linenoise - zygaena/hammerhead

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linenoise Plain Text 1073 lines 35.7 KB
Copyright (c) 2010-2014, Salvatore Sanfilippo <antirez at gmail dot com>
Copyright (c) 2010-2013, Pieter Noordhuis <pcnoordhuis at gmail dot com>

All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright notice,
  this list of conditions and the following disclaimer.

* Redistributions in binary form must reproduce the above copyright notice,
  this list of conditions and the following disclaimer in the documentation
  and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
linenoise
linenoise_example: linenoise.h linenoise.c

linenoise_example: linenoise.c example.c
	$(CC) -Wall -W -Os -g -o linenoise_example linenoise.c example.c

clean:
	rm -f linenoise_example
# Linenoise

A minimal, zero-config, BSD licensed, readline replacement used in Redis,
MongoDB, and Android.

* Single and multi line editing mode with the usual key bindings implemented.
* History handling.
* Completion.
* About 1,100 lines of BSD license source code.
* Only uses a subset of VT100 escapes (ANSI.SYS compatible).

## Can a line editing library be 20k lines of code?

Line editing with some support for history is a really important feature for command line utilities. Instead of retyping almost the same stuff again and again it's just much better to hit the up arrow and edit on syntax errors, or in order to try a slightly different command. But apparently code dealing with terminals is some sort of Black Magic: readline is 30k lines of code, libedit 20k. Is it reasonable to link small utilities to huge libraries just to get a minimal support for line editing?

So what usually happens is either:

 * Large programs with configure scripts disabling line editing if readline is not present in the system, or not supporting it at all since readline is GPL licensed and libedit (the BSD clone) is not as known and available as readline is (Real world example of this problem: Tclsh).
 * Smaller programs not using a configure script not supporting line editing at all (A problem we had with Redis-cli for instance).
 
The result is a pollution of binaries without line editing support.

So I spent more or less two hours doing a reality check resulting in this little library: is it *really* needed for a line editing library to be 20k lines of code? Apparently not, it is possibe to get a very small, zero configuration, trivial to embed library, that solves the problem. Smaller programs will just include this, supporing line editing out of the box. Larger programs may use this little library or just checking with configure if readline/libedit is available and resorting to linenoise if not.

## Terminals, in 2010.

Apparently almost every terminal you can happen to use today has some kind of support for basic VT100 escape sequences. So I tried to write a lib using just very basic VT100 features. The resulting library appears to work everywhere I tried to use it, and now can work even on ANSI.SYS compatible terminals, since no
VT220 specific sequences are used anymore.

The library is currently about 1100 lines of code. In order to use it in your project just look at the *example.c* file in the source distribution, it is trivial. Linenoise is BSD code, so you can use both in free software and commercial software.

## Tested with...

 * Linux text only console ($TERM = linux)
 * Linux KDE terminal application ($TERM = xterm)
 * Linux xterm ($TERM = xterm)
 * Linux Buildroot ($TERM = vt100)
 * Mac OS X iTerm ($TERM = xterm)
 * Mac OS X default Terminal.app ($TERM = xterm)
 * OpenBSD 4.5 through an OSX Terminal.app ($TERM = screen)
 * IBM AIX 6.1
 * FreeBSD xterm ($TERM = xterm)
 * ANSI.SYS

Please test it everywhere you can and report back!

## Let's push this forward!

Patches should be provided in the respect of linenoise sensibility for small
easy to understand code.

Send feedbacks to antirez at gmail
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "linenoise.h"


void completion(const char *buf, linenoiseCompletions *lc) {
    if (buf[0] == 'h') {
        linenoiseAddCompletion(lc,"hello");
        linenoiseAddCompletion(lc,"hello there");
    }
}

int main(int argc, char **argv) {
    char *line;
    char *prgname = argv[0];

    /* Parse options, with --multiline we enable multi line editing. */
    while(argc > 1) {
        argc--;
        argv++;
        if (!strcmp(*argv,"--multiline")) {
            linenoiseSetMultiLine(1);
            printf("Multi-line mode enabled.\n");
        } else if (!strcmp(*argv,"--keycodes")) {
            linenoisePrintKeyCodes();
            exit(0);
        } else {
            fprintf(stderr, "Usage: %s [--multiline] [--keycodes]\n", prgname);
            exit(1);
        }
    }

