1 | /* vi: set sw=4 ts=4: */
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2 | /*
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3 | * Mini more implementation for busybox
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4 | *
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5 | * Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
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6 | * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
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7 | *
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8 | * Latest version blended together by Erik Andersen <andersen@codepoet.org>,
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9 | * based on the original more implementation by Bruce, and code from the
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10 | * Debian boot-floppies team.
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11 | *
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12 | * Termios corrects by Vladimir Oleynik <dzo@simtreas.ru>
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13 | *
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14 | * Licensed under GPLv2 or later, see file License in this tarball for details.
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15 | */
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16 |
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17 | #include "libbb.h"
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18 | #if ENABLE_FEATURE_USE_TERMIOS
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19 | #include <termios.h>
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20 | #endif /* FEATURE_USE_TERMIOS */
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21 |
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22 |
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23 | #if ENABLE_FEATURE_USE_TERMIOS
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24 |
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25 | struct globals {
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26 | int cin_fileno;
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27 | struct termios initial_settings;
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28 | struct termios new_settings;
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29 | };
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30 | #define G (*(struct globals*)bb_common_bufsiz1)
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31 | //#define G (*ptr_to_globals)
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32 | #define INIT_G() ((void)0)
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33 | //#define INIT_G() PTR_TO_GLOBALS = xzalloc(sizeof(G))
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34 | #define initial_settings (G.initial_settings)
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35 | #define new_settings (G.new_settings )
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36 | #define cin_fileno (G.cin_fileno )
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37 |
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38 | #define setTermSettings(fd, argp) tcsetattr(fd, TCSANOW, argp)
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39 | #define getTermSettings(fd, argp) tcgetattr(fd, argp)
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40 |
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41 | static void gotsig(int sig)
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42 | {
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43 | putchar('\n');
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44 | setTermSettings(cin_fileno, &initial_settings);
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45 | exit(EXIT_FAILURE);
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46 | }
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47 |
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48 | #else /* !FEATURE_USE_TERMIOS */
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49 | #define INIT_G() ((void)0)
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50 | #define setTermSettings(fd, argp) ((void)0)
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51 | #endif /* FEATURE_USE_TERMIOS */
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52 |
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53 | #define CONVERTED_TAB_SIZE 8
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54 |
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55 | int more_main(int argc, char **argv);
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56 | int more_main(int argc, char **argv)
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57 | {
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58 | int c = c; /* for gcc */
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59 | int lines;
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60 | int input = 0;
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61 | int spaces = 0;
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62 | int please_display_more_prompt;
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63 | struct stat st;
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64 | FILE *file;
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65 | FILE *cin;
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66 | int len;
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67 | int terminal_width;
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68 | int terminal_height;
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69 |
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70 | INIT_G();
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71 |
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72 | argv++;
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73 | /* Another popular pager, most, detects when stdout
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74 | * is not a tty and turns into cat. This makes sense. */
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75 | if (!isatty(STDOUT_FILENO))
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76 | return bb_cat(argv);
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77 | cin = fopen(CURRENT_TTY, "r");
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78 | if (!cin)
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79 | return bb_cat(argv);
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80 |
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81 | #if ENABLE_FEATURE_USE_TERMIOS
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82 | cin_fileno = fileno(cin);
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83 | getTermSettings(cin_fileno, &initial_settings);
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84 | new_settings = initial_settings;
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85 | new_settings.c_lflag &= ~ICANON;
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86 | new_settings.c_lflag &= ~ECHO;
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87 | new_settings.c_cc[VMIN] = 1;
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88 | new_settings.c_cc[VTIME] = 0;
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89 | setTermSettings(cin_fileno, &new_settings);
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90 | signal(SIGINT, gotsig);
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91 | signal(SIGQUIT, gotsig);
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92 | signal(SIGTERM, gotsig);
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93 | #endif
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94 |
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95 | do {
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96 | file = stdin;
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97 | if (*argv) {
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98 | file = fopen_or_warn(*argv, "r");
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99 | if (!file)
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100 | continue;
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101 | }
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102 | st.st_size = 0;
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103 | fstat(fileno(file), &st);
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104 |
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105 | please_display_more_prompt = 0;
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106 | /* never returns w, h <= 1 */
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107 | get_terminal_width_height(fileno(cin), &terminal_width, &terminal_height);
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108 | terminal_height -= 1;
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109 |
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110 | len = 0;
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111 | lines = 0;
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112 | while (spaces || (c = getc(file)) != EOF) {
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113 | int wrap;
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114 | if (spaces)
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115 | spaces--;
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116 | loop_top:
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117 | if (input != 'r' && please_display_more_prompt) {
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118 | len = printf("--More-- ");
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119 | if (st.st_size > 0) {
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120 | len += printf("(%d%% of %"OFF_FMT"d bytes)",
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121 | (int) (ftello(file)*100 / st.st_size),
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122 | st.st_size);
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123 | }
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124 | fflush(stdout);
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125 |
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126 | /*
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127 | * We've just displayed the "--More--" prompt, so now we need
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128 | * to get input from the user.
