HTTP and HTTPS library for Mbed OS 5

Dependents:   MQTTGateway2 MQTTGatewayK64 http-example-wnc GuardRoom ... more

For the example program, see: sandbox/http-example.

This library is used to make HTTP and HTTPS calls from Mbed OS 5 applications.

HTTP Request API

NetworkInterface* network = /* obtain a NetworkInterface object */

const char body[] = "{\"hello\":\"world\"}";

HttpRequest* request = new HttpRequest(network, HTTP_POST, "http://httpbin.org/post");
request->set_header("Content-Type", "application/json");
HttpResponse* response = request->send(body, strlen(body));
// if response is NULL, check response->get_error()

printf("status is %d - %s\n", response->get_status_code(), response->get_status_message());
printf("body is:\n%s\n", response->get_body_as_string().c_str());

delete request; // also clears out the response

HTTPS Request API

// pass in the root certificates that you trust, there is no central CA registry in Mbed OS
const char SSL_CA_PEM[] = "-----BEGIN CERTIFICATE-----\n"
    /* rest of the CA root certificates */;

NetworkInterface* network = /* obtain a NetworkInterface object */

const char body[] = "{\"hello\":\"world\"}";

HttpsRequest* request = new HttpsRequest(network, SSL_CA_PEM, HTTP_GET "https://httpbin.org/status/418");
HttpResponse* response = request->send();
// if response is NULL, check response->get_error()

printf("status is %d - %s\n", response->get_status_code(), response->get_status_message());
printf("body is:\n%s\n", response->get_body().c_str());

delete request;

Note: You can get the root CA for a domain easily from Firefox. Click on the green padlock, click More information > Security > View certificate > Details. Select the top entry in the 'Certificate Hierarchy' and click Export.... This gives you a PEM file. Add the content of the PEM file to your root CA list (here's an image).

Mbed TLS Entropy configuration

If your target does not have a built-in TRNG, or other entropy sources, add the following macros to your mbed_app.json file to disable entropy:

{
    "macros": [
        "MBEDTLS_TEST_NULL_ENTROPY",
        "MBEDTLS_NO_DEFAULT_ENTROPY_SOURCES"
    ]
}

Note that this is not secure, and you should not deploy this device into production with this configuration.

Memory usage

Small requests where the body of the response is cached by the library (like the one found in main-http.cpp), require 4K of RAM. When the request is finished they require 1.5K of RAM, depending on the size of the response. This applies both to HTTP and HTTPS. If you need to handle requests that return a large response body, see 'Dealing with large body'.

HTTPS requires additional memory: on FRDM-K64F about 50K of heap space (at its peak). This means that you cannot use HTTPS on devices with less than 128K of memory, asyou also need to reserve memory for the stack and network interface.

Dealing with large response body

By default the library will store the full request body on the heap. This works well for small responses, but you'll run out of memory when receiving a large response body. To mitigate this you can pass in a callback as the last argument to the request constructor. This callback will be called whenever a chunk of the body is received. You can set the request chunk size in the HTTP_RECEIVE_BUFFER_SIZE macro (see mbed_lib.json for the definition) although it also depends on the buffer size ofthe underlying network connection.

void body_callback(const char* data, uint32_t data_len) {
    // do something with the data
}

HttpRequest* req = new HttpRequest(network, HTTP_GET, "http://pathtolargefile.com", &body_callback);
req->send(NULL, 0);

Dealing with a large request body

If you cannot load the full request into memory, you can pass a callback into the send function. Through this callback you can feed in chunks of the request body. This is very useful if you want to send files from a file system.

const void * get_chunk(uint32_t* out_size) {
    // set the value of out_size (via *out_size = 10) to the size of the buffer
    // return the buffer

    // if you don't have any more data, set *out_size to 0
}

HttpRequest* req = new HttpRequest(network, HTTP_POST, "http://my_api.com/upload");
req->send(callback(&get_chunk));

Socket re-use

By default the library opens a new socket per request. This is wasteful, especially when dealing with TLS requests. You can re-use sockets like this:

HTTP

TCPSocket* socket = new TCPSocket();

nsapi_error_t open_result = socket->open(network);
// check open_result

nsapi_error_t connect_result = socket->connect("httpbin.org", 80);
// check connect_result

// Pass in `socket`, instead of `network` as first argument
HttpRequest* req = new HttpRequest(socket, HTTP_GET, "http://httpbin.org/status/418");

