Simple Text Editro a ncurses based text editor made for educational purposes
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ste/ste.c

752 lines
18 KiB

#include <ncurses.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <locale.h>
/* defines */
#define CTRL(k) ((k) & 0x1f) // Control mask modifier
#define TABSIZE 4 // Tab size as used in render
#define STAT_SIZE 128
#define _XOPEN_SOURCE_EXTENDED 1
#define EROW {0, NULL, 0, 0, NULL}
/* main data structure containing:
* -cursor position
* +real (matching memory)
* +offset (memory and screen offset)
* +render (drawn on the screen)
* -window size
* -statusbar message */
struct term {
struct {
int x;
int y;
int off_x;
int off_y;
int r_x;
int r_y;
} cur;
struct {
int x;
int y;
} dim;
char statusbar[STAT_SIZE];
int pad;
} t;
/* Row structure, defines actual and
* render chars, actual and render size
* and difference between render and
* real size of the row
* Utf-8 continuation chars */
typedef struct row {
int size;
char *chars;
int r_size;
int utf;
char *render;
} row;
/* Rows structure (or file buffer)
* defines rows and teh number of rows */
struct {
row *rw;
int rownum;
} rows;
/* Prototypes */
/* draw operations */
static void drawBar (char *s);
static void drawScreen ();
static void drawLines (void);
static void updateRender (row *rw);
static void curUpdateRender (void);
static void cursorMove(int a);
static int decimalSize (int n);
static inline void lnMove (int y, int x);
/* Row operations */
static inline void rowInit (void);
static void rowAddChar (row *rw, char c, int pos);
static int rowDeleteChar (row *rw, int select, int pos);
static void rowCpy (row *to, row *from);
static void rowAddRow (int pos);
static void rowFree (row *rw);
static void rowAppendString (row *rw, char *s, int len);
static void rowDeleteRow (int pos);
/* Terminal operations */
static void termInit (void);
static void termExit (void);
static void termDie (char *s);
/* file operations */
static void fileOpen (char *filename);
void fileSave (char *filename);
/* buffer operations */
static void rowAddLast (char *s, int len);
/* garbage */
static void handleDel (int select);
/* testing */
static void updateInfo (void);
static int whatsThat (void);
static inline int isUtf (int c);
static inline int isCont (int c);
static inline int isStart (int c);
/* --------------------------------- main ------------------------------------ */
int main (int argc, char *argv[])
{
/* Initialize the first row */
rowInit();
/* Try to open the file */
if (argc < 2) {
perror("File not found");
exit(1);
} else fileOpen(argv[1]);
/* Initialize the terminal in raw mode,
* start curses and initialize the term struct */
termInit();
/* Set the statusbar left (static) message */
snprintf(t.statusbar, STAT_SIZE, "%s %d lines %dx%d", argv[1], rows.rownum, t.dim.y, t.dim.x);
/* remember the initial row number */
int irow = decimalSize(rows.rownum);
/* Main event loop */
int c;
while (1) {
updateInfo();
/* Redraw the screen */
drawScreen();
/* Wait for an event (keypress) */
switch (c = getch()) {
case (CTRL('q')):
termExit();
break;
case (KEY_LEFT):
case (KEY_RIGHT):
case (KEY_UP):
case (KEY_DOWN):
cursorMove(c);
break;
case (KEY_BACKSPACE):
handleDel(0);
break;
case (KEY_DC):
handleDel(1);
break;
case (KEY_ENTER):
case (10):
case ('\r'):
rowAddRow(t.cur.y);
t.cur.y++;
t.cur.x = 0;
break;
case (KEY_END):
t.cur.y = rows.rownum - 1;
break;
case (KEY_HOME):
t.cur.y = 0;
break;
default:
if (c == KEY_STAB) c = '\t';
rowAddChar(&rows.rw[t.cur.y], c, t.cur.x);
t.cur.x++;
break;
}
