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First sort-of-working version of edit.c. Work-in-progress.
This commit is contained in:
Bobbi Webber-Manners
parent
7175a78ec8
commit
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598
apps/edit.c
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598
apps/edit.c
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/////////////////////////////////////////////////////////////////////////////
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// Prototype of text editor
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// Bobbi July 2020
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/////////////////////////////////////////////////////////////////////////////
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// TODO: There is still an issue where if deleting (left or right) removes
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// lines, the rest of the screen doesn't get drawn as it should.
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// TODO: it is possible to scroll off beginning or end of doc
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// TODO: Probably should convert tabs to space in loading and when tab key
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// is pressed. Much easier to deal with. Implications for reading
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// long file in chunks??
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// TODO: The code doesn't check for error cases when calling gap buffer
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// functions.
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#include <stdio.h>
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#include <stdlib.h>
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#include <conio.h>
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#include <peekpoke.h>
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#define NCOLS 80 // Width of editing screen
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#define NROWS 21 // Height of editing screen
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#define CURSORROW 10 // Row cursor is initially shown on (if enough text)
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#define EOL '\r' // For ProDOS
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#define BELL 0x07
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#define BACKSPC 0x08
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#define NORMAL 0x0e
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#define INVERSE 0x0f
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#define CLREOL 0x1d
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typedef unsigned char uint8_t;
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typedef unsigned short uint16_t;
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#define BUFSZ 10000 // 65535
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char gapbuf[BUFSZ];
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uint16_t gapbegin = 0;
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uint16_t gapend = BUFSZ - 1;
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uint8_t rowlen[NROWS]; // Number of chars on each row of screen
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// Interface to read_char_update_pos()
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uint8_t do_print;
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uint16_t pos;
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uint8_t row, col;
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uint8_t cursrow, curscol; // Cursor position is kept here by draw_screen()
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/*
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* Return number of bytes of freespace in gapbuf
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*/
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#define FREESPACE() (gapend - gapbegin + 1)
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/*
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* Return number of bytes of data in gapbuf
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*/
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#define DATASIZE() (gapbegin + (BUFSZ - 1 - gapend))
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/*
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* Obtain current position in gapbuf
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* This is the positon where the next character will be inserted
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*/
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#define GETPOS() (gapbegin)
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/*
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* Insert a character into gapbuf at current position
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* c - character to insert
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* Returns 0 on success, 1 on failure (insufficient space)
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*/
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uint8_t insert_char(char c) {
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if (FREESPACE()) {
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gapbuf[gapbegin++] = c;
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return 0;
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}
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return 1;
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}
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/*
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* Delete the character to the left of the current position
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* Returns 0 on success, 1 on failure (nothing to delete)
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*/
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uint8_t delete_char(void) {
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if (gapbegin == 0)
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return 1;
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--gapbegin;
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}
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/*
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* Delete the character to the right of the current position
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* Returns 0 on success, 1 on failure (nothing to delete)
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*/
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uint8_t delete_char_right(void) {
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if (gapend == BUFSZ - 1)
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return 1;
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++gapend;
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}
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/*
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* Obtain the next character (to the right of the current position)
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* and advance the position.
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* c - character is returned throught this pointer
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* Returns 0 on success, 1 if at end of the buffer.
