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10
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1 /* gzio.c -- IO on .gz files
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2 * Copyright (C) 1995 Jean-loup Gailly.
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3 * For conditions of distribution and use, see copyright notice in zlib.h
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4 */
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5
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6 /* $Id: gzio.c,v 1.1.1.1 1997/12/06 04:37:16 darius Exp $ */
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7
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8 #include <stdio.h>
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9
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10 #include "zutil.h"
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11
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12 struct internal_state {int dummy;}; /* for buggy compilers */
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13
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14 #define Z_BUFSIZE 4096
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15
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16 #define ALLOC(size) zcalloc((voidp)0, 1, size)
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17 #define TRYFREE(p) {if (p) zcfree((voidp)0, p);}
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18
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19 #define GZ_MAGIC_1 0x1f
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20 #define GZ_MAGIC_2 0x8b
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21
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22 /* gzip flag byte */
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23 #define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */
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24 #define HEAD_CRC 0x02 /* bit 1 set: header CRC present */
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25 #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
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26 #define ORIG_NAME 0x08 /* bit 3 set: original file name present */
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27 #define COMMENT 0x10 /* bit 4 set: file comment present */
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28 #define RESERVED 0xE0 /* bits 5..7: reserved */
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29
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30 #ifndef SEEK_CUR
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31 # define SEEK_CUR 1
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32 #endif
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33
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34 typedef struct gz_stream {
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35 z_stream stream;
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36 int z_err; /* error code for last stream operation */
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37 int z_eof; /* set if end of input file */
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38 FILE *file; /* .gz file */
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39 Byte *inbuf; /* input buffer */
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40 Byte *outbuf; /* output buffer */
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41 uLong crc; /* crc32 of uncompressed data */
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42 char *msg; /* error message */
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43 char *path; /* path name for debugging only */
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44 int transparent; /* 1 if input file is not a .gz file */
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45 char mode; /* 'w' or 'r' */
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46 } gz_stream;
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47
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48
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49 local int destroy __P((gz_stream *s));
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50 local gzFile gz_open __P((char *path, char *mode, int fd));
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51 local void putLong __P((FILE *file, uLong x));
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52 local uLong getLong __P((Byte *buf));
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53
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54 /* ===========================================================================
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55 * Cleanup then free the given gz_stream. Return a zlib error code.
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56 */
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57 local int destroy (s)
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58 gz_stream *s;
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59 {
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60 int err = Z_OK;
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61
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62 if (!s) return Z_STREAM_ERROR;
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63
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64 TRYFREE(s->inbuf);
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65 TRYFREE(s->outbuf);
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66 TRYFREE(s->path);
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67 TRYFREE(s->msg);
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68
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69 if (s->stream.state != NULL) {
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70 if (s->mode == 'w') {
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71 err = deflateEnd(&(s->stream));
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72 } else if (s->mode == 'r') {
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73 err = inflateEnd(&(s->stream));
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74 }
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75 }
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76 if (s->file != NULL && fclose(s->file)) {
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77 err = Z_ERRNO;
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78 }
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79 if (s->z_err < 0) err = s->z_err;
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80 zcfree((voidp)0, s);
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81 return err;
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82 }
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83
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84 /* ===========================================================================
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85 Opens a gzip (.gz) file for reading or writing. The mode parameter
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86 is as in fopen ("rb" or "wb"). The file is given either by file descritor
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87 or path name (if fd == -1).
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88 gz_open return NULL if the file could not be opened or if there was
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89 insufficient memory to allocate the (de)compression state; errno
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90 can be checked to distinguish the two cases (if errno is zero, the
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91 zlib error is Z_MEM_ERROR).
