/* Based on src/http/ngx_http_parse.c from NGINX copyright Igor Sysoev
 *
 * Additional changes are licensed under the same terms as NGINX and
 * copyright Joyent, Inc. and other Node contributors. All rights reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */
#include "http_parser.h"
#include <assert.h>
#include <stddef.h>
#include <ctype.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>

#ifndef ULLONG_MAX
# define ULLONG_MAX ((uint64_t) -1) /* 2^64-1 */
#endif

#ifndef MIN
# define MIN(a,b) ((a) < (b) ? (a) : (b))
#endif


#if HTTP_PARSER_DEBUG
#define SET_ERRNO(e)                                                 \
do {                                                                 \
  parser->http_errno = (e);                                          \
  parser->error_lineno = __LINE__;                                   \
} while (0)
#else
#define SET_ERRNO(e)                                                 \
do {                                                                 \
  parser->http_errno = (e);                                          \
} while(0)
#endif


/* Run the notify callback FOR, returning ER if it fails */
#define CALLBACK_NOTIFY_(FOR, ER)                                    \
do {                                                                 \
  assert(HTTP_PARSER_ERRNO(parser) == HPE_OK);                       \
																	 \
  if (settings->on_##FOR) {                                          \
	if (0 != settings->on_##FOR(parser)) {                           \
	  SET_ERRNO(HPE_CB_##FOR);                                       \
	}                                                                \
																	 \
	/* We either errored above or got paused; get out */             \
	if (HTTP_PARSER_ERRNO(parser) != HPE_OK) {                       \
	  return (ER);                                                   \
	}                                                                \
  }                                                                  \
} while (0)

/* Run the notify callback FOR and consume the current byte */
#define CALLBACK_NOTIFY(FOR)            CALLBACK_NOTIFY_(FOR, p - data + 1)

/* Run the notify callback FOR and don't consume the current byte */
#define CALLBACK_NOTIFY_NOADVANCE(FOR)  CALLBACK_NOTIFY_(FOR, p - data)

/* Run data callback FOR with LEN bytes, returning ER if it fails */
#define CALLBACK_DATA_(FOR, LEN, ER)                                 \
do {                                                                 \
  assert(HTTP_PARSER_ERRNO(parser) == HPE_OK);                       \
																	 \
  if (FOR##_mark) {                                                  \
	if (settings->on_##FOR) {                                        \
	  if (0 != settings->on_##FOR(parser, FOR##_mark, (LEN))) {      \
		SET_ERRNO(HPE_CB_##FOR);                                     \
	  }                                                              \
																	 \
	  /* We either errored above or got paused; get out */           \
	  if (HTTP_PARSER_ERRNO(parser) != HPE_OK) {                     \
		return (ER);                                                 \
	  }                                                              \
	}                                                                \
	FOR##_mark = NULL;                                               \
  }                                                                  \
} while (0)

/* Run the data callback FOR and consume the current byte */
#define CALLBACK_DATA(FOR)                                           \
	CALLBACK_DATA_(FOR, p - FOR##_mark, p - data + 1)

/* Run the data callback FOR and don't consume the current byte */
#define CALLBACK_DATA_NOADVANCE(FOR)                                 \
	CALLBACK_DATA_(FOR, p - FOR##_mark, p - data)

/* Set the mark FOR; non-destructive if mark is already set */
#define MARK(FOR)                                                    \
do {                                                                 \
  if (!FOR##_mark) {                                                 \
	FOR##_mark = p;                                                  \
  }                                                                  \
} while (0)


#define PROXY_CONNECTION "proxy-connection"
#define CONNECTION "connection"
#define CONTENT_LENGTH "content-length"
#define TRANSFER_ENCODING "transfer-encoding"
#define UPGRADE "upgrade"
#define CHUNKED "chunked"
#define KEEP_ALIVE "keep-alive"
#define CLOSE "close"


static const char *method_strings[] =
  {
#define XX(num, name, string) #string,
  HTTP_METHOD_MAP(XX)
#undef XX
  };


/* Tokens as defined by rfc 2616. Also lowercases them.
 *        token       = 1*<any CHAR except CTLs or separators>
 *     separators     = "(" | ")" | "<" | ">" | "@"
 *                    | "," | ";" | ":" | "\" | <">
 *                    | "/" | "[" | "]" | "?" | "="
 *                    | "{" | "}" | SP | HT
 */
static const char tokens[256] = {
/*   0 nul    1 soh    2 stx    3 etx    4 eot    5 enq    6 ack    7 bel  */
		0,       0,       0,       0,       0,       0,       0,       0,
/*   8 bs     9 ht    10 nl    11 vt    12 np    13 cr    14 so    15 si   */
		0,       0,       0,       0,       0,       0,       0,       0,
/*  16 dle   17 dc1   18 dc2   19 dc3   20 dc4   21 nak   22 syn   23 etb */
		0,       0,       0,       0,       0,       0,       0,       0,
/*  24 can   25 em    26 sub   27 esc   28 fs    29 gs    30 rs    31 us  */
		0,       0,       0,       0,       0,       0,       0,       0,
/*  32 sp    33  !    34  "    35  #    36  $    37  %    38  &    39  '  */
		0,      '!',      0,      '#',     '$',     '%',     '&',    '\'',
/*  40  (    41  )    42  *    43  +    44  ,    45  -    46  .    47  /  */
		0,       0,      '*',     '+',      0,      '-',     '.',      0,
/*  48  0    49  1    50  2    51  3    52  4    53  5    54  6    55  7  */
	   '0',     '1',     '2',     '3',     '4',     '5',     '6',     '7',
/*  56  8    57  9    58  :    59  ;    60  <    61  =    62  >    63  ?  */
	   '8',     '9',      0,       0,       0,       0,       0,       0,
/*  64  @    65  A    66  B    67  C    68  D    69  E    70  F    71  G  */
		0,      'a',     'b',     'c',     'd',     'e',     'f',     'g',
/*  72  H    73  I    74  J    75  K    76  L    77  M    78  N    79  O  */
	   'h',     'i',     'j',     'k',     'l',     'm',     'n',     'o',
/*  80  P    81  Q    82  R    83  S    84  T    85  U    86  V    87  W  */
	   'p',     'q',     'r',     's',     't',     'u',     'v',     'w',
/*  88  X    89  Y    90  Z    91  [    92  \    93  ]    94  ^    95  _  */
	   'x',     'y',     'z',      0,       0,       0,      '^',     '_',
/*  96  `    97  a    98  b    99  c   100  d   101  e   102  f   103  g  */
	   '`',     'a',     'b',     'c',     'd',     'e',     'f',     'g',
/* 104  h   105  i   106  j   107  k   108  l   109  m   110  n   111  o  */
	   'h',     'i',     'j',     'k',     'l',     'm',     'n',     'o',
/* 112  p   113  q   114  r   115  s   116  t   117  u   118  v   119  w  */
	   'p',     'q',     'r',     's',     't',     'u',     'v',     'w',
/* 120  x   121  y   122  z   123  {   124  |   125  }   126  ~   127 del */
	   'x',     'y',     'z',      0,      '|',      0,      '~',       0 };


