editor.c

#define _DEFAULT_SOURCE
#define _BSD_SOURCE
#define _GNU_SOURCE

#include <unistd.h>
#include <termio.h>
#include <stdlib.h>
#include <ctype.h>
#include <stdio.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <string.h>
#define zr_VERSION "0.0.1"
#define CTRL_KEY(k) ((k) & 0x1f)

// enum editorKey{
//     ARROW_LEFT = 'h',
//     ARROW_RIGHT = 'l',
//     ARROW_UP = 'k',
//     ARROW_DOWN = 'j',
//     PAGE_UP = '[',
//     PAGE_DOWN = ']'
// };
//赋予上下左右一个比较大的值，以至于他们不会和传统按键冲突，但是只后需要将char 改为int
//这里的1000是无意义的
enum editorKey{
    ARROW_LEFT = 1000,
    ARROW_RIGHT,
    ARROW_UP ,
    ARROW_DOWN,
    DEL_KEY,
    HOME_KEY,
    END_KEY,
    PAGE_UP,
    PAGE_DOWN
};
/*** data ***/
//存储文本的一行
typedef struct erow{
    int size;
    char *chars;
} erow;

struct  editorConfig{
    //cx，cy用于记录光标位置
    int cx,cy;
    int screenrows;
    int screencols;
    //numrows 存储一共使用了多少行
    int numrows;
    //存储多行
    erow *row;
    struct termios orig_termios;
};
struct editorConfig E;


/*** terminal ***/
void die(const char* s){
    write(STDOUT_FILENO,"\x1b[2J",4);
    write(STDOUT_FILENO,"\x1b[H",3); 
    perror(s);
    exit(-1);
}
void disableRawMode(){
    tcsetattr(STDIN_FILENO,TCSAFLUSH,&E.orig_termios);
}
void enableRawMode(){
    if(tcgetattr(STDIN_FILENO,&E.orig_termios) == -1) die("tcgetattr");
    atexit(disableRawMode);
    struct termios raw = E.orig_termios;
    raw.c_lflag &= ~(ECHO | ICANON | ISIG |IEXTEN);
    raw.c_iflag &= ~(IXON | ICRNL | INPCK| ISTRIP | BRKINT);
    raw.c_oflag &= ~(OPOST);
    raw.c_cflag |= (CS8);
    raw.c_cc[VMIN] = 0;
    raw.c_cc[VTIME] = 1;
    if(tcsetattr(STDIN_FILENO,TCSAFLUSH,&raw) == -1) die("tcsetattr");
    
    
}
int editorReadKey(){
    int nread;
    char c;
    while ((nread = read(STDIN_FILENO,&c,1)) != 1){
        if(nread == -1 && errno != EAGAIN) die("read");
       
    }
    // 使用Arrow按键 上下移动光标
    if( c == '\x1b'){
        //这里只需要2个字节，定义3个字节 是为了以后使用
        char seq[3];
        //继续读一个字节，存入seq[0],如果没有读到，则返回'\x1b'
        if(read(STDIN_FILENO,&seq[0],1) != 1) return '\x1b';
        if(read(STDIN_FILENO,&seq[1],1) != 1) return '\x1b';
        //<esc>[5~ 为Page up按钮 <esc>[6~为Page down 按钮
        //注意这里全写死了，只能使用
        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]){
                        //HOME可以是(<esc>[1~, <esc>[7~, <esc>[H, or <esc>OH) , END可以是(<esc>[4~, <esc>[8~, <esc>[F, or <esc>OF) 这主要取决于OS或者你的终端模拟器
                        case '1': return HOME_KEY;
                        case '3': return DEL_KEY;
                        case '4': return END_KEY;
                        case '5': return PAGE_UP;
                        case '6': return PAGE_DOWN;
                        case '7': return HOME_KEY;
                        case '8': return END_KEY;
                    }
                }
            }else{
                switch(seq[1]){
                    case 'A': return ARROW_UP;
                    case 'B': return ARROW_DOWN;
                    case 'C': return ARROW_RIGHT;
                    case 'D': return ARROW_LEFT;
                    case 'H': return HOME_KEY;
                    case 'F': return END_KEY;
                }
            }
        }else if (seq[0] == '0'){
            switch(seq[1]){
                case 'H': return HOME_KEY;
                case 'F': return END_KEY;
            } 
        }
        
        return '\x1b';
    }else{
        return c;
    }
    

    
}

//获取光标位置
int getCursorPosition(int *rows,int *cols){ 
    char buf[32];
    unsigned int i = 0;
    
    //读入缓冲区 一直读取 知道读取到R字符
    if(write(STDIN_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';
    if (buf[0] != '\x1b' || buf[1] != '[') return -1;
    if (sscanf(&buf[2], "%d;%d", rows, cols) != 2) return -1;
    //printf("\r\n&buf[1]: '%s'\r\n", &buf[1]);
    
    // printf("\r\n");
    // char c =0;
    // while (read(STDIN_FILENO,&c,1) == 1){
    //     if(iscntrl(c)){
    //         printf("%d\r\n");
    //     }else{
    //         printf("%d ('%c')\r\n", c, c);
    //     }
    // }
    editorReadKey();
    return -1;
    
