source: trunk/minix/commands/elvis/fmt.c@ 20

/* fmt.c */

/* usage: fmt [-width] [files]...
 *
 * Fmt rearrages text in order to make each line have roughly the
 * same width.  Indentation and word spacing is preserved.
 *
 * The default width is 72 characters, but you can override that via -width.
 * If no files are given on the command line, then it reads stdin.
 */

#include <stdio.h>

#ifndef TRUE
# define TRUE   1
# define FALSE  0
#endif



int     width = 72;     /* the desired line width */
int     isblank;        /* is the current output line blank? */
int     indent;         /* width of the indentation */
char    ind[512];       /* indentation text */
char    word[1024];     /* word buffer */

/* This function displays a usage message and quits */
void usage()
{
        fprintf(stderr, "usage: fmt [-width] [files]...\n");
        exit(2);
}



/* This function outputs a single word.  It takes care of spacing and the
 * newlines within a paragraph.
 */
void putword()
{
        int             i;              /* index into word[], or whatever */
        int             ww;             /* width of the word */
        int             sw;             /* width of spacing after word */
        static int      psw;            /* space width of previous word */
        static int      tab;            /* the width of text already written */


        /* separate the word and its spacing */
        for (ww = 0; word[ww] && word[ww] != ' '; ww++)
        {
        }
        sw = strlen(word) - ww;
        word[ww] = '\0';

        /* if no spacing (that is, the word was at the end of the line) then
         * assume 1 space unless the last char of the word was punctuation
         */
        if (sw == 0)
        {
                sw = 1;
                if (word[ww - 1] == '.' || word[ww - 1] == '?' || word[ww - 1] == '!')
                        sw = 2;
        }

        /* if this is the first word on the line... */
        if (isblank)
        {
                /* output the indentation first */
                fputs(ind, stdout);
                tab = indent;
        }
        else /* text has already been written to this output line */
        {
                /* will the word fit on this line? */
                if (psw + ww + tab <= width)
                {
                        /* yes - so write the previous word's spacing */
                        for (i = 0; i < psw; i++)
                        {
                                putchar(' ');
                        }
                        tab += psw;
                }
                else
                {
                        /* no, so write a newline and the indentation */
                        putchar('\n');
                        fputs(ind, stdout);
                        tab = indent;
                }
        }

        /* write the word itself */
        fputs(word, stdout);
        tab += ww;

        /* remember this word's spacing */
        psw = sw;

        /* this output line isn't blank anymore. */
        isblank = FALSE;
}



/* This function reformats text. */
void fmt(in)
        FILE    *in;            /* the name of the input stream */
{
        int     ch;             /* character from input stream */
        int     prevch;         /* the previous character in the loop */
        int     i;              /* index into ind[] or word[] */
        int     inword;         /* boolean: are we between indent & newline? */


        /* for each character in the stream... */
        for (indent = -1, isblank = TRUE, inword = FALSE, i = 0, prevch = '\n';
             (ch = getc(in)) != EOF;
             prevch = ch)
        {
                /* is this the end of a line? */
                if (ch == '\n')
                {
                        /* if end of last word in the input line */
                        if (inword)
                        {
                                /* if it really is a word */
                                if (i > 0)
                                {
                                        /* output it */
                                        word[i] = '\0';
                                        putword();
                                }
                        }
                        else /* blank line in input */
                        {
                                /* finish the previous paragraph */
                                if (!isblank)
                                {
                                        putchar('\n');
                                        isblank = TRUE;
                                }

                                /* output a blank line */
                                putchar('\n');
                        }

                        /* continue with next input line... */
                        indent = -1;
                        i = 0;
                        inword = FALSE;
                        continue;
                }

                /* if we're expecting indentation now... */
                if (indent < 0)
                {
                        /* if this is part of the indentation... */
                        if (ch == ' ' || ch == '\t')
                        {
                                /* remember it */
                                ind[i++] = ch;
                        }
                        else /* end of indentation */
                        {
                                /* mark the end of the indentation string */
                                ind[i] = '\0';

                                /* calculate the width of the indentation */
                                for (i = indent = 0; ind[i]; i++)
                                {
                                        if (ind[i] == '\t')
                                                indent = (indent | 7) + 1;
                                        else
                                                indent++;
                                }

                                /* reset the word index */
                                i = 0;

                                /* reprocess that last character */
                                ungetc(ch, in);
                        }

                        /* continue in the for-loop */
                        continue;
                }

                /* if we get here, we're either in a word or in the space
                 * after a word.
                 */
                inword = TRUE;

                /* is this the start of a new word? */
                if (ch != ' ' && prevch == ' ')
                {
                        /* yes!  output the previous word */
                        word[i] = '\0';
                        putword();

                        /* reset `i' to the start of the word[] buffer */
                        i = 0;
                }
                word[i++] = ch;
        }

        /* if necessary, write a final newline */
        if (!isblank)
        {
                putchar('\n');
                isblank = TRUE;
        }
}





int main(argc, argv)
        int     argc;
        char    **argv;
{
        FILE    *in;    /* an input stream */
        int     error;  /* if non-zero, then an error occurred */
        int     i;


        /* handle the -width flag, if given */
        if (argc > 1 && argv[1][0] == '-')
        {
                width = atoi(argv[1] + 1);
                if (width <= 0)
                {
                        usage();
                }
                argc--;
                argv++;
        }

        /* if no filenames given, then process stdin */
        if (argc == 1)
        {
                fmt(stdin);
        }
        else /* one or more filenames given */
        {
                for (error = 0, i = 1; i < argc; i++)
                {
                        in = fopen(argv[i], "r");
                        if (!in)
                        {
                                perror(argv[i]);
                                error = 3;
                        }
                        else
                        {
                                fmt(in);
                                fclose(in);
                        }
                }
        }

        /* exit, possibly indicating an error */
        exit(error);
        /*NOTREACHED*/
}