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92 */
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93 local gzFile gz_open (path, mode, fd)
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94 char *path;
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95 char *mode;
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96 int fd;
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97 {
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98 int err;
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99 char *p = mode;
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100 gz_stream *s = (gz_stream *)ALLOC(sizeof(gz_stream));
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101
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102 if (!s) return Z_NULL;
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103
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104 s->stream.zalloc = (alloc_func)0;
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105 s->stream.zfree = (free_func)0;
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106 s->stream.next_in = s->inbuf = Z_NULL;
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107 s->stream.next_out = s->outbuf = Z_NULL;
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108 s->stream.avail_in = s->stream.avail_out = 0;
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109 s->file = NULL;
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110 s->z_err = Z_OK;
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111 s->z_eof = 0;
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112 s->crc = crc32(0L, Z_NULL, 0);
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113 s->msg = NULL;
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114 s->transparent = 0;
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115
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116 s->path = (char*)ALLOC(strlen(path)+1);
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117 if (s->path == NULL) {
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118 return destroy(s), (gzFile)Z_NULL;
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119 }
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120 strcpy(s->path, path); /* do this early for debugging */
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121
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122 s->mode = '\0';
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123 do {
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124 if (*p == 'r') s->mode = 'r';
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125 if (*p == 'w') s->mode = 'w';
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126 } while (*p++);
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127 if (s->mode == '\0') return destroy(s), (gzFile)Z_NULL;
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128
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129 if (s->mode == 'w') {
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130 err = deflateInit2(&(s->stream), Z_DEFAULT_COMPRESSION,
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131 DEFLATED, -MAX_WBITS, DEF_MEM_LEVEL, 0);
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132 /* windowBits is passed < 0 to suppress zlib header */
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133
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134 s->stream.next_out = s->outbuf = ALLOC(Z_BUFSIZE);
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135
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136 if (err != Z_OK || s->outbuf == Z_NULL) {
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137 return destroy(s), (gzFile)Z_NULL;
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138 }
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139 } else {
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140 err = inflateInit2(&(s->stream), -MAX_WBITS);
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141 s->stream.next_in = s->inbuf = ALLOC(Z_BUFSIZE);
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142
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143 if (err != Z_OK || s->inbuf == Z_NULL) {
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144 return destroy(s), (gzFile)Z_NULL;
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145 }
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146 }
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147 s->stream.avail_out = Z_BUFSIZE;
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148
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149 errno = 0;
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150 s->file = fd < 0 ? FOPEN(path, mode) : fdopen(fd, mode);
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151
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152 if (s->file == NULL) {
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153 return destroy(s), (gzFile)Z_NULL;
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154 }
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155 if (s->mode == 'w') {
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156 /* Write a very simple .gz header:
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157 */
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158 fprintf(s->file, "%c%c%c%c%c%c%c%c%c%c", GZ_MAGIC_1, GZ_MAGIC_2,
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159 DEFLATED, 0 /*flags*/, 0,0,0,0 /*time*/, 0 /*xflags*/, OS_CODE);
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160 } else {
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161 /* Check and skip the header:
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162 */
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163 Byte c1 = 0, c2 = 0;
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164 Byte method = 0;
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165 Byte flags = 0;
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166 Byte xflags = 0;
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167 Byte time[4];
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168 Byte osCode;
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169 int c;
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170
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171 s->stream.avail_in = fread(s->inbuf, 1, 2, s->file);
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172 if (s->stream.avail_in != 2 || s->inbuf[0] != GZ_MAGIC_1
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173 || s->inbuf[1] != GZ_MAGIC_2) {
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174 s->transparent = 1;
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175 return (gzFile)s;
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176 }
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177 s->stream.avail_in = 0;
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178 fscanf(s->file,"%c%c%4c%c%c", &method, &flags, time, &xflags, &osCode);
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179
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180 if (method != DEFLATED || feof(s->file) || (flags & RESERVED) != 0) {
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181 s->z_err = Z_DATA_ERROR;
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182 return (gzFile)s;
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183 }
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184 if ((flags & EXTRA_FIELD) != 0) { /* skip the extra field */
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185 long len;
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186 fscanf(s->file, "%c%c", &c1, &c2);
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187 len = c1 + ((long)c2<<8);
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188 fseek(s->file, len, SEEK_CUR);
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189 }
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190 if ((flags & ORIG_NAME) != 0) { /* skip the original file name */
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191 while ((c = getc(s->file)) != 0 && c != EOF) ;
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192 }
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193 if ((flags & COMMENT) != 0) { /* skip the .gz file comment */
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194 while ((c = getc(s->file)) != 0 && c != EOF) ;
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195 }
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196 if ((flags & HEAD_CRC) != 0) { /* skip the header crc */
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197 fscanf(s->file, "%c%c", &c1, &c2);
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198 }
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199 if (feof(s->file)) {
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200 s->z_err = Z_DATA_ERROR;
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201 }
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202 }
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203 return (gzFile)s;
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204 }
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205
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206 /* ===========================================================================
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207 Opens a gzip (.gz) file for reading or writing.
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208 */
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209 gzFile gzopen (path, mode)
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210 char *path;
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211 char *mode;
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212 {
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213 return gz_open (path, mode, -1);
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214 }
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215
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216 /* ===========================================================================
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217 Associate a gzFile with the file descriptor fd.
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218 */
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219 gzFile gzdopen (fd, mode)
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220 int fd;
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221 char *mode;
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222 {
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223 char name[20];
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224 sprintf(name, "<fd:%d>", fd); /* for debugging */
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225
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226 return gz_open (name, mode, fd);
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227 }
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228
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229 /* ===========================================================================
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230 Reads the given number of uncompressed bytes from the compressed file.