    /* Set the completion callback. This will be called every time the
     * user uses the <tab> key. */
    linenoiseSetCompletionCallback(completion);

    /* Load history from file. The history file is just a plain text file
     * where entries are separated by newlines. */
    linenoiseHistoryLoad("history.txt"); /* Load the history at startup */

    /* Now this is the main loop of the typical linenoise-based application.
     * The call to linenoise() will block as long as the user types something
     * and presses enter.
     *
     * The typed string is returned as a malloc() allocated string by
     * linenoise, so the user needs to free() it. */
    while((line = linenoise("hello> ")) != NULL) {
        /* Do something with the string. */
        if (line[0] != '\0' && line[0] != '/') {
            printf("echo: '%s'\n", line);
            linenoiseHistoryAdd(line); /* Add to the history. */
            linenoiseHistorySave("history.txt"); /* Save the history on disk. */
        } else if (!strncmp(line,"/historylen",11)) {
            /* The "/historylen" command will change the history len. */
            int len = atoi(line+11);
            linenoiseHistorySetMaxLen(len);
        } else if (line[0] == '/') {
            printf("Unreconized command: %s\n", line);
        }
        free(line);
    }
    return 0;
}
/* linenoise.c -- VERSION 1.0
 *
 * Guerrilla line editing library against the idea that a line editing lib
 * needs to be 20,000 lines of C code.
 *
 * You can find the latest source code at:
 *
 *   http://github.com/antirez/linenoise
 *
 * Does a number of crazy assumptions that happen to be true in 99.9999% of
 * the 2010 UNIX computers around.
 *
 * ------------------------------------------------------------------------
 *
 * Copyright (c) 2010-2014, Salvatore Sanfilippo <antirez at gmail dot com>
 * Copyright (c) 2010-2013, Pieter Noordhuis <pcnoordhuis at gmail dot com>
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *  *  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *  *  Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * ------------------------------------------------------------------------
 *
 * References:
 * - http://invisible-island.net/xterm/ctlseqs/ctlseqs.html
 * - http://www.3waylabs.com/nw/WWW/products/wizcon/vt220.html
 *
 * Todo list:
 * - Filter bogus Ctrl+<char> combinations.
 * - Win32 support
 *
 * Bloat:
 * - History search like Ctrl+r in readline?
 *
 * List of escape sequences used by this program, we do everything just
 * with three sequences. In order to be so cheap we may have some
 * flickering effect with some slow terminal, but the lesser sequences
 * the more compatible.
 *
 * EL (Erase Line)
 *    Sequence: ESC [ n K
 *    Effect: if n is 0 or missing, clear from cursor to end of line
 *    Effect: if n is 1, clear from beginning of line to cursor
 *    Effect: if n is 2, clear entire line
 *
 * CUF (CUrsor Forward)
 *    Sequence: ESC [ n C
 *    Effect: moves cursor forward n chars
 *
 * CUB (CUrsor Backward)
 *    Sequence: ESC [ n D
 *    Effect: moves cursor backward n chars
 *
 * The following is used to get the terminal width if getting
 * the width with the TIOCGWINSZ ioctl fails
 *
 * DSR (Device Status Report)
 *    Sequence: ESC [ 6 n
 *    Effect: reports the current cusor position as ESC [ n ; m R
 *            where n is the row and m is the column
 *
 * When multi line mode is enabled, we also use an additional escape
 * sequence. However multi line editing is disabled by default.
 *
 * CUU (Cursor Up)
 *    Sequence: ESC [ n A
 *    Effect: moves cursor up of n chars.
 *
 * CUD (Cursor Down)
 *    Sequence: ESC [ n B
 *    Effect: moves cursor down of n chars.
 *
 * When linenoiseClearScreen() is called, two additional escape sequences
 * are used in order to clear the screen and position the cursor at home
 * position.
 *
 * CUP (Cursor position)
 *    Sequence: ESC [ H
 *    Effect: moves the cursor to upper left corner
 *
 * ED (Erase display)
 *    Sequence: ESC [ 2 J
 *    Effect: clear the whole screen
 *
 */

