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kilo.c
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kilo.c
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/*** includes ***/
#include <ctype.h>
#include <errno.h>
#include <termios.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <stdio.h>
#include <ctype.h>
/*** defines ***/
#define KILO_VERSION "0.0.1"
#define CTRL_KEY(k) ((k) & 0x1f)
enum editorKey
{
ARROW_LEFT = 1000,
ARROW_RIGHT,
ARROW_UP,
ARROW_DOWN,
PAGE_UP,
PAGE_DOWN,
HOME_KEY,
END_KEY,
DEL_KEY,
};
/*** data ***/
// erow: storing a row of text in our editor.
typedef struct erow
{
int size;
char *chars;
} erow;
struct editorConfig
{
/*
keep track of cursor's x and y position
E.cx is the horizontal coordinate of the cursor (the column) and E.cy is the vertical coordinate (the row)
*/
int cx, cy;
int screenrows;
int screencols;
int numrows;
// stores a line of text as a pointer to the dynamically-allocated character data and a length
erow *row;
struct termios orig_termios;
};
struct editorConfig E;
/*** terminal ***/
void printAndExit(const char *s)
{
write(STDOUT_FILENO, "\x1b[2J", 4);
write(STDOUT_FILENO, "\x1b[H", 3);
perror(s);
exit(1);
}
void disableRawMode(void)
{
if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &E.orig_termios) == -1)
printAndExit("tcsetattr");
}
void enableRawMode(void)
{
if (tcgetattr(STDIN_FILENO, &E.orig_termios) == -1)
printAndExit("tcgetattr");
atexit(disableRawMode);
struct termios raw = E.orig_termios;
raw.c_iflag &= ~(BRKINT | ICRNL | INPCK | ISTRIP | IXON);
raw.c_oflag &= ~(OPOST);
raw.c_cflag |= (CS8);
raw.c_lflag &= ~(ECHO | ICANON | IEXTEN | ISIG);
// set a timeout for read, so read() returns if it doesn't get any input for a certain amount of time.
raw.c_cc[VMIN] = 0; // set to 0, so that read returns as soon as there is any input to be read.
raw.c_cc[VTIME] = 1000; // set 1/1000 seconds, 1 milliseconds.
if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw) == 1)
printAndExit("tcsetattr");
}
int editorReadKey(void)
{
char c;
int nread;
while ((nread = read(STDIN_FILENO, &c, 1)) != 1)
{
if (nread == -1 && errno != EAGAIN)
printAndExit("read");
}
if (c == '\x1b')
{
char seq[3];
if (read(STDIN_FILENO, &seq[0], 1) != 1)
return '\x1b';
if (read(STDIN_FILENO, &seq[1], 1) != 1)
return '\x1b';
if (seq[0] == '[')
{
if (seq[1] >= 0 && seq[1] <= 9)
{
if (read(STDIN_FILENO, &seq[2], 1) != 1)
return '\x1b';
if (seq[2] == '~')
{
switch (seq[1])
{
case '1':
return HOME_KEY; // <esc>[1~
case '3':
return DEL_KEY; // <esc>[3~
case '4':
return END_KEY; // <esc>[4~
case '5': // page up: `\x1b[5~`
return PAGE_UP;
case '6': // page up: `\x1b[6~`
return PAGE_DOWN;
case '7':
return HOME_KEY; // <esc>[7~
case '8':
return END_KEY; // <esc>[8~
}
}
}
else
{
switch (seq[1])
{
case 'A':
return ARROW_LEFT;
case 'B':
return ARROW_DOWN;
case 'C':
return ARROW_RIGHT;
case 'D':
return ARROW_UP;
case 'H':
return HOME_KEY; // <esc>[H
case 'F':
return END_KEY; // <esc>[F
}
}
}
else if (seq[0] == 'O')
{
switch (seq[1])
{
case 'H':
return HOME_KEY; // <esc>OH
case 'F':
return END_KEY; // <esc>OF
}
}
return '\x1b';
}
return c;
}
int getCursorPosition(int *rows, int *cols)
{
char buf[32];
unsigned int i = 0;
if (write(STDOUT_FILENO, "\x1b[6n", 4) != 4)
return -1;
while (i < sizeof(buf) - 1)
{
if (read(STDIN_FILENO, &buf[i], 1) != 1)
break;
if (buf[i] == 'R')
break;
i++;
}
buf[i] = '\0';
// &buf[1]: '[36;131'
printf("\r\n&buf[1]: '%s'\r\n", &buf[1]);
if (buf[0] != '\x1b' || buf[1] != '[')
return -1;
if (sscanf(&buf[2], "%d;%d", rows, cols) != 2)
return -1;
return 0;
}
int getWindowSize(int *rows, int *cols)
{
struct winsize ws;
if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) == -1 || ws.ws_col == 0)
{
if (write(STDOUT_FILENO, "\x1b[999C\x1b[999B", 12) != 12)
return -1;
return getCursorPosition(rows, cols);
}
else
{
*rows = ws.ws_row;
*cols = ws.ws_col;
return 0;
}
}
/*** row operations ***/
void editorAppendRow(char *s, size_t len)
{
E.row = realloc(E.row, sizeof(erow) * (E.numrows + 1));
int at = E.numrows;
E.row[at].size = len;
E.row[at].chars = malloc(len + 1);
memcpy(E.row[at].chars, s, len);
E.row[at].chars[len] = '\0';
E.numrows++;
}
/*** file io ***/
// let’s allow the user to open an actual file. We’ll read and display the first line of the file.
void editorOpen(char *filename)
{
FILE *fp = fopen(filename, "r");
if (!fp)
printAndExit("fopen");
char *line = NULL;
size_t linecap = 0;
ssize_t linelen;
while ((linelen = getline(&line, &linecap, fp)) != -1)
{
while (linelen > 0 && (line[linelen - 1] == '\n' || line[linelen - 1] == '\r'))
linelen--;
editorAppendRow(line, linelen);
}
free(line);
fclose(fp);
}
/*** append buffer ***/
/*
An append buffer consists of a pointer to our buffer in memory, and a length.