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*/
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uint8_t get_char(char *c) {
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if (gapend == BUFSZ - 1)
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return 1;
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*c = gapbuf[gapbegin++] = gapbuf[++gapend];
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return 0;
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}
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/*
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* Move the current position
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* pos - position to which to move
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* Returns 0 on success, 1 if pos is invalid
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*/
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uint8_t jump_pos(uint16_t pos) {
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if (pos > BUFSZ - 1)
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return 1;
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if (pos == GETPOS())
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return 0;
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if (pos > GETPOS())
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do {
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gapbuf[gapbegin++] = gapbuf[++gapend];
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} while (pos > GETPOS());
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else
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do {
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gapbuf[gapend--] = gapbuf[--gapbegin];
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} while (pos < GETPOS());
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return 0;
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}
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/*
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* Load a file from disk into the gapbuf
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* filename - name of file to load
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* Returns 0 on success
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* 1 if file can't be opened
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* 2 if file too big
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*/
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uint8_t load_file(char *filename) {
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FILE *fp = fopen(filename, "r");
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if (!fp)
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return 1;
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gapbegin = 0;
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gapend = BUFSZ - 1;
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while (!feof(fp)) {
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gapbuf[gapbegin++] = fgetc(fp);
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if (!FREESPACE()) {
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fclose(fp);
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return 2;
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}
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}
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--gapbegin; // Eat EOF character
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fclose(fp);
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return 0;
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}
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/*
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* Save gapbuf to file
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* filename - name of file to load
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* Returns 0 on success
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* 1 if file can't be opened
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* 2 gapbuf is corrupt
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*/
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uint8_t save_file(char *filename) {
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char c;
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FILE *fp = fopen(filename, "w");
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if (!fp)
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return 1;
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if (jump_pos(0))
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return 2;
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while (get_char(&c) == 0)
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fputc(c, fp);
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fclose(fp);
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return 0;
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}
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/*
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* Go to next tabstop
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*/
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uint8_t next_tabstop(uint8_t col) {
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return (col / 8) * 8 + 8;
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}
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/*
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* Read next char from gapbuf[] and update state.
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* Returns 1 on EOL, 0 otherwise
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* If do_print is set, print char on the screen.
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* Interface is via the following globals:
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* do_print - if 1, update screen
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* pos - position in buffer, advanced by one
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* row, col - position on screen
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* rowlen[] - length of each screen row in chars
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*/
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uint8_t read_char_update_pos(void) {
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char c;
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c = gapbuf[pos++];
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switch (c) {
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case EOL:
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if (do_print) {
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rowlen[row] = col + 1;
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putchar(CLREOL);
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putchar('\r');
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}
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++row;
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col = 0;
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return 1;
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case '\t':
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if (do_print)
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for (c = 0; c < next_tabstop(col) - col; ++c)
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putchar(' ');
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col = next_tabstop(col);
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break;
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default:
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if (do_print)
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putchar(c);
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++col;
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}
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if (col >= NCOLS) {
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if (do_print)
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rowlen[row] = NCOLS;
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++row;
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col = 0;
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}
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return 0;
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}
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/*
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* Draw screenful of text
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*/
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void draw_screen(void) {
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uint16_t startpos;
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uint8_t rowsabove, cursorrow;
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// First we have to scan back to work out where in the buffer to
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// start drawing on the screen at the top left. This is at most
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// CURSORROW * NCOLS chars, however we go a little bit further back
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// in order to handle the case where files have extremely long lines
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// better.
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startpos = gapbegin;
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if (startpos > NROWS * NCOLS)
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startpos -= NROWS * NCOLS;
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else
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startpos = 0;
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// Format the text and work out the number of rows it takes up
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pos = startpos;
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row = col = 0;
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do_print = 0;
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while (pos < gapbegin)
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read_char_update_pos();
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rowsabove = row; // Number of complete rows above cursor
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if (rowsabove <= CURSORROW) {
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pos = 0;
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cursorrow = rowsabove;
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} else {
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cursorrow = CURSORROW;
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// Now repeat the formatting of the text, eating the first
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// (rowsabove - cursorrow) lines
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pos = startpos;
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row = col = 0;
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while (row < (rowsabove - cursorrow))
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read_char_update_pos();
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}
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// Finally actually write the text to the screen!