static const int8_t unhex[256] =
  {-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1
  ,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1
  ,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1
  , 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,-1,-1,-1,-1,-1,-1
  ,-1,10,11,12,13,14,15,-1,-1,-1,-1,-1,-1,-1,-1,-1
  ,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1
  ,-1,10,11,12,13,14,15,-1,-1,-1,-1,-1,-1,-1,-1,-1
  ,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1
  };


static const uint8_t normal_url_char[256] = {
/*   0 nul    1 soh    2 stx    3 etx    4 eot    5 enq    6 ack    7 bel  */
		0,       0,       0,       0,       0,       0,       0,       0,
/*   8 bs     9 ht    10 nl    11 vt    12 np    13 cr    14 so    15 si   */
		0,       0,       0,       0,       0,       0,       0,       0,
/*  16 dle   17 dc1   18 dc2   19 dc3   20 dc4   21 nak   22 syn   23 etb */
		0,       0,       0,       0,       0,       0,       0,       0,
/*  24 can   25 em    26 sub   27 esc   28 fs    29 gs    30 rs    31 us  */
		0,       0,       0,       0,       0,       0,       0,       0,
/*  32 sp    33  !    34  "    35  #    36  $    37  %    38  &    39  '  */
		0,       1,       1,       0,       1,       1,       1,       1,
/*  40  (    41  )    42  *    43  +    44  ,    45  -    46  .    47  /  */
		1,       1,       1,       1,       1,       1,       1,       1,
/*  48  0    49  1    50  2    51  3    52  4    53  5    54  6    55  7  */
		1,       1,       1,       1,       1,       1,       1,       1,
/*  56  8    57  9    58  :    59  ;    60  <    61  =    62  >    63  ?  */
		1,       1,       1,       1,       1,       1,       1,       0,
/*  64  @    65  A    66  B    67  C    68  D    69  E    70  F    71  G  */
		1,       1,       1,       1,       1,       1,       1,       1,
/*  72  H    73  I    74  J    75  K    76  L    77  M    78  N    79  O  */
		1,       1,       1,       1,       1,       1,       1,       1,
/*  80  P    81  Q    82  R    83  S    84  T    85  U    86  V    87  W  */
		1,       1,       1,       1,       1,       1,       1,       1,
/*  88  X    89  Y    90  Z    91  [    92  \    93  ]    94  ^    95  _  */
		1,       1,       1,       1,       1,       1,       1,       1,
/*  96  `    97  a    98  b    99  c   100  d   101  e   102  f   103  g  */
		1,       1,       1,       1,       1,       1,       1,       1,
/* 104  h   105  i   106  j   107  k   108  l   109  m   110  n   111  o  */
		1,       1,       1,       1,       1,       1,       1,       1,
/* 112  p   113  q   114  r   115  s   116  t   117  u   118  v   119  w  */
		1,       1,       1,       1,       1,       1,       1,       1,
/* 120  x   121  y   122  z   123  {   124  |   125  }   126  ~   127 del */
		1,       1,       1,       1,       1,       1,       1,       0, };


enum state
  { s_dead = 1 /* important that this is > 0 */

  , s_start_req_or_res
  , s_res_or_resp_H
  , s_start_res
  , s_res_H
  , s_res_HT
  , s_res_HTT
  , s_res_HTTP
  , s_res_first_http_major
  , s_res_http_major
  , s_res_first_http_minor
  , s_res_http_minor
  , s_res_first_status_code
  , s_res_status_code
  , s_res_status
  , s_res_line_almost_done

  , s_start_req

  , s_req_method
  , s_req_spaces_before_url
  , s_req_schema
  , s_req_schema_slash
  , s_req_schema_slash_slash
  , s_req_host_start
  , s_req_host_v6_start
  , s_req_host_v6
  , s_req_host_v6_end
  , s_req_host
  , s_req_port_start
  , s_req_port
  , s_req_path
  , s_req_query_string_start
  , s_req_query_string
  , s_req_fragment_start
  , s_req_fragment
  , s_req_http_start
  , s_req_http_H
  , s_req_http_HT
  , s_req_http_HTT
  , s_req_http_HTTP
  , s_req_first_http_major
  , s_req_http_major
  , s_req_first_http_minor
  , s_req_http_minor
  , s_req_line_almost_done

  , s_header_field_start
  , s_header_field
  , s_header_value_start
  , s_header_value
  , s_header_value_lws

  , s_header_almost_done

  , s_chunk_size_start
  , s_chunk_size
  , s_chunk_parameters
  , s_chunk_size_almost_done

  , s_headers_almost_done
  , s_headers_done

  /* Important: 's_headers_done' must be the last 'header' state. All
   * states beyond this must be 'body' states. It is used for overflow
   * checking. See the PARSING_HEADER() macro.
   */

  , s_chunk_data
  , s_chunk_data_almost_done
  , s_chunk_data_done

  , s_body_identity
  , s_body_identity_eof

  , s_message_done
  };


#define PARSING_HEADER(state) (state <= s_headers_done)


enum header_states
  { h_general = 0
  , h_C
  , h_CO
  , h_CON

  , h_matching_connection
  , h_matching_proxy_connection
  , h_matching_content_length
  , h_matching_transfer_encoding
  , h_matching_upgrade

  , h_connection
  , h_content_length
  , h_transfer_encoding
  , h_upgrade

  , h_matching_transfer_encoding_chunked
  , h_matching_connection_keep_alive
  , h_matching_connection_close

  , h_transfer_encoding_chunked
  , h_connection_keep_alive
  , h_connection_close
  };


/* Macros for character classes; depends on strict-mode  */
#define CR                  '\r'
#define LF                  '\n'
#define LOWER(c)            (unsigned char)(c | 0x20)
#define IS_ALPHA(c)         (LOWER(c) >= 'a' && LOWER(c) <= 'z')
#define IS_NUM(c)           ((c) >= '0' && (c) <= '9')
#define IS_ALPHANUM(c)      (IS_ALPHA(c) || IS_NUM(c))
#define IS_HEX(c)           (IS_NUM(c) || (LOWER(c) >= 'a' && LOWER(c) <= 'f'))

#if HTTP_PARSER_STRICT
#define TOKEN(c)            (tokens[(unsigned char)c])
#define IS_URL_CHAR(c)      (normal_url_char[(unsigned char) (c)])
#define IS_HOST_CHAR(c)     (IS_ALPHANUM(c) || (c) == '.' || (c) == '-')
#else
#define TOKEN(c)            ((c == ' ') ? ' ' : tokens[(unsigned char)c])
#define IS_URL_CHAR(c)                                                         \
  (normal_url_char[(unsigned char) (c)] || ((c) & 0x80))
#define IS_HOST_CHAR(c)                                                        \
  (IS_ALPHANUM(c) || (c) == '.' || (c) == '-' || (c) == '_')
#endif


#define start_state (parser->type == HTTP_REQUEST ? s_start_req : s_start_res)


#if HTTP_PARSER_STRICT
# define STRICT_CHECK(cond)                                          \
do {                                                                 \
  if (cond) {                                                        \
	SET_ERRNO(HPE_STRICT);                                           \
	goto error;                                                      \
  }                                                                  \
} while (0)
# define NEW_MESSAGE() (http_should_keep_alive(parser) ? start_state : s_dead)
#else
# define STRICT_CHECK(cond)
# define NEW_MESSAGE() start_state
#endif


