diff options
Diffstat (limited to 'src/cut.c')
| -rw-r--r-- | src/cut.c | 601 |
1 files changed, 601 insertions, 0 deletions
diff --git a/src/cut.c b/src/cut.c new file mode 100644 index 0000000..b4edbab --- /dev/null +++ b/src/cut.c @@ -0,0 +1,601 @@ +/* cut - remove parts of lines of files + Copyright (C) 1997-2023 Free Software Foundation, Inc. + Copyright (C) 1984 David M. Ihnat + + 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 3 of the License, 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, see <https://www.gnu.org/licenses/>. */ + +/* Written by David Ihnat. */ + +/* POSIX changes, bug fixes, long-named options, and cleanup + by David MacKenzie <djm@gnu.ai.mit.edu>. + + Rewrite cut_fields and cut_bytes -- Jim Meyering. */ + +#include <config.h> + +#include <stdio.h> +#include <getopt.h> +#include <sys/types.h> +#include "system.h" + +#include "assure.h" +#include "fadvise.h" +#include "getndelim2.h" + +#include "set-fields.h" + +/* The official name of this program (e.g., no 'g' prefix). */ +#define PROGRAM_NAME "cut" + +#define AUTHORS \ + proper_name ("David M. Ihnat"), \ + proper_name ("David MacKenzie"), \ + proper_name ("Jim Meyering") + +#define FATAL_ERROR(Message) \ + do \ + { \ + error (0, 0, (Message)); \ + usage (EXIT_FAILURE); \ + } \ + while (0) + + +/* Pointer inside RP. When checking if a byte or field is selected + by a finite range, we check if it is between CURRENT_RP.LO + and CURRENT_RP.HI. If the byte or field index is greater than + CURRENT_RP.HI then we make CURRENT_RP to point to the next range pair. */ +static struct field_range_pair *current_rp; + +/* This buffer is used to support the semantics of the -s option + (or lack of same) when the specified field list includes (does + not include) the first field. In both of those cases, the entire + first field must be read into this buffer to determine whether it + is followed by a delimiter or a newline before any of it may be + output. Otherwise, cut_fields can do the job without using this + buffer. */ +static char *field_1_buffer; + +/* The number of bytes allocated for FIELD_1_BUFFER. */ +static size_t field_1_bufsize; + +/* If true, do not output lines containing no delimiter characters. + Otherwise, all such lines are printed. This option is valid only + with field mode. */ +static bool suppress_non_delimited; + +/* If true, print all bytes, characters, or fields _except_ + those that were specified. */ +static bool complement; + +/* The delimiter character for field mode. */ +static unsigned char delim; + +/* The delimiter for each line/record. */ +static unsigned char line_delim = '\n'; + +/* The length of output_delimiter_string. */ +static size_t output_delimiter_length; + +/* The output field separator string. Defaults to the 1-character + string consisting of the input delimiter. */ +static char *output_delimiter_string; + +/* The output delimiter string contents, if the default. */ +static char output_delimiter_default[1]; + +/* True if we have ever read standard input. */ +static bool have_read_stdin; + +/* For long options that have no equivalent short option, use a + non-character as a pseudo short option, starting with CHAR_MAX + 1. */ +enum +{ + OUTPUT_DELIMITER_OPTION = CHAR_MAX + 1, + COMPLEMENT_OPTION +}; + +static struct option const longopts[] = +{ + {"bytes", required_argument, nullptr, 'b'}, + {"characters", required_argument, nullptr, 'c'}, + {"fields", required_argument, nullptr, 'f'}, + {"delimiter", required_argument, nullptr, 'd'}, + {"only-delimited", no_argument, nullptr, 's'}, + {"output-delimiter", required_argument, nullptr, OUTPUT_DELIMITER_OPTION}, + {"complement", no_argument, nullptr, COMPLEMENT_OPTION}, + {"zero-terminated", no_argument, nullptr, 'z'}, + {GETOPT_HELP_OPTION_DECL}, + {GETOPT_VERSION_OPTION_DECL}, + {nullptr, 0, nullptr, 0} +}; + +void +usage (int status) +{ + if (status != EXIT_SUCCESS) + emit_try_help (); + else + { + printf (_("\ +Usage: %s OPTION... [FILE]...