if (decimalSize(rows.rownum) - irow) updateInfo();
}
/* If by chance i find myself here be sure
* end curses mode and clenaup */
termExit();
return 0;
}
/* ----------------------------- end of main ---------------------------------- */
void termInit (void)
{
/* Init locales */
setlocale(LC_ALL, "");
/* Init the screen and refresh */
initscr();
refresh();
/* Enable raw mode, this makes the termianl ignore
* interrupt signals like CTRL+C and CTRL+Z
* allowing us to make our own bindings */
raw();
/* Allow use of function keys */
keypad(stdscr, TRUE);
/* Turn off echoing */
noecho();
/* Set the tab size */
set_tabsize(TABSIZE);
/* Start color mode */
start_color();
init_pair(2, COLOR_BLACK, COLOR_CYAN);
init_pair(1, COLOR_RED, COLOR_BLACK);
/* Set default color */
//bkgd(COLOR_PAIR(1));
/* Populate the main data structure */
updateInfo();
/* Initialize the data staructure */
t.cur.x = t.cur.off_x = 0;
t.cur.y = t.cur.off_y = 0;
}
/* Calculate the correct spacing for the line numbers
* based on the size of the file */
int decimalSize (int n)
{
static int l;
for (l = 0; n > 0; l++) n /= 10;
return l + 1;
}
void termExit (void)
{
erase();
refresh();
endwin();
exit(0);
}
void termDie (char *s)
{
erase();
refresh();
endwin();
perror(s);
exit(1);
}
/* ----------------------------- term operations -------------------------------- */
void drawScreen ()
{
/* Clear the screen */
erase();
/* Update Scroll */
curUpdateRender();
/* draw the lines */
drawLines();
/* draw the bar */
drawBar(t.statusbar);
/* move back to the cursor position */
lnMove(t.cur.r_y, t.cur.r_x);
/* refresh the screen */
refresh();
}
/* Draw all the appropriate lines (following cursor) to the screen */
void drawLines (void)
{
register short ln, i;
register int start;
for (i = 0, ln = 0; i < t.dim.y + t.cur.off_y; i++) {
ln = i + t.cur.off_y;
if (ln >= rows.rownum) break;
/* Draw the line number */
attron(COLOR_PAIR(1));
mvprintw(i, 0, "%d", ln + 1);
attroff(COLOR_PAIR(1));
lnMove(i, 0);
/* Draw the line matcing render memory */
if (&rows.rw[ln] == NULL) termDie("drawlines NULL");
if (rows.rw[ln].r_size > t.cur.off_x) {
start = t.cur.off_x;
while (isCont(rows.rw[ln].render[start])) start++;
addnstr(&rows.rw[ln].render[start], (t.dim.x + 1) + (rows.rw[ln].utf >> 2));
}
lnMove(i + 1, 0);
}
lnMove(t.cur.y, t.cur.x);
}
/* Move avoiding the space allocated for line numbers */
inline void lnMove (int y, int x)
{
move(y, x + t.pad);
}
/* Draw the status bar at the bottom of the screen */
void drawBar (char *s)
{
/* Set maximum contrast for bar */
attron(COLOR_PAIR(2));
/* get the length of the statusbar text */
int len = strlen(s);
/* Print the message */
mvprintw(t.dim.y, 0, s);
/* Fill everything else with spaces */
static int i;
for (i = len; i <= t.dim.x + t.pad; i++)
mvaddch(t.dim.y, i, ' ');
static char m[40];
sprintf(m, "x: %d y: %d Zoom: %c", t.cur.x, t.cur.y, whatsThat());
mvaddstr(t.dim.y, t.dim.x + t.pad - strlen(m), m);
/* Return to normal contrast mode */
attroff(COLOR_PAIR(2));
}
void updateRender (row *rw)
{
/* count the special characters
* spaces, utf-8 continuation chars */
static int tabs, i, off, cc, ut;
for (i = 0, tabs = 0, cc = 0, ut = 0; i < rw->size; i++) {
if (rw->chars[i] == '\t') tabs++;
else if (isCont(rw->chars[i])) cc++;
else if (isUtf(rw->chars[i])) ut++;
}
rw->render = NULL;
free(rw->render);
/* Render is long as size with the added tab spaces - 1
* (we already count for the \t as a char) */
rw->render = malloc(rw->size + tabs * (TABSIZE - 1) + 1);
if (rw->render == NULL) termDie ("malloc in updateRender");
