Source Code 1992 March/Source_Code_CD-ROM_Walnut_Creek_March_1992.iso/usenet/altsrcs/1/1456/editline.c

C/C++ Source or Header | 1990-12-28 | 4.5 KB | 194 lines

/*
 * Copyright (C) 1990 Jay Konigsberg - see Makefile for details
 * This is Free Software, distrubited under the GNU Software Aggrement.
 */

#include "simped.h"

char **editline(text, linenum, delimiter)
char **text;
int  linenum;
char delimiter;
{
int    position(),        /* where is oldtext in text[], -1 if err */
    cleanup(),
    puts(),
    fputs(),
    fflush(),
    printf(),
    fprintf();

char    *realloc(),
    *getline();


char    *oldtext,
    *newtext,
    buffer[LINELEN+2];

int    text_entered,        /* boolean to tell if something was entered */
    textinx=0,        /* index for the subsitutation */
    textlen,        /* length of the original string */
    newlen,            /* length of new text */
    oldlen,            /* length of old text */
    point=0;        /* subscript of text[] where oldtext begins */

textlen=strlen(text[linenum-1]);
if ( ! delimiter )
    {
    printf("%3d> ", linenum);
    fputs(text[linenum-1], stdout);
    puts("Return by itself to insert at the beginning.");
    }
    for(;;)
    {
    if ( ! delimiter)
    {
    fputs("Old text: ", stdout);
    fflush(stdout);
    }
    if (getline(buffer, &text_entered, stdin, delimiter, TRUE))
    {
    if ( ! delimiter)
        {
        printf("Max line is %d characters, continuing...\n", LINELEN);
        }
    else
        {
        /* printf("%c%c", delimiter, BELL); */
        }
    buffer[LINELEN+1]='\n';
    buffer[LINELEN+2]='\0';
    }
    fflush(stdout);
    /* if (text_entered == FALSE) */
    if ( strlen(buffer) == 1) /* a single '\n' was entered */
    {
    /* setup to insert at the begining of the line */
    oldlen=0;
    break;
    }
    else
    {
    buffer[strlen(buffer)-1]='\0';
    oldtext=strdup(buffer);
    oldlen=strlen(oldtext);
    if( (point=position(oldtext, text[linenum-1])) == -1)
        {
        printf("\nstring: %s, not found in line %d\n", oldtext, linenum);
        delimiter='\0';
        }
    else
        {
        break;
        }
    }
    }
if ( ! delimiter )
    {
    fputs("New text: ", stdout);
    fflush(stdout);
    }
if(getline(buffer, &text_entered, stdin, delimiter, TRUE))
    {
    if ( ! delimiter )
        {
        printf("Max line is %d characters, continuing...\n", LINELEN);
        }
    else
        {
        /* printf("%c%c", delimiter, BELL); */
        fflush(stdout);
        }
    buffer[LINELEN+1]='\n';
    buffer[LINELEN+2]='\0';
    }
/* if (text_entered == FALSE && oldlen == 0) */
if (strlen(buffer) == 1 && oldlen == 0) /* a singal '\n' was entered */
    {
    /* nothing entered, exit */
    puts("\nNo change...");
    return(text);
    }
if (text_entered == FALSE)
    {
    buffer[0]='\0';
    }
else
    {
    buffer[strlen(buffer)-1]='\0';
    }
newtext=strdup(buffer);
newlen=strlen(newtext);
/* Conditions to handle
 *
 *                * no realloc
 * 1) oldlen == newlen        - strings are same length
 *                * relloc after change so no text is lost
 * 2) newlen == 0 & oldlen > 1    - remove some text
 * 3) newlen <  oldlen        - downsize text[]
 *                * realloc before change so there is
 *                  room for more characters
 * 4) oldlen == 0 & newlen > 1    - insert at beginning of line
 * 5) newlen >  oldlen        - increase size-of text[]
 */
if (newlen == oldlen) /* case 1, same length */
    {
    for (textinx=point; textinx < point+newlen; ++textinx)
    {
    text[linenum-1][textinx] = newtext[textinx-point];
    }
    }
else
    {
    if (newlen < oldlen) /* case 2 & 3 - have extra space */
    {
    /* copy over old text - non-op if new=0 */
    for (textinx=point; textinx < point+newlen; ++textinx)
        {
        text[linenum-1][textinx] = newtext[textinx-point];
        }
    /* roll remaining text back over the oldtext */
    point=textinx;
    for (textinx=point; textinx < textlen; ++textinx)
        {
        text[linenum-1][textinx]=text[linenum-1][textinx+oldlen-newlen];
        }
    text[linenum-1][textlen+newlen-oldlen]='\0';
    if((text[linenum-1]=realloc(text[linenum-1],
        (unsigned int)(textinx+FUDGE)))==NULL)
        {
        fprintf(stderr, "realloc: error=%d\n", errno);
        cleanup(2);
        }
    }
    else /* case 4 & 5 - more space is needed */
    {
    if((text[linenum-1]=realloc(text[linenum-1],
        (unsigned int)(textlen+newlen-oldlen+FUDGE)))==NULL)
        {
        fprintf(stderr, "realloc: error=%d\n", errno);
        cleanup(2);
        }
    /* roll out char to make room for insert */

    for (textinx=textlen+newlen-oldlen;
        textinx >= point+newlen-oldlen; --textinx)
        {
        text[linenum-1][textinx]=text[linenum-1][textinx-newlen+oldlen];
        }
    /* place newtext in the text area */
    for (textinx=point; textinx < point+newlen; ++textinx)
        {
        text[linenum-1][textinx] = newtext[textinx-point];
        }
    text[linenum-1][textlen+newlen-oldlen-1]='\n';
    text[linenum-1][textlen+newlen-oldlen]='\0';
    }
    }
printf("\n%3d> ", linenum);
fputs(text[linenum-1], stdout);
return(text);
}