pdutils/gapbuffer.c at master · mooseman/pdutils · GitHub

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/*  gapbuffer.c                                 */
/*  A simple gapbuffer implementation.          */
/*  This code is released to the public domain. */
/*  "Share and enjoy..."  ;)                    */


#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <malloc.h>


char *slice(char *array, int first, int last)
{
    char *retarray = (char*) malloc(last-first);

    /*  Do the array slice  */
    strncpy(retarray, array+first, last);

    return retarray;
    free(retarray);
    retarray = NULL;
}


/* A pointer to move around the text */
/* This works! Very handy to move around our text. */
/* It returns the text from the letter pointed at */
/* to the end */
char *ptr(char *text, int pos)
{
   return &text[pos];
}


/* Subtracting two pointers gives the number of */
/* array elements between them. We use that here. */
int index(char *ptr1, char *ptr2)
{
   int retval = ptr2 - ptr1;
   return retval;
}


/*  Print the text  */
void print_text(char *text)
{
   printf("Text is %s \n", text);
}


/*  Return the first text buffer */
char *buf1(char *text, int pos)
{
   char *buffer1 = slice(text, 0, pos);
   return buffer1;
}


/*  Return the second text buffer */
char *buf2(char *text, int pos)
{
   char *buffer2 = slice(text, pos, strlen(text) );
   return buffer2;
}


/*  Return the cursor position */
void cursorpos()
{


}


/*  Create a gap in the middle of the text.  */
void makegap(char *text, int pos)
{


}


/*  Remove the gap (before moving it).  */
void removegap(char *text)
{


}


/*  Move the cursor (and the gap).  */
void movepos(char *text, int num)
{


}


/* Test the code.  */
int main()
{

  /* Create a text string to work with.  */
  char *text = "Mary had a little lamb, its fleece was white as snow." ;
  print_text(text);

  char *buffer1 = buf1(text, 14);
  char *buffer2 = buf2(text, 14);

  printf("Buffer1: %s \n", buffer1);
  printf("Buffer2: %s \n", buffer2);

  char *test = ptr("obsidian", 3);
  printf("Ptr: %s \n", test);

  char *foo = "obsidian";
  /* Create another pointer by adding to foo. */
  char *bar = foo + 3;

  /* Get the first part of the text */
  char baz[4];
  strncpy(baz, foo, 3);
  /* Null-terminate the text */
  baz[3]=0 ;

  /* Get the middle of the string */
  /* "*foo" is "obsidian".  */
  /* "*bar" is *foo + 3. "idian" in other words. */
  char middle[4];
  strncpy(middle, bar, 3);
  middle[3]=0;

  int myindex = index(foo, bar);
  printf("Index: %d \n", myindex);

  printf("Foo: %s \n", foo);
  printf("Bar: %s \n", bar);
  printf("Baz: %s \n", baz);
  printf("Middle: %s \n", middle);


  return 0;

}