/* Map errno values to strings for human-readable output */
#define HTTP_STRERROR_GEN(n, s) { "HPE_" #n, s },
static struct {
  const char *name;
  const char *description;
} http_strerror_tab[] = {
  HTTP_ERRNO_MAP(HTTP_STRERROR_GEN)
};
#undef HTTP_STRERROR_GEN

/* Our URL parser.
 *
 * This is designed to be shared by http_parser_execute() for URL validation,
 * hence it has a state transition + byte-for-byte interface. In addition, it
 * is meant to be embedded in http_parser_parse_url(), which does the dirty
 * work of turning state transitions URL components for its API.
 *
 * This function should only be invoked with non-space characters. It is
 * assumed that the caller cares about (and can detect) the transition between
 * URL and non-URL states by looking for these.
 */
static enum state
parse_url_char(enum state s, const char ch)
{
  assert(!isspace(ch));

  switch (s) {
	case s_req_spaces_before_url:
	  /* Proxied requests are followed by scheme of an absolute URI (alpha).
	   * All methods except CONNECT are followed by '/' or '*'.
	   */

	  if (ch == '/' || ch == '*') {
		return s_req_path;
	  }

	  if (IS_ALPHA(ch)) {
		return s_req_schema;
	  }

	  break;

	case s_req_schema:
	  if (IS_ALPHA(ch)) {
		return s;
	  }

	  if (ch == ':') {
		return s_req_schema_slash;
	  }

	  break;

	case s_req_schema_slash:
	  if (ch == '/') {
		return s_req_schema_slash_slash;
	  }

	  break;

	case s_req_schema_slash_slash:
	  if (ch == '/') {
		return s_req_host_start;
	  }

	  break;

	case s_req_host_start:
	  if (ch == '[') {
		return s_req_host_v6_start;
	  }

	  if (IS_HOST_CHAR(ch)) {
		return s_req_host;
	  }

	  break;

	case s_req_host:
	  if (IS_HOST_CHAR(ch)) {
		return s_req_host;
	  }

	  /* FALLTHROUGH */
	case s_req_host_v6_end:
	  switch (ch) {
		case ':':
		  return s_req_port_start;

		case '/':
		  return s_req_path;

		case '?':
		  return s_req_query_string_start;
	  }

	  break;

	case s_req_host_v6:
	  if (ch == ']') {
		return s_req_host_v6_end;
	  }

	  /* FALLTHROUGH */
	case s_req_host_v6_start:
	  if (IS_HEX(ch) || ch == ':') {
		return s_req_host_v6;
	  }
	  break;

	case s_req_port:
	  switch (ch) {
		case '/':
		  return s_req_path;

		case '?':
		  return s_req_query_string_start;
	  }

	  /* FALLTHROUGH */
	case s_req_port_start:
	  if (IS_NUM(ch)) {
		return s_req_port;
	  }

	  break;

	case s_req_path:
	  if (IS_URL_CHAR(ch)) {
		return s;
	  }

	  switch (ch) {
		case '?':
		  return s_req_query_string_start;

		case '#':
		  return s_req_fragment_start;
	  }

	  break;

	case s_req_query_string_start:
	case s_req_query_string:
	  if (IS_URL_CHAR(ch)) {
		return s_req_query_string;
	  }

	  switch (ch) {
		case '?':
		  /* allow extra '?' in query string */
		  return s_req_query_string;

		case '#':
		  return s_req_fragment_start;
	  }

	  break;

	case s_req_fragment_start:
	  if (IS_URL_CHAR(ch)) {
		return s_req_fragment;
	  }

	  switch (ch) {
		case '?':
		  return s_req_fragment;

		case '#':
		  return s;
	  }

	  break;

	case s_req_fragment:
	  if (IS_URL_CHAR(ch)) {
		return s;
	  }

	  switch (ch) {
		case '?':
		case '#':
		  return s;
	  }

	  break;

	default:
	  break;
  }

  /* We should never fall out of the switch above unless there's an error */
  return s_dead;
}

size_t http_parser_execute (http_parser *parser,
							const http_parser_settings *settings,
							const char *data,
							size_t len)
{
  char c, ch;
  int8_t unhex_val;
  const char *p = data;
  const char *header_field_mark = 0;
  const char *header_value_mark = 0;
  const char *url_mark = 0;
  const char *body_mark = 0;

  /* We're in an error state. Don't bother doing anything. */
  if (HTTP_PARSER_ERRNO(parser) != HPE_OK) {
	return 0;
  }

  if (len == 0) {
	switch (parser->state) {
	  case s_body_identity_eof:
		/* Use of CALLBACK_NOTIFY() here would erroneously return 1 byte read if
		 * we got paused.
		 */
		CALLBACK_NOTIFY_NOADVANCE(message_complete);
		return 0;

	  case s_dead:
	  case s_start_req_or_res:
	  case s_start_res:
	  case s_start_req:
		return 0;

	  default:
		SET_ERRNO(HPE_INVALID_EOF_STATE);
		return 1;
	}
  }


  if (parser->state == s_header_field)
	header_field_mark = data;
  if (parser->state == s_header_value)
	header_value_mark = data;
  switch (parser->state) {
  case s_req_path:
  case s_req_schema:
  case s_req_schema_slash:
  case s_req_schema_slash_slash:
  case s_req_host_start:
  case s_req_host_v6_start:
  case s_req_host_v6:
  case s_req_host_v6_end:
  case s_req_host:
  case s_req_port_start:
  case s_req_port:
  case s_req_query_string_start:
  case s_req_query_string:
  case s_req_fragment_start:
  case s_req_fragment:
	url_mark = data;
	break;
  }

  for (p=data; p != data + len; p++) {
	ch = *p;

	if (PARSING_HEADER(parser->state)) {
	  ++parser->nread;
	  /* Buffer overflow attack */
	  if (parser->nread > HTTP_MAX_HEADER_SIZE) {
		SET_ERRNO(HPE_HEADER_OVERFLOW);
		goto error;
	  }
	}

	reexecute_byte:
	switch (parser->state) {

	  case s_dead:
		/* this state is used after a 'Connection: close' message
		 * the parser will error out if it reads another message
		 */
		if (ch == CR || ch == LF)
		  break;

		SET_ERRNO(HPE_CLOSED_CONNECTION);
		goto error;

	  case s_start_req_or_res:
	  {
		if (ch == CR || ch == LF)
		  break;
		parser->flags = 0;
		parser->content_length = ULLONG_MAX;

		if (ch == 'H') {
		  parser->state = s_res_or_resp_H;

