src/HttpHdrContRange.cc

   1
   2 /*
   3  * $Id: HttpHdrContRange.cc,v 1.6 1998/07/20 17:19:02 wessels Exp $
   4  *
   5  * DEBUG: section 68    HTTP Content-Range Header
   6  * AUTHOR: Alex Rousskov
   7  *
   8  * SQUID Internet Object Cache  http://squid.nlanr.net/Squid/
   9  * --------------------------------------------------------
  10  *
  11  *  Squid is the result of efforts by numerous individuals from the
  12  *  Internet community.  Development is led by Duane Wessels of the
  13  *  National Laboratory for Applied Network Research and funded by
  14  *  the National Science Foundation.
  15  *
  16  *  This program is free software; you can redistribute it and/or modify
  17  *  it under the terms of the GNU General Public License as published by
  18  *  the Free Software Foundation; either version 2 of the License, or
  19  *  (at your option) any later version.
  20  *
  21  *  This program is distributed in the hope that it will be useful,
  22  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  23  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  24  *  GNU General Public License for more details.
  25  *
  26  *  You should have received a copy of the GNU General Public License
  27  *  along with this program; if not, write to the Free Software
  28  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
  29  *
  30  */
  31
  32 #include "squid.h"
  33
  34 /*
  35  *    Currently only byte ranges are supported
  36  *
  37  *    Content-Range = "Content-Range" ":" content-range-spec
  38  *    content-range-spec      = byte-content-range-spec
  39  *    byte-content-range-spec = bytes-unit SP
  40  *                              ( byte-range-resp-spec | "*") "/"
  41  *                              ( entity-length | "*" )
  42  *    byte-range-resp-spec = first-byte-pos "-" last-byte-pos
  43  *    entity-length        = 1*DIGIT
  44  */
  45
  46
  47 /* local constants */
  48 #define range_spec_unknown ((size_t)-1)
  49
  50 /* local routines */
  51 #define known_spec(s) ((s) != range_spec_unknown)
  52 #define size_min(a,b) ((a) <= (b) ? (a) : (b))
  53 #define size_diff(a,b) ((a) >= (b) ? ((a)-(b)) : 0)
  54
  55 /* globals */
  56
  57 /* parses range-resp-spec and inits spec, returns true on success */
  58 static int
  59 httpHdrRangeRespSpecParseInit(HttpHdrRangeSpec * spec, const char *field, int flen)
  60 {
  61     const char *p;
  62     assert(spec);
  63     spec->offset = spec->length = range_spec_unknown;
  64     if (flen < 2)
  65         return 0;
  66     /* is spec given ? */
  67     if (*field == '*')
  68         return 1;
  69     /* check format, must be %d-%d */
  70     if (!((p = strchr(field, '-')) && (p - field < flen))) {
  71         debug(68, 2) ("invalid (no '-') resp-range-spec near: '%s'\n", field);
  72         return 0;
  73     }
  74     /* parse offset */
  75     if (!httpHeaderParseSize(field, &spec->offset))
  76         return 0;
  77     p++;
  78     /* do we have last-pos ? */
  79     if (p - field < flen) {
  80         size_t last_pos;
  81         if (!httpHeaderParseSize(p, &last_pos))
  82             return 0;
  83         spec->length = size_diff(last_pos + 1, spec->offset);
  84     }
  85     /* we managed to parse, check if the result makes sence */
  86     if (known_spec(spec->length) && !spec->length) {
  87         debug(68, 2) ("invalid range (%d += %d) in resp-range-spec near: '%s'\n",
  88             spec->offset, spec->length, field);
  89         return 0;
  90     }
  91     return 1;
  92 }
  93
  94 static void
  95 httpHdrRangeRespSpecPackInto(const HttpHdrRangeSpec * spec, Packer * p)
  96 {
  97     if (!known_spec(spec->offset) || !known_spec(spec->length))
  98         packerPrintf(p, "*");
  99     else
 100         packerPrintf(p, "%d-%d",
 101             spec->offset, spec->offset + spec->length - 1);
 102 }
 103
 104 /*
 105  * Content Range
 106  */
 107
 108 HttpHdrContRange *
 109 httpHdrContRangeCreate()
 110 {
 111     HttpHdrContRange *r = memAllocate(MEM_HTTP_HDR_CONTENT_RANGE);
 112     r->spec.offset = r->spec.length = range_spec_unknown;
 113     r->elength = range_spec_unknown;
 114     return r;
 115 }
 116
 117 HttpHdrContRange *
 118 httpHdrContRangeParseCreate(const char *str)
 119 {
 120     HttpHdrContRange *r = httpHdrContRangeCreate();
 121     if (!httpHdrContRangeParseInit(r, str)) {
 122         httpHdrContRangeDestroy(r);
 123         r = NULL;
 124     }
 125     return r;
 126 }
 127
 128 /* returns true if ranges are valid; inits HttpHdrContRange */
 129 int
 130 httpHdrContRangeParseInit(HttpHdrContRange * range, const char *str)
 131 {
 132     const char *p;
 133     assert(range && str);
 134     debug(68, 8) ("parsing content-range field: '%s'\n", str);
 135     /* check range type */
 136     if (strncasecmp(str, "bytes ", 6))
 137         return 0;
 138     str += 6;
 139     /* split */
 140     if (!(p = strchr(str, '/')))
 141         return 0;
 142     if (*str == '*')
 143         range->spec.offset = range->spec.length = range_spec_unknown;
 144     else if (!httpHdrRangeRespSpecParseInit(&range->spec, str, p - str))
 145         return 0;
 146     p++;
 147     if (*p == '*')
 148         range->elength = range_spec_unknown;
 149     else if (!httpHeaderParseSize(p, &range->elength))
 150         return 0;
 151     debug(68, 8) ("parsed content-range field: %d-%d / %d\n",
 152         range->spec.offset, range->spec.offset + range->spec.length - 1,
 153         range->elength);
 154     return 1;
 155 }
 156
 157 void
 158 httpHdrContRangeDestroy(HttpHdrContRange * range)
 159 {
 160     assert(range);
 161     memFree(MEM_HTTP_HDR_CONTENT_RANGE, range);
 162 }
 163
 164 HttpHdrContRange *
 165 httpHdrContRangeDup(const HttpHdrContRange * range)
 166 {
 167     HttpHdrContRange *dup;
 168     assert(range);
 169     dup = httpHdrContRangeCreate();
 170     *dup = *range;
 171     return dup;
 172 }
 173
 174 void
 175 httpHdrContRangePackInto(const HttpHdrContRange * range, Packer * p)
 176 {
 177     assert(range && p);
 178     httpHdrRangeRespSpecPackInto(&range->spec, p);
 179     if (!known_spec(range->elength))
 180         packerPrintf(p, "/*");
 181     else
 182         packerPrintf(p, "/%d", range->elength);
 183 }
 184
 185 void
 186 httpHdrContRangeSet(HttpHdrContRange *cr, HttpHdrRangeSpec spec, size_t ent_len)
 187 {
 188     assert(cr && ent_len >= 0);
 189     cr->spec = spec;
 190     cr->elength = ent_len;
 191 }