#include <stand.h>
#include "linenoise.h"
#include "bootstrap.h"

#define LINENOISE_DEFAULT_HISTORY_MAX_LEN 100
#define LINENOISE_MAX_LINE 256
static linenoiseCompletionCallback *completionCallback = NULL;

static int mlmode = 1;  /* Multi line mode. Default is single line. */
static int history_max_len = LINENOISE_DEFAULT_HISTORY_MAX_LEN;
static int history_len = 0;
static char **history = NULL;

/* The linenoiseState structure represents the state during line editing.
 * We pass this state to functions implementing specific editing
 * functionalities. */
struct linenoiseState {
    char *buf;          /* Edited line buffer. */
    size_t buflen;      /* Edited line buffer size. */
    const char *prompt; /* Prompt to display. */
    size_t plen;        /* Prompt length. */
    size_t pos;         /* Current cursor position. */
    size_t oldpos;      /* Previous refresh cursor position. */
    size_t len;         /* Current edited line length. */
    size_t cols;        /* Number of columns in terminal. */
    size_t maxrows;     /* Maximum num of rows used so far (multiline mode) */
    int history_index;  /* The history index we are currently editing. */
};

enum KEY_ACTION{
	KEY_NULL = 0,	    /* NULL */
	CTRL_A = 1,         /* Ctrl+a */
	CTRL_B = 2,         /* Ctrl-b */
	CTRL_C = 3,         /* Ctrl-c */
	CTRL_D = 4,         /* Ctrl-d */
	CTRL_E = 5,         /* Ctrl-e */
	CTRL_F = 6,         /* Ctrl-f */
	CTRL_H = 8,         /* Ctrl-h */
	TAB = 9,            /* Tab */
	CTRL_K = 11,        /* Ctrl+k */
	CTRL_L = 12,        /* Ctrl+l */
	ENTER = 13,         /* Enter */
	CTRL_N = 14,        /* Ctrl-n */
	CTRL_P = 16,        /* Ctrl-p */
	CTRL_T = 20,        /* Ctrl-t */
	CTRL_U = 21,        /* Ctrl+u */
	CTRL_W = 23,        /* Ctrl+w */
	ESC = 27,           /* Escape */
	BACKSPACE =  127    /* Backspace */
};

static void refreshLine(struct linenoiseState *l);

/* ======================= Low level terminal handling ====================== */

static int
put_bytes(const char *s, int len)
{
    int i;
    if (s == NULL)
	return -1;

    for (i = 0; i < len; i++)
	putchar(s[i]);
    return (i);
}

/* Set if to use or not the multi line mode. */
void linenoiseSetMultiLine(int ml) {
    mlmode = ml;
}

/* Clear the screen. Used to handle ctrl+l */
void linenoiseClearScreen(void) {
    if (put_bytes("\x1b[H\x1b[J", 6) <= 0) {
        /* nothing to do, just to avoid warning. */
    }
}

static int
getColumns(void)
{
	char *columns = getenv("screen-#cols");
	if (columns == NULL)
		return (80);
	return (strtol(columns, NULL, 0));
}

/* Beep, used for completion when there is nothing to complete or when all
 * the choices were already shown. */
static void linenoiseBeep(void) {
    put_bytes("\x7", 1);
}

/* ============================== Completion ================================ */

/* Free a list of completion option populated by linenoiseAddCompletion(). */
static void freeCompletions(linenoiseCompletions *lc) {
    size_t i;
    for (i = 0; i < lc->len; i++)
        free(lc->cvec[i]);
    if (lc->cvec != NULL)
        free(lc->cvec);
}

/* This is an helper function for linenoiseEdit() and is called when the
 * user types the <tab> key in order to complete the string currently in the
 * input.
 *
 * The state of the editing is encapsulated into the pointed linenoiseState
 * structure as described in the structure definition. */
static int completeLine(struct linenoiseState *ls) {
    linenoiseCompletions lc = { 0, NULL };
    int nwritten;
    char c = 0;

    completionCallback(ls->buf,&lc);
    if (lc.len == 0) {
        linenoiseBeep();
    } else {
        size_t stop = 0, i = 0;

        while(!stop) {
            /* Show completion or original buffer */
            if (i < lc.len) {
                struct linenoiseState saved = *ls;