/* put all the characters (substituing all special chars)
* into the render buffer */
for (i = 0, off = 0; i < rw->size; i++) {
if (rw->chars[i] == '\t') {
for (int j = 0; j < TABSIZE; j++){
//if (!j) rw->render[off++] = '|';
//else rw->render[off++] = ' ';
rw->render[off++] = ' ';
}
} else {
rw->render[off++] = rw->chars[i];
}
}
rw->render[off] = '\0';
rw->r_size = off - cc;
rw->utf = cc + ut;
}
/* -------------------------------- draw operations -------------------------------- */
/* Open a file and put it into a buffer line by line */
void fileOpen (char *filename)
{
FILE *fp = fopen(filename, "r");
if (fp == NULL) termDie("Cannot open file");
/* Init the linebuffer */
char *line = NULL;
/* Set linecap to 0 so getline will atumatically allocate
* memory for the line buffer*/
size_t linecap = 0;
ssize_t linelen;
/* getline returns -1 if no new line is present */
while ((linelen = getline(&line, &linecap, fp)) != -1) {
while (linelen > 0 && (line[linelen - 1] == '\n' || line[linelen - 1] == '\r'))
linelen--;
rowAddLast(line, linelen);
}
/* free the line buffer */
free(line);
/* close the file */
fclose(fp);
}
/*------------------------------------- file operations ----------------------------------*/
/* Add a row to the file buffer */
void rowAddLast (char *s, int len)
{
/* Extend the block of memory containing the lines */
row *newr = realloc(rows.rw, (rows.rownum + 1) * sizeof(row));
if (newr == NULL) termDie("realloc in rowAddLast");
else rows.rw = newr;
/* Allocate memory for the line and copy it
* at the current row number */
rows.rw[rows.rownum].chars = malloc(len + 1);
if (rows.rw[rows.rownum].chars == NULL) termDie("malloc in rowAddLast chars");
memcpy(rows.rw[rows.rownum].chars, s, len);
rows.rw[rows.rownum].chars[len] = '\0';
rows.rw[rows.rownum].size = len;
updateRender(&rows.rw[rows.rownum]);
rows.rownum++;
}
void rowInit (void)
{
rows.rw = NULL;
rows.rownum = 0;
}
void rowAddChar (row *rw, char c, int pos)
{
/* Check if char is valid */
if (!c || (iscntrl(c) && c != '\t')) return;
/* extend the string */
rw->size++;
char *t = realloc(rw->chars, rw->size + 1);
if (t == NULL) termDie("realloc in rowAddchar");
rw->chars = t;
/* make space for the new char */
memcpy(&rw->chars[pos + 1], &rw->chars[pos], (rw->size + 1) - (pos + 1));
/* add the new char */
rw->chars[pos] = c;
updateRender(rw);
}
int rowDeleteChar (row *rw, int select, int pos) // WIP
{
/* Check if the character is valid */
if (rw->chars[pos - 1] == '\0' && pos) return 0;
if (!pos && !select) return 0;
if (rw->chars[pos] == '\0' && select) return 0;
//change pos based on the command
if (!select) pos--;
memcpy(&rw->chars[pos], &rw->chars[pos + 1], rw->size - pos);
char *s = realloc(rw->chars, rw->size);
if (s != NULL) rw->chars = s;
rw->size--;
updateRender(rw);
return 1;
}
void rowAddRow (int pos) // WIP; TO DOCUMENT
{
/* MOVE THE ROWS AWAY */
/* add another line to the bottom containing the previous
* (last) line, effectively making new space */
rowAddLast(rows.rw[rows.rownum - 1].chars, rows.rw[rows.rownum - 1].size);
/* copy all other lines until the specified position to the next one */
for (int last = rows.rownum - 1; last > pos; last--)
rowCpy(&rows.rw[last], &rows.rw[last - 1]);
/* SPLIT THE ROW AT POS AND STORE IT */
/* Get the row length at position after the cursor */
int len = rows.rw[pos].size - t.cur.x;
/* create a dummy row as the new row souce */
row nex = EROW;
/* allocate a buffer */
char *s = malloc(len + 1);
if (s == NULL) termDie("malloc in rowAddRow s");
/* copy the contents of the pos row after the cursor into the buffer */
