root / prex-0.9.0 / usr / lib / libc / stdio / fvwrite.c @ 03e9c04a
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1 | 03e9c04a | Brad Neuman | /*-
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2 | * Copyright (c) 1990, 1993
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3 | * The Regents of the University of California. All rights reserved.
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4 | *
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5 | * This code is derived from software contributed to Berkeley by
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6 | * Chris Torek.
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7 | *
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8 | * Redistribution and use in source and binary forms, with or without
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9 | * modification, are permitted provided that the following conditions
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10 | * are met:
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11 | * 1. Redistributions of source code must retain the above copyright
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12 | * notice, this list of conditions and the following disclaimer.
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13 | * 2. Redistributions in binary form must reproduce the above copyright
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14 | * notice, this list of conditions and the following disclaimer in the
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15 | * documentation and/or other materials provided with the distribution.
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16 | * 3. Neither the name of the University nor the names of its contributors
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17 | * may be used to endorse or promote products derived from this software
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18 | * without specific prior written permission.
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19 | *
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20 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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21 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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22 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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23 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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24 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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25 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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26 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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27 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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28 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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29 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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30 | * SUCH DAMAGE.
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31 | */
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32 | |||
33 | #include <stdio.h> |
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34 | #include <string.h> |
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35 | #include "local.h" |
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36 | #include "fvwrite.h" |
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37 | |||
38 | /*
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39 | * Write some memory regions. Return zero on success, EOF on error.
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40 | *
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41 | * This routine is large and unsightly, but most of the ugliness due
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42 | * to the three different kinds of output buffering is handled here.
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43 | */
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44 | int
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45 | __sfvwrite(fp, uio) |
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46 | FILE *fp; |
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47 | struct __suio *uio;
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48 | { |
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49 | size_t len; |
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50 | char *p;
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51 | struct __siov *iov;
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52 | int w, s;
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53 | char *nl;
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54 | int nlknown, nldist;
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55 | |||
56 | if ((len = uio->uio_resid) == 0) |
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57 | return (0); |
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58 | /* make sure we can write */
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59 | if (cantwrite(fp))
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60 | return (EOF); |
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61 | |||
62 | #define MIN(a, b) ((a) < (b) ? (a) : (b))
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63 | #define COPY(n) (void)memcpy((void *)fp->_p, (void *)p, (size_t)(n)) |
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64 | |||
65 | iov = uio->uio_iov; |
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66 | p = iov->iov_base; |
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67 | len = iov->iov_len; |
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68 | iov++; |
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69 | #define GETIOV(extra_work) \
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70 | while (len == 0) { \ |
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71 | extra_work; \ |
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72 | p = iov->iov_base; \ |
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73 | len = iov->iov_len; \ |
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74 | iov++; \ |
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75 | } |
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76 | if (fp->_flags & __SNBF) {
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77 | /*
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78 | * Unbuffered: write up to BUFSIZ bytes at a time.
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79 | */
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80 | do {
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81 | GETIOV(;); |
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82 | w = __swrite(fp, p, MIN(len, BUFSIZ)); |
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83 | if (w <= 0) |
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84 | goto err;
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85 | p += w; |
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86 | len -= w; |
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87 | } while ((uio->uio_resid -= w) != 0); |
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88 | } else if ((fp->_flags & __SLBF) == 0) { |
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89 | /*
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90 | * Fully buffered: fill partially full buffer, if any,
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91 | * and then flush. If there is no partial buffer, write
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92 | * one _bf._size byte chunk directly (without copying).
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93 | *
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94 | * String output is a special case: write as many bytes
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95 | * as fit, but pretend we wrote everything. This makes
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96 | * snprintf() return the number of bytes needed, rather
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97 | * than the number used, and avoids its write function
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98 | * (so that the write function can be invalid).
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99 | */
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100 | do {
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101 | GETIOV(;); |
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102 | w = fp->_w; |
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103 | if (fp->_flags & __SSTR) {
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104 | if (len < w)
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105 | w = len; |
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106 | COPY(w); /* copy MIN(fp->_w,len), */
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107 | fp->_w -= w; |
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108 | fp->_p += w; |
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109 | w = len; /* but pretend copied all */
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110 | } else if (fp->_p > fp->_bf._base && len > w) { |
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111 | /* fill and flush */
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112 | COPY(w); |
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113 | /* fp->_w -= w; */ /* unneeded */ |
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114 | fp->_p += w; |
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115 | if (fflush(fp))
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116 | goto err;
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117 | } else if (len >= (w = fp->_bf._size)) { |
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118 | /* write directly */
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119 | w = __swrite(fp, p, w); |
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120 | if (w <= 0) |
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121 | goto err;
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122 | } else {
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123 | /* fill and done */
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124 | w = len; |
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125 | COPY(w); |
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126 | fp->_w -= w; |
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127 | fp->_p += w; |
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128 | } |
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129 | p += w; |
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130 | len -= w; |
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131 | } while ((uio->uio_resid -= w) != 0); |
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132 | } else {
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133 | /*
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134 | * Line buffered: like fully buffered, but we
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135 | * must check for newlines. Compute the distance
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136 | * to the first newline (including the newline),
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137 | * or `infinity' if there is none, then pretend
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138 | * that the amount to write is MIN(len,nldist).
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139 | */
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140 | nlknown = 0;
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141 | nldist = 0; /* XXX just to keep gcc happy */ |
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142 | do {
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143 | GETIOV(nlknown = 0);
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144 | if (!nlknown) {
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145 | nl = memchr((void *)p, '\n', len); |
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146 | nldist = nl ? nl + 1 - p : len + 1; |
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147 | nlknown = 1;
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148 | } |
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149 | s = MIN(len, nldist); |
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150 | w = fp->_w + fp->_bf._size; |
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151 | if (fp->_p > fp->_bf._base && s > w) {
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152 | COPY(w); |
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153 | /* fp->_w -= w; */
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154 | fp->_p += w; |
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155 | if (fflush(fp))
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156 | goto err;
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157 | } else if (s >= (w = fp->_bf._size)) { |
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158 | w = __swrite(fp, p, w); |
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159 | if (w <= 0) |
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160 | goto err;
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161 | } else {
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162 | w = s; |
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163 | COPY(w); |
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164 | fp->_w -= w; |
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165 | fp->_p += w; |
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166 | } |
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167 | if ((nldist -= w) == 0) { |
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168 | /* copied the newline: flush and forget */
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169 | if (fflush(fp))
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170 | goto err;
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171 | nlknown = 0;
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172 | } |
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173 | p += w; |
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174 | len -= w; |
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175 | } while ((uio->uio_resid -= w) != 0); |
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176 | } |
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177 | return (0); |
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178 | |||
179 | err:
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180 | fp->_flags |= __SERR; |
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181 | return (EOF); |
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182 | } |