1 | /* |
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2 | * This file is part of libtrace |
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3 | * |
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4 | * Copyright (c) 2007,2008,2009,2010 The University of Waikato, Hamilton, |
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5 | * New Zealand. |
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6 | * |
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7 | * Authors: Daniel Lawson |
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8 | * Perry Lorier |
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9 | * Shane Alcock |
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10 | * |
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11 | * All rights reserved. |
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12 | * |
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13 | * This code has been developed by the University of Waikato WAND |
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14 | * research group. For further information please see http://www.wand.net.nz/ |
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15 | * |
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16 | * libtrace is free software; you can redistribute it and/or modify |
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17 | * it under the terms of the GNU General Public License as published by |
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18 | * the Free Software Foundation; either version 2 of the License, or |
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19 | * (at your option) any later version. |
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20 | * |
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21 | * libtrace is distributed in the hope that it will be useful, |
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22 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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23 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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24 | * GNU General Public License for more details. |
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25 | * |
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26 | * You should have received a copy of the GNU General Public License |
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27 | * along with libtrace; if not, write to the Free Software |
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28 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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29 | * |
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30 | * $Id$ |
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31 | * |
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32 | */ |
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33 | |
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34 | |
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35 | #include "wandio.h" |
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36 | #include <zlib.h> |
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37 | #include <sys/types.h> |
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38 | #include <sys/stat.h> |
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39 | #include <fcntl.h> |
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40 | #include <stdlib.h> |
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41 | #include <string.h> |
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42 | #include <errno.h> |
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43 | |
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44 | /* Libtrace IO module implementing a zlib reader */ |
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45 | |
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46 | enum err_t { |
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47 | ERR_OK = 1, |
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48 | ERR_EOF = 0, |
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49 | ERR_ERROR = -1 |
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50 | }; |
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51 | |
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52 | struct zlib_t { |
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53 | Bytef inbuff[1024*1024]; /* bytef is what zlib uses for buffer pointers */ |
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54 | z_stream strm; |
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55 | io_t *parent; |
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56 | int outoffset; |
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57 | enum err_t err; |
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58 | }; |
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59 | |
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60 | |
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61 | extern io_source_t zlib_source; |
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62 | |
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63 | #define DATA(io) ((struct zlib_t *)((io)->data)) |
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64 | #define min(a,b) ((a)<(b) ? (a) : (b)) |
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65 | |
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66 | io_t *zlib_open(io_t *parent) |
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67 | { |
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68 | io_t *io; |
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69 | if (!parent) |
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70 | return NULL; |
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71 | io = malloc(sizeof(io_t)); |
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72 | io->source = &zlib_source; |
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73 | io->data = malloc(sizeof(struct zlib_t)); |
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74 | |
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75 | DATA(io)->parent = parent; |
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76 | |
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77 | DATA(io)->strm.next_in = NULL; |
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78 | DATA(io)->strm.avail_in = 0; |
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79 | DATA(io)->strm.next_out = NULL; |
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80 | DATA(io)->strm.avail_out = 0; |
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81 | DATA(io)->strm.zalloc = Z_NULL; |
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82 | DATA(io)->strm.zfree = Z_NULL; |
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83 | DATA(io)->strm.opaque = NULL; |
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84 | DATA(io)->err = ERR_OK; |
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85 | |
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86 | inflateInit2(&DATA(io)->strm, 15 | 32); |
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87 | |
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88 | return io; |
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89 | } |
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90 | |
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91 | |
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92 | static off_t zlib_read(io_t *io, void *buffer, off_t len) |
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93 | { |
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94 | if (DATA(io)->err == ERR_EOF) |
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95 | return 0; /* EOF */ |
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96 | if (DATA(io)->err == ERR_ERROR) { |
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97 | errno=EIO; |
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98 | return -1; /* ERROR! */ |
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99 | } |
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100 | |
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101 | DATA(io)->strm.avail_out = len; |
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102 | DATA(io)->strm.next_out = (Bytef*)buffer; |
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103 | |
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104 | while (DATA(io)->err == ERR_OK && DATA(io)->strm.avail_out > 0) { |
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105 | while (DATA(io)->strm.avail_in <= 0) { |
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106 | int bytes_read = wandio_read(DATA(io)->parent, |
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107 | (char*)DATA(io)->inbuff, |
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108 | sizeof(DATA(io)->inbuff)); |
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109 | if (bytes_read == 0) { |
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110 | /* EOF */ |
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111 | if (DATA(io)->strm.avail_out == (uint32_t)len) { |
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112 | DATA(io)->err = ERR_EOF; |
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113 | return 0; |
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114 | } |
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115 | /* Return how much data we've managed to read so far. */ |
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116 | return len-DATA(io)->strm.avail_out; |
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117 | } |
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118 | if (bytes_read < 0) { /* Error */ |
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119 | /* errno should be set */ |
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120 | DATA(io)->err = ERR_ERROR; |
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121 | /* Return how much data we managed to read ok */ |
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122 | if (DATA(io)->strm.avail_out != (uint32_t)len) { |
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123 | return len-DATA(io)->strm.avail_out; |
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124 | } |
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125 | /* Now return error */ |
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126 | return -1; |
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127 | } |
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128 | DATA(io)->strm.next_in = DATA(io)->inbuff; |
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129 | DATA(io)->strm.avail_in = bytes_read; |
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130 | } |
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131 | /* Decompress some data into the output buffer */ |
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132 | int err=inflate(&DATA(io)->strm, 0); |
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133 | switch(err) { |
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134 | case Z_OK: |
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135 | DATA(io)->err = ERR_OK; |
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136 | break; |
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137 | case Z_STREAM_END: |
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138 | /* You would think that an "EOF" on the stream would mean we'd |
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139 | * want to pass on an EOF? Nope. Some tools (*cough* corel *cough*) |
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140 | * annoyingly close and reopen the gzip stream leaving Z_STREAM_END |
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141 | * mines for us to find. |
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142 | */ |
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143 | inflateEnd(&DATA(io)->strm); |
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144 | inflateInit2(&DATA(io)->strm, 15 | 32); |
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145 | DATA(io)->err = ERR_OK; |
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146 | break; |
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147 | default: |
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148 | errno=EIO; |
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149 | DATA(io)->err = ERR_ERROR; |
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150 | } |
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151 | } |
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152 | /* Return the number of bytes decompressed */ |
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153 | return len-DATA(io)->strm.avail_out; |
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154 | } |
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155 | |
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156 | static void zlib_close(io_t *io) |
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157 | { |
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158 | inflateEnd(&DATA(io)->strm); |
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159 | wandio_destroy(DATA(io)->parent); |
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160 | free(io->data); |
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161 | free(io); |
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162 | } |
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163 | |
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164 | io_source_t zlib_source = { |
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165 | "zlib", |
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166 | zlib_read, |
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167 | NULL, /* peek */ |
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168 | NULL, /* tell */ |
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169 | NULL, /* seek */ |
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170 | zlib_close |
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171 | }; |
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172 | |
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