272
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1 /* Word-wrapping and line-truncating streams
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2 Copyright (C) 1997-1999,2001,2002,2003,2005 Free Software Foundation, Inc.
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3 This file is part of the GNU C Library.
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4 Written by Miles Bader <miles@gnu.ai.mit.edu>.
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5
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6 This program is free software: you can redistribute it and/or modify
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7 it under the terms of the GNU General Public License as published by
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8 the Free Software Foundation; either version 3 of the License, or
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9 (at your option) any later version.
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10
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11 This program is distributed in the hope that it will be useful,
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12 but WITHOUT ANY WARRANTY; without even the implied warranty of
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13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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14 GNU General Public License for more details.
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15
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16 You should have received a copy of the GNU General Public License
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17 along with this program. If not, see <http://www.gnu.org/licenses/>. */
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18
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19 /* This package emulates glibc `line_wrap_stream' semantics for systems that
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20 don't have that. */
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21
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22 #ifdef HAVE_CONFIG_H
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23 # include <config.h>
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24 #endif
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25
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26 #include <stdlib.h>
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27 #include <string.h>
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28 #include <errno.h>
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29 #include <stdarg.h>
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30 #include <ctype.h>
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31
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32 #include "argp-fmtstream.h"
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33 #include "argp-namefrob.h"
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34
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35 #ifndef ARGP_FMTSTREAM_USE_LINEWRAP
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36
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37 #ifndef isblank
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38 #define isblank(ch) ((ch)==' ' || (ch)=='\t')
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39 #endif
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40
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41 #if defined _LIBC && defined USE_IN_LIBIO
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42 # include <wchar.h>
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43 # include <libio/libioP.h>
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44 # define __vsnprintf(s, l, f, a) _IO_vsnprintf (s, l, f, a)
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45 #endif
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46
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47 #define INIT_BUF_SIZE 200
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48 #define PRINTF_SIZE_GUESS 150
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49
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50 /* Return an argp_fmtstream that outputs to STREAM, and which prefixes lines
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51 written on it with LMARGIN spaces and limits them to RMARGIN columns
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52 total. If WMARGIN >= 0, words that extend past RMARGIN are wrapped by
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53 replacing the whitespace before them with a newline and WMARGIN spaces.
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54 Otherwise, chars beyond RMARGIN are simply dropped until a newline.
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55 Returns NULL if there was an error. */
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56 argp_fmtstream_t
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57 __argp_make_fmtstream (FILE *stream,
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58 size_t lmargin, size_t rmargin, ssize_t wmargin)
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59 {
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60 argp_fmtstream_t fs;
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61
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62 fs = (struct argp_fmtstream *) malloc (sizeof (struct argp_fmtstream));
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63 if (fs != NULL)
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64 {
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65 fs->stream = stream;
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66
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67 fs->lmargin = lmargin;
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68 fs->rmargin = rmargin;
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69 fs->wmargin = wmargin;
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70 fs->point_col = 0;
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71 fs->point_offs = 0;
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72
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73 fs->buf = (char *) malloc (INIT_BUF_SIZE);
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74 if (! fs->buf)
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75 {
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76 free (fs);
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77 fs = 0;
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78 }
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79 else
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80 {
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81 fs->p = fs->buf;
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82 fs->end = fs->buf + INIT_BUF_SIZE;
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83 }
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84 }
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85
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86 return fs;
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87 }
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88 #if 0
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89 /* Not exported. */
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90 #ifdef weak_alias
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91 weak_alias (__argp_make_fmtstream, argp_make_fmtstream)
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92 #endif
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93 #endif
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94
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95 /* Flush FS to its stream, and free it (but don't close the stream). */
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96 void
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97 __argp_fmtstream_free (argp_fmtstream_t fs)
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98 {
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99 __argp_fmtstream_update (fs);
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100 if (fs->p > fs->buf)
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101 {
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102 #ifdef USE_IN_LIBIO
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103 __fxprintf (fs->stream, "%.*s", (int) (fs->p - fs->buf), fs->buf);
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104 #else
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105 fwrite_unlocked (fs->buf, 1, fs->p - fs->buf, fs->stream);
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106 #endif
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107 }
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108 free (fs->buf);
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109 free (fs);
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110 }
