new file mode 100644
--- /dev/null
+++ b/src/libvterm/src/vterm_internal.h
@@ -0,0 +1,237 @@
+#ifndef __VTERM_INTERNAL_H__
+#define __VTERM_INTERNAL_H__
+
+#include "vterm.h"
+
+#include <stdarg.h>
+
+#if defined(__GNUC__)
+# define INTERNAL __attribute__((visibility("internal")))
+# define UNUSED __attribute__((unused))
+#else
+# define INTERNAL
+# define UNUSED
+#endif
+
+#ifdef DEBUG
+# define DEBUG_LOG(s) fprintf(stderr, s)
+# define DEBUG_LOG1(s, a) fprintf(stderr, s, a)
+# define DEBUG_LOG2(s, a, b) fprintf(stderr, s, a, b)
+# define DEBUG_LOG3(s, a, b, c) fprintf(stderr, s, a, b, c)
+#else
+# define DEBUG_LOG(s)
+# define DEBUG_LOG1(s, a)
+# define DEBUG_LOG2(s, a, b)
+# define DEBUG_LOG3(s, a, b, c)
+#endif
+
+#define ESC_S "\x1b"
+
+typedef struct VTermEncoding VTermEncoding;
+
+typedef struct {
+  VTermEncoding *enc;
+
+  /* This size should be increased if required by other stateful encodings */
+  char           data[4*sizeof(uint32_t)];
+} VTermEncodingInstance;
+
+struct VTermPen
+{
+  VTermColor fg;
+  VTermColor bg;
+  unsigned int bold:1;
+  unsigned int underline:2;
+  unsigned int italic:1;
+  unsigned int blink:1;
+  unsigned int reverse:1;
+  unsigned int strike:1;
+  unsigned int font:4; /* To store 0-9 */
+};
+
+int vterm_color_equal(VTermColor a, VTermColor b);
+
+#if defined(DEFINE_INLINES) || USE_INLINE
+INLINE int vterm_color_equal(VTermColor a, VTermColor b)
+{
+  return a.red == b.red && a.green == b.green && a.blue == b.blue;
+}
+#endif
+
+struct VTermState
+{
+  VTerm *vt;
+
+  const VTermStateCallbacks *callbacks;
+  void *cbdata;
+
+  const VTermParserCallbacks *fallbacks;
+  void *fbdata;
+
+  int rows;
+  int cols;
+
+  /* Current cursor position */
+  VTermPos pos;
+
+  int at_phantom; /* True if we're on the "81st" phantom column to defer a wraparound */
+
+  int scrollregion_top;
+  int scrollregion_bottom; /* -1 means unbounded */
+#define SCROLLREGION_BOTTOM(state) ((state)->scrollregion_bottom > -1 ? (state)->scrollregion_bottom : (state)->rows)
+  int scrollregion_left;
+#define SCROLLREGION_LEFT(state)  ((state)->mode.leftrightmargin ? (state)->scrollregion_left : 0)
+  int scrollregion_right; /* -1 means unbounded */
+#define SCROLLREGION_RIGHT(state) ((state)->mode.leftrightmargin && (state)->scrollregion_right > -1 ? (state)->scrollregion_right : (state)->cols)
+
+  /* Bitvector of tab stops */
+  unsigned char *tabstops;
+
+  VTermLineInfo *lineinfo;
+#define ROWWIDTH(state,row) ((state)->lineinfo[(row)].doublewidth ? ((state)->cols / 2) : (state)->cols)
+#define THISROWWIDTH(state) ROWWIDTH(state, (state)->pos.row)
+
+  /* Mouse state */
+  int mouse_col, mouse_row;
+  int mouse_buttons;
+  int mouse_flags;
+#define MOUSE_WANT_CLICK 0x01
+#define MOUSE_WANT_DRAG  0x02
+#define MOUSE_WANT_MOVE  0x04
+
+  enum { MOUSE_X10, MOUSE_UTF8, MOUSE_SGR, MOUSE_RXVT } mouse_protocol;
+
+  /* Last glyph output, for Unicode recombining purposes */
+  uint32_t *combine_chars;
+  size_t combine_chars_size; /* Number of ELEMENTS in the above */
+  int combine_width; /* The width of the glyph above */
+  VTermPos combine_pos;   /* Position before movement */
+
+  struct {
+    unsigned int keypad:1;
