/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/*  reflow.c                    by alan partis, thundernet development group */
/*                              (c) copyright 2002.  all rights reserved.    */
/*                                                                           */
/*  Reflows long lines in the input stream to a given column.  Lines are     */
/*  split on the last white space before the 'wrap' column.  If no white     */
/*  space appears on a line, it will be split at the wrap column.            */
/*                                                                           */
/*  args:                                                                    */
/*      n       reflow column                                                */
/*                                                                           */
/*  usage: reflow <n>                                                        */
/*                                                                           */
/*  Functions:                                                               */
/*      main()      program entry point                                      */
/*                                                                           */
/*  Date    Who     Comment                                                  */
/*  -----------------------------------------------------------------------  */
/*  22feb02 acp     initial creation                                         */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <stdapms.h>

void reflow(FILE *in, FILE *out, int wrap);



/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/*  main()                      by alan partis, thundernet development group */
/*                              (c) copyright 2002.  all rights reserved.    */
/*                                                                           */
/*  Program entry point.  Executes program algorithm.                        */
/*                                                                           */
/*  args:   argc        number of command line arguments                     */
/*          argv        array of command line argument strings               */
/*                                                                           */
/*  return: int         program exit status -- 0 on success,                 */
/*                                                                           */
/*  Date        who     Comments                                             */
/*  -----------------------------------------------------------------------  */
/*  22feb02     acp     initial creation                                     */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
int main (int argc, char *argv[])
{
    int     rc = EXIT_SUCCESS;

    if (argc == 2) {
        reflow(stdin, stdout, atoi(argv[1]));
    } else {
        printf("usage\n\tentab <tabstop>\n");
    }

    return rc;

}   /* end of function main() */



/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/*  reflow()                    by alan partis, thundernet development group */
/*                              (c) copyright 2002.  all rights reserved.    */
/*                                                                           */
/*  From the given input stream, reflows long lines in the input stream on   */
/*  the given column and writes them to the output stream.                   */
/*                                                                           */
/*  args:   in          FILE input stream                                    */
/*          out         FILE output stream                                   */
/*          wrap        column at which to wrap                              */
/*                                                                           */
/*  return: none                                                             */
/*                                                                           */
/*  Date        who     Comments                                             */
/*  -----------------------------------------------------------------------  */
/*  22feb02     acp     initial creation                                     */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
void reflow(FILE *in, FILE *out, int wrap)
{
    char   *buffer;
    char    c;
    int     column;
    int     i, j;
    int     last_whitespace;
    int     leftover;

    //
    // initial setup
    //
    buffer = malloc(wrap + 1); memset(buffer, 0, wrap + 1);
    last_whitespace = column = 0;

    while ((c = getc(in)) != EOF) {
        buffer[column] = c;

        column++;
        if ((c == LF) || (c == CR)) {
            //
            // end of line found ... go ahead and dump
            //  out the buffer and go to the next line.
            //
            i = 0;
            while (buffer[i] != 0) {
                putc(buffer[i++], out);
            }

            memset(buffer, 0, wrap + 1);
            last_whitespace = column = 0;
        } else if (column >= wrap) {
            //
            // time to execute a wrap
            //
            if (last_whitespace > 0) {
                for (i = 0; i < last_whitespace; i++) {
                    putc(buffer[i], out);
                }
                leftover = column - i;
                putc(LF, out);
                for (j = 0; j < (wrap + 1); j++) {
                    buffer[j] = (i <= column) ? buffer[i++] : 0;
                }

                last_whitespace = 0;
                column = leftover;
            } else {
                i = 0;
                while (buffer[i]) putc(buffer[i++], out);
                putc(LF, out);
                memset(buffer, 0, wrap + 1);
                last_whitespace = column = 0;
            }

        } else if (isspace(c)) {
            // update the whitespace pointer
            last_whitespace = column;
        }
    }

    free(buffer);

}   /* end of function reflow() */