		  CALLBACK_NOTIFY(message_begin);
		} else {
		  parser->type = HTTP_REQUEST;
		  parser->state = s_start_req;
		  goto reexecute_byte;
		}

		break;
	  }

	  case s_res_or_resp_H:
		if (ch == 'T') {
		  parser->type = HTTP_RESPONSE;
		  parser->state = s_res_HT;
		} else {
		  if (ch != 'E') {
			SET_ERRNO(HPE_INVALID_CONSTANT);
			goto error;
		  }

		  parser->type = HTTP_REQUEST;
		  parser->method = HTTP_HEAD;
		  parser->index = 2;
		  parser->state = s_req_method;
		}
		break;

	  case s_start_res:
	  {
		parser->flags = 0;
		parser->content_length = ULLONG_MAX;

		switch (ch) {
		  case 'H':
			parser->state = s_res_H;
			break;

		  case CR:
		  case LF:
			break;

		  default:
			SET_ERRNO(HPE_INVALID_CONSTANT);
			goto error;
		}

		CALLBACK_NOTIFY(message_begin);
		break;
	  }

	  case s_res_H:
		STRICT_CHECK(ch != 'T');
		parser->state = s_res_HT;
		break;

	  case s_res_HT:
		STRICT_CHECK(ch != 'T');
		parser->state = s_res_HTT;
		break;

	  case s_res_HTT:
		STRICT_CHECK(ch != 'P');
		parser->state = s_res_HTTP;
		break;

	  case s_res_HTTP:
		STRICT_CHECK(ch != '/');
		parser->state = s_res_first_http_major;
		break;

	  case s_res_first_http_major:
		if (ch < '0' || ch > '9') {
		  SET_ERRNO(HPE_INVALID_VERSION);
		  goto error;
		}

		parser->http_major = ch - '0';
		parser->state = s_res_http_major;
		break;

	  /* major HTTP version or dot */
	  case s_res_http_major:
	  {
		if (ch == '.') {
		  parser->state = s_res_first_http_minor;
		  break;
		}

		if (!IS_NUM(ch)) {
		  SET_ERRNO(HPE_INVALID_VERSION);
		  goto error;
		}

		parser->http_major *= 10;
		parser->http_major += ch - '0';

		if (parser->http_major > 999) {
		  SET_ERRNO(HPE_INVALID_VERSION);
		  goto error;
		}

		break;
	  }

	  /* first digit of minor HTTP version */
	  case s_res_first_http_minor:
		if (!IS_NUM(ch)) {
		  SET_ERRNO(HPE_INVALID_VERSION);
		  goto error;
		}

		parser->http_minor = ch - '0';
		parser->state = s_res_http_minor;
		break;

	  /* minor HTTP version or end of request line */
	  case s_res_http_minor:
	  {
		if (ch == ' ') {
		  parser->state = s_res_first_status_code;
		  break;
		}

		if (!IS_NUM(ch)) {
		  SET_ERRNO(HPE_INVALID_VERSION);
		  goto error;
		}

		parser->http_minor *= 10;
		parser->http_minor += ch - '0';

		if (parser->http_minor > 999) {
		  SET_ERRNO(HPE_INVALID_VERSION);
		  goto error;
		}

		break;
	  }

	  case s_res_first_status_code:
	  {
		if (!IS_NUM(ch)) {
		  if (ch == ' ') {
			break;
		  }

		  SET_ERRNO(HPE_INVALID_STATUS);
		  goto error;
		}
		parser->status_code = ch - '0';
		parser->state = s_res_status_code;
		break;
	  }

	  case s_res_status_code:
	  {
		if (!IS_NUM(ch)) {
		  switch (ch) {
			case ' ':
			  parser->state = s_res_status;
			  break;
			case CR:
			  parser->state = s_res_line_almost_done;
			  break;
			case LF:
			  parser->state = s_header_field_start;
			  break;
			default:
			  SET_ERRNO(HPE_INVALID_STATUS);
			  goto error;
		  }
		  break;
		}

		parser->status_code *= 10;
		parser->status_code += ch - '0';

		if (parser->status_code > 999) {
		  SET_ERRNO(HPE_INVALID_STATUS);
		  goto error;
		}

		break;
	  }

	  case s_res_status:
		/* the human readable status. e.g. "NOT FOUND"
		 * we are not humans so just ignore this */
		if (ch == CR) {
		  parser->state = s_res_line_almost_done;
		  break;
		}

		if (ch == LF) {
		  parser->state = s_header_field_start;
		  break;
		}
		break;

	  case s_res_line_almost_done:
		STRICT_CHECK(ch != LF);
		parser->state = s_header_field_start;
		break;

	  case s_start_req:
	  {
		if (ch == CR || ch == LF)
		  break;
		parser->flags = 0;
		parser->content_length = ULLONG_MAX;

		if (!IS_ALPHA(ch)) {
		  SET_ERRNO(HPE_INVALID_METHOD);
		  goto error;
		}

		parser->method = (enum http_method) 0;
		parser->index = 1;
		switch (ch) {
		  case 'C': parser->method = HTTP_CONNECT; /* or COPY, CHECKOUT */ break;
		  case 'D': parser->method = HTTP_DELETE; break;
		  case 'G': parser->method = HTTP_GET; break;
		  case 'H': parser->method = HTTP_HEAD; break;
		  case 'L': parser->method = HTTP_LOCK; break;
		  case 'M': parser->method = HTTP_MKCOL; /* or MOVE, MKACTIVITY, MERGE, M-SEARCH */ break;
		  case 'N': parser->method = HTTP_NOTIFY; break;
		  case 'O': parser->method = HTTP_OPTIONS; break;
		  case 'P': parser->method = HTTP_POST;
			/* or PROPFIND|PROPPATCH|PUT|PATCH|PURGE */
			break;
		  case 'R': parser->method = HTTP_REPORT; break;
		  case 'S': parser->method = HTTP_SUBSCRIBE; /* or SEARCH */ break;
		  case 'T': parser->method = HTTP_TRACE; break;
		  case 'U': parser->method = HTTP_UNLOCK; /* or UNSUBSCRIBE */ break;
		  default:
			SET_ERRNO(HPE_INVALID_METHOD);
			goto error;
		}
		parser->state = s_req_method;

		CALLBACK_NOTIFY(message_begin);

		break;
	  }

	  case s_req_method:
	  {
		const char *matcher;
		if (ch == '\0') {
		  SET_ERRNO(HPE_INVALID_METHOD);
		  goto error;
		}

