Cleaned up input method code, added preview function

3 files changed, 135 insertions, 68 deletions

diff --git a/im.h b/im.h
index 12d8ac8..dc171a8 100644
--- a/im.h
+++ b/im.h
@@ -1,21 +1,52 @@
+//Input Method Functions and Variables
 //#include "imtable.h"
 #include "boshiamy.h"
 #define IM_BUFFER_LEN 32
+#define IM_PREVIEW 1
+#define IM_PREVIEW_ENTRIES 6
+#define IM_PREVIEW_WIDTH 4*IM_PREVIEW_ENTRIES
 #define ENTER_KEY 0x0D
 #define BACKSPACE_KEY 0x7F
-//#define BACKSPACE_KEY '+'
 //setting it to the actual escape character interferes with arrow keys and
 //whatnot
 //#define ESCAPE_KEY 0x1B
 #define ESCAPE_KEY '`'
 //Vertical Tab Ctrl+K
 #define TOGGLE_KEY 0x0B
+#define IM_KEY_RANGE_LEN 7
+//Array of Input method key ranges(inclusive) seperate from the above
+char im_key_ranges[IM_KEY_RANGE_LEN][2] = {
+	{'a','z'},
+	{'0','9'},
+	{' ',' '},
+	{',',','},
+	{'.','.'},
+	{'[','['},
+	{']',']'},
+};
+int is_im_key(char input) {
+	for (int i = 0; i < IM_KEY_RANGE_LEN; i++) {
+		if (input >= im_key_ranges[i][0] && input <= im_key_ranges[i][1]) {
+			return 1;
+		}
+	}
+	return 0;
+}
 char im_buffer[IM_BUFFER_LEN+1];
 char im_buffer_pos = 0;
 int im_on = 1;
+//clears the im buffer
+void clear_im_buffer() {
+	im_buffer[0] = 0;
+	im_buffer_pos = 0;
+}
 //recursive search, returns -1 on failure
-//searches from [start, end)
-int im_search(char * input, int start, int end) {
+//searches from [start, end), 
+//can limit itself to n bytes, if n=0, use IM_TABLE_ENTRY_LEN
+int im_search(char * input, int start, int end, int n) {
+	if (n == 0) {
+		n = IM_TABLE_ENTRY_LEN;
+	}
 	// 0 width search
 	if (end <= start) {
 		return -1;
@@ -23,7 +54,7 @@ int im_search(char * input, int start, int end) {
 	//test for middle, works even for 1 width middle=start
 	int middle = start + (end-start)/2;
 	//printf("testing:%s\n",im_table[middle][0]);
-	int test = strncmp(im_table[middle][0], input, IM_TABLE_ENTRY_LEN);
+	int test = strncmp(im_table[middle][0], input, n);
 	if (test == 0) {
 		return middle;
 	}
@@ -39,30 +70,32 @@ int im_search(char * input, int start, int end) {
 		return 0;
 	} else {
 		if (test > 0) {
-			return im_search(input,start,middle);
+			return im_search(input,start,middle,n);
 		} else {
-			return im_search(input,middle,end);
+			return im_search(input,middle,end,n);
 		}
 	}
 	
