src/HttpHdrContRange.cc

   1
   2 /*
   3  * $Id: HttpHdrContRange.cc,v 1.18 2007/04/28 22:26:37 hno Exp $
   4  *
   5  * DEBUG: section 68    HTTP Content-Range Header
   6  * AUTHOR: Alex Rousskov
   7  *
   8  * SQUID Web Proxy Cache          http://www.squid-cache.org/
   9  * ----------------------------------------------------------
  10  *
  11  *  Squid is the result of efforts by numerous individuals from
  12  *  the Internet community; see the CONTRIBUTORS file for full
  13  *  details.   Many organizations have provided support for Squid's
  14  *  development; see the SPONSORS file for full details.  Squid is
  15  *  Copyrighted (C) 2001 by the Regents of the University of
  16  *  California; see the COPYRIGHT file for full details.  Squid
  17  *  incorporates software developed and/or copyrighted by other
  18  *  sources; see the CREDITS file for full details.
  19  *
  20  *  This program is free software; you can redistribute it and/or modify
  21  *  it under the terms of the GNU General Public License as published by
  22  *  the Free Software Foundation; either version 2 of the License, or
  23  *  (at your option) any later version.
  24  *
  25  *  This program is distributed in the hope that it will be useful,
  26  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  27  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  28  *  GNU General Public License for more details.
  29  *
  30  *  You should have received a copy of the GNU General Public License
  31  *  along with this program; if not, write to the Free Software
  32  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
  33  *
  34  */
  35
  36 #include "squid.h"
  37 #include "HttpHdrContRange.h"
  38
  39 /*
  40  *    Currently only byte ranges are supported
  41  *
  42  *    Content-Range = "Content-Range" ":" content-range-spec
  43  *    content-range-spec      = byte-content-range-spec
  44  *    byte-content-range-spec = bytes-unit SP
  45  *                              ( byte-range-resp-spec | "*") "/"
  46  *                              ( entity-length | "*" )
  47  *    byte-range-resp-spec = first-byte-pos "-" last-byte-pos
  48  *    entity-length        = 1*DIGIT
  49  */
  50
  51
  52 /* local constants */
  53 #define range_spec_unknown ((size_t)-1)
  54
  55 /* local routines */
  56 #define known_spec(s) ((s) != range_spec_unknown)
  57 #define size_min(a,b) ((a) <= (b) ? (a) : (b))
  58 #define size_diff(a,b) ((a) >= (b) ? ((a)-(b)) : 0)
  59
  60 /* globals */
  61
  62 /* parses range-resp-spec and inits spec, returns true on success */
  63 static int
  64 httpHdrRangeRespSpecParseInit(HttpHdrRangeSpec * spec, const char *field, int flen)
  65 {
  66     const char *p;
  67     assert(spec);
  68     spec->offset = spec->length = range_spec_unknown;
  69
  70     if (flen < 2)
  71         return 0;
  72
  73     /* is spec given ? */
  74     if (*field == '*')
  75         return 1;
  76
  77     /* check format, must be %d-%d */
  78     if (!((p = strchr(field, '-')) && (p - field < flen))) {
  79         debugs(68, 2, "invalid (no '-') resp-range-spec near: '" << field << "'");
  80         return 0;
  81     }
  82
  83     /* parse offset */
  84     if (!httpHeaderParseSize(field, &spec->offset))
  85         return 0;
  86
  87     p++;
  88
  89     /* do we have last-pos ? */
  90     if (p - field < flen) {
  91         ssize_t last_pos;
  92
  93         if (!httpHeaderParseSize(p, &last_pos))
  94             return 0;
  95
  96         spec->length = size_diff(last_pos + 1, spec->offset);
  97     }
  98
  99     /* Ensure typecast is safe */
 100     assert (spec->length >= 0);
 101
 102     /* we managed to parse, check if the result makes sence */