		matcher = method_strings[parser->method];
		if (ch == ' ' && matcher[parser->index] == '\0') {
		  parser->state = s_req_spaces_before_url;
		} else if (ch == matcher[parser->index]) {
		  ; /* nada */
		} else if (parser->method == HTTP_CONNECT) {
		  if (parser->index == 1 && ch == 'H') {
			parser->method = HTTP_CHECKOUT;
		  } else if (parser->index == 2  && ch == 'P') {
			parser->method = HTTP_COPY;
		  } else {
			goto error;
		  }
		} else if (parser->method == HTTP_MKCOL) {
		  if (parser->index == 1 && ch == 'O') {
			parser->method = HTTP_MOVE;
		  } else if (parser->index == 1 && ch == 'E') {
			parser->method = HTTP_MERGE;
		  } else if (parser->index == 1 && ch == '-') {
			parser->method = HTTP_MSEARCH;
		  } else if (parser->index == 2 && ch == 'A') {
			parser->method = HTTP_MKACTIVITY;
		  } else {
			goto error;
		  }
		} else if (parser->method == HTTP_SUBSCRIBE) {
		  if (parser->index == 1 && ch == 'E') {
			parser->method = HTTP_SEARCH;
		  } else {
			goto error;
		  }
		} else if (parser->index == 1 && parser->method == HTTP_POST) {
		  if (ch == 'R') {
			parser->method = HTTP_PROPFIND; /* or HTTP_PROPPATCH */
		  } else if (ch == 'U') {
			parser->method = HTTP_PUT; /* or HTTP_PURGE */
		  } else if (ch == 'A') {
			parser->method = HTTP_PATCH;
		  } else {
			goto error;
		  }
		} else if (parser->index == 2) {
		  if (parser->method == HTTP_PUT) {
			if (ch == 'R') parser->method = HTTP_PURGE;
		  } else if (parser->method == HTTP_UNLOCK) {
			if (ch == 'S') parser->method = HTTP_UNSUBSCRIBE;
		  }
		} else if (parser->index == 4 && parser->method == HTTP_PROPFIND && ch == 'P') {
		  parser->method = HTTP_PROPPATCH;
		} else {
		  SET_ERRNO(HPE_INVALID_METHOD);
		  goto error;
		}

		++parser->index;
		break;
	  }

	  case s_req_spaces_before_url:
	  {
		if (ch == ' ') break;

		MARK(url);
		if (parser->method == HTTP_CONNECT) {
		  parser->state = s_req_host_start;
		}

		parser->state = parse_url_char((enum state)parser->state, ch);
		if (parser->state == s_dead) {
		  SET_ERRNO(HPE_INVALID_URL);
		  goto error;
		}

		break;
	  }

	  case s_req_schema:
	  case s_req_schema_slash:
	  case s_req_schema_slash_slash:
	  case s_req_host_start:
	  case s_req_host_v6_start:
	  case s_req_host_v6:
	  case s_req_port_start:
	  {
		switch (ch) {
		  /* No whitespace allowed here */
		  case ' ':
		  case CR:
		  case LF:
			SET_ERRNO(HPE_INVALID_URL);
			goto error;
		  default:
			parser->state = parse_url_char((enum state)parser->state, ch);
			if (parser->state == s_dead) {
			  SET_ERRNO(HPE_INVALID_URL);
			  goto error;
			}
		}

		break;
	  }

	  case s_req_host:
	  case s_req_host_v6_end:
	  case s_req_port:
	  case s_req_path:
	  case s_req_query_string_start:
	  case s_req_query_string:
	  case s_req_fragment_start:
	  case s_req_fragment:
	  {
		switch (ch) {
		  case ' ':
			parser->state = s_req_http_start;
			CALLBACK_DATA(url);
			break;
		  case CR:
		  case LF:
			parser->http_major = 0;
			parser->http_minor = 9;
			parser->state = (ch == CR) ?
			  s_req_line_almost_done :
			  s_header_field_start;
			CALLBACK_DATA(url);
			break;
		  default:
			parser->state = parse_url_char((enum state)parser->state, ch);
			if (parser->state == s_dead) {
			  SET_ERRNO(HPE_INVALID_URL);
			  goto error;
			}
		}
		break;
	  }

	  case s_req_http_start:
		switch (ch) {
		  case 'H':
			parser->state = s_req_http_H;
			break;
		  case ' ':
			break;
		  default:
			SET_ERRNO(HPE_INVALID_CONSTANT);
			goto error;
		}
		break;

	  case s_req_http_H:
		STRICT_CHECK(ch != 'T');
		parser->state = s_req_http_HT;
		break;

	  case s_req_http_HT:
		STRICT_CHECK(ch != 'T');
		parser->state = s_req_http_HTT;
		break;

	  case s_req_http_HTT:
		STRICT_CHECK(ch != 'P');
		parser->state = s_req_http_HTTP;
		break;

	  case s_req_http_HTTP:
		STRICT_CHECK(ch != '/');
		parser->state = s_req_first_http_major;
		break;

	  /* first digit of major HTTP version */
	  case s_req_first_http_major:
		if (ch < '1' || ch > '9') {
		  SET_ERRNO(HPE_INVALID_VERSION);
		  goto error;
		}

		parser->http_major = ch - '0';
		parser->state = s_req_http_major;
		break;

	  /* major HTTP version or dot */
	  case s_req_http_major:
	  {
		if (ch == '.') {
		  parser->state = s_req_first_http_minor;
		  break;
		}

		if (!IS_NUM(ch)) {
		  SET_ERRNO(HPE_INVALID_VERSION);
		  goto error;
		}

		parser->http_major *= 10;
		parser->http_major += ch - '0';

		if (parser->http_major > 999) {
		  SET_ERRNO(HPE_INVALID_VERSION);
		  goto error;
		}

		break;
	  }

	  /* first digit of minor HTTP version */
	  case s_req_first_http_minor:
		if (!IS_NUM(ch)) {
		  SET_ERRNO(HPE_INVALID_VERSION);
		  goto error;
		}

		parser->http_minor = ch - '0';
		parser->state = s_req_http_minor;
		break;

	  /* minor HTTP version or end of request line */
	  case s_req_http_minor:
	  {
		if (ch == CR) {
		  parser->state = s_req_line_almost_done;
		  break;
		}

		if (ch == LF) {
		  parser->state = s_header_field_start;
		  break;
		}

		/* XXX allow spaces after digit? */

		if (!IS_NUM(ch)) {
		  SET_ERRNO(HPE_INVALID_VERSION);
		  goto error;
		}

		parser->http_minor *= 10;
		parser->http_minor += ch - '0';

		if (parser->http_minor > 999) {
		  SET_ERRNO(HPE_INVALID_VERSION);
		  goto error;
		}

		break;
	  }

	  /* end of request line */
	  case s_req_line_almost_done:
	  {
		if (ch != LF) {
		  SET_ERRNO(HPE_LF_EXPECTED);
		  goto error;
		}

		parser->state = s_header_field_start;
		break;
	  }

	  case s_header_field_start:
	  {
		if (ch == CR) {
		  parser->state = s_headers_almost_done;
		  break;
		}

		if (ch == LF) {
		  /* they might be just sending \n instead of \r\n so this would be
		   * the second \n to denote the end of headers*/
		  parser->state = s_headers_almost_done;
		  goto reexecute_byte;
		}

		c = TOKEN(ch);

		if (!c) {
		  SET_ERRNO(HPE_INVALID_HEADER_TOKEN);
		  goto error;
		}

		MARK(header_field);

		parser->index = 0;
		parser->state = s_header_field;

		switch (c) {
		  case 'c':
			parser->header_state = h_C;
			break;

		  case 'p':
			parser->header_state = h_matching_proxy_connection;
			break;

		  case 't':
			parser->header_state = h_matching_transfer_encoding;
			break;

		  case 'u':
			parser->header_state = h_matching_upgrade;
			break;

		  default:
			parser->header_state = h_general;
			break;
		}
		break;
	  }

	  case s_header_field:
	  {
		c = TOKEN(ch);

		if (c) {
		  switch (parser->header_state) {
			case h_general:
			  break;

			case h_C:
			  parser->index++;
			  parser->header_state = (c == 'o' ? h_CO : h_general);
			  break;

			case h_CO:
			  parser->index++;
			  parser->header_state = (c == 'n' ? h_CON : h_general);
			  break;

			case h_CON:
			  parser->index++;
			  switch (c) {
				case 'n':
				  parser->header_state = h_matching_connection;
				  break;
				case 't':
				  parser->header_state = h_matching_content_length;
				  break;
				default:
				  parser->header_state = h_general;
				  break;
			  }
			  break;

