made the escape state machien also keep track of cursor save/restore parity and

clear screen sequences, have the im_disp_routine only update when these are
equal and a clear screen sequence has been sent

2 files changed, 69 insertions, 24 deletions

diff --git a/escape.h b/escape.h
index 103139a..20ec740 100644
--- a/escape.h
+++ b/escape.h
@@ -12,6 +12,16 @@
 //nF	ESC[0x20-02F]*[0x30-0x7E]
 //Fp	ESC[0x30-0x3F] save and clear
 
+
+//Clearing commands
+//ESC c
+//ESC [ [1-3] J
+
+//ESC [ [1-2] K
+//ESC [ m @
+//	note: these two can't clear im preview b/c of scroll locking
+
+
 //last read key
 enum esc_state {
 	//C0 except BEL or ESC, \n ,\r and \f
@@ -59,14 +69,22 @@ int safe_state(enum esc_state state) {
 enum esc_state in_state = NORMAL;
 //global pty -> stdout ESC state
 enum esc_state out_state = NORMAL;
+//global output parity
+int out_c_parity = 0;
+//global output clear state, cleared by im_routine_update
+int out_clr = 0;
 
-//c0 c1 c2 osc, sf nF sequences
+//updates the state, the return is the type of the last character read
 
-//also ESC 7 and ESC 8 up down bit
-//have a semaphore and above lock, IM will draw if available when input updates
-//or if some time has passed since output has been written
+//updates c parity depending on cursor store and restore
+	//if c parity is not NULL
+//sets clr to 1 if it encounters a cursor clear escape sequence
+	// if clr is not NULL
 
-enum esc_state update_esc_state(char * buff,unsigned int buff_len, enum esc_state state) {
+enum esc_state update_esc_state(char * buff,unsigned int buff_len, 
+	enum esc_state state, 
+	int * c_parity, int * clr) 
+{
 	for (int i = 0; i < buff_len; i++) {
 		char c = buff[i];
 		switch (state) {
@@ -92,8 +110,13 @@ enum esc_state update_esc_state(char * buff,unsigned int buff_len, enum esc_stat
 				}
 			break;
 			case ESC:
+				if (c == 'c') {
+					if (clr != NULL) {
+						*clr = 1;
+					}
+				}
 				//fix length C1
-				if (c == 'N' || c == 'O') {
+				else if (c == 'N' || c == 'O') {
 					state = C1;
 				}
 				else if (c == '[') {
@@ -103,18 +126,32 @@ enum esc_state update_esc_state(char * buff,unsigned int buff_len, enum esc_stat
 				else if (c == ']' || c =='P' || c == '^' || c == 'X' || c == '_') {
 					state = C1_START;
 				}
-				//nF
-				else if (c >= 0x20 && c <= 0x2F) {
-					state = nF_START;
-				}
 				else if (c == '\\') {
 					state - ST;
 				}
 				else if (c == '7') {
 					state = DECSC;
+					if ( c_parity != NULL) {
+						*c_parity++;
+					}
 				}
 				else if (c == '8') {
-					state = DECSC;
+					state = DECRC;
+					if ( c_parity != NULL) {
+						*c_parity--;
+					}
+				}
+				//nF
+				else if (c >= 0x20 && c <= 0x2F) {
+					state = nF_START;
+				}
+				//all other Fe/C1 Sequences, should be fixed len
+				else if (c >= 0x40 && c <= 0x5F) {
+					state = C1;
+				}
+				//Fs Sequences
+				else if (c >= 0x60 && c <= 0x7E) {
+					state = C1;
 				}
 				else if (c == 0x1B) {
 					state = DOUBLE_ESC;
@@ -134,7 +171,12 @@ enum esc_state update_esc_state(char * buff,unsigned int buff_len, enum esc_stat
 			break;
 			case CSI_START:
 			case CSI_MID:
-				if (c >= 0x30 && c <= 0x3F) {
+				if (c == 'J') {
+					state = CSI_END;	
+					if (clr != NULL) {
+						*clr = 1;
+					}
+				} else if (c >= 0x30 && c <= 0x3F) {
 					state = CSI_MID;
 				} else if (c >= 0x20 && c <= 0x2F) {
 					state = CSI_MID;
@@ -159,3 +201,4 @@ enum esc_state update_esc_state(char * buff,unsigned int buff_len, enum esc_stat
 	}
 	return state;
 }
+
diff --git a/ptyim.c b/ptyim.c
index 5ff0eee..3ac78d0 100644
--- a/ptyim.c
+++ b/ptyim.c
@@ -49,8 +49,6 @@ pthread_t om_thread;
 pthread_t im_disp_thread;
 //stdout semaphore
 sem_t out_sem;
-//tracks whether the screen has been updated by om
-int  om_updated = 1;
 
 
 //return 0 on success, -1 on error
@@ -111,29 +109,33 @@ void * om_routine( void *arg) {
 		// pty_master -> STDOUT
 		int wchars_read = read(pty_master,write_buffer, WRITE_BUFFER_LEN);
 		if (wchars_read >0) {
-			out_state = update_esc_state(write_buffer, wchars_read, out_state);
-			fprintf(stderr, "%c: %d\n", write_buffer[wchars_read-1], out_state);
 			sem_wait(&out_sem);
+			out_state = update_esc_state(write_buffer, wchars_read, out_state,
+				&out_c_parity, &out_clr);
+			fprintf(stderr, "%c: %d\n", write_buffer[wchars_read-1], out_state);
 			write(STDOUT_FILENO,write_buffer,wchars_read);
 			sem_post(&out_sem);
-			//sets update flag, im_disp_routine will set it to 0
-			om_updated = 1;
 		}
 	}
 }
 void * im_disp_routine (void *args) {
 	while (running) {
 		// Every run of this loop, it checks to see if im_buffer has
-		// updated, if it has, and no escape sequences have been written
-		// so far, it will display the im
-		if (im_updated |om_updated) {
-			fprintf(stderr, "printing im statusline\n");
+		// updated, or if the screen has been cleared
+
+		//then checks if the cursor save parity is right, and if the
+		//last output tot the terminal is safe to append to
+		if (im_updated | out_clr) {
+			if (out_c_parity != 0) {
+				continue;
+			}
 			if (safe_state(out_state)) {
+				fprintf(stderr, "printing im statusline\n");
 				sem_wait(&out_sem);
 				disp_im(STDIN_FILENO, trows, tcols);
 				sem_post(&out_sem);
 				im_updated = 0;
-				om_updated = 0;
+				out_clr = 0;
 			}
 		}
 	}
@@ -235,7 +237,7 @@ int main (int argc, char * argv[], char * envp[]) {
 			if (rchars_read > 0) {
 				//feeds input char into the escape state
 				//machine
-				in_state = update_esc_state(read_buffer, 1, in_state);
+				in_state = update_esc_state(read_buffer, 1, in_state, NULL, NULL);
 				//skips if the char was anything but
 				//normal
 				if (in_state == NORMAL || in_state ==DOUBLE_ESC) {