/*
 * $Id: HttpHdrContRange.c,v 1.12.2.1 2001/01/12 00:51:43 wessels Exp $
 *
 * DEBUG: section 68    HTTP Content-Range Header
 * AUTHOR: Alex Rousskov
 *
 * SQUID Web Proxy Cache          http://www.squid-cache.org/
 * ----------------------------------------------------------
 *
 *  Squid is the result of efforts by numerous individuals from
 *  the Internet community; see the CONTRIBUTORS file for full
 *  details.   Many organizations have provided support for Squid's
 *  development; see the SPONSORS file for full details.  Squid is
 *  Copyrighted (C) 2001 by the Regents of the University of
 *  California; see the COPYRIGHT file for full details.  Squid
 *  incorporates software developed and/or copyrighted by other
 *  sources; see the CREDITS file for full details.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *  
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *  
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
 *
 */

#include "squid.h"

/*
 *    Currently only byte ranges are supported
 *
 *    Content-Range = "Content-Range" ":" content-range-spec
 *    content-range-spec      = byte-content-range-spec
 *    byte-content-range-spec = bytes-unit SP
 *                              ( byte-range-resp-spec | "*") "/"
 *                              ( entity-length | "*" )
 *    byte-range-resp-spec = first-byte-pos "-" last-byte-pos
 *    entity-length        = 1*DIGIT
 */


/* local constants */
#define range_spec_unknown ((size_t)-1)

/* local routines */
#define known_spec(s) ((s) != range_spec_unknown)
#define size_min(a,b) ((a) <= (b) ? (a) : (b))
#define size_diff(a,b) ((a) >= (b) ? ((a)-(b)) : 0)

/* globals */

/* parses range-resp-spec and inits spec, returns true on success */
static int
httpHdrRangeRespSpecParseInit(HttpHdrRangeSpec * spec, const char *field, int flen)
{
    const char *p;
    assert(spec);
    spec->offset = spec->length = range_spec_unknown;
    if (flen < 2)
	return 0;
    /* is spec given ? */
    if (*field == '*')
	return 1;
    /* check format, must be %d-%d */
    if (!((p = strchr(field, '-')) && (p - field < flen))) {
	debug(68, 2) ("invalid (no '-') resp-range-spec near: '%s'\n", field);
	return 0;
    }
    /* parse offset */
    if (!httpHeaderParseSize(field, &spec->offset))
	return 0;
    p++;
    /* do we have last-pos ? */
    if (p - field < flen) {
	ssize_t last_pos;
	if (!httpHeaderParseSize(p, &last_pos))
	    return 0;
	spec->length = size_diff(last_pos + 1, spec->offset);
    }
    /* we managed to parse, check if the result makes sence */
    if (known_spec(spec->length) && !spec->length) {
	debug(68, 2) ("invalid range (%d += %d) in resp-range-spec near: '%s'\n",
	    spec->offset, spec->length, field);
	return 0;
    }
    return 1;
}

static void
httpHdrRangeRespSpecPackInto(const HttpHdrRangeSpec * spec, Packer * p)
{
    if (!known_spec(spec->offset) || !known_spec(spec->length))
	packerPrintf(p, "*");
    else
	packerPrintf(p, "bytes %d-%d",
	    spec->offset, spec->offset + spec->length - 1);
}

/*
 * Content Range
 */

HttpHdrContRange *
httpHdrContRangeCreate(void)
{
    HttpHdrContRange *r = memAllocate(MEM_HTTP_HDR_CONTENT_RANGE);
    r->spec.offset = r->spec.length = range_spec_unknown;
    r->elength = range_spec_unknown;
    return r;
}

HttpHdrContRange *
httpHdrContRangeParseCreate(const char *str)
{
    HttpHdrContRange *r = httpHdrContRangeCreate();
    if (!httpHdrContRangeParseInit(r, str)) {
	httpHdrContRangeDestroy(r);
	r = NULL;
    }
    return r;
}

/* returns true if ranges are valid; inits HttpHdrContRange */
int
httpHdrContRangeParseInit(HttpHdrContRange * range, const char *str)
{
    const char *p;
    assert(range && str);
    debug(68, 8) ("parsing content-range field: '%s'\n", str);
    /* check range type */
    if (strncasecmp(str, "bytes ", 6))
	return 0;
    str += 6;
    /* split */
    if (!(p = strchr(str, '/')))
	return 0;
    if (*str == '*')
	range->spec.offset = range->spec.length = range_spec_unknown;
    else if (!httpHdrRangeRespSpecParseInit(&range->spec, str, p - str))
	return 0;
    p++;
    if (*p == '*')
	range->elength = range_spec_unknown;
    else if (!httpHeaderParseSize(p, &range->elength))
	return 0;
    debug(68, 8) ("parsed content-range field: %d-%d / %d\n",
	range->spec.offset, range->spec.offset + range->spec.length - 1,
	range->elength);
    return 1;
}

void
httpHdrContRangeDestroy(HttpHdrContRange * range)
{
    assert(range);
    memFree(range, MEM_HTTP_HDR_CONTENT_RANGE);
}

HttpHdrContRange *
httpHdrContRangeDup(const HttpHdrContRange * range)
{
    HttpHdrContRange *dup;
    assert(range);
    dup = httpHdrContRangeCreate();
    *dup = *range;
    return dup;
}

void
httpHdrContRangePackInto(const HttpHdrContRange * range, Packer * p)
{
    assert(range && p);
    httpHdrRangeRespSpecPackInto(&range->spec, p);
    if (!known_spec(range->elength))
	packerPrintf(p, "/*");
    else
	packerPrintf(p, "/%d", range->elength);
}

void
httpHdrContRangeSet(HttpHdrContRange * cr, HttpHdrRangeSpec spec, ssize_t ent_len)
{
    assert(cr && ent_len >= 0);
    cr->spec = spec;
    cr->elength = ent_len;
}