 }
-//returns output len, since we want to be able to handle null bytes as well
+//update_im_state is fed input characters 1 at a time, and gives 0 to
+//IM_BUFFER_LEN output characters. 
+//returns output len
 int update_im_state(char input, char * output) {
 	if (input == TOGGLE_KEY) {
 		im_on = !im_on;
 		//clears the im buffer if its toggling off
 		if (!im_on) {
-			im_buffer[0] = 0;
-			im_buffer_pos = 0;
+			clear_im_buffer();
 		}
 	}
-	//just exit if the im is off
+	//just passthrough if the im is off
 	if (!im_on) {
 		output[0] = input;
 		output[1] = 0;
 		return 1;
 	}
-	if ( ('a' <= input && input <= 'z')||('0' <= input && input  <= '9') ||(input == ' ') || (input == ',') || (input == '.')) {
+	if ( is_im_key(input) ) {
+		//check if there's enough room in the im buffer
 		if ( (im_buffer_pos < IM_BUFFER_LEN) && (im_buffer_pos < IM_TABLE_ENTRY_LEN) ){
 			im_buffer[im_buffer_pos] = input;
 			im_buffer_pos++;
@@ -74,13 +107,14 @@ int update_im_state(char input, char * output) {
 			return 1;
 		}
 		//if there's a match return it
-		int im_entry = im_search(im_buffer, 0, IM_TABLE_LEN);
+		int im_entry = im_search(im_buffer, 0, IM_TABLE_LEN, 0);
 		if (im_entry != -1) {
 			//clear the buffer
-			im_buffer[0] = 0;
-			im_buffer_pos = 0;
+			clear_im_buffer();
 			strncpy(output, im_table[im_entry][1], IM_TABLE_ENTRY_LEN);
 			return strlen(im_table[im_entry][1]);
+		} else {
+			return 0;
 		}
 	} else {
 		//these only do something if there's something in the buffer, otherwise
@@ -89,18 +123,15 @@ int update_im_state(char input, char * output) {
 			switch (input) {
 				//escape, cancels
 				case ESCAPE_KEY:
-					im_buffer[0] = 0;
-					im_buffer_pos = 0;
+					clear_im_buffer();
 					return 0;
 				break;
-				//enter, enters the buffer
+				//enter, enters the buffer instead of sending it
+				//to im
 				case ENTER_KEY:
-					for (int i = 0; i <im_buffer_pos; i++) {
-						output[i] = im_buffer[i];
-					}
-					output[im_buffer_pos] = 0;
+					strncpy(output, im_buffer, IM_BUFFER_LEN);
 					int tmp = im_buffer_pos;
-					im_buffer_pos = 0;
+					clear_im_buffer();
 					return tmp;
 				break;
 				//backspace
@@ -113,10 +144,85 @@ int update_im_state(char input, char * output) {
 				break;
 			}
 		}
-		//default behavior of passthrough
-		output[0] = input;
-		output[1] = 0;
-		return 1;
 	}
+	//default behavior of passthrough
+	output[0] = input;
+	output[1] = 0;
+	return 1;
 	
 }
+//prints im preview, assumes im_disp already moved it to the proper location
+void im_preview(int fd, int trows, int tcols) {
+	//searches for any im entries that match the im buffer, up to the
+	//im_buffer length, because it's branching search it's not guaranteed to
+	//be the first entry in the table that matches
+	int first_entry = im_search(im_buffer, 0, IM_TABLE_LEN, im_buffer_pos);
+	if (first_entry == -1) {
+		return;
+	}
+	//keeps iterating until it finds the first entry in the table that
+	//matches
+	for (int i = first_entry; i>0 && i < IM_TABLE_LEN && (!strncmp(im_table[i][0],im_buffer,im_buffer_pos)); i--) {
+		first_entry = i;
+	}
+	//preview buffer, each utf8 char could be up to 4 bytes, each new entry
+	//catted on could be IM_TABLE_ENTRY_LEN*2 before next detection in loop,
+	//so that + 1 margin for null byte
+	char preview_buffer[IM_PREVIEW_ENTRIES*IM_TABLE_ENTRY_LEN*2+1] = "";
+	//tracks how many entries we've added to the buffer so far
+	int k = 0;
+	for (int j = first_entry; j> 0 && j < IM_TABLE_LEN && (!strncmp(im_table[j][0],im_buffer,im_buffer_pos)); j++) {
+		if (k >= IM_PREVIEW_ENTRIES) {
+			break;
+		}
+		//even if the string is the same as im_buffer_pos, it will point
+		//to a null pointer, which is treated as empty
+		strncat(preview_buffer,&(im_table[j][0][im_buffer_pos]),1);
+		strncat(preview_buffer,":",1);
+		//assuming that each output is only 2 characters wide display
+		strncat(preview_buffer,im_table[j][1], IM_TABLE_ENTRY_LEN);
+		k++;
+	}
+	//writes the preview
+	write(fd,preview_buffer,strlen(preview_buffer));
+}
+//Displays the IM on the bottom line, input is the number of actual physical
+//rows and columns on the terminal descibed by fd
+void disp_im(int fd, int trows, int tcols) {
+	//generates the position escape sequence for the bottom left corner
+	//4 spaces for the im indicator +1 for automargin
+	int im_col = tcols - IM_TABLE_ENTRY_LEN - 4 - 1;
+	if (IM_PREVIEW) {
+		im_col = im_col - IM_PREVIEW_WIDTH;
+	}
+	char pos_str[32] = "";
+	int l = snprintf(pos_str, 32, "\033[%d;%df", trows, im_col);
+
+	write(fd,"\0337",2); //saves previous cursor position
+	write(fd, pos_str,l);
+	write(fd,"\033[7m",4); //invert video
+
+	//overwrite what was there previously, this works out to leaving 1 space
+	//at the end for automargin b/c you need (tcols-im_col)+1 spaces, but
+	//want -1 space so it doesn't write to the last character position
+	write(fd,"                                                                  ",
+		tcols-im_col);
+
+	write(fd, pos_str,l);
+	//im mode indicator
+	if (im_on) {
+		write(fd,"漢[",4);
+	} else {
+		write(fd,"英[",4);
+	}
+	//actual buffer
+	write(fd,im_buffer,im_buffer_pos);
+	write(fd,"]",1);
+	//if preview is set do that
+	if (IM_PREVIEW) {
+		im_preview(fd, trows, tcols);
+	}
+	//restore cursor pos and attrbutes
+	write(fd,"\033[0m",4);
+	write(fd,"\0338",2);
+}
diff --git a/imtable.h b/imtable.h
index 66c7f78..f045cc0 100644
--- a/imtable.h
+++ b/imtable.h
@@ -1,3 +1,4 @@
+//Generic Input Method Used in Testing, see boshiamy.h for full implementation
 #define IM_TABLE_LEN 5
 #define IM_TABLE_ENTRY_LEN 8
 //assumes this is sorted
diff --git a/ptyim.c b/ptyim.c
index 6fa6ac1..35f5563 100644
--- a/ptyim.c
+++ b/ptyim.c
@@ -34,47 +34,7 @@ void winchhook(int a) {
 	ioctl(pty_slave, TIOCSWINSZ, &sz);
 