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videomode(VIDEOMODE_80COL);
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clrscr();
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row = col = 0;
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do_print = 1;
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while (pos < gapbegin)
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read_char_update_pos();
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curscol = col;
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cursrow = row;
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// Now write the text after the cursor up to the end of the screen
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pos = gapend + 1;
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while ((pos < BUFSZ) && (row < NROWS))
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read_char_update_pos();
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gotoxy(curscol, cursrow);
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cursor(1);
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}
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/*
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* Scroll screen up and update rowlen[]
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*/
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void scroll_up() {
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draw_screen();
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}
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/*
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* Scroll screen down and update rowlen[]
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*/
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void scroll_down() {
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draw_screen();
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}
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/*
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* Update screen after delete_char_right()
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*/
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void update_after_delete_char_right(void) {
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uint8_t eol = 0;
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uint8_t prevcol;
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col = curscol;
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row = cursrow;
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do_print = 1;
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// Print rest of line up to EOL
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pos = gapend + 1;
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while (!eol && (pos < BUFSZ) && (row < NROWS)) {
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prevcol = col;
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eol = read_char_update_pos();
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}
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// If necessary, print rest of screen
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if ((gapbuf[gapend] == EOL) || (prevcol == 0))
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while ((pos < BUFSZ) && (row < NROWS))
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read_char_update_pos();
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gotoxy(curscol, cursrow);
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cursor(1);
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}
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/*
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* Update screen after delete_char()
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*/
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void update_after_delete_char(void) {
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uint8_t eol = 0;
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uint8_t prevcol;
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col = curscol;
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row = cursrow;
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if (gapbuf[gapbegin] == EOL) {
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// Special handling if we deleted an EOL
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if (row > 0)
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col = rowlen[--row] - 1;
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else {
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scroll_up();
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return;
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}
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} else {
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// Erase char to left of cursor & update row, col
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putchar(BACKSPC);
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if (col > 0)
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--col;
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else {
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col = 0;
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if (row > 0)
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--row;
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else {
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scroll_up();
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return;
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}
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}
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}
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curscol = col;
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cursrow = row;
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gotoxy(curscol, cursrow);
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do_print = 1;
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// Print rest of line up to EOL
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pos = gapend + 1;
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while (!eol && (pos < BUFSZ) && (row < NROWS)) {
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prevcol = col;
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eol = read_char_update_pos();
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}
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// If necessary, print rest of screen
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if ((gapbuf[gapbegin] == EOL) || (prevcol == 0))
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while ((pos < BUFSZ) && (row < NROWS))
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read_char_update_pos();
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gotoxy(curscol, cursrow);
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cursor(1);
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}
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/*
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* Update screen after insert_char()
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*/
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void update_after_insert_char(void) {
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uint8_t eol = 0;
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uint8_t prevcol;
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col = curscol;
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row = cursrow;
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// Print character just inserted
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pos = gapbegin - 1;
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do_print = 1;
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read_char_update_pos();
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curscol = col;
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cursrow = row;
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if (cursrow == NROWS) {
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scroll_down();
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return;
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}
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// Print rest of line up to EOL
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pos = gapend + 1;
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while (!eol && (pos < BUFSZ) && (row < NROWS)) {
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prevcol = col;
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eol = read_char_update_pos();
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}
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// If necessary, print rest of screen
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if ((gapbuf[gapbegin - 1] == EOL) || (prevcol == 0))
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while ((pos < BUFSZ) && (row < NROWS))
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read_char_update_pos();
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gotoxy(curscol, cursrow);
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cursor(1);
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}
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/*
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* Move the cursor left
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*/
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void cursor_left(void) {
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if (gapbegin > 0)
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gapbuf[gapend--] = gapbuf[--gapbegin];
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else {
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putchar(BELL);
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return;
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}
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if (curscol == 0) {
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if (cursrow == 0)
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scroll_up();
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else
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--cursrow;
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curscol = rowlen[cursrow];
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} else
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--curscol;
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gotoxy(curscol, cursrow);
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}
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/*
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* Move the cursor right
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*/
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void cursor_right(void) {
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if (gapbegin < DATASIZE())
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gapbuf[gapbegin++] = gapbuf[++gapend];
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else {
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putchar(BELL);
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return;
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}
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++curscol;
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if (curscol == rowlen[cursrow]) {
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if (cursrow == NROWS)
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scroll_down();
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else
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++cursrow;
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curscol = 0;
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}
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gotoxy(curscol, cursrow);
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}
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/*
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* Move the cursor up
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*/
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void cursor_up(void) {
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uint8_t i;
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if (cursrow == 0) {
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scroll_up();
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++cursrow;
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}
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for (i = 0; i < curscol; ++i)
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gapbuf[gapend--] = gapbuf[--gapbegin];
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--cursrow;
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// Short line ...