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111 #if 0
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112 /* Not exported. */
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113 #ifdef weak_alias
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114 weak_alias (__argp_fmtstream_free, argp_fmtstream_free)
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115 #endif
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116 #endif
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117
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118 /* Process FS's buffer so that line wrapping is done from POINT_OFFS to the
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119 end of its buffer. This code is mostly from glibc stdio/linewrap.c. */
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120 void
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121 __argp_fmtstream_update (argp_fmtstream_t fs)
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122 {
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123 char *buf, *nl;
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124 size_t len;
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125
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126 /* Scan the buffer for newlines. */
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127 buf = fs->buf + fs->point_offs;
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128 while (buf < fs->p)
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129 {
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130 size_t r;
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131
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132 if (fs->point_col == 0 && fs->lmargin != 0)
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133 {
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134 /* We are starting a new line. Print spaces to the left margin. */
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135 const size_t pad = fs->lmargin;
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136 if (fs->p + pad < fs->end)
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137 {
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138 /* We can fit in them in the buffer by moving the
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139 buffer text up and filling in the beginning. */
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140 memmove (buf + pad, buf, fs->p - buf);
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141 fs->p += pad; /* Compensate for bigger buffer. */
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142 memset (buf, ' ', pad); /* Fill in the spaces. */
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143 buf += pad; /* Don't bother searching them. */
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144 }
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145 else
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146 {
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147 /* No buffer space for spaces. Must flush. */
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148 size_t i;
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149 for (i = 0; i < pad; i++)
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150 {
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151 #ifdef USE_IN_LIBIO
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152 if (_IO_fwide (fs->stream, 0) > 0)
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153 putwc_unlocked (L' ', fs->stream);
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154 else
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155 #endif
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156 putc_unlocked (' ', fs->stream);
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157 }
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158 }
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159 fs->point_col = pad;
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160 }
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161
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162 len = fs->p - buf;
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163 nl = memchr (buf, '\n', len);
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164
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165 if (fs->point_col < 0)
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166 fs->point_col = 0;
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167
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168 if (!nl)
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169 {
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170 /* The buffer ends in a partial line. */
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171
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172 if (fs->point_col + len < fs->rmargin)
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173 {
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174 /* The remaining buffer text is a partial line and fits
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175 within the maximum line width. Advance point for the
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176 characters to be written and stop scanning. */
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177 fs->point_col += len;
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178 break;
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179 }
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180 else
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181 /* Set the end-of-line pointer for the code below to
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182 the end of the buffer. */
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183 nl = fs->p;
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184 }
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185 else if (fs->point_col + (nl - buf) < (ssize_t) fs->rmargin)
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186 {
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187 /* The buffer contains a full line that fits within the maximum
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188 line width. Reset point and scan the next line. */
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189 fs->point_col = 0;
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190 buf = nl + 1;
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191 continue;
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192 }
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193
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194 /* This line is too long. */
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195 r = fs->rmargin - 1;
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196
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197 if (fs->wmargin < 0)
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198 {
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199 /* Truncate the line by overwriting the excess with the
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200 newline and anything after it in the buffer. */
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201 if (nl < fs->p)
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202 {
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203 memmove (buf + (r - fs->point_col), nl, fs->p - nl);
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204 fs->p -= buf + (r - fs->point_col) - nl;
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205 /* Reset point for the next line and start scanning it. */
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206 fs->point_col = 0;
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207 buf += r + 1; /* Skip full line plus \n. */
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208 }
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209 else
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210 {
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211 /* The buffer ends with a partial line that is beyond the
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212 maximum line width. Advance point for the characters
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213 written, and discard those past the max from the buffer. */
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214 fs->point_col += len;
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215 fs->p -= fs->point_col - r;
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216 break;
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217 }
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218 }
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219 else
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220 {
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221 /* Do word wrap. Go to the column just past the maximum line
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222 width and scan back for the beginning of the word there.
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223 Then insert a line break. */
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224
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225 char *p, *nextline;
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226 int i;
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227
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228 p = buf + (r + 1 - fs->point_col);
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229 while (p >= buf && !isblank (*p))
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230 --p;
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231 nextline = p + 1; /* This will begin the next line. */
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232
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233 if (nextline > buf)
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234 {
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235 /* Swallow separating blanks. */
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236 if (p >= buf)
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237 do
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238 --p;
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239 while (p >= buf && isblank (*p));
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240 nl = p + 1; /* The newline will replace the first blank. */
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241 }
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242 else
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243 {
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244 /* A single word that is greater than the maximum line width.
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245 Oh well. Put it on an overlong line by itself. */
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246 p = buf + (r + 1 - fs->point_col);
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247 /* Find the end of the long word. */
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248 if (p < nl)
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249 do
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250 ++p;
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251 while (p < nl && !isblank (*p));
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252 if (p == nl)
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253 {
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254 /* It already ends a line. No fussing required. */
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255 fs->point_col = 0;
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256 buf = nl + 1;
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257 continue;
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258 }
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259 /* We will move the newline to replace the first blank. */
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260 nl = p;
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261 /* Swallow separating blanks. */
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262 do
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263 ++p;
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264 while (isblank (*p));
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265 /* The next line will start here. */
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266 nextline = p;
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267 }
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268
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269 /* Note: There are a bunch of tests below for
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270 NEXTLINE == BUF + LEN + 1; this case is where NL happens to fall
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271 at the end of the buffer, and NEXTLINE is in fact empty (and so
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272 we need not be careful to maintain its contents). */
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273
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274 if ((nextline == buf + len + 1
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275 ? fs->end - nl < fs->wmargin + 1
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276 : nextline - (nl + 1) < fs->wmargin)
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277 && fs->p > nextline)
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278 {
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279 /* The margin needs more blanks than we removed. */
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280 if (fs->end - fs->p > fs->wmargin + 1)
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281 /* Make some space for them. */
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282 {
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283 size_t mv = fs->p - nextline;
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284 memmove (nl + 1 + fs->wmargin, nextline, mv);
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285 nextline = nl + 1 + fs->wmargin;
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286 len = nextline + mv - buf;
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287 *nl++ = '\n';
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288 }
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289 else
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290 /* Output the first line so we can use the space. */
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291 {
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292 #ifdef _LIBC
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293 __fxprintf (fs->stream, "%.*s\n",
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294 (int) (nl - fs->buf), fs->buf);
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295 #else
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296 if (nl > fs->buf)
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297 fwrite_unlocked (fs->buf, 1, nl - fs->buf, fs->stream);
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298 putc_unlocked ('\n', fs->stream);
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299 #endif
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300
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301 len += buf - fs->buf;
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302 nl = buf = fs->buf;
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303 }
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304 }
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305 else
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306 /* We can fit the newline and blanks in before
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307 the next word. */
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308 *nl++ = '\n';
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309
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310 if (nextline - nl >= fs->wmargin
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311 || (nextline == buf + len + 1 && fs->end - nextline >= fs->wmargin))
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312 /* Add blanks up to the wrap margin column. */
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313 for (i = 0; i < fs->wmargin; ++i)
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314 *nl++ = ' ';
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315 else
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316 for (i = 0; i < fs->wmargin; ++i)
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317 #ifdef USE_IN_LIBIO
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318 if (_IO_fwide (fs->stream, 0) > 0)
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319 putwc_unlocked (L' ', fs->stream);
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320 else
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321 #endif
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322 putc_unlocked (' ', fs->stream);
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323
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324 /* Copy the tail of the original buffer into the current buffer
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325 position. */
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326 if (nl < nextline)
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327 memmove (nl, nextline, buf + len - nextline);