HTTPS

TLSSocket* socket = new TLSSocket();

nsapi_error_t r;
// make sure to check the return values for the calls below (should return NSAPI_ERROR_OK)
r = socket->open(network);
r = socket->set_root_ca_cert(SSL_CA_PEM);
r = socket->connect("httpbin.org", 443);

// Pass in `socket`, instead of `network` as first argument, and omit the `SSL_CA_PEM` argument
HttpsRequest* get_req = new HttpsRequest(socket, HTTP_GET, "https://httpbin.org/status/418");

Request logging

To make debugging easier you can log the raw request body that goes over the line. This also works with chunked encoding.

uint8_t *request_buffer = (uint8_t*)calloc(2048, 1);
req->set_request_log_buffer(request_buffer, 2048);

// after the request is done:
printf("\n----- Request buffer -----\n");
for (size_t ix = 0; ix < req->get_request_log_buffer_length(); ix++) {
    printf("%02x ", request_buffer[ix]);
}
printf("\n");

Integration tests

Integration tests are located in the TESTS folder and are ran through Greentea. Instructions on how to run the tests are in http-example.

Mbed OS 5.10 or lower

If you want to use this library on Mbed OS 5.10 or lower, you need to add the TLSSocket library to your project. This library is included in Mbed OS 5.11 and up.

Tested on

  • K64F with Ethernet.
  • NUCLEO_F411RE with ESP8266.
  • ODIN-W2 with WiFi.
  • K64F with Atmel 6LoWPAN shield.
  • DISCO-L475VG-IOT01A with WiFi.
  • Mbed Simulator.

http_parser/http_parser.c

Committer:
Jan Jongboom
Date:
23 months ago
Revision:
39:a8d157986ad8
Parent:
29:383e9bfbfbed

File content as of revision 39:a8d157986ad8:

/* 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

#ifndef ARRAY_SIZE
# define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
#endif

#ifndef BIT_AT
# define BIT_AT(a, i)                                                \
  (!!((unsigned int) (a)[(unsigned int) (i) >> 3] &                  \
   (1 << ((unsigned int) (i) & 7))))
#endif

#ifndef ELEM_AT
# define ELEM_AT(a, i, v) ((unsigned int) (i) < ARRAY_SIZE(a) ? (a)[(i)] : (v))
#endif

#define SET_ERRNO(e)                                                 \
do {                                                                 \
  parser->http_errno = (e);                                          \
} while(0)

#define CURRENT_STATE() p_state
#define UPDATE_STATE(V) p_state = (enum state) (V);
#define RETURN(V)                                                    \
do {                                                                 \
  parser->state = CURRENT_STATE();                                   \
  return (V);                                                        \
} while (0);
#define REEXECUTE()                                                  \
  goto reexecute;                                                    \


#ifdef __GNUC__
# define LIKELY(X) __builtin_expect(!!(X), 1)
# define UNLIKELY(X) __builtin_expect(!!(X), 0)
#else
# define LIKELY(X) (X)
# define UNLIKELY(X) (X)
#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 (LIKELY(settings->on_##FOR)) {                                  \
    parser->state = CURRENT_STATE();                                 \
    if (UNLIKELY(0 != settings->on_##FOR(parser))) {                 \
      SET_ERRNO(HPE_CB_##FOR);                                       \
    }                                                                \
    UPDATE_STATE(parser->state);                                     \
                                                                     \
    /* We either errored above or got paused; get out */             \
    if (UNLIKELY(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 (LIKELY(settings->on_##FOR)) {                                \
      parser->state = CURRENT_STATE();                               \
      if (UNLIKELY(0 !=                                              \
                   settings->on_##FOR(parser, FOR##_mark, (LEN)))) { \
        SET_ERRNO(HPE_CB_##FOR);                                     \
      }                                                              \
      UPDATE_STATE(parser->state);                                   \
                                                                     \
      /* We either errored above or got paused; get out */           \
      if (UNLIKELY(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)

/* Don't allow the total size of the HTTP headers (including the status
 * line) to exceed HTTP_MAX_HEADER_SIZE.  This check is here to protect
 * embedders against denial-of-service attacks where the attacker feeds
 * us a never-ending header that the embedder keeps buffering.
 *
 * This check is arguably the responsibility of embedders but we're doing
 * it on the embedder's behalf because most won't bother and this way we
 * make the web a little safer.  HTTP_MAX_HEADER_SIZE is still far bigger
 * than any reasonable request or response so this should never affect
 * day-to-day operation.
 */
#define COUNT_HEADER_SIZE(V)                                         \
do {                                                                 \
  parser->nread += (V);                                              \
  if (UNLIKELY(parser->nread > (HTTP_MAX_HEADER_SIZE))) {            \
    SET_ERRNO(HPE_HEADER_OVERFLOW);                                  \
    goto error;                                                      \
  }                                                                  \
} 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
  };