			/* connection */

			case h_matching_connection:
			  parser->index++;
			  if (parser->index > sizeof(CONNECTION)-1
				  || c != CONNECTION[parser->index]) {
				parser->header_state = h_general;
			  } else if (parser->index == sizeof(CONNECTION)-2) {
				parser->header_state = h_connection;
			  }
			  break;

			/* proxy-connection */

			case h_matching_proxy_connection:
			  parser->index++;
			  if (parser->index > sizeof(PROXY_CONNECTION)-1
				  || c != PROXY_CONNECTION[parser->index]) {
				parser->header_state = h_general;
			  } else if (parser->index == sizeof(PROXY_CONNECTION)-2) {
				parser->header_state = h_connection;
			  }
			  break;

			/* content-length */

			case h_matching_content_length:
			  parser->index++;
			  if (parser->index > sizeof(CONTENT_LENGTH)-1
				  || c != CONTENT_LENGTH[parser->index]) {
				parser->header_state = h_general;
			  } else if (parser->index == sizeof(CONTENT_LENGTH)-2) {
				parser->header_state = h_content_length;
			  }
			  break;

			/* transfer-encoding */

			case h_matching_transfer_encoding:
			  parser->index++;
			  if (parser->index > sizeof(TRANSFER_ENCODING)-1
				  || c != TRANSFER_ENCODING[parser->index]) {
				parser->header_state = h_general;
			  } else if (parser->index == sizeof(TRANSFER_ENCODING)-2) {
				parser->header_state = h_transfer_encoding;
			  }
			  break;

			/* upgrade */

			case h_matching_upgrade:
			  parser->index++;
			  if (parser->index > sizeof(UPGRADE)-1
				  || c != UPGRADE[parser->index]) {
				parser->header_state = h_general;
			  } else if (parser->index == sizeof(UPGRADE)-2) {
				parser->header_state = h_upgrade;
			  }
			  break;

			case h_connection:
			case h_content_length:
			case h_transfer_encoding:
			case h_upgrade:
			  if (ch != ' ') parser->header_state = h_general;
			  break;

			default:
			  assert(0 && "Unknown header_state");
			  break;
		  }
		  break;
		}

		if (ch == ':') {
		  parser->state = s_header_value_start;
		  CALLBACK_DATA(header_field);
		  break;
		}

		if (ch == CR) {
		  parser->state = s_header_almost_done;
		  CALLBACK_DATA(header_field);
		  break;
		}

		if (ch == LF) {
		  parser->state = s_header_field_start;
		  CALLBACK_DATA(header_field);
		  break;
		}

		SET_ERRNO(HPE_INVALID_HEADER_TOKEN);
		goto error;
	  }

	  case s_header_value_start:
	  {
		if (ch == ' ' || ch == '\t') break;

		MARK(header_value);

		parser->state = s_header_value;
		parser->index = 0;

		if (ch == CR) {
		  parser->header_state = h_general;
		  parser->state = s_header_almost_done;
		  CALLBACK_DATA(header_value);
		  break;
		}

		if (ch == LF) {
		  parser->state = s_header_field_start;
		  CALLBACK_DATA(header_value);
		  break;
		}

		c = LOWER(ch);

		switch (parser->header_state) {
		  case h_upgrade:
			parser->flags |= F_UPGRADE;
			parser->header_state = h_general;
			break;

		  case h_transfer_encoding:
			/* looking for 'Transfer-Encoding: chunked' */
			if ('c' == c) {
			  parser->header_state = h_matching_transfer_encoding_chunked;
			} else {
			  parser->header_state = h_general;
			}
			break;

		  case h_content_length:
			if (!IS_NUM(ch)) {
			  SET_ERRNO(HPE_INVALID_CONTENT_LENGTH);
			  goto error;
			}

			parser->content_length = ch - '0';
			break;

		  case h_connection:
			/* looking for 'Connection: keep-alive' */
			if (c == 'k') {
			  parser->header_state = h_matching_connection_keep_alive;
			/* looking for 'Connection: close' */
			} else if (c == 'c') {
			  parser->header_state = h_matching_connection_close;
			} else {
			  parser->header_state = h_general;
			}
			break;

		  default:
			parser->header_state = h_general;
			break;
		}
		break;
	  }

	  case s_header_value:
	  {

		if (ch == CR) {
		  parser->state = s_header_almost_done;
		  CALLBACK_DATA(header_value);
		  break;
		}

		if (ch == LF) {
		  parser->state = s_header_almost_done;
		  CALLBACK_DATA_NOADVANCE(header_value);
		  goto reexecute_byte;
		}

		c = LOWER(ch);

		switch (parser->header_state) {
		  case h_general:
			break;

		  case h_connection:
		  case h_transfer_encoding:
			assert(0 && "Shouldn't get here.");
			break;

		  case h_content_length:
		  {
			uint64_t t;

			if (ch == ' ') break;

			if (!IS_NUM(ch)) {
			  SET_ERRNO(HPE_INVALID_CONTENT_LENGTH);
			  goto error;
			}

			t = parser->content_length;
			t *= 10;
			t += ch - '0';

			/* Overflow? */
			if (t < parser->content_length || t == ULLONG_MAX) {
			  SET_ERRNO(HPE_INVALID_CONTENT_LENGTH);
			  goto error;
			}

			parser->content_length = t;
			break;
		  }

		  /* Transfer-Encoding: chunked */
		  case h_matching_transfer_encoding_chunked:
			parser->index++;
			if (parser->index > sizeof(CHUNKED)-1
				|| c != CHUNKED[parser->index]) {
			  parser->header_state = h_general;
			} else if (parser->index == sizeof(CHUNKED)-2) {
			  parser->header_state = h_transfer_encoding_chunked;
			}
			break;

		  /* looking for 'Connection: keep-alive' */
		  case h_matching_connection_keep_alive:
			parser->index++;
			if (parser->index > sizeof(KEEP_ALIVE)-1
				|| c != KEEP_ALIVE[parser->index]) {
			  parser->header_state = h_general;
			} else if (parser->index == sizeof(KEEP_ALIVE)-2) {
			  parser->header_state = h_connection_keep_alive;
			}
			break;