memcpy(s, &rows.rw[pos].chars[t.cur.x], len);
s[len] = '\0';
/* update the dummy row */
nex.chars = s;
nex.size = strlen(s);
/* MAKE THE SPLIT INTO TWO LINES */
/* shrink the line at pos */
char *p = realloc(rows.rw[pos].chars, t.cur.x + 1);
if (p == NULL) termDie("realloc in rowAddRow");
rows.rw[pos].chars = p;
/* and terminate it with null like a good boi */
rows.rw[pos].chars[t.cur.x] = '\0';
/* update info and render */
rows.rw[pos].size = t.cur.x;
updateRender(&rows.rw[pos]);
/* copy the dummy to the new line and free */
rowCpy(&rows.rw[pos + 1], &nex);
rowFree(&nex);
}
void rowFree (row *rw) // WIP
{
/* Free both render and memory strings */
free(rw->render);
free(rw->chars);
/* clear sizes */
rw->size = 0;
rw->r_size = 0;
rw->utf = 0;
}
void rowCpy (row *to, row *from) // WIP
{
/* Free the destination row (without destroying it) */
rowFree(to);
/* Allocate space for the new string */
to->chars = (char*) malloc(strlen(from->chars) + 1);
if (to->chars == NULL) termDie("malloc in rowCpy");
/* And update the size */
to->size = from->size;
/* Then copy the chars from the source row to the destination row */
memcpy(to->chars, from->chars, to->size);
to->chars[to->size] = '\0';
/* Then update the render */
updateRender(to);
}
void rowAppendString (row *rw, char *s, int len)
{
/* reallocate the row to accomodate for the added string */
char *temp = realloc(rw->chars, rw->size + len + 1);
if (temp == NULL) termDie("realloc in rowAppendString");
rw->chars = temp;
memcpy(&rw->chars[rw->size], s, len);
rw->size += len;
rw->chars[rw->size] = '\0';
updateRender(rw);
}
void rowDeleteRow (int pos)
{
if (rows.rownum == 1) return;
if (pos >= rows.rownum) return;
if (pos < 0) return;
for (; pos < rows.rownum - 1; pos++) {
rowCpy(&rows.rw[pos], &rows.rw[pos + 1]); // rowcpy already frees the row
}
rows.rownum--;
rowFree(&rows.rw[rows.rownum]);
row *temp = realloc(rows.rw, sizeof(row) * rows.rownum);
if (temp == NULL) termDie("realloc in rowDeleteRow");
rows.rw = temp;
}
/* ----------------------------- row operations --------------------------- */
/* take care of the cursor movement */
void cursorMove (int a)
{
switch (a) {
case (KEY_LEFT):
if (t.cur.x <= 0) {
if (t.cur.y) {
t.cur.y--;
t.cur.x = rows.rw[t.cur.y].size;
}
} else if (isCont(rows.rw[t.cur.y].chars[t.cur.x - 1])) {
do {
t.cur.x--;
} while(!isStart(rows.rw[t.cur.y].chars[t.cur.x]));
} else
t.cur.x--;
break;
case (KEY_RIGHT):
if (t.cur.x >= rows.rw[t.cur.y].size) {
if (t.cur.y < rows.rownum - 1) {
t.cur.y++;
t.cur.x = 0;
}
} else if (isStart(rows.rw[t.cur.y].chars[t.cur.x])) {
do {
t.cur.x++;
} while(isCont(rows.rw[t.cur.y].chars[t.cur.x]));
} else
t.cur.x++;
break;
case (KEY_UP):
if (t.cur.y) {
t.cur.y--;
if (t.cur.x > rows.rw[t.cur.y].size)
t.cur.x = rows.rw[t.cur.y].size;
}
break;
case (KEY_DOWN):
if (t.cur.y < rows.rownum - 1) {
t.cur.y++;
if (t.cur.x > rows.rw[t.cur.y].size)
t.cur.x = rows.rw[t.cur.y].size;
}
break;
}
}
void curUpdateRender ()
{
/*
Whole file (memory)
_____________________________
|(0, 0) |
| |
| off_y |
| +--------------+ |
| | | |
| | | |
| | | off_x |
| off_x| | + |
| | | dim_x |
| | | |
| | | |
| | | |
| +--------------+ |
| off_y + dim.y |
| |
| |
| |
|_____________________________| rows.rownum
The inner sqaure represents the render area
and it is delimited by:
left: x -> t.cur.off_x
right: x -> t.cur.off_x + (t.dim.x - 1)
upper: y -> t.cur.off_y
lower: y -> t.cur.off_y + (t.dim.y - 1)
The rows are drawn top to botom, starting
from the left most char of the render area
until row end or when the characters hit
the right bound.