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231 gzread returns the number of bytes actually read (0 for end of file).
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232 */
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233 int gzread (file, buf, len)
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234 gzFile file;
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235 voidp buf;
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236 unsigned len;
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237 {
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238 gz_stream *s = (gz_stream*)file;
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239
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240 if (s == NULL || s->mode != 'r') return Z_STREAM_ERROR;
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241
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242 if (s->transparent) {
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243 unsigned n = 0;
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244 Byte *b = (Byte*)buf;
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245 /* Copy the first two (non-magic) bytes if not done already */
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246 while (s->stream.avail_in > 0 && len > 0) {
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247 *b++ = *s->stream.next_in++;
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248 s->stream.avail_in--;
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249 len--; n++;
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250 }
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251 if (len == 0) return n;
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252 return n + fread(b, 1, len, s->file);
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253 }
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254 if (s->z_err == Z_DATA_ERROR) return -1; /* bad .gz file */
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255 if (s->z_err == Z_STREAM_END) return 0; /* don't read crc as data */
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256
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257 s->stream.next_out = buf;
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258 s->stream.avail_out = len;
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259
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260 while (s->stream.avail_out != 0) {
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261
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262 if (s->stream.avail_in == 0 && !s->z_eof) {
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263
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264 errno = 0;
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265 s->stream.avail_in =
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266 fread(s->inbuf, 1, Z_BUFSIZE, s->file);
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267 if (s->stream.avail_in == 0) {
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268 s->z_eof = 1;
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269 } else if (s->stream.avail_in == (uInt)EOF) {
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270 s->stream.avail_in = 0;
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271 s->z_eof = 1;
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272 s->z_err = Z_ERRNO;
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273 break;
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274 }
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275 s->stream.next_in = s->inbuf;
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276 }
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277 s->z_err = inflate(&(s->stream), Z_NO_FLUSH);
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278
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279 if (s->z_err == Z_STREAM_END ||
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280 s->z_err != Z_OK || s->z_eof) break;
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281 }
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282 len -= s->stream.avail_out;
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283 s->crc = crc32(s->crc, buf, len);
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284 return len;
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285 }
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286
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287 /* ===========================================================================
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288 Writes the given number of uncompressed bytes into the compressed file.
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289 gzwrite returns the number of bytes actually written (0 in case of error).
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290 */
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291 int gzwrite (file, buf, len)
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292 gzFile file;
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293 voidp buf;
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294 unsigned len;
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295 {
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296 gz_stream *s = (gz_stream*)file;
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297
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298 if (s == NULL || s->mode != 'w') return Z_STREAM_ERROR;
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299
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300 s->stream.next_in = buf;
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301 s->stream.avail_in = len;
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302
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303 while (s->stream.avail_in != 0) {
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304
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305 if (s->stream.avail_out == 0) {
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306
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307 s->stream.next_out = s->outbuf;
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308 if (fwrite(s->outbuf, 1, Z_BUFSIZE, s->file) != Z_BUFSIZE) {
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309 s->z_err = Z_ERRNO;
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310 break;
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311 }
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312 s->stream.avail_out = Z_BUFSIZE;
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313 }
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314 s->z_err = deflate(&(s->stream), Z_NO_FLUSH);
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315
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316 if (s->z_err != Z_OK) break;
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317 }
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318 s->crc = crc32(s->crc, buf, len);
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319
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320 return len - s->stream.avail_in;
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321 }
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322
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323 /* ===========================================================================
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324 Flushes all pending output into the compressed file. The parameter
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325 flush is as in the deflate() function.
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326 gzflush should be called only when strictly necessary because it can
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327 degrade compression.