#if HTTP_PARSER_STRICT
# define T(v) 0
#else
# define T(v) v
#endif


static const uint8_t normal_url_char[32] = {
/*   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    | T(2)   |   0    |   0    | T(16)  |   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    |   2    |   4    |   0    |   16   |   32   |   64   |  128,
/*  40  (    41  )    42  *    43  +    44  ,    45  -    46  .    47  /  */
        1    |   2    |   4    |   8    |   16   |   32   |   64   |  128,
/*  48  0    49  1    50  2    51  3    52  4    53  5    54  6    55  7  */
        1    |   2    |   4    |   8    |   16   |   32   |   64   |  128,
/*  56  8    57  9    58  :    59  ;    60  <    61  =    62  >    63  ?  */
        1    |   2    |   4    |   8    |   16   |   32   |   64   |   0,
/*  64  @    65  A    66  B    67  C    68  D    69  E    70  F    71  G  */
        1    |   2    |   4    |   8    |   16   |   32   |   64   |  128,
/*  72  H    73  I    74  J    75  K    76  L    77  M    78  N    79  O  */
        1    |   2    |   4    |   8    |   16   |   32   |   64   |  128,
/*  80  P    81  Q    82  R    83  S    84  T    85  U    86  V    87  W  */
        1    |   2    |   4    |   8    |   16   |   32   |   64   |  128,
/*  88  X    89  Y    90  Z    91  [    92  \    93  ]    94  ^    95  _  */
        1    |   2    |   4    |   8    |   16   |   32   |   64   |  128,
/*  96  `    97  a    98  b    99  c   100  d   101  e   102  f   103  g  */
        1    |   2    |   4    |   8    |   16   |   32   |   64   |  128,
/* 104  h   105  i   106  j   107  k   108  l   109  m   110  n   111  o  */
        1    |   2    |   4    |   8    |   16   |   32   |   64   |  128,
/* 112  p   113  q   114  r   115  s   116  t   117  u   118  v   119  w  */
        1    |   2    |   4    |   8    |   16   |   32   |   64   |  128,
/* 120  x   121  y   122  z   123  {   124  |   125  }   126  ~   127 del */
        1    |   2    |   4    |   8    |   16   |   32   |   64   |   0, };

#undef T

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_start
  , 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_server_start
  , s_req_server
  , s_req_server_with_at
  , 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_discard_ws
  , s_header_value_discard_ws_almost_done
  , s_header_value_discard_lws
  , 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_token_start
  , h_matching_connection_keep_alive
  , h_matching_connection_close
  , h_matching_connection_upgrade
  , h_matching_connection_token

  , h_transfer_encoding_chunked
  , h_connection_keep_alive
  , h_connection_close
  , h_connection_upgrade
  };

enum http_host_state
  {
    s_http_host_dead = 1
  , s_http_userinfo_start
  , s_http_userinfo
  , s_http_host_start
  , s_http_host_v6_start
  , s_http_host
  , s_http_host_v6
  , s_http_host_v6_end
  , s_http_host_v6_zone_start
  , s_http_host_v6_zone
  , s_http_host_port_start
  , s_http_host_port
};

/* 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'))
#define IS_MARK(c)          ((c) == '-' || (c) == '_' || (c) == '.' || \
  (c) == '!' || (c) == '~' || (c) == '*' || (c) == '\'' || (c) == '(' || \
  (c) == ')')
#define IS_USERINFO_CHAR(c) (IS_ALPHANUM(c) || IS_MARK(c) || (c) == '%' || \
  (c) == ';' || (c) == ':' || (c) == '&' || (c) == '=' || (c) == '+' || \
  (c) == '$' || (c) == ',')

#define STRICT_TOKEN(c)     (tokens[(unsigned char)c])

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

/**
 * Verify that a char is a valid visible (printable) US-ASCII
 * character or %x80-FF
 **/
#define IS_HEADER_CHAR(ch)                                                     \
  (ch == CR || ch == LF || ch == 9 || ((unsigned char)ch > 31 && ch != 127))

#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

int http_message_needs_eof(const http_parser *parser);

/* 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)
{
  if (ch == ' ' || ch == '\r' || ch == '\n') {
    return s_dead;
  }