\n\ +"), + program_name); + fputs (_("\ +Print selected parts of lines from each FILE to standard output.\n\ +"), stdout); + + emit_stdin_note (); + emit_mandatory_arg_note (); + + fputs (_("\ + -b, --bytes=LIST select only these bytes\n\ + -c, --characters=LIST select only these characters\n\ + -d, --delimiter=DELIM use DELIM instead of TAB for field delimiter\n\ +"), stdout); + fputs (_("\ + -f, --fields=LIST select only these fields; also print any line\n\ + that contains no delimiter character, unless\n\ + the -s option is specified\n\ + -n (ignored)\n\ +"), stdout); + fputs (_("\ + --complement complement the set of selected bytes, characters\n\ + or fields\n\ +"), stdout); + fputs (_("\ + -s, --only-delimited do not print lines not containing delimiters\n\ + --output-delimiter=STRING use STRING as the output delimiter\n\ + the default is to use the input delimiter\n\ +"), stdout); + fputs (_("\ + -z, --zero-terminated line delimiter is NUL, not newline\n\ +"), stdout); + fputs (HELP_OPTION_DESCRIPTION, stdout); + fputs (VERSION_OPTION_DESCRIPTION, stdout); + fputs (_("\ +\n\ +Use one, and only one of -b, -c or -f. Each LIST is made up of one\n\ +range, or many ranges separated by commas. Selected input is written\n\ +in the same order that it is read, and is written exactly once.\n\ +"), stdout); + fputs (_("\ +Each range is one of:\n\ +\n\ + N N'th byte, character or field, counted from 1\n\ + N- from N'th byte, character or field, to end of line\n\ + N-M from N'th to M'th (included) byte, character or field\n\ + -M from first to M'th (included) byte, character or field\n\ +"), stdout); + emit_ancillary_info (PROGRAM_NAME); + } + exit (status); +} + + +/* Increment *ITEM_IDX (i.e., a field or byte index), + and if required CURRENT_RP. */ + +static inline void +next_item (uintmax_t *item_idx) +{ + (*item_idx)++; + if ((*item_idx) > current_rp->hi) + current_rp++; +} + +/* Return nonzero if the K'th field or byte is printable. */ + +static inline bool +print_kth (uintmax_t k) +{ + return current_rp->lo <= k; +} + +/* Return nonzero if K'th byte is the beginning of a range. */ + +static inline bool +is_range_start_index (uintmax_t k) +{ + return k == current_rp->lo; +} + +/* Read from stream STREAM, printing to standard output any selected bytes. */ + +static void +cut_bytes (FILE *stream) +{ + uintmax_t byte_idx; /* Number of bytes in the line so far. */ + /* Whether to begin printing delimiters between ranges for the current line. + Set after we've begun printing data corresponding to the first range. */ + bool print_delimiter; + + byte_idx = 0; + print_delimiter = false; + current_rp = frp; + while (true) + { + int c; /* Each character from the file. */ + + c = getc (stream); + + if (c == line_delim) + { + if (putchar (c) < 0) + write_error (); + byte_idx = 0; + print_delimiter = false; + current_rp = frp; + } + else if (c == EOF) + { + if (byte_idx > 0) + { + if (putchar (line_delim) < 0) + write_error (); + } + break; + } + else + { + next_item (&byte_idx); + if (print_kth (byte_idx)) + { + if (output_delimiter_string != output_delimiter_default) + { + if (print_delimiter && is_range_start_index (byte_idx)) + { + if (fwrite (output_delimiter_string, sizeof (char), + output_delimiter_length, stdout) + != output_delimiter_length) + write_error (); + } + print_delimiter = true; + } + + if (putchar (c) < 0) + write_error (); + } + } + } +} + +/* Read from stream STREAM, printing to standard output any selected fields. */ + +static void +cut_fields (FILE *stream) +{ + int c; /* Each character from the file. */ + uintmax_t field_idx = 1; + bool found_any_selected_field = false; + bool buffer_first_field; + + current_rp = frp; + + c = getc (stream); + if (c == EOF) + return; + + ungetc (c, stream); + c = 0; + + /* To support the semantics of the -s flag, we may have to buffer + all of the first field to determine whether it is 'delimited.' + But that is unnecessary if all non-delimited lines must be printed + and the first field has been selected, or if non-delimited lines + must be suppressed and the first field has *not* been selected. + That is because a non-delimited line has exactly one field. */ + buffer_first_field = (suppress_non_delimited ^ !print_kth (1)); + + while (true) + { + if (field_idx == 1 && buffer_first_field) + { + ssize_t len; + size_t n_bytes; + + len = getndelim2 (&field_1_buffer, &field_1_bufsize, 0, + GETNLINE_NO_LIMIT, delim, line_delim, stream); + if (len < 0) + { + free (field_1_buffer); + field_1_buffer = nullptr; + if (ferror (stream) || feof (stream)) + break; + xalloc_die (); + } + + n_bytes = len; + affirm (n_bytes != 0); + + c = 0; + + /* If the first field extends to the end of line (it is not + delimited) and we are printing all non-delimited lines, + print this one. */ + if (to_uchar (field_1_buffer[n_bytes - 1]) != delim) + { + if (suppress_non_delimited) + { + /* Empty. */ + } + else + { + if (fwrite (field_1_buffer, sizeof (char), n_bytes, stdout) + != n_bytes) + write_error (); + /* Make sure the output line is newline terminated. */ + if (field_1_buffer[n_bytes - 1] != line_delim) + { + if (putchar (line_delim) < 0) + write_error (); + } + c = line_delim; + } + continue; + } + + if (print_kth (1)) + { + /* Print the field, but not the trailing delimiter. */ + if (fwrite (field_1_buffer, sizeof (char), n_bytes - 1, stdout) + != n_bytes - 1) + write_error (); + + /* With -d$'\n' don't treat the last '\n' as a delimiter. */ + if (delim == line_delim) + { + int last_c = getc (stream); + if (last_c != EOF) + { + ungetc (last_c, stream); + found_any_selected_field = true; + } + } + else + { + found_any_selected_field = true; + } + } + next_item (&field_idx); + } + + int prev_c = c; + + if (print_kth (field_idx)) + { + if (found_any_selected_field) + { + if (fwrite (output_delimiter_string, sizeof (char), + output_delimiter_length, stdout) + != output_delimiter_length) + write_error (); + } + found_any_selected_field = true; + + while ((c = getc (stream)) != delim && c != line_delim && c != EOF) + { + if (putchar (c) < 0) + write_error (); + prev_c = c; + } + } + else + { + while ((c = getc (stream)) != delim && c != line_delim && c != EOF) + prev_c = c; + } + + /* With -d$'\n' don't treat the last '\n' as a delimiter. */ + if (delim == line_delim && c == delim) + { + int last_c = getc (stream); + if (last_c != EOF) + ungetc (last_c, stream); + else + c = last_c; + } + + if (c == delim) + next_item (&field_idx); + else if (c == line_delim || c == EOF) + { + if (found_any_selected_field + || !