+    unsigned int cursor:1;
+    unsigned int autowrap:1;
+    unsigned int insert:1;
+    unsigned int newline:1;
+    unsigned int cursor_visible:1;
+    unsigned int cursor_blink:1;
+    unsigned int cursor_shape:2;
+    unsigned int alt_screen:1;
+    unsigned int origin:1;
+    unsigned int screen:1;
+    unsigned int leftrightmargin:1;
+    unsigned int bracketpaste:1;
+  } mode;
+
+  VTermEncodingInstance encoding[4], encoding_utf8;
+  int gl_set, gr_set, gsingle_set;
+
+  struct VTermPen pen;
+
+  VTermColor default_fg;
+  VTermColor default_bg;
+  VTermColor colors[16]; /* Store the 8 ANSI and the 8 ANSI high-brights only */
+
+  int fg_index;
+  int bg_index;
+  int bold_is_highbright;
+
+  unsigned int protected_cell : 1;
+
+  /* Saved state under DEC mode 1048/1049 */
+  struct {
+    VTermPos pos;
+    struct VTermPen pen;
+
+    struct {
+      int cursor_visible:1;
+      int cursor_blink:1;
+      unsigned int cursor_shape:2;
+    } mode;
+  } saved;
+};
+
+struct VTerm
+{
+  VTermAllocatorFunctions *allocator;
+  void *allocdata;
+
+  int rows;
+  int cols;
+
+  struct {
+    unsigned int utf8:1;
+    unsigned int ctrl8bit:1;
+  } mode;
+
+  enum VTermParserState {
+    NORMAL,
+    CSI,
+    OSC,
+    DCS,
+    ESC,
+    ESC_IN_OSC,
+    ESC_IN_DCS
+  } parser_state;
+  const VTermParserCallbacks *parser_callbacks;
+  void *cbdata;
+
+  /* len == malloc()ed size; cur == number of valid bytes */
+  char  *strbuffer;
+  size_t strbuffer_len;
+  size_t strbuffer_cur;
+
+  char  *outbuffer;
+  size_t outbuffer_len;
+  size_t outbuffer_cur;
+
+  VTermState *state;
+  VTermScreen *screen;
+};
+
+struct VTermEncoding {
+  void (*init) (VTermEncoding *enc, void *data);
+  void (*decode)(VTermEncoding *enc, void *data,
+                 uint32_t cp[], int *cpi, int cplen,
+                 const char bytes[], size_t *pos, size_t len);
+};
+
+typedef enum {
+  ENC_UTF8,
+  ENC_SINGLE_94
+} VTermEncodingType;
+
+void *vterm_allocator_malloc(VTerm *vt, size_t size);
+void  vterm_allocator_free(VTerm *vt, void *ptr);
+
+void vterm_push_output_bytes(VTerm *vt, const char *bytes, size_t len);
+void vterm_push_output_vsprintf(VTerm *vt, const char *format, va_list args);
+void vterm_push_output_sprintf(VTerm *vt, const char *format, ...);
+void vterm_push_output_sprintf_ctrl(VTerm *vt, unsigned char ctrl, const char *fmt, ...);
+void vterm_push_output_sprintf_dcs(VTerm *vt, const char *fmt, ...);
+
+void vterm_state_free(VTermState *state);
+
+void vterm_state_newpen(VTermState *state);
+void vterm_state_resetpen(VTermState *state);
+void vterm_state_setpen(VTermState *state, const long args[], int argcount);
+int  vterm_state_getpen(VTermState *state, long args[], int argcount);
+void vterm_state_savepen(VTermState *state, int save);
+
+enum {
+  C1_SS3 = 0x8f,
+  C1_DCS = 0x90,
+  C1_CSI = 0x9b,
+  C1_ST  = 0x9c
+};
+
+void vterm_state_push_output_sprintf_CSI(VTermState *vts, const char *format, ...);
+
+void vterm_screen_free(VTermScreen *screen);
+
+VTermEncoding *vterm_lookup_encoding(VTermEncodingType type, char designation);
+
+int vterm_unicode_width(uint32_t codepoint);
+int vterm_unicode_is_combining(uint32_t codepoint);
+
+#endif