 103     if (known_spec((size_t)spec->length) && spec->length == 0) {
 104         debugs(68, 2, "invalid range (" << (long int) spec->offset << " += " <<
 105                (long int) spec->length << ") in resp-range-spec near: '" << field << "'");
 106         return 0;
 107     }
 108
 109     return 1;
 110 }
 111
 112 static void
 113 httpHdrRangeRespSpecPackInto(const HttpHdrRangeSpec * spec, Packer * p)
 114 {
 115     /* Ensure typecast is safe */
 116     assert (spec->length >= 0);
 117     assert (spec->length >= 0);
 118
 119     if (!known_spec((size_t)spec->offset) || !known_spec((size_t)spec->length))
 120         packerPrintf(p, "*");
 121     else
 122         packerPrintf(p, "bytes %ld-%ld",
 123                      (long int) spec->offset, (long int) spec->offset + spec->length - 1);
 124 }
 125
 126 /*
 127  * Content Range
 128  */
 129
 130 HttpHdrContRange *
 131 httpHdrContRangeCreate(void)
 132 {
 133     HttpHdrContRange *r = (HttpHdrContRange *)memAllocate(MEM_HTTP_HDR_CONTENT_RANGE);
 134     r->spec.offset = r->spec.length = range_spec_unknown;
 135     r->elength = range_spec_unknown;
 136     return r;
 137 }
 138
 139 HttpHdrContRange *
 140 httpHdrContRangeParseCreate(const char *str)
 141 {
 142     HttpHdrContRange *r = httpHdrContRangeCreate();
 143
 144     if (!httpHdrContRangeParseInit(r, str)) {
 145         httpHdrContRangeDestroy(r);
 146         r = NULL;
 147     }
 148
 149     return r;
 150 }
 151
 152 /* returns true if ranges are valid; inits HttpHdrContRange */
 153 int
 154 httpHdrContRangeParseInit(HttpHdrContRange * range, const char *str)
 155 {
 156     const char *p;
 157     assert(range && str);
 158     debugs(68, 8, "parsing content-range field: '" << str << "'");
 159     /* check range type */
 160
 161     if (strncasecmp(str, "bytes ", 6))
 162         return 0;
 163
 164     str += 6;
 165
 166     /* split */
 167     if (!(p = strchr(str, '/')))
 168         return 0;
 169
 170     if (*str == '*')
 171         range->spec.offset = range->spec.length = range_spec_unknown;
 172     else if (!httpHdrRangeRespSpecParseInit(&range->spec, str, p - str))
 173         return 0;
 174
 175     p++;
 176
 177     if (*p == '*')
 178         range->elength = range_spec_unknown;
 179     else if (!httpHeaderParseSize(p, &range->elength))
 180         return 0;
 181
 182         debugs(68, 8, "parsed content-range field: " <<
 183                (long int) range->spec.offset << "-" <<
 184                (long int) range->spec.offset + range->spec.length - 1 << " / " <<
 185                (long int) range->elength);
 186
 187     return 1;
 188 }
 189
 190 void
 191 httpHdrContRangeDestroy(HttpHdrContRange * range)
 192 {
 193     assert(range);
 194     memFree(range, MEM_HTTP_HDR_CONTENT_RANGE);
 195 }
 196
 197 HttpHdrContRange *
 198 httpHdrContRangeDup(const HttpHdrContRange * range)
 199 {
 200     HttpHdrContRange *dup;
 201     assert(range);
 202     dup = httpHdrContRangeCreate();
 203     *dup = *range;
 204     return dup;
 205 }
 206
 207 void
 208 httpHdrContRangePackInto(const HttpHdrContRange * range, Packer * p)
 209 {
 210     assert(range && p);
 211     httpHdrRangeRespSpecPackInto(&range->spec, p);
 212     /* Ensure typecast is safe */
 213     assert (range->elength >= 0);
 214
 215     if (!known_spec((size_t)range->elength))
 216         packerPrintf(p, "/*");
 217     else
 218         packerPrintf(p, "/%ld", (long int) range->elength);
 219 }
 220
 221 void
 222 httpHdrContRangeSet(HttpHdrContRange * cr, HttpHdrRangeSpec spec, ssize_t ent_len)
 223 {
 224     assert(cr && ent_len >= 0);
 225     cr->spec = spec;
 226     cr->elength = ent_len;
 227 }