		  /* looking for 'Connection: close' */
		  case h_matching_connection_close:
			parser->index++;
			if (parser->index > sizeof(CLOSE)-1 || c != CLOSE[parser->index]) {
			  parser->header_state = h_general;
			} else if (parser->index == sizeof(CLOSE)-2) {
			  parser->header_state = h_connection_close;
			}
			break;

		  case h_transfer_encoding_chunked:
		  case h_connection_keep_alive:
		  case h_connection_close:
			if (ch != ' ') parser->header_state = h_general;
			break;

		  default:
			parser->state = s_header_value;
			parser->header_state = h_general;
			break;
		}
		break;
	  }

	  case s_header_almost_done:
	  {
		STRICT_CHECK(ch != LF);

		parser->state = s_header_value_lws;

		switch (parser->header_state) {
		  case h_connection_keep_alive:
			parser->flags |= F_CONNECTION_KEEP_ALIVE;
			break;
		  case h_connection_close:
			parser->flags |= F_CONNECTION_CLOSE;
			break;
		  case h_transfer_encoding_chunked:
			parser->flags |= F_CHUNKED;
			break;
		  default:
			break;
		}

		break;
	  }

	  case s_header_value_lws:
	  {
		if (ch == ' ' || ch == '\t')
		  parser->state = s_header_value_start;
		else
		{
		  parser->state = s_header_field_start;
		  goto reexecute_byte;
		}
		break;
	  }

	  case s_headers_almost_done:
	  {
		STRICT_CHECK(ch != LF);

		if (parser->flags & F_TRAILING) {
		  /* End of a chunked request */
		  parser->state = NEW_MESSAGE();
		  CALLBACK_NOTIFY(message_complete);
		  break;
		}

		parser->state = s_headers_done;

		/* Set this here so that on_headers_complete() callbacks can see it */
		parser->upgrade =
		  (parser->flags & F_UPGRADE || parser->method == HTTP_CONNECT);

		/* Here we call the headers_complete callback. This is somewhat
		 * different than other callbacks because if the user returns 1, we
		 * will interpret that as saying that this message has no body. This
		 * is needed for the annoying case of recieving a response to a HEAD
		 * request.
		 *
		 * We'd like to use CALLBACK_NOTIFY_NOADVANCE() here but we cannot, so
		 * we have to simulate it by handling a change in errno below.
		 */
		if (settings->on_headers_complete) {
		  switch (settings->on_headers_complete(parser)) {
			case 0:
			  break;

			case 1:
			  parser->flags |= F_SKIPBODY;
			  break;

			default:
			  SET_ERRNO(HPE_CB_headers_complete);
			  return p - data; /* Error */
		  }
		}

		if (HTTP_PARSER_ERRNO(parser) != HPE_OK) {
		  return p - data;
		}

		goto reexecute_byte;
	  }

	  case s_headers_done:
	  {
		STRICT_CHECK(ch != LF);

		parser->nread = 0;

		/* Exit, the rest of the connect is in a different protocol. */
		if (parser->upgrade) {
		  parser->state = NEW_MESSAGE();
		  CALLBACK_NOTIFY(message_complete);
		  return (p - data) + 1;
		}

		if (parser->flags & F_SKIPBODY) {
		  parser->state = NEW_MESSAGE();
		  CALLBACK_NOTIFY(message_complete);
		} else if (parser->flags & F_CHUNKED) {
		  /* chunked encoding - ignore Content-Length header */
		  parser->state = s_chunk_size_start;
		} else {
		  if (parser->content_length == 0) {
			/* Content-Length header given but zero: Content-Length: 0\r\n */
			parser->state = NEW_MESSAGE();
			CALLBACK_NOTIFY(message_complete);
		  } else if (parser->content_length != ULLONG_MAX) {
			/* Content-Length header given and non-zero */
			parser->state = s_body_identity;
		  } else {
			if (parser->type == HTTP_REQUEST ||
				!http_message_needs_eof(parser)) {
			  /* Assume content-length 0 - read the next */
			  parser->state = NEW_MESSAGE();
			  CALLBACK_NOTIFY(message_complete);
			} else {
			  /* Read body until EOF */
			  parser->state = s_body_identity_eof;
			}
		  }
		}

		break;
	  }

	  case s_body_identity:
	  {
		uint64_t to_read = MIN(parser->content_length,
							   (uint64_t) ((data + len) - p));

		assert(parser->content_length != 0
			&& parser->content_length != ULLONG_MAX);

		/* The difference between advancing content_length and p is because
		 * the latter will automaticaly advance on the next loop iteration.
		 * Further, if content_length ends up at 0, we want to see the last
		 * byte again for our message complete callback.
		 */
		MARK(body);
		parser->content_length -= to_read;
		p += to_read - 1;

		if (parser->content_length == 0) {
		  parser->state = s_message_done;

		  /* Mimic CALLBACK_DATA_NOADVANCE() but with one extra byte.
		   *
		   * The alternative to doing this is to wait for the next byte to
		   * trigger the data callback, just as in every other case. The
		   * problem with this is that this makes it difficult for the test
		   * harness to distinguish between complete-on-EOF and
		   * complete-on-length. It's not clear that this distinction is
		   * important for applications, but let's keep it for now.
		   */
		  CALLBACK_DATA_(body, p - body_mark + 1, p - data);
		  goto reexecute_byte;
		}

		break;
	  }

	  /* read until EOF */
	  case s_body_identity_eof:
		MARK(body);
		p = data + len - 1;

		break;

	  case s_message_done:
		parser->state = NEW_MESSAGE();
		CALLBACK_NOTIFY(message_complete);
		break;

	  case s_chunk_size_start:
	  {
		assert(parser->nread == 1);
		assert(parser->flags & F_CHUNKED);

		unhex_val = unhex[(unsigned char)ch];
		if (unhex_val == -1) {
		  SET_ERRNO(HPE_INVALID_CHUNK_SIZE);
		  goto error;
		}

		parser->content_length = unhex_val;
		parser->state = s_chunk_size;
		break;
	  }

	  case s_chunk_size:
	  {
		uint64_t t;

		assert(parser->flags & F_CHUNKED);

		if (ch == CR) {
		  parser->state = s_chunk_size_almost_done;
		  break;
		}

		unhex_val = unhex[(unsigned char)ch];

		if (unhex_val == -1) {
		  if (ch == ';' || ch == ' ') {
			parser->state = s_chunk_parameters;
			break;
		  }

		  SET_ERRNO(HPE_INVALID_CHUNK_SIZE);
		  goto error;
		}

		t = parser->content_length;
		t *= 16;
		t += unhex_val;

		/* Overflow? */
		if (t < parser->content_length || t == ULLONG_MAX) {
		  SET_ERRNO(HPE_INVALID_CONTENT_LENGTH);
		  goto error;
		}

		parser->content_length = t;
		break;
	  }

	  case s_chunk_parameters:
	  {
		assert(parser->flags & F_CHUNKED);
		/* just ignore this shit. TODO check for overflow */
		if (ch == CR) {
		  parser->state = s_chunk_size_almost_done;
		  break;
		}
		break;
	  }

	  case s_chunk_size_almost_done:
	  {
		assert(parser->flags & F_CHUNKED);
		STRICT_CHECK(ch != LF);

		parser->nread = 0;

		if (parser->content_length == 0) {
		  parser->flags |= F_TRAILING;
		  parser->state = s_header_field_start;
		} else {
		  parser->state = s_chunk_data;
		}
		break;
	  }

	  case s_chunk_data:
	  {
		uint64_t to_read = MIN(parser->content_length,
							   (uint64_t) ((data + len) - p));

		assert(parser->flags & F_CHUNKED);
		assert(parser->content_length != 0
			&& parser->content_length != ULLONG_MAX);