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328 */
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329 int gzflush (file, flush)
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330 gzFile file;
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331 int flush;
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332 {
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333 uInt len;
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334 int done = 0;
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335 gz_stream *s = (gz_stream*)file;
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336
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337 if (s == NULL || s->mode != 'w') return Z_STREAM_ERROR;
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338
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339 s->stream.avail_in = 0; /* should be zero already anyway */
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340
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341 for (;;) {
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342 len = Z_BUFSIZE - s->stream.avail_out;
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343
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344 if (len != 0) {
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345 if (fwrite(s->outbuf, 1, len, s->file) != len) {
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346 s->z_err = Z_ERRNO;
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347 return Z_ERRNO;
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348 }
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349 s->stream.next_out = s->outbuf;
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350 s->stream.avail_out = Z_BUFSIZE;
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351 }
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352 if (done) break;
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353 s->z_err = deflate(&(s->stream), flush);
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354
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355 /* deflate has finished flushing only when it hasn't used up
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356 * all the available space in the output buffer:
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357 */
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358 done = (s->stream.avail_out != 0 || s->z_err == Z_STREAM_END);
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359
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360 if (s->z_err != Z_OK && s->z_err != Z_STREAM_END) break;
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361 }
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362 return s->z_err == Z_STREAM_END ? Z_OK : s->z_err;
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363 }
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364
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365 /* ===========================================================================
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366 Outputs a long in LSB order to the given file
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367 */
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368 local void putLong (file, x)
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369 FILE *file;
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370 uLong x;
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371 {
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372 int n;
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373 for (n = 0; n < 4; n++) {
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374 fputc((int)(x & 0xff), file);
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375 x >>= 8;
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376 }
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377 }
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378
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379 /* ===========================================================================
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380 Reads a long in LSB order from the given buffer
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381 */
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382 local uLong getLong (buf)
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383 Byte *buf;
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384 {
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385 uLong x = 0;
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386 Byte *p = buf+4;
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387
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388 do {
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389 x <<= 8;
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390 x |= *--p;
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391 } while (p != buf);
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392 return x;
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393 }
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394
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395 /* ===========================================================================
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396 Flushes all pending output if necessary, closes the compressed file
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397 and deallocates all the (de)compression state.
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398 */
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399 int gzclose (file)
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400 gzFile file;
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401 {
|
|
|
402 uInt n;
|
|
|
403 int err;
|
|
|
404 gz_stream *s = (gz_stream*)file;
|
|
|
405
|
|
|
406 if (s == NULL) return Z_STREAM_ERROR;
|
|
|
407
|
|
|
408 if (s->mode == 'w') {
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|
|
409 err = gzflush (file, Z_FINISH);
|
|
|
410 if (err != Z_OK) return destroy(file);
|
|
|
411
|
|
|
412 putLong (s->file, s->crc);
|
|
|
413 putLong (s->file, s->stream.total_in);
|
|
|
414
|
|
|
415 } else if (s->mode == 'r' && s->z_err == Z_STREAM_END) {
|
|
|
416
|
|
|
417 /* slide CRC and original size if they are at the end of inbuf */
|
|
|
418 if ((n = s->stream.avail_in) < 8 && !s->z_eof) {
|
|
|
419 Byte *p = s->inbuf;
|
|
|
420 Byte *q = s->stream.next_in;
|
|
|
421 while (n--) { *p++ = *q++; };
|
|
|
422
|
|
|
423 n = s->stream.avail_in;
|
|
|
424 n += fread(p, 1, 8, s->file);
|
|
|
425 s->stream.next_in = s->inbuf;
|
|
|
426 }
|
|
|
427 /* check CRC and original size */
|
|
|
428 if (n < 8 ||
|
|
|
429 getLong(s->stream.next_in) != s->crc ||
|
|
|
430 getLong(s->stream.next_in + 4) != s->stream.total_out) {
|
|
|
431
|
|
|
432 s->z_err = Z_DATA_ERROR;
|
|
|
433 }
|
|
|
434 }
|
|
|
435 return destroy(file);
|
|
|
436 }
|
|
|
437
|
|
|
438 /* ===========================================================================
|
|
|
439 Returns the error message for the last error which occured on the
|
|
|
440 given compressed file. errnum is set to zlib error number. If an
|
|
|
441 error occured in the file system and not in the compression library,
|
|
|
442 errnum is set to Z_ERRNO and the application may consult errno
|
|
|
443 to get the exact error code.
|
|
|
444 */
|
|
|
445 char* gzerror (file, errnum)
|
|
|
446 gzFile file;
|
|
|
447 int *errnum;
|
|
|
448 {
|
|
|
449 char *m;
|
|
|
450 gz_stream *s = (gz_stream*)file;
|
|
|
451
|
|
|
452 if (s == NULL) {
|
|
|
453 *errnum = Z_STREAM_ERROR;
|
|
|
454 return z_errmsg[1-Z_STREAM_ERROR];
|
|
|
455 }
|
|
|
456 *errnum = s->z_err;
|
|
|
457 if (*errnum == Z_OK) return "";
|
|
|
458
|
|
|
459 m = *errnum == Z_ERRNO ? zstrerror(errno) : s->stream.msg;
|
|
|
460
|
|
|
461 if (m == NULL || *m == '\0') m = z_errmsg[1-s->z_err];
|
|
|
462
|
|
|
463 TRYFREE(s->msg);
|
|
|
464 s->msg = (char*)ALLOC(strlen(s->path) + strlen(m) + 3);
|
|
|
465 strcpy(s->msg, s->path);
|
|
|
466 strcat(s->msg, ": ");
|
|
|
467 strcat(s->msg, m);
|
|
|
468 return s->msg;
|
|
|
469 }
|