We define an ABUF_INIT constant which represents an empty buffer. This acts as a constructor for our abuf type.
*/
struct abuf
{
char *b;
int len;
};
#define ABUF_INIT \
{ \
NULL, 0 \
}
/*
To append a string s to an abuf, the first thing we do is make sure we allocate enough memory to hold the new string.
We ask realloc() to give us a block of memory that is the size of the current string plus the size of the string
we are appending.
realloc() will either extend the size of the block of memory we already have allocated,
or it will take care of free()ing the current block of memory
and allocating a new block of memory somewhere else that is big enough for our new string.
Then we use memcpy() to copy the string s after the end of the current data in the buffer,
and we update the pointer and length of the abuf to the new values.
*/
void abAppend(struct abuf *ab, const char *s, int len)
{
char *new = realloc(ab->b, ab->len + len);
if (new == NULL)
return;
memcpy(&new[ab->len], s, len);
ab->b = new;
ab->len += len;
}
void abFree(struct abuf *ab)
{
free(ab->b);
}
/*** output ***/
void editorDrawRows(struct abuf *ab)
{
int y;
for (y = 0; y < E.screenrows; y++)
{
if (y >= E.numrows)
{
if (E.numrows == 0 && y == E.screenrows / 3)
{
char welcome[88];
int welLen = snprintf(welcome, sizeof(welcome), "Kilo editor -- version: %s", KILO_VERSION);
if (welLen > E.screencols)
welLen = E.screencols;
int padding = (E.screencols - welLen) / 2;
if (padding)
{
abAppend(ab, "~", 1);
padding--;
}
while (padding--)
abAppend(ab, " ", 1);
abAppend(ab, welcome, welLen);
}
else
{
abAppend(ab, "~", 1);
}
}
else
{
int len = E.row[y].size;
if (len > E.screencols)
len = E.screencols;
abAppend(ab, E.row[y].chars, len);
}
// clear each line
abAppend(ab, "\x1b[K", 3);
if (y < E.screenrows - 1)
{
abAppend(ab, "\r\n", 2);
}
}
}
void editorRefreshSceen(void)
{
struct abuf ab = ABUF_INIT;
abAppend(&ab, "\x1b[?25l", 6);
abAppend(&ab, "\x1b[H", 3);
editorDrawRows(&ab);
// move cursor to the position cy, cx
char buf[32];
snprintf(buf, sizeof(buf), "\x1b[%d;%dH", E.cy + 1, E.cx + 1);
abAppend(&ab, buf, strlen(buf));
abAppend(&ab, "\x1b[?25h", 6);
write(STDOUT_FILENO, ab.b, ab.len);
abFree(&ab);
}
/*** input ***/
void editorMoveCursor(int key)
{
switch (key)
{
case ARROW_UP:
if (E.cx != 0)
{
E.cx--;
}
break;
case ARROW_RIGHT:
if (E.cx != E.screencols - 1)
{
E.cx++;
}
break;
case ARROW_LEFT:
if (E.cy != 0)
{
E.cy--;
}
break;
case ARROW_DOWN:
if (E.cy != E.screenrows - 1)
{
E.cy++;
}
break;
default:
break;
}
}
void editorProcessKeypress(void)
{
int c = editorReadKey();
switch (c)
{
case CTRL_KEY('q'):
write(STDOUT_FILENO, "\x1b[2J", 4);
write(STDOUT_FILENO, "\x1b[H", 3);
exit(0);
break;
case HOME_KEY:
E.cx = 0; // move to head of line
break;
case END_KEY:
E.cx = E.screencols - 1; // move to the end of line
break;
case PAGE_UP:
case PAGE_DOWN:
{
int times = E.screenrows;
while (times--)
{
editorMoveCursor(c == PAGE_UP ? ARROW_UP : ARROW_DOWN);
}
}
case ARROW_UP:
case ARROW_DOWN:
case ARROW_LEFT:
case ARROW_RIGHT:
editorMoveCursor(c);
break;
}
}
/*** init ***/
void initEditor(void)
{
// init cx and cy = 0, we want the cursor to start at the top-left of the screen.
E.cx = 0;
E.cy = 0;
E.numrows = 0;
E.row = NULL;
if (getWindowSize(&E.screenrows, &E.screencols) == -1)
printAndExit("getWindowSize");
}
int main(int argc, char *argv[])
{
enableRawMode();
initEditor();
if (argc >= 2)
{
editorOpen(argv[1]);
}
while (1)
{
editorRefreshSceen();
editorProcessKeypress();
}
return 0;
}