(suppress_non_delimited && field_idx == 1)) + { + /* Make sure the output line is newline terminated. */ + if (c == line_delim || prev_c != line_delim + || delim == line_delim) + { + if (putchar (line_delim) < 0) + write_error (); + } + } + if (c == EOF) + break; + + /* Start processing the next input line. */ + field_idx = 1; + current_rp = frp; + found_any_selected_field = false; + } + } +} + +/* Process file FILE to standard output, using CUT_STREAM. + Return true if successful. */ + +static bool +cut_file (char const *file, void (*cut_stream) (FILE *)) +{ + FILE *stream; + + if (STREQ (file, "-")) + { + have_read_stdin = true; + stream = stdin; + assume (stream); /* Pacify GCC bug#109613. */ + } + else + { + stream = fopen (file, "r"); + if (stream == nullptr) + { + error (0, errno, "%s", quotef (file)); + return false; + } + } + + fadvise (stream, FADVISE_SEQUENTIAL); + + cut_stream (stream); + + int err = errno; + if (!ferror (stream)) + err = 0; + if (STREQ (file, "-")) + clearerr (stream); /* Also clear EOF. */ + else if (fclose (stream) == EOF) + err = errno; + if (err) + { + error (0, err, "%s", quotef (file)); + return false; + } + return true; +} + +int +main (int argc, char **argv) +{ + int optc; + bool ok; + bool delim_specified = false; + bool byte_mode = false; + char *spec_list_string = nullptr; + + initialize_main (&argc, &argv); + set_program_name (argv[0]); + setlocale (LC_ALL, ""); + bindtextdomain (PACKAGE, LOCALEDIR); + textdomain (PACKAGE); + + atexit (close_stdout); + + /* By default, all non-delimited lines are printed. */ + suppress_non_delimited = false; + + delim = '\0'; + have_read_stdin = false; + + while ((optc = getopt_long (argc, argv, "b:c:d:f:nsz", longopts, nullptr)) + != -1) + { + switch (optc) + { + case 'b': + case 'c': + /* Build the byte list. */ + byte_mode = true; + FALLTHROUGH; + case 'f': + /* Build the field list. */ + if (spec_list_string) + FATAL_ERROR (_("only one list may be specified")); + spec_list_string = optarg; + break; + + case 'd': + /* New delimiter. */ + /* Interpret -d '' to mean 'use the NUL byte as the delimiter.' */ + if (optarg[0] != '\0' && optarg[1] != '\0') + FATAL_ERROR (_("the delimiter must be a single character")); + delim = optarg[0]; + delim_specified = true; + break; + + case OUTPUT_DELIMITER_OPTION: + /* Interpret --output-delimiter='' to mean + 'use the NUL byte as the delimiter.' */ + output_delimiter_length = (optarg[0] == '\0' + ? 1 : strlen (optarg)); + output_delimiter_string = optarg; + break; + + case 'n': + break; + + case 's': + suppress_non_delimited = true; + break; + + case 'z': + line_delim = '\0'; + break; + + case COMPLEMENT_OPTION: + complement = true; + break; + + case_GETOPT_HELP_CHAR; + case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS); + default: + usage (EXIT_FAILURE); + } + } + + if (!spec_list_string) + FATAL_ERROR (_("you must specify a list of bytes, characters, or fields")); + + if (byte_mode) + { + if (delim_specified) + FATAL_ERROR (_("an input delimiter may be specified only\ + when operating on fields")); + + if (suppress_non_delimited) + FATAL_ERROR (_("suppressing non-delimited lines makes sense\n\ +\tonly when operating on fields")); + } + + set_fields (spec_list_string, + ((byte_mode ? SETFLD_ERRMSG_USE_POS : 0) + | (complement ? SETFLD_COMPLEMENT : 0))); + + if (!delim_specified) + delim = '\t'; + + if (output_delimiter_string == nullptr) + { + output_delimiter_default[0] = delim; + output_delimiter_string = output_delimiter_default; + output_delimiter_length = 1; + } + + void (*cut_stream) (FILE *) = byte_mode ? cut_bytes : cut_fields; + if (optind == argc) + ok = cut_file ("-", cut_stream); + else + for (ok = true; optind < argc; optind++) + ok &= cut_file (argv[optind], cut_stream); + + + if (have_read_stdin && fclose (stdin) == EOF) + { + error (0, errno, "-"); + ok = false; + } + + return ok ? EXIT_SUCCESS : EXIT_FAILURE; +} |