#if HTTP_PARSER_STRICT
  if (ch == '\t' || ch == '\f') {
    return s_dead;
  }
#endif

  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_server_start;
      }

      break;

    case s_req_server_with_at:
      if (ch == '@') {
        return s_dead;
      }

    /* FALLTHROUGH */
    case s_req_server_start:
    case s_req_server:
      if (ch == '/') {
        return s_req_path;
      }

      if (ch == '?') {
        return s_req_query_string_start;
      }

      if (ch == '@') {
        return s_req_server_with_at;
      }

      if (IS_USERINFO_CHAR(ch) || ch == '[' || ch == ']') {
        return s_req_server;
      }

      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;
}

uint32_t http_parser_execute (http_parser *parser,
                            const http_parser_settings *settings,
                            const char *data,
                            uint32_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;
  const char *status_mark = 0;
  enum state p_state = (enum state) parser->state;
  const unsigned int lenient = parser->lenient_http_headers;

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

  if (len == 0) {
    switch (CURRENT_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 (CURRENT_STATE() == s_header_field)
    header_field_mark = data;
  if (CURRENT_STATE() == s_header_value)
    header_value_mark = data;
  switch (CURRENT_STATE()) {
  case s_req_path:
  case s_req_schema:
  case s_req_schema_slash:
  case s_req_schema_slash_slash:
  case s_req_server_start:
  case s_req_server:
  case s_req_server_with_at:
  case s_req_query_string_start:
  case s_req_query_string:
  case s_req_fragment_start:
  case s_req_fragment:
    url_mark = data;
    break;
  case s_res_status:
    status_mark = data;
    break;
  default:
    break;
  }

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

    if (PARSING_HEADER(CURRENT_STATE()))
      COUNT_HEADER_SIZE(1);

reexecute:
    switch (CURRENT_STATE()) {

      case s_dead:
        /* this state is used after a 'Connection: close' message
         * the parser will error out if it reads another message
         */
        if (LIKELY(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') {
          UPDATE_STATE(s_res_or_resp_H);

          CALLBACK_NOTIFY(message_begin);
        } else {
          parser->type = HTTP_REQUEST;
          UPDATE_STATE(s_start_req);
          REEXECUTE();
        }

        break;
      }

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

          parser->type = HTTP_REQUEST;
          parser->method = HTTP_HEAD;
          parser->index = 2;
          UPDATE_STATE(s_req_method);
        }
        break;

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

        switch (ch) {
          case 'H':
            UPDATE_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');
        UPDATE_STATE(s_res_HT);
        break;

      case s_res_HT:
        STRICT_CHECK(ch != 'T');
        UPDATE_STATE(s_res_HTT);
        break;

      case s_res_HTT:
        STRICT_CHECK(ch != 'P');
        UPDATE_STATE(s_res_HTTP);
        break;

      case s_res_HTTP:
        STRICT_CHECK(ch != '/');
        UPDATE_STATE(s_res_first_http_major);
        break;

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

        parser->http_major = ch - '0';
        UPDATE_STATE(s_res_http_major);
        break;

      /* major HTTP version or dot */
      case s_res_http_major:
      {
        if (ch == '.') {
          UPDATE_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 (UNLIKELY(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 (UNLIKELY(!IS_NUM(ch))) {
          SET_ERRNO(HPE_INVALID_VERSION);
          goto error;
        }

        parser->http_minor = ch - '0';
        UPDATE_STATE(s_res_http_minor);
        break;

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

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

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

        if (UNLIKELY(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';
        UPDATE_STATE(s_res_status_code);
        break;
      }

      case s_res_status_code:
      {
        if (!IS_NUM(ch)) {
          switch (ch) {
            case ' ':
              UPDATE_STATE(s_res_status_start);
              break;
            case CR:
              UPDATE_STATE(s_res_line_almost_done);
              break;
            case LF:
              UPDATE_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 (UNLIKELY(parser->status_code > 999)) {
          SET_ERRNO(HPE_INVALID_STATUS);
          goto error;
        }

        break;
      }

      case s_res_status_start:
      {
        if (ch == CR) {
          UPDATE_STATE(s_res_line_almost_done);
          break;
        }

        if (ch == LF) {
          UPDATE_STATE(s_header_field_start);
          break;
        }