                ls->len = ls->pos = strlen(lc.cvec[i]);
                ls->buf = lc.cvec[i];
                refreshLine(ls);
                ls->len = saved.len;
                ls->pos = saved.pos;
                ls->buf = saved.buf;
            } else {
                refreshLine(ls);
            }

            c = getchar();
            if (c <= 0) {
                freeCompletions(&lc);
                return -1;
            }

            switch(c) {
                case 9: /* tab */
                    i = (i+1) % (lc.len+1);
                    if (i == lc.len) linenoiseBeep();
                    break;
                case 27: /* escape */
                    /* Re-show original buffer */
                    if (i < lc.len) refreshLine(ls);
                    stop = 1;
                    break;
                default:
                    /* Update buffer and return */
                    if (i < lc.len) {
                        nwritten = snprintf(ls->buf,ls->buflen,"%s",lc.cvec[i]);
                        ls->len = ls->pos = nwritten;
                    }
                    stop = 1;
                    break;
            }
        }
    }

    freeCompletions(&lc);
    return c; /* Return last read character */
}

/* Register a callback function to be called for tab-completion. */
void linenoiseSetCompletionCallback(linenoiseCompletionCallback *fn) {
    completionCallback = fn;
}

/* This function is used by the callback function registered by the user
 * in order to add completion options given the input string when the
 * user typed <tab>. See the example.c source code for a very easy to
 * understand example. */
void linenoiseAddCompletion(linenoiseCompletions *lc, const char *str) {
    size_t len = strlen(str);
    char *copy, **cvec;

    copy = malloc(len+1);
    if (copy == NULL) return;
    memcpy(copy,str,len+1);
    cvec = realloc(lc->cvec,sizeof(char*)*(lc->len+1));
    if (cvec == NULL) {
        free(copy);
        return;
    }
    lc->cvec = cvec;
    lc->cvec[lc->len++] = copy;
}

/* =========================== Line editing ================================= */

/* We define a very simple "append buffer" structure, that is an heap
 * allocated string where we can append to. This is useful in order to
 * write all the escape sequences in a buffer and flush them to the standard
 * output in a single call, to avoid flickering effects. */
struct abuf {
    char *b;
    int len;
};

static void abInit(struct abuf *ab) {
    ab->b = NULL;
    ab->len = 0;
}

static void abAppend(struct abuf *ab, const char *s, int len) {
    char *new = malloc(ab->len+len);

    if (new == NULL) return;
    memcpy(new, ab->b, ab->len);
    memcpy(new+ab->len,s,len);
    free(ab->b);
    ab->b = new;
    ab->len += len;
}

static void abFree(struct abuf *ab) {
    free(ab->b);
}

/* Single line low level line refresh.
 *
 * Rewrite the currently edited line accordingly to the buffer content,
 * cursor position, and number of columns of the terminal. */
static void refreshSingleLine(struct linenoiseState *l) {
    char seq[64];
    size_t plen = strlen(l->prompt);
    char *buf = l->buf;
    size_t len = l->len;
    size_t pos = l->pos;
    struct abuf ab;

    while((plen+pos) >= l->cols) {
        buf++;
        len--;
        pos--;
    }
    while (plen+len > l->cols) {
        len--;
    }

    abInit(&ab);
    /* Cursor to left edge */
    snprintf(seq,64,"\r");
    abAppend(&ab,seq,strlen(seq));
    /* Write the prompt and the current buffer content */
    abAppend(&ab,l->prompt,strlen(l->prompt));
    abAppend(&ab,buf,len);
    /* Erase to right */
    snprintf(seq,64,"\x1b[K");
    abAppend(&ab,seq,strlen(seq));
    /* Move cursor to original position. */
    snprintf(seq,64,"\r\x1b[%dC", (int)(pos+plen));
    abAppend(&ab,seq,strlen(seq));
    put_bytes(ab.b, ab.len);

    abFree(&ab);
}

/* Multi line low level line refresh.
 *
 * Rewrite the currently edited line accordingly to the buffer content,
 * cursor position, and number of columns of the terminal. */
static void refreshMultiLine(struct linenoiseState *l) {
    char seq[64];
    int plen = strlen(l->prompt);
    int rows = (plen+l->len+l->cols)/l->cols; /* rows used by current buf. */
    int rpos = (plen+l->oldpos+l->cols)/l->cols; /* cursor relative row. */
    int rpos2; /* rpos after refresh. */
    int col; /* colum position, zero-based. */
    int old_rows = l->maxrows;
    int j;
    struct abuf ab;

    /* Update maxrows if needed. */
    if (rows > (int)l->maxrows) l->maxrows = rows;

    /* First step: clear all the lines used before. To do so start by
     * going to the last row. */
    abInit(&ab);
    if (old_rows-rpos > 0) {
        snprintf(seq,64,"\x1b[%dB", old_rows-rpos);
        abAppend(&ab,seq,strlen(seq));
    }

    /* Now for every row clear it, go up. */
    for (j = 0; j < old_rows-1; j++) {
        snprintf(seq,64,"\r\x1b[0K\x1b[1A");
        abAppend(&ab,seq,strlen(seq));
    }

    /* Clean the top line. */
    snprintf(seq,64,"\r\x1b[0K");
    abAppend(&ab,seq,strlen(seq));

    /* Write the prompt and the current buffer content */
    abAppend(&ab,l->prompt,strlen(l->prompt));
    abAppend(&ab,l->buf,l->len);

    /* If we are at the very end of the screen with our prompt, we need to
     * emit a newline and move the prompt to the first column. */
    if (l->pos &&
        l->pos == l->len &&
        (l->pos+plen) % l->cols == 0)
    {
        abAppend(&ab,"\n",1);
        snprintf(seq,64,"\r");
        abAppend(&ab,seq,strlen(seq));
        rows++;
        if (rows > (int)l->maxrows) l->maxrows = rows;
    }

    /* Move cursor to right position. */
    rpos2 = (plen+l->pos+l->cols)/l->cols; /* current cursor relative row. */

    /* Go up till we reach the expected positon. */
    if (rows-rpos2 > 0) {
        snprintf(seq,64,"\x1b[%dA", rows-rpos2);
        abAppend(&ab,seq,strlen(seq));
    }

    /* Set column. */
    col = (plen+(int)l->pos) % (int)l->cols;
    if (col)
        snprintf(seq,64,"\r\x1b[%dC", col);
    else
        snprintf(seq,64,"\r");
    abAppend(&ab,seq,strlen(seq));

    l->oldpos = l->pos;

    put_bytes(ab.b, ab.len);
    abFree(&ab);
}

/* Calls the two low level functions refreshSingleLine() or
 * refreshMultiLine() according to the selected mode. */
static void refreshLine(struct linenoiseState *l) {
    if (mlmode)
        refreshMultiLine(l);
    else
        refreshSingleLine(l);
}

/* Insert the character 'c' at cursor current position.
 *
 * On error writing to the terminal -1 is returned, otherwise 0. */
static int
linenoiseEditInsert(struct linenoiseState *l, char c) {
    if (l->len < l->buflen) {
        if (l->len == l->pos) {
            l->buf[l->pos] = c;
            l->pos++;
            l->len++;
            l->buf[l->len] = '\0';
            if ((!mlmode && l->plen+l->len < l->cols) /* || mlmode */) {
                /* Avoid a full update of the line in the
                 * trivial case. */
                putchar(c);
            } else {
                refreshLine(l);
            }
        } else {
            memmove(l->buf+l->pos+1,l->buf+l->pos,l->len-l->pos);
            l->buf[l->pos] = c;
            l->len++;
            l->pos++;
            l->buf[l->len] = '\0';
            refreshLine(l);
        }
    }
    return 0;
}

/* Move cursor on the left. */
static void
linenoiseEditMoveLeft(struct linenoiseState *l) {
    if (l->pos > 0) {
        l->pos--;
        refreshLine(l);
    }
}

/* Move cursor on the right. */
static void
linenoiseEditMoveRight(struct linenoiseState *l) {
    if (l->pos != l->len) {
        l->pos++;
        refreshLine(l);
    }
}

/* Move cursor to the start of the line. */
static void
linenoiseEditMoveHome(struct linenoiseState *l) {
    if (l->pos != 0) {
        l->pos = 0;
        refreshLine(l);
    }
}

/* Move cursor to the end of the line. */
static void
linenoiseEditMoveEnd(struct linenoiseState *l) {
    if (l->pos != l->len) {
        l->pos = l->len;
        refreshLine(l);
    }
}

/* Substitute the currently edited line with the next or previous history
 * entry as specified by 'dir'. */
#define LINENOISE_HISTORY_NEXT 0
#define LINENOISE_HISTORY_PREV 1
static void
linenoiseEditHistoryNext(struct linenoiseState *l, int dir) {
    if (history_len > 1) {
        /* Update the current history entry before to
         * overwrite it with the next one. */
        free(history[history_len - 1 - l->history_index]);
        history[history_len - 1 - l->history_index] = strdup(l->buf);
        /* Show the new entry */
        l->history_index += (dir == LINENOISE_HISTORY_PREV) ? 1 : -1;
        if (l->history_index < 0) {
            l->history_index = 0;
            return;
        } else if (l->history_index >= history_len) {
            l->history_index = history_len-1;
            return;
        }
        strncpy(l->buf,history[history_len - 1 - l->history_index],l->buflen);
        l->buf[l->buflen-1] = '\0';
        l->len = l->pos = strlen(l->buf);
        refreshLine(l);
    }
}

/* Delete the character at the right of the cursor without altering the cursor
 * position. Basically this is what happens with the "Delete" keyboard key. */
static void
linenoiseEditDelete(struct linenoiseState *l) {
    if (l->len > 0 && l->pos < l->len) {
        memmove(l->buf+l->pos,l->buf+l->pos+1,l->len-l->pos-1);
        l->len--;
        l->buf[l->len] = '\0';
        refreshLine(l);
    }
}

/* Backspace implementation. */
static void
linenoiseEditBackspace(struct linenoiseState *l) {
    if (l->pos > 0 && l->len > 0) {
        memmove(l->buf+l->pos-1,l->buf+l->pos,l->len-l->pos);
        l->pos--;
        l->len--;
        l->buf[l->len] = '\0';
        refreshLine(l);
    }
}

/* Delete the previosu word, maintaining the cursor at the start of the
 * current word. */
static void
linenoiseEditDeletePrevWord(struct linenoiseState *l) {
    size_t old_pos = l->pos;
    size_t diff;

    while (l->pos > 0 && l->buf[l->pos-1] == ' ')
        l->pos--;
    while (l->pos > 0 && l->buf[l->pos-1] != ' ')
        l->pos--;
    diff = old_pos - l->pos;
    memmove(l->buf+l->pos,l->buf+old_pos,l->len-old_pos+1);
    l->len -= diff;
    refreshLine(l);
}

/* This function is the core of the line editing capability of linenoise.
 * It expects 'fd' to be already in "raw mode" so that every key pressed
 * will be returned ASAP to read().
 *
 * The resulting string is put into 'buf' when the user type enter, or
 * when ctrl+d is typed.
 *
 * The function returns the length of the current buffer. */
static int linenoiseEdit(char *buf, size_t buflen, const char *prompt)
{
    struct linenoiseState l;

    /* Populate the linenoise state that we pass to functions implementing
     * specific editing functionalities. */
    l.buf = buf;
    l.buflen = buflen;
    l.prompt = prompt;
    l.plen = strlen(prompt);
    l.oldpos = l.pos = 0;
    l.len = 0;
    l.cols = getColumns();
    l.maxrows = 0;
    l.history_index = 0;

    /* Buffer starts empty. */
    l.buf[0] = '\0';
    l.buflen--; /* Make sure there is always space for the nulterm */

    /* The latest history entry is always our current buffer, that
     * initially is just an empty string. */
    linenoiseHistoryAdd("");

    printf ("%s", prompt);
    while(1) {
        char c;
        char seq[3];

        c = getchar();
	if (c == -1)
		continue;