 }
-void disp_im() {
-	//3 spaces for the im indicator +1 for automargin
-	int im_col = tcols - IM_TABLE_ENTRY_LEN - 4;
-	char pos_str[32] = "";
-	int l = sprintf(pos_str, "\033[%d;%df",trows, im_col);
-	//printf("\0337");
-	//printf("\033[%d;%df",trows,im_col);
-	//printf("\033[0;0f",trows,im_col);
-	//printf("\033[7m");
-	//if (im_on) {
-	//	printf("漢");
-	//} else {
-	//	printf("英");
-	//}
-	//printf("%s",im_buffer);
-	//printf("\033[0m");
-	//printf("\0338");
-	write(STDOUT_FILENO,"\0337",2);
-	//also writes to top left the current im buffer
-	//write(STDOUT_FILENO,"\033[33;14f",8);
-	//write(STDOUT_FILENO,"\033[0;4f",6);
-	//write to the bottom left corner
-	write(STDOUT_FILENO, pos_str,l);
-	//invert video
-	write(STDOUT_FILENO,"\033[7m",4);
-	//overwrite what was there previously
-	write(STDOUT_FILENO,"                            ",
-		IM_TABLE_ENTRY_LEN+4);
-	write(STDOUT_FILENO, pos_str,l);
-	//im mode indicator
-	if (im_on) {
-		write(STDOUT_FILENO,"漢:",4);
-	} else {
-		write(STDOUT_FILENO,"英:",4);
-	}
-	//actual buffer
-	write(STDOUT_FILENO,im_buffer,im_buffer_pos);
-	//restore cursor pos and attrbutes
-	write(STDOUT_FILENO,"\033[0m",4);
-	write(STDOUT_FILENO,"\0338",2);
-}
+
 int main (int argc, char * argv[], char * envp[]) {
 	//creates the pty master
 	int pty_master = posix_openpt(O_RDWR);
@@ -187,7 +147,7 @@ int main (int argc, char * argv[], char * envp[]) {
 				if (im_chars >0) {
 					write(pty_master,input_buffer,im_chars);
 				}
-				disp_im();
+				disp_im(STDIN_FILENO, trows, tcols);
 			}
 		}
 	}