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if (curscol >= rowlen[cursrow])
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curscol = rowlen[cursrow] - 1;
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for (i = 0; i < rowlen[cursrow] - curscol; ++i)
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gapbuf[gapend--] = gapbuf[--gapbegin];
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gotoxy(curscol, cursrow);
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}
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/*
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* Move the cursor down
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*/
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void cursor_down(void) {
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uint8_t i;
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if (cursrow == NROWS) {
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scroll_down();
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--cursrow;
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}
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for (i = 0; i < rowlen[cursrow] - curscol; ++i)
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gapbuf[gapbegin++] = gapbuf[++gapend];
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++cursrow;
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// Short line ...
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if (curscol >= rowlen[cursrow])
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curscol = rowlen[cursrow] - 1;
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for (i = 0; i < curscol; ++i)
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gapbuf[gapbegin++] = gapbuf[++gapend];
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gotoxy(curscol, cursrow);
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}
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/*
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* Goto beginning of line
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*/
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void goto_bol(void) {
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while (curscol > 0)
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cursor_left();
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}
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/*
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* Goto end of line
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*/
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void goto_eol(void) {
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while (curscol < rowlen[cursrow] - 1)
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cursor_right();
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}
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/*
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* Jump forward 15 screen lines
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*/
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void page_down(void) {
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uint8_t i;
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for (i = 0; i < 15; ++i)
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cursor_down();
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}
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/*
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* Jump back 15 screen lines
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*/
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void page_up(void) {
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uint8_t i;
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for (i = 0; i < 15; ++i)
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cursor_up();
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}
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||||
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int main() {
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char c;
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uint16_t pos;
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videomode(VIDEOMODE_80COL);
|
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if (load_file("test.txt")) {
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puts("load_file error");
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exit(1);
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}
|
||||
if (jump_pos(0)) {
|
||||
puts("move error");
|
||||
exit(1);
|
||||
}
|
||||
pos = 0;
|
||||
draw_screen();
|
||||
while (1) {
|
||||
c = cgetc();
|
||||
switch (c) {
|
||||
case 0x01: // Ctrl-A "HOME"
|
||||
goto_bol();
|
||||
break;
|
||||
case 0x02: // Ctrl-B "PAGE UP"
|
||||
page_up();
|
||||
break;
|
||||
case 0x04: // Ctrl-D "DELETE"
|
||||
delete_char_right();
|
||||
update_after_delete_char_right();
|
||||
break;
|
||||
case 0x05: // Ctrl-E "END"
|
||||
goto_eol();
|
||||
break;
|
||||
case 0x06: // Ctrl-F "PAGE DOWN"
|
||||
page_down();
|
||||
break;
|
||||
case 0x0C: // Ctrl-L "REFRESH"
|
||||
draw_screen();
|
||||
break;
|
||||
case 0x11: // Ctrl-Q "QUIT"
|
||||
exit(0);
|
||||
break;
|
||||
case 0x7f: // DEL "BACKSPACE"
|
||||
delete_char();
|
||||
update_after_delete_char();
|
||||
break;
|
||||
case 0x08: // Left
|
||||
cursor_left();
|
||||
break;
|
||||
case 0x15: // Right
|
||||
cursor_right();
|
||||
break;
|
||||
case 0x0b: // Up
|
||||
cursor_up();
|
||||
break;
|
||||
case 0x0a: // Down
|
||||
cursor_down();
|
||||
break;
|
||||
default:
|
||||
insert_char(c);
|
||||
update_after_insert_char();
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user