        /* Only autocomplete when the callback is set. It returns < 0 when
         * there was an error reading from fd. Otherwise it will return the
         * character that should be handled next. */
        if (c == 9 && completionCallback != NULL) {
            c = completeLine(&l);
            /* Return on errors */
            if (c < 0) return l.len;
            /* Read next character when 0 */
            if (c == 0) continue;
        }

        switch(c) {
        case ENTER:    /* enter */
            history_len--;
            free(history[history_len]);
            if (mlmode) linenoiseEditMoveEnd(&l);
            return (int)l.len;
        case CTRL_C:     /* ctrl-c */
            buf[0] = '\0';
            l.pos = l.len = 0;
            refreshLine(&l);
	    break;
        case BACKSPACE:   /* backspace */
        case 8:     /* ctrl-h */
            linenoiseEditBackspace(&l);
            break;
        case CTRL_D:     /* ctrl-d, remove char at right of cursor. */
            if (l.len > 0) {
                linenoiseEditDelete(&l);
            }
            break;
        case CTRL_T:    /* ctrl-t, swaps current character with previous. */
            if (l.pos > 0 && l.pos < l.len) {
                int aux = buf[l.pos-1];
                buf[l.pos-1] = buf[l.pos];
                buf[l.pos] = aux;
                if (l.pos != l.len-1) l.pos++;
                refreshLine(&l);
            }
            break;
        case CTRL_B:     /* ctrl-b */
            linenoiseEditMoveLeft(&l);
            break;
        case CTRL_F:     /* ctrl-f */
            linenoiseEditMoveRight(&l);
            break;
        case CTRL_P:    /* ctrl-p */
            linenoiseEditHistoryNext(&l, LINENOISE_HISTORY_PREV);
            break;
        case CTRL_N:    /* ctrl-n */
            linenoiseEditHistoryNext(&l, LINENOISE_HISTORY_NEXT);
            break;
        case ESC:    /* escape sequence */
            /* Read the next two bytes representing the escape sequence.
             * Use two calls to handle slow terminals returning the two
             * chars at different times. */
            seq[0] = getchar();
            seq[1] = getchar();

            /* ESC [ sequences. */
            if (seq[0] == '[') {
                if (seq[1] >= '0' && seq[1] <= '9') {
                    /* Extended escape, read additional byte. */
                    seq[2] = getchar();
                    if (seq[2] == '~') {
                        switch(seq[1]) {
                        case '3': /* Delete key. */
                            linenoiseEditDelete(&l);
                            break;
                        }
                    }
                } else {
                    switch(seq[1]) {
                    case 'A': /* Up */
                        linenoiseEditHistoryNext(&l, LINENOISE_HISTORY_PREV);
                        break;
                    case 'B': /* Down */
                        linenoiseEditHistoryNext(&l, LINENOISE_HISTORY_NEXT);
                        break;
                    case 'C': /* Right */
                        linenoiseEditMoveRight(&l);
                        break;
                    case 'D': /* Left */
                        linenoiseEditMoveLeft(&l);
                        break;
                    case 'H': /* Home */
                        linenoiseEditMoveHome(&l);
                        break;
                    case 'F': /* End*/
                        linenoiseEditMoveEnd(&l);
                        break;
                    }
                }
            }

            /* ESC O sequences. */
            else if (seq[0] == 'O') {
                switch(seq[1]) {
                case 'H': /* Home */
                    linenoiseEditMoveHome(&l);
                    break;
                case 'F': /* End*/
                    linenoiseEditMoveEnd(&l);
                    break;
                }
            }
            break;
        default:
            if (linenoiseEditInsert(&l,c)) return -1;
            break;
        case CTRL_U: /* Ctrl+u, delete the whole line. */
            buf[0] = '\0';
            l.pos = l.len = 0;
            refreshLine(&l);
            break;
        case CTRL_K: /* Ctrl+k, delete from current to end of line. */
            buf[l.pos] = '\0';
            l.len = l.pos;
            refreshLine(&l);
            break;
        case CTRL_A: /* Ctrl+a, go to the start of the line */
            linenoiseEditMoveHome(&l);
            break;
        case CTRL_E: /* ctrl+e, go to the end of the line */
            linenoiseEditMoveEnd(&l);
            break;
        case CTRL_L: /* ctrl+l, clear screen */
            linenoiseClearScreen();
            refreshLine(&l);
            break;
        case CTRL_W: /* ctrl+w, delete previous word */
            linenoiseEditDeletePrevWord(&l);
            break;
        }
    }
    return l.len;
}