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328 len -= nextline - buf;
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329
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330 /* Continue the scan on the remaining lines in the buffer. */
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331 buf = nl;
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332
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333 /* Restore bufp to include all the remaining text. */
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334 fs->p = nl + len;
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335
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336 /* Reset the counter of what has been output this line. If wmargin
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337 is 0, we want to avoid the lmargin getting added, so we set
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338 point_col to a magic value of -1 in that case. */
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339 fs->point_col = fs->wmargin ? fs->wmargin : -1;
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340 }
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341 }
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342
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343 /* Remember that we've scanned as far as the end of the buffer. */
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344 fs->point_offs = fs->p - fs->buf;
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345 }
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346
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347 /* Ensure that FS has space for AMOUNT more bytes in its buffer, either by
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348 growing the buffer, or by flushing it. True is returned iff we succeed. */
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349 int
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350 __argp_fmtstream_ensure (struct argp_fmtstream *fs, size_t amount)
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351 {
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352 if ((size_t) (fs->end - fs->p) < amount)
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353 {
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354 ssize_t wrote;
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355
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356 /* Flush FS's buffer. */
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357 __argp_fmtstream_update (fs);
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358
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359 #ifdef _LIBC
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360 __fxprintf (fs->stream, "%.*s", (int) (fs->p - fs->buf), fs->buf);
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361 wrote = fs->p - fs->buf;
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362 #else
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363 wrote = fwrite_unlocked (fs->buf, 1, fs->p - fs->buf, fs->stream);
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364 #endif
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365 if (wrote == fs->p - fs->buf)
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366 {
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367 fs->p = fs->buf;
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368 fs->point_offs = 0;
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369 }
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370 else
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371 {
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372 fs->p -= wrote;
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373 fs->point_offs -= wrote;
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374 memmove (fs->buf, fs->buf + wrote, fs->p - fs->buf);
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375 return 0;
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376 }
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377
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378 if ((size_t) (fs->end - fs->buf) < amount)
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379 /* Gotta grow the buffer. */
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380 {
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381 size_t old_size = fs->end - fs->buf;
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382 size_t new_size = old_size + amount;
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383 char *new_buf;
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384
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385 if (new_size < old_size || ! (new_buf = realloc (fs->buf, new_size)))
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386 {
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387 __set_errno (ENOMEM);
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388 return 0;
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389 }
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390
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391 fs->buf = new_buf;
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392 fs->end = new_buf + new_size;
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393 fs->p = fs->buf;
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394 }
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395 }
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396
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397 return 1;
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398 }
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399
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400 ssize_t
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401 __argp_fmtstream_printf (struct argp_fmtstream *fs, const char *fmt, ...)
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402 {
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403 int out;
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404 size_t avail;
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405 size_t size_guess = PRINTF_SIZE_GUESS; /* How much space to reserve. */
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406
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407 do
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408 {
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409 va_list args;
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410
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411 if (! __argp_fmtstream_ensure (fs, size_guess))
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412 return -1;
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413
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414 va_start (args, fmt);
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415 avail = fs->end - fs->p;
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416 out = __vsnprintf (fs->p, avail, fmt, args);
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417 va_end (args);
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418 if ((size_t) out >= avail)
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419 size_guess = out + 1;
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420 }
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421 while ((size_t) out >= avail);
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422
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423 fs->p += out;
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424
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425 return out;
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426 }
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427 #if 0
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428 /* Not exported. */
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429 #ifdef weak_alias
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430 weak_alias (__argp_fmtstream_printf, argp_fmtstream_printf)
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431 #endif
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432 #endif
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433
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434 #endif /* !ARGP_FMTSTREAM_USE_LINEWRAP */
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