diff options
Diffstat (limited to 'src/fold.c')
| -rw-r--r-- | src/fold.c | 250 |
1 files changed, 250 insertions, 0 deletions
diff --git a/src/fold.c b/src/fold.c new file mode 100644 index 000000000..d5d4ae3fe --- /dev/null +++ b/src/fold.c @@ -0,0 +1,250 @@ +/* fold -- wrap each input line to fit in specified width. + Copyright (C) 1991 Free Software Foundation, Inc. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2, or (at your option) + any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ + +/* Written by David MacKenzie. */ + +#define _GNU_SOURCE +#include <ctype.h> +#ifndef isblank +#define isblank(c) ((c) == ' ' || (c) == '\t') +#endif +#include <stdio.h> +#include <getopt.h> +#include <sys/types.h> +#include "system.h" + +char *xrealloc (); +int adjust_column (); +int fold_file (); +void error (); + +/* If nonzero, try to break on whitespace. */ +int break_spaces; + +/* If nonzero, count bytes, not column positions. */ +int count_bytes; + +/* If nonzero, at least one of the files we read was standard input. */ +int have_read_stdin; + +/* The name this program was run with. */ +char *program_name; + +struct option longopts[] = +{ + {"bytes", 0, NULL, 'b'}, + {"spaces", 0, NULL, 's'}, + {"width", 1, NULL, 'w'}, + {NULL, 0, NULL, 0} +}; + +void +main (argc, argv) + int argc; + char **argv; +{ + int width = 80; + int i; + int optc; + int errs = 0; + + program_name = argv[0]; + break_spaces = count_bytes = have_read_stdin = 0; + + while ((optc = getopt_long (argc, argv, "bsw:", longopts, (int *) 0)) + != EOF) + { + switch (optc) + { + case 'b': /* Count bytes rather than columns. */ + count_bytes = 1; + break; + + case 's': /* Break at word boundaries. */ + break_spaces = 1; + break; + + case 'w': /* Line width. */ + width = atoi (optarg); + if (width < 1) + error (1, 0, "%s: invalid line width", optarg); + break; + + default: + fprintf (stderr, "\ +Usage: %s [-bs] [-w width] [--bytes] [--spaces] [--width=width] [file...]\n", + argv[0]); + exit (1); + } + } + + if (argc == optind) + errs |= fold_file ("-", width); + else + for (i = optind; i < argc; i++) + errs |= fold_file (argv[i], width); + + if (have_read_stdin && fclose (stdin) == EOF) + error (1, errno, "-"); + if (fclose (stdout) == EOF) + error (1, errno, "write error"); + + exit (errs); +} + +/* Fold file FILENAME, or standard input if FILENAME is "-", + to stdout, with maximum line length WIDTH. + Return 0 if successful, 1 if an error occurs. */ + +int +fold_file (filename, width) + char *filename; + int width; +{ + FILE *istream; + register int c; + int column = 0; /* Screen column where next char will go. */ + int offset_out = 0; /* Index in `line_out' for next char. */ + static char *line_out = NULL; + static size_t allocated_out = 0; + + if (!strcmp (filename, "-")) + { + istream = stdin; + have_read_stdin = 1; + } + else + istream = fopen (filename, "r"); + + if (istream == NULL) + { + error (0, errno, "%s", filename); + return 1; + } + + while ((c = getc (istream)) != EOF) + { + if (offset_out + 1 >= allocated_out) + { + allocated_out += 1024; + line_out = xrealloc (line_out, allocated_out); + } + + if (c == '\n') + { + line_out[offset_out++] = c; + fwrite (line_out, sizeof (char), offset_out, stdout); + column = offset_out = 0; + continue; + } + + rescan: + column = adjust_column (column, c); + + if (column > width) + { + /* This character would make the line too long. + Print the line plus a newline, and make this character + start the next line. */ + if (break_spaces) + { + /* Look for the last blank. */ + int logical_end; + + for (logical_end = offset_out - 1; logical_end >= 0; + logical_end--) + if (isblank (line_out[logical_end])) + break; + if (logical_end >= 0) + { + int i; + + /* Found a blank. Don't output the part after it. */ + logical_end++; + fwrite (line_out, sizeof (char), logical_end, stdout); + putchar ('\n'); + /* Move the remainder to the beginning of the next line. + The areas being copied here might overlap. */ + bcopy (line_out + logical_end, line_out, + offset_out - logical_end); + offset_out -= logical_end; + for (column = i = 0; i < offset_out; i++) + column = adjust_column (column, line_out[i]); + goto rescan; + } + } + line_out[offset_out++] = '\n'; + fwrite (line_out, sizeof (char), offset_out, stdout); + column = offset_out = 0; + goto rescan; + } + + line_out[offset_out++] = c; + } + + if (offset_out) + fwrite (line_out, sizeof (char), offset_out, stdout); + + if (ferror (istream)) + { + error (0, errno, "%s", filename); + if (strcmp (filename, "-")) + fclose (istream); + return 1; + } + if (strcmp (filename, "-") && fclose (istream) == EOF) + { + error (0, errno, "%s", filename); + return 1; + } + + if (ferror (stdout)) + { + error (0, errno, "write error"); + return 1; + } + + return 0; +} + +/* Assuming the current column is COLUMN, return the column that + printing C will move the cursor to. + The first column is 0. */ + +int +adjust_column (column, c) + int column; + char c; +{ + if (!count_bytes) + { + if (c == '\b') + { + if (column > 0) + column--; + } + else if (c == '\r') + column = 0; + else if (c == '\t') + column = column + 8 - column % 8; + else /* if (isprint (c)) */ + column++; + } + else + column++; + return column; +} |