/* The high level function that is the main API of the linenoise library.
 * This function checks if the terminal has basic capabilities, just checking
 * for a blacklist of stupid terminals, and later either calls the line
 * editing function or uses dummy fgets() so that you will be able to type
 * something even in the most desperate of the conditions. */
char *linenoise(const char *prompt) {
    char buf[LINENOISE_MAX_LINE];
    int count;

    cons_mode(C_MODERAW);
    count = linenoiseEdit(buf,LINENOISE_MAX_LINE,prompt);
    cons_mode(0);
    printf("\n");
    if (count == -1) return NULL;
    return strdup(buf);
}

/* ================================ History ================================= */

/* This is the API call to add a new entry in the linenoise history.
 * It uses a fixed array of char pointers that are shifted (memmoved)
 * when the history max length is reached in order to remove the older
 * entry and make room for the new one, so it is not exactly suitable for huge
 * histories, but will work well for a few hundred of entries.
 *
 * Using a circular buffer is smarter, but a bit more complex to handle. */
int linenoiseHistoryAdd(const char *line) {
    char *linecopy;

    if (history_max_len == 0) return 0;

    /* Initialization on first call. */
    if (history == NULL) {
        history = malloc(sizeof(char*)*history_max_len);
        if (history == NULL) return 0;
        memset(history,0,(sizeof(char*)*history_max_len));
    }

    /* Don't add duplicated lines. */
    if (history_len && !strcmp(history[history_len-1], line)) return 0;

    /* Add an heap allocated copy of the line in the history.
     * If we reached the max length, remove the older line. */
    linecopy = strdup(line);
    if (!linecopy) return 0;
    if (history_len == history_max_len) {
        free(history[0]);
        memmove(history,history+1,sizeof(char*)*(history_max_len-1));
        history_len--;
    }
    history[history_len] = linecopy;
    history_len++;
    return 1;
}

/* Set the maximum length for the history. This function can be called even
 * if there is already some history, the function will make sure to retain
 * just the latest 'len' elements if the new history length value is smaller
 * than the amount of items already inside the history. */
int linenoiseHistorySetMaxLen(int len) {
    char **new;

    if (len < 1) return 0;
    if (history) {
        int tocopy = history_len;

        new = malloc(sizeof(char*)*len);
        if (new == NULL) return 0;

        /* If we can't copy everything, free the elements we'll not use. */
        if (len < tocopy) {
            int j;

            for (j = 0; j < tocopy-len; j++) free(history[j]);
            tocopy = len;
        }
        memset(new,0,sizeof(char*)*len);
        memcpy(new,history+(history_len-tocopy), sizeof(char*)*tocopy);
        free(history);
        history = new;
    }
    history_max_len = len;
    if (history_len > history_max_len)
        history_len = history_max_len;
    return 1;
}
/* linenoise.h -- VERSION 1.0
 *
 * Guerrilla line editing library against the idea that a line editing lib
 * needs to be 20,000 lines of C code.
 *
 * See linenoise.c for more information.
 *
 * ------------------------------------------------------------------------
 *
 * Copyright (c) 2010-2014, Salvatore Sanfilippo <antirez at gmail dot com>
 * Copyright (c) 2010-2013, Pieter Noordhuis <pcnoordhuis at gmail dot com>
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *  *  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *  *  Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef __LINENOISE_H
#define __LINENOISE_H

#ifdef __cplusplus
extern "C" {
#endif

typedef struct linenoiseCompletions {
  size_t len;
  char **cvec;
} linenoiseCompletions;

typedef void(linenoiseCompletionCallback)(const char *, linenoiseCompletions *);
void linenoiseSetCompletionCallback(linenoiseCompletionCallback *);
void linenoiseAddCompletion(linenoiseCompletions *, const char *);

char *linenoise(const char *prompt);
int linenoiseHistoryAdd(const char *line);
int linenoiseHistorySetMaxLen(int len);
int linenoiseHistorySave(const char *filename);
int linenoiseHistoryLoad(const char *filename);
void linenoiseClearScreen(void);
void linenoiseSetMultiLine(int ml);
void linenoisePrintKeyCodes(void);

#ifdef __cplusplus
}
#endif

#endif /* __LINENOISE_H */