        MARK(status);
        UPDATE_STATE(s_res_status);
        parser->index = 0;
        break;
      }

      case s_res_status:
        if (ch == CR) {
          UPDATE_STATE(s_res_line_almost_done);
          CALLBACK_DATA(status);
          break;
        }

        if (ch == LF) {
          UPDATE_STATE(s_header_field_start);
          CALLBACK_DATA(status);
          break;
        }

        break;

      case s_res_line_almost_done:
        STRICT_CHECK(ch != LF);
        UPDATE_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 (UNLIKELY(!IS_ALPHA(ch))) {
          SET_ERRNO(HPE_INVALID_METHOD);
          goto error;
        }

        parser->method = (enum http_method) 0;
        parser->index = 1;
        switch (ch) {
          case 'A': parser->method = HTTP_ACL; break;
          case 'B': parser->method = HTTP_BIND; break;
          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; /* or LINK */ break;
          case 'M': parser->method = HTTP_MKCOL; /* or MOVE, MKACTIVITY, MERGE, M-SEARCH, MKCALENDAR */ 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; /* or REBIND */ 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, UNBIND, UNLINK */ break;
          default:
            SET_ERRNO(HPE_INVALID_METHOD);
            goto error;
        }
        UPDATE_STATE(s_req_method);

        CALLBACK_NOTIFY(message_begin);

        break;
      }

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

        matcher = method_strings[parser->method];
        if (ch == ' ' && matcher[parser->index] == '\0') {
          UPDATE_STATE(s_req_spaces_before_url);
        } else if (ch == matcher[parser->index]) {
          ; /* nada */
        } else if (IS_ALPHA(ch)) {

          switch (parser->method << 16 | parser->index << 8 | ch) {
#define XX(meth, pos, ch, new_meth) \
            case (HTTP_##meth << 16 | pos << 8 | ch): \
              parser->method = HTTP_##new_meth; break;

            XX(POST,      1, 'U', PUT)
            XX(POST,      1, 'A', PATCH)
            XX(CONNECT,   1, 'H', CHECKOUT)
            XX(CONNECT,   2, 'P', COPY)
            XX(MKCOL,     1, 'O', MOVE)
            XX(MKCOL,     1, 'E', MERGE)
            XX(MKCOL,     2, 'A', MKACTIVITY)
            XX(MKCOL,     3, 'A', MKCALENDAR)
            XX(SUBSCRIBE, 1, 'E', SEARCH)
            XX(REPORT,    2, 'B', REBIND)
            XX(POST,      1, 'R', PROPFIND)
            XX(PROPFIND,  4, 'P', PROPPATCH)
            XX(PUT,       2, 'R', PURGE)
            XX(LOCK,      1, 'I', LINK)
            XX(UNLOCK,    2, 'S', UNSUBSCRIBE)
            XX(UNLOCK,    2, 'B', UNBIND)
            XX(UNLOCK,    3, 'I', UNLINK)
#undef XX

            default:
              SET_ERRNO(HPE_INVALID_METHOD);
              goto error;
          }
        } else if (ch == '-' &&
                   parser->index == 1 &&
                   parser->method == HTTP_MKCOL) {
          parser->method = HTTP_MSEARCH;
        } 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) {
          UPDATE_STATE(s_req_server_start);
        }

        UPDATE_STATE(parse_url_char(CURRENT_STATE(), ch));
        if (UNLIKELY(CURRENT_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_server_start:
      {
        switch (ch) {
          /* No whitespace allowed here */
          case ' ':
          case CR:
          case LF:
            SET_ERRNO(HPE_INVALID_URL);
            goto error;
          default:
            UPDATE_STATE(parse_url_char(CURRENT_STATE(), ch));
            if (UNLIKELY(CURRENT_STATE() == s_dead)) {
              SET_ERRNO(HPE_INVALID_URL);
              goto error;
            }
        }

        break;
      }

      case s_req_server:
      case s_req_server_with_at:
      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 ' ':
            UPDATE_STATE(s_req_http_start);
            CALLBACK_DATA(url);
            break;
          case CR:
          case LF:
            parser->http_major = 0;
            parser->http_minor = 9;
            UPDATE_STATE((ch == CR) ?
              s_req_line_almost_done :
              s_header_field_start);
            CALLBACK_DATA(url);
            break;
          default:
            UPDATE_STATE(parse_url_char(CURRENT_STATE(), ch));
            if (UNLIKELY(CURRENT_STATE() == s_dead)) {
              SET_ERRNO(HPE_INVALID_URL);
              goto error;
            }
        }
        break;
      }

      case s_req_http_start:
        switch (ch) {
          case 'H':
            UPDATE_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');
        UPDATE_STATE(s_req_http_HT);
        break;

      case s_req_http_HT:
        STRICT_CHECK(ch != 'T');
        UPDATE_STