1 | /* vi: set sw=4 ts=4: */
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2 | /* fold -- wrap each input line to fit in specified width.
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3 |
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4 | Written by David MacKenzie, djm@gnu.ai.mit.edu.
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5 | Copyright (C) 91, 1995-2002 Free Software Foundation, Inc.
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6 |
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7 | Modified for busybox based on coreutils v 5.0
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8 | Copyright (C) 2003 Glenn McGrath
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9 |
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10 | Licensed under GPLv2 or later, see file LICENSE in this source tree.
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11 | */
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12 | #include "libbb.h"
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13 | #include "unicode.h"
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14 |
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15 | /* This is a NOEXEC applet. Be very careful! */
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16 |
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17 | /* Must match getopt32 call */
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18 | #define FLAG_COUNT_BYTES 1
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19 | #define FLAG_BREAK_SPACES 2
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20 | #define FLAG_WIDTH 4
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21 |
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22 | /* Assuming the current column is COLUMN, return the column that
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23 | printing C will move the cursor to.
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24 | The first column is 0. */
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25 | static int adjust_column(unsigned column, char c)
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26 | {
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27 | if (option_mask32 & FLAG_COUNT_BYTES)
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28 | return ++column;
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29 |
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30 | if (c == '\t')
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31 | return column + 8 - column % 8;
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32 |
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33 | if (c == '\b') {
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34 | if ((int)--column < 0)
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35 | column = 0;
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36 | }
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37 | else if (c == '\r')
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38 | column = 0;
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39 | else { /* just a printable char */
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40 | if (unicode_status != UNICODE_ON /* every byte is a new char */
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41 | || (c & 0xc0) != 0x80 /* it isn't a 2nd+ byte of a Unicode char */
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42 | ) {
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43 | column++;
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44 | }
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45 | }
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46 | return column;
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47 | }
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48 |
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49 | /* Note that this function can write NULs, unlike fputs etc. */
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50 | static void write2stdout(const void *buf, unsigned size)
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51 | {
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52 | fwrite(buf, 1, size, stdout);
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53 | }
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54 |
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55 | int fold_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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56 | int fold_main(int argc UNUSED_PARAM, char **argv)
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57 | {
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58 | char *line_out = NULL;
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59 | const char *w_opt = "80";
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60 | unsigned width;
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61 | smallint exitcode = EXIT_SUCCESS;
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62 |
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63 | init_unicode();
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64 |
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65 | if (ENABLE_INCLUDE_SUSv2) {
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66 | /* Turn any numeric options into -w options. */
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67 | int i;
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68 | for (i = 1; argv[i]; i++) {
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69 | const char *a = argv[i];
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70 | if (*a == '-') {
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71 | a++;
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72 | if (*a == '-' && !a[1]) /* "--" */
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73 | break;
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74 | if (isdigit(*a))
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75 | argv[i] = xasprintf("-w%s", a);
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76 | }
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77 | }
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78 | }
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79 |
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80 | getopt32(argv, "bsw:", &w_opt);
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81 | width = xatou_range(w_opt, 1, 10000);
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82 |
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83 | argv += optind;
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84 | if (!*argv)
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85 | *--argv = (char*)"-";
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86 |
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87 | do {
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88 | FILE *istream = fopen_or_warn_stdin(*argv);
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89 | int c;
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90 | unsigned column = 0; /* Screen column where next char will go */
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91 | unsigned offset_out = 0; /* Index in 'line_out' for next char */
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92 |
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93 | if (istream == NULL) {
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94 | exitcode = EXIT_FAILURE;
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95 | continue;
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96 | }
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97 |
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98 | while ((c = getc(istream)) != EOF) {
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99 | /* We grow line_out in chunks of 0x1000 bytes */
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100 | if ((offset_out & 0xfff) == 0) {
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101 | line_out = xrealloc(line_out, offset_out + 0x1000);
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102 | }
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103 | rescan:
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104 | line_out[offset_out] = c;
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105 | if (c == '\n') {
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106 | write2stdout(line_out, offset_out + 1);
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107 | column = offset_out = 0;
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108 | continue;
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109 | }
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110 | column = adjust_column(column, c);
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111 | if (column <= width || offset_out == 0) {
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112 | /* offset_out == 0 case happens
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113 | * with small width (say, 1) and tabs.
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114 | * The very first tab already goes to column 8,
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115 | * but we must not wrap it */
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116 | offset_out++;
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117 | continue;
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118 | }
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119 |
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120 | /* This character would make the line too long.
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121 | * Print the line plus a newline, and make this character
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122 | * start the next line */
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123 | if (option_mask32 & FLAG_BREAK_SPACES) {
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124 | unsigned i;
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125 | unsigned logical_end;
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126 |
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127 | /* Look for the last blank. */
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128 | for (logical_end = offset_out - 1; (int)logical_end >= 0; logical_end--) {
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129 | if (!isblank(line_out[logical_end]))
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130 | continue;
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131 |
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132 | /* Found a space or tab.
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133 | * Output up to and including it, and start a new line */
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134 | logical_end++;
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135 | /*line_out[logical_end] = '\n'; - NO! this nukes one buffered character */
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136 | write2stdout(line_out, logical_end);
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137 | putchar('\n');
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138 | /* Move the remainder to the beginning of the next line.
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139 | * The areas being copied here might overlap. */
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140 | memmove(line_out, line_out + logical_end, offset_out - logical_end);
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141 | offset_out -= logical_end;
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142 | for (column = i = 0; i < offset_out; i++) {
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143 | column = adjust_column(column, line_out[i]);
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144 | }
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145 | goto rescan;
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146 | }
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147 | /* No blank found, wrap will split the overlong word */
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148 | }
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149 | /* Output what we accumulated up to now, and start a new line */
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150 | line_out[offset_out] = '\n';
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151 | write2stdout(line_out, offset_out + 1);
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152 | column = offset_out = 0;
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153 | goto rescan;
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154 | } /* while (not EOF) */
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155 |
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156 | if (offset_out) {
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157 | write2stdout(line_out, offset_out);
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158 | }
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159 |
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160 | if (fclose_if_not_stdin(istream)) {
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161 | bb_simple_perror_msg(*argv);
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162 | exitcode = EXIT_FAILURE;
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163 | }
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164 | } while (*++argv);
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165 |
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166 | fflush_stdout_and_exit(exitcode);
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167 | }
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