++)
+      if(col % 8 == 0)
+	set_col_tabstop(state, col);
+      else
+	clear_col_tabstop(state, col);
+  }
+
+  {
+    int row;
+    for(row = 0; row < state->rows; row++)
+      set_lineinfo(state, row, FORCE, DWL_OFF, DHL_OFF);
+  }
+
+  if(state->callbacks && state->callbacks->initpen)
+    (*state->callbacks->initpen)(state->cbdata);
+
+  vterm_state_resetpen(state);
+
+  default_enc = state->vt->mode.utf8 ?
+      vterm_lookup_encoding(ENC_UTF8,      'u') :
+      vterm_lookup_encoding(ENC_SINGLE_94, 'B');
+
+  {
+    int i;
+    for(i = 0; i < 4; i++) {
+      state->encoding[i].enc = default_enc;
+      if(default_enc->init)
+	(*default_enc->init)(default_enc, state->encoding[i].data);
+    }
+  }
+
+  state->gl_set = 0;
+  state->gr_set = 1;
+  state->gsingle_set = 0;
+
+  state->protected_cell = 0;
+
+  /* Initialise the props */
+  settermprop_bool(state, VTERM_PROP_CURSORVISIBLE, 1);
+  settermprop_bool(state, VTERM_PROP_CURSORBLINK,   1);
+  settermprop_int (state, VTERM_PROP_CURSORSHAPE,   VTERM_PROP_CURSORSHAPE_BLOCK);
+
+  if(hard) {
+    VTermRect rect = { 0, 0, 0, 0 };
+
+    state->pos.row = 0;
+    state->pos.col = 0;
+    state->at_phantom = 0;
+
+    rect.end_row = state->rows;
+    rect.end_col =  state->cols;
+    erase(state, rect, 0);
+  }
+}
+
+void vterm_state_get_cursorpos(const VTermState *state, VTermPos *cursorpos)
+{
+  *cursorpos = state->pos;
+}
+
+void vterm_state_set_callbacks(VTermState *state, const VTermStateCallbacks *callbacks, void *user)
+{
+  if(callbacks) {
+    state->callbacks = callbacks;
+    state->cbdata = user;
+
+    if(state->callbacks && state->callbacks->initpen)
+      (*state->callbacks->initpen)(state->cbdata);
+  }
+  else {
+    state->callbacks = NULL;
+    state->cbdata = NULL;
+  }
+}
+
+void *vterm_state_get_cbdata(VTermState *state)
+{
+  return state->cbdata;
+}
+
+void vterm_state_set_unrecognised_fallbacks(VTermState *state, const VTermParserCallbacks *fallbacks, void *user)
+{
+  if(fallbacks) {
+    state->fallbacks = fallbacks;
+    state->fbdata = user;
+  }
+  else {
+    state->fallbacks = NULL;
+    state->fbdata = NULL;
+  }
+}
+
+void *vterm_state_get_unrecognised_fbdata(VTermState *state)
+{
+  return state->fbdata;
+}
+
+int vterm_state_set_termprop(VTermState *state, VTermProp prop, VTermValue *val)
+{
+  /* Only store the new value of the property if usercode said it was happy.
+   * This is especially important for altscreen switching */
+  if(state->callbacks && state->callbacks->settermprop)
+    if(!(*state->callbacks->settermprop)(prop, val, state->cbdata))
+      return 0;
+
+  switch(prop) {
+  case VTERM_PROP_TITLE:
+  case VTERM_PROP_ICONNAME:
+    /* we don't store these, just transparently pass through */
+    return 1;
+  case VTERM_PROP_CURSORVISIBLE:
+    state->mode.cursor_visible = val->boolean;
+    return 1;
+  case VTERM_PROP_CURSORBLINK:
+    state->mode.cursor_blink = val->boolean;
+    return 1;
+  case VTERM_PROP_CURSORSHAPE:
+    state->mode.cursor_shape = val->number;
+    return 1;
+  case VTERM_PROP_REVERSE:
+    state->mode.screen = val->boolean;
+    return 1;
+  case VTERM_PROP_ALTSCREEN:
+    state->mode.alt_screen = val->boolean;
+    if(state->mode.alt_screen) {
+      VTermRect rect = {0, 0, 0, 0};
+      rect.end_row = state->rows;
+      rect.end_col = state->cols;
+      erase(state, rect, 0);
+    }
+    return 1;
+  case VTERM_PROP_MOUSE:
+    state->mouse_flags = 0;
+    if(val->number)
+      state->mouse_flags |= MOUSE_WANT_CLICK;
+    if(val->number == VTERM_PROP_MOUSE_DRAG)
+      state->mouse_flags |= MOUSE_WANT_DRAG;
+    if(val->number == VTERM_PROP_MOUSE_MOVE)
+      state->mouse_flags |= MOUSE_WANT_MOVE;
+    return 1;
+  }
+
+  return 0;
+}
+
+const VTermLineInfo *vterm_state_get_lineinfo(const VTermState *state, int row)
+{
+  return state->lineinfo + row;
+}