*/
if (t.cur.y >= t.cur.off_y && t.cur.y < t.cur.off_y + t.dim.y) {
t.cur.r_y = t.cur.y - t.cur.off_y;
} else if (t.cur.y >= t.cur.off_y + t.dim.y) {
if (t.cur.y == t.cur.off_y + t.dim.y) t.cur.off_y++;
else t.cur.off_y += t.cur.y - (t.cur.off_y + t.dim.y);
t.cur.r_y = t.dim.y - 1;
} else if (t.cur.y < t.cur.off_y) {
t.cur.off_y -= t.cur.off_y - t.cur.y;
t.cur.r_y = 0;
}
// x
static int i, c;
for (c = i = 0, t.cur.r_x = 0; i < t.cur.x; i++) {
c = rows.rw[t.cur.y].chars[i];
/* continue (skip increment) if you encounter a continuation char */
if (isCont(c)) continue;
else if (isStart(c)) t.cur.r_x++;
if (c == '\t') t.cur.r_x += (TABSIZE - 1);
t.cur.r_x++;
}
if (t.cur.r_x >= t.cur.off_x && t.cur.r_x < t.cur.off_x + t.dim.x) {
t.cur.r_x -= t.cur.off_x;
} else if (t.cur.r_x < t.cur.off_x) {
t.cur.off_x -= t.cur.off_x - t.cur.r_x;
t.cur.r_x = 0;
} else if (t.cur.r_x >= t.cur.off_x + t.dim.x) {
t.cur.off_x += t.cur.r_x - t.cur.off_x - t.dim.x;
t.cur.r_x = t.dim.x;
}
}
/*---------------------------------- scroll ------------------------------------*/
/* See whats under the cursor (memory) */
int whatsThat (void) {
int c = rows.rw[t.cur.y].chars[t.cur.x];
switch (c) {
case ('\t'):
return '^';
break;
case (' '):
return '~';
break;
case ('\0'):
return '.';
break;
default:
return c;
break;
}
return 0;
}
void handleDel (int select)
{
if (!select) {
if (t.cur.x <= 0 && t.cur.y > 0) {
t.cur.x = rows.rw[t.cur.y - 1].size;
rowAppendString(&rows.rw[t.cur.y - 1], rows.rw[t.cur.y].chars, rows.rw[t.cur.y].size);
rowDeleteRow(t.cur.y);
t.cur.y--;
} else {
if (isUtf(rows.rw[t.cur.y].chars[t.cur.x - 1])) {
do {
if (rowDeleteChar(&rows.rw[t.cur.y], 0, t.cur.x))
t.cur.x--;
} while (!isStart(rows.rw[t.cur.y].chars[t.cur.x - 1]));
}
if (rowDeleteChar(&rows.rw[t.cur.y], 0, t.cur.x))
t.cur.x--;
}
} else {
if (t.cur.x >= rows.rw[t.cur.y].size) {
rowAppendString(&rows.rw[t.cur.y], rows.rw[t.cur.y + 1].chars, rows.rw[t.cur.y + 1].size);
rowDeleteRow(t.cur.y + 1);
} else {
if (isStart(rows.rw[t.cur.y].chars[t.cur.x])) {
do {
rowDeleteChar(&rows.rw[t.cur.y], 1, t.cur.x);
} while (isCont(rows.rw[t.cur.y].chars[t.cur.x]));
} else rowDeleteChar(&rows.rw[t.cur.y], 1, t.cur.x);
}
}
}
void updateInfo (void)
{
getmaxyx(stdscr, t.dim.y, t.dim.x);
t.dim.y -= 1;
t.pad = decimalSize(rows.rownum - 1);
t.dim.x -= t.pad + 1;
}
/* Check for utf-8 char type */
int isUtf (int c) {
return (c >= 0x80 || c < 0 ? 1 : 0);
}
int isCont (int c) {
return ((c &= 0xC0) == 0x80 ? 1 : 0);
}
int isStart (int c) {
return (isUtf(c) && !isCont(c) ? 1 : 0);
}
/*--------------------------------- testing ------------------------------------*/