}
int getWindowSize(int *rows,int *cols){
    struct winsize ws;
    if(ioctl(STDIN_FILENO,TIOCGWINSZ,&ws) == -1 || ws.ws_col == 0){
        //将光标移动到右下角
        //我们写了2个逃逸字符: C command 将光标移动到右侧, B Command将光标移动到下方 . C和B命令有一点的好处是可以阻止越过屏幕边缘
        //[C Command](http://vt100.net/docs/vt100-ug/chapter3.html#CUF)   [B Command](http://vt100.net/docs/vt100-ug/chapter3.html#CUD)
        //参数说明移动多少步 这里就是999，999的原因时确保到达右边或者下边
        //if(write(STDIN_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) );
    //使用at索引我们想初始化的行
    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 i/o ***/
void editorOpen(char *filename){
    FILE *fp = fopen(filename,"r");
    if(!fp) die("fopen");
    
    //line 指向要分配字符串的内存
    char *line = NULL;
    //line capacity  linecap 存储分配了多少内存
    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);
    free(fp);
    
    
    
    // char *line = "HelloWorld";
    // ssize_t linelen =13;

    // E.row.size = linelen;
    // E.row.chars = malloc(linelen +1);
    // memcpy(E.row.chars,line,linelen);
    // E.row.chars[linelen] = '\0';
    // E.numrows = 1;
}

/***append buffer ***/
//write如果一次只写入一个字节那么终端可能会闪烁
//所以我门定义了此结构体,使得write是一次完成的
struct abuf
{
    char *b;
    int len;
};
//定义一个空的常量buffer
#define ABUF_INIT {NULL,0}
//把字符串s添加到ab里
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;
}
//释放空间
void abFree(struct abuf *ab){
    free(ab->b);
}

/*** output ***/
void editorDrawRows(struct abuf *ab){
    //y为行数
    for(int y=0;y<E.screenrows;y++){
        if(y >= E.numrows){
            //使得读取文件之后 不显示欢迎界面
            if(E.numrows ==0 && y == E.screenrows / 3){
            char welcome[80];
            int welcomelen = snprintf(welcome,sizeof(welcome),
            "zr editor --version %s",zr_VERSION);
            if(welcomelen > E.screencols) welcomelen = E.screencols;
            
            //将信息显示到中间
            int padding = (E.screencols - welcomelen) / 2;
            if (padding) {
                abAppend(ab, "~", 1);
                padding--;
            }
                while (padding--) abAppend(ab, " ", 1);
                abAppend(ab,welcome,welcomelen);
        
            }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);
        }
        //K命令清除当前行的一部分  0为默认,清除光标右边的部分，2清除整行, 1清除光标左边部分
        abAppend(ab,"\x1b[K",3);
        if(y < E.screenrows -1){
            abAppend(ab,"\r\n",2);
        }
    }
}
void editorRefreshScreen(){
    struct abuf ab = ABUF_INIT;
    
    //l命令
    abAppend(&ab,"\x1b[?25l",6);

    abAppend(&ab, "\x1b[H", 3);
    
    editorDrawRows(&ab);
    //h命令
    //初始化光标位置
    char buf[32];
    //格式化字符串"\x1b[%d;%dH"，并将格式化后的字符串写入到buf中
    //+1 的目的是终端使用的索引是以1开始的，而我们使用的索引是从0开始的
    snprintf(buf,sizeof(buf),"\x1b[%d;%dH",E.cy+1,E.cx+1);
    abAppend(&ab,buf,strlen(buf));
    
    abAppend(&ab, "\x1b[?25h", 6);

    write(STDIN_FILENO,ab.b,ab.len);
    abFree(&ab);
}
/*** input ***/
void editorMoveCursor(int key){
    switch (key){
        case ARROW_LEFT :
            if(E.cx != 0){E.cx--;}break;
        case ARROW_RIGHT :
            if(E.cx != E.screencols -1){E.cx++;}break;
        case ARROW_UP :
            if(E.cy != 0){E.cy--;}break;
        case ARROW_DOWN :
            if(E.cy != E.screenrows -1){E.cy++;}break;
    }
}
void editorProcessKeypress(){
    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 PAGE_UP:
        case PAGE_DOWN:
            {
                int times = E.screenrows;
                while(times--){
                    editorMoveCursor(c == PAGE_UP ? ARROW_UP : ARROW_DOWN);
                }
            }
            break;
        
        case ARROW_UP:
        case ARROW_DOWN:
        case ARROW_LEFT:
        case ARROW_RIGHT:
            editorMoveCursor(c);
            break;
        //目前先把HOME和END操作设置为将光标移到左边和右边
        case HOME_KEY:
            E.cx = 0;
            break;
        case END_KEY:
            E.cx = E.screencols -1;
            break;
    }
}
/*** init ***/
void initEditor(){
    //设置初始化的光标位置
    E.cx = 0;
    E.cy = 0;
    E.numrows = 0;
    E.row = NULL;
    //获取窗口大小
    if(getWindowSize(&E.screenrows,&E.screencols) == -1) die("getWindowSize");
}
int main(int argc,char *argv[]){
    enableRawMode();
    initEditor();
    if(argc >=2){
        editorOpen(argv[1]);
    }
    while(1){
        editorRefreshScreen();
        editorProcessKeypress();
    }


    return 0;
}