		/* See the explanation in s_body_identity for why the content
		 * length and data pointers are managed this way.
		 */
		MARK(body);
		parser->content_length -= to_read;
		p += to_read - 1;

		if (parser->content_length == 0) {
		  parser->state = s_chunk_data_almost_done;
		}

		break;
	  }

	  case s_chunk_data_almost_done:
		assert(parser->flags & F_CHUNKED);
		assert(parser->content_length == 0);
		STRICT_CHECK(ch != CR);
		parser->state = s_chunk_data_done;
		CALLBACK_DATA(body);
		break;

	  case s_chunk_data_done:
		assert(parser->flags & F_CHUNKED);
		STRICT_CHECK(ch != LF);
		parser->nread = 0;
		parser->state = s_chunk_size_start;
		break;

	  default:
		assert(0 && "unhandled state");
		SET_ERRNO(HPE_INVALID_INTERNAL_STATE);
		goto error;
	}
  }

  /* Run callbacks for any marks that we have leftover after we ran our of
   * bytes. There should be at most one of these set, so it's OK to invoke
   * them in series (unset marks will not result in callbacks).
   *
   * We use the NOADVANCE() variety of callbacks here because 'p' has already
   * overflowed 'data' and this allows us to correct for the off-by-one that
   * we'd otherwise have (since CALLBACK_DATA() is meant to be run with a 'p'
   * value that's in-bounds).
   */

  assert(((header_field_mark ? 1 : 0) +
		  (header_value_mark ? 1 : 0) +
		  (url_mark ? 1 : 0)  +
		  (body_mark ? 1 : 0)) <= 1);

  CALLBACK_DATA_NOADVANCE(header_field);
  CALLBACK_DATA_NOADVANCE(header_value);
  CALLBACK_DATA_NOADVANCE(url);
  CALLBACK_DATA_NOADVANCE(body);

  return len;

error:
  if (HTTP_PARSER_ERRNO(parser) == HPE_OK) {
	SET_ERRNO(HPE_UNKNOWN);
  }

  return (p - data);
}


/* Does the parser need to see an EOF to find the end of the message? */
int
http_message_needs_eof (http_parser *parser)
{
  if (parser->type == HTTP_REQUEST) {
	return 0;
  }

  /* See RFC 2616 section 4.4 */
  if (parser->status_code / 100 == 1 || /* 1xx e.g. Continue */
	  parser->status_code == 204 ||     /* No Content */
	  parser->status_code == 304 ||     /* Not Modified */
	  parser->flags & F_SKIPBODY) {     /* response to a HEAD request */
	return 0;
  }

  if ((parser->flags & F_CHUNKED) || parser->content_length != ULLONG_MAX) {
	return 0;
  }

  return 1;
}


int
http_should_keep_alive (http_parser *parser)
{
  if (parser->http_major > 0 && parser->http_minor > 0) {
	/* HTTP/1.1 */
	if (parser->flags & F_CONNECTION_CLOSE) {
	  return 0;
	}
  } else {
	/* HTTP/1.0 or earlier */
	if (!(parser->flags & F_CONNECTION_KEEP_ALIVE)) {
	  return 0;
	}
  }

  return !http_message_needs_eof(parser);
}


const char * http_method_str (enum http_method m)
{
  return method_strings[m];
}


void
http_parser_init (http_parser *parser, enum http_parser_type t)
{
  void *data = parser->data; /* preserve application data */
  memset(parser, 0, sizeof(*parser));
  parser->data = data;
  parser->type = t;
  parser->state = (t == HTTP_REQUEST ? s_start_req : (t == HTTP_RESPONSE ? s_start_res : s_start_req_or_res));
  parser->http_errno = HPE_OK;
}

const char *
http_errno_name(enum http_errno err) {
  assert(err < (sizeof(http_strerror_tab)/sizeof(http_strerror_tab[0])));
  return http_strerror_tab[err].name;
}

const char *
http_errno_description(enum http_errno err) {
  assert(err < (sizeof(http_strerror_tab)/sizeof(http_strerror_tab[0])));
  return http_strerror_tab[err].description;
}

int
http_parser_parse_url(const char *buf, size_t buflen, int is_connect,
					  struct http_parser_url *u)
{
  enum state s;
  const char *p;
  enum http_parser_url_fields uf, old_uf;

  u->port = u->field_set = 0;
  s = is_connect ? s_req_host_start : s_req_spaces_before_url;
  uf = old_uf = UF_MAX;

  for (p = buf; p < buf + buflen; p++) {
	s = parse_url_char(s, *p);

	/* Figure out the next field that we're operating on */
	switch (s) {
	  case s_dead:
		return 1;

	  /* Skip delimeters */
	  case s_req_schema_slash:
	  case s_req_schema_slash_slash:
	  case s_req_host_start:
	  case s_req_host_v6_start:
	  case s_req_host_v6_end:
	  case s_req_port_start:
	  case s_req_query_string_start:
	  case s_req_fragment_start:
		continue;

	  case s_req_schema:
		uf = UF_SCHEMA;
		break;

	  case s_req_host:
	  case s_req_host_v6:
		uf = UF_HOST;
		break;

	  case s_req_port:
		uf = UF_PORT;
		break;

	  case s_req_path:
		uf = UF_PATH;
		break;

	  case s_req_query_string:
		uf = UF_QUERY;
		break;

	  case s_req_fragment:
		uf = UF_FRAGMENT;
		break;

	  default:
		assert(!"Unexpected state");
		return 1;
	}

	/* Nothing's changed; soldier on */
	if (uf == old_uf) {
	  u->field_data[uf].len++;
	  continue;
	}

	u->field_data[uf].off = p - buf;
	u->field_data[uf].len = 1;

	u->field_set |= (1 << uf);
	old_uf = uf;
  }

  /* CONNECT requests can only contain "hostname:port" */
  if (is_connect && u->field_set != ((1 << UF_HOST)|(1 << UF_PORT))) {
	return 1;
  }

  /* Make sure we don't end somewhere unexpected */
  switch (s) {
  case s_req_host_v6_start:
  case s_req_host_v6:
  case s_req_host_v6_end:
  case s_req_host:
  case s_req_port_start:
	return 1;
  default:
	break;
  }

  if (u->field_set & (1 << UF_PORT)) {
	/* Don't bother with endp; we've already validated the string */
	unsigned long v = strtoul(buf + u->field_data[UF_PORT].off, NULL, 10);

	/* Ports have a max value of 2^16 */
	if (v > 0xffff) {
	  return 1;
	}

	u->port = (uint16_t) v;
  }

  return 0;
}

void
http_parser_pause(http_parser *parser, int paused) {
  /* Users should only be pausing/unpausing a parser that is not in an error
   * state. In non-debug builds, there's not much that we can do about this
   * other than ignore it.
   */
  if (HTTP_PARSER_ERRNO(parser) == HPE_OK ||
	  HTTP_PARSER_ERRNO(parser) == HPE_PAUSED) {
	SET_ERRNO((paused) ? HPE_PAUSED : HPE_OK);
  } else {
	assert(0 && "Attempting to pause parser in error state");
  }
}