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129 | */
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130 | for (;;) {
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131 | input = getc(cin);
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132 | input = tolower(input);
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133 | #if !ENABLE_FEATURE_USE_TERMIOS
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134 | printf("\033[A"); /* up cursor */
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135 | #endif
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136 | /* Erase the last message */
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137 | printf("\r%*s\r", len, "");
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138 |
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139 | /* Due to various multibyte escape
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140 | * sequences, it's not ok to accept
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141 | * any input as a command to scroll
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142 | * the screen. We only allow known
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143 | * commands, else we show help msg. */
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144 | if (input == ' ' || input == '\n' || input == 'q' || input == 'r')
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145 | break;
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146 | len = printf("(Enter:next line Space:next page Q:quit R:show the rest)");
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147 | }
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148 | len = 0;
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149 | lines = 0;
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150 | please_display_more_prompt = 0;
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151 |
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152 | if (input == 'q')
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153 | goto end;
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154 |
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155 | /* The user may have resized the terminal.
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156 | * Re-read the dimensions. */
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157 | #if ENABLE_FEATURE_USE_TERMIOS
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158 | get_terminal_width_height(cin_fileno, &terminal_width, &terminal_height);
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159 | terminal_height -= 1;
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160 | #endif
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161 | }
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162 |
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163 | /* Crudely convert tabs into spaces, which are
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164 | * a bajillion times easier to deal with. */
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165 | if (c == '\t') {
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166 | spaces = CONVERTED_TAB_SIZE - 1;
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167 | c = ' ';
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168 | }
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169 |
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170 | /*
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171 | * There are two input streams to worry about here:
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172 | *
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173 | * c : the character we are reading from the file being "mored"
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174 | * input: a character received from the keyboard
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175 | *
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176 | * If we hit a newline in the _file_ stream, we want to test and
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177 | * see if any characters have been hit in the _input_ stream. This
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178 | * allows the user to quit while in the middle of a file.
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179 | */
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180 | wrap = (++len > terminal_width);
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181 | if (c == '\n' || wrap) {
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182 | /* Then outputting this character
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183 | * will move us to a new line. */
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184 | if (++lines >= terminal_height || input == '\n')
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185 | please_display_more_prompt = 1;
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186 | len = 0;
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187 | }
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188 | if (c != '\n' && wrap) {
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189 | /* Then outputting this will also put a character on
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190 | * the beginning of that new line. Thus we first want to
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191 | * display the prompt (if any), so we skip the putchar()
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192 | * and go back to the top of the loop, without reading
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193 | * a new character. */
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194 | goto loop_top;
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195 | }
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196 | /* My small mind cannot fathom backspaces and UTF-8 */
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197 | putchar(c);
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198 | }
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199 | fclose(file);
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200 | fflush(stdout);
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201 | } while (*argv && *++argv);
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202 | end:
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203 | setTermSettings(cin_fileno, &initial_settings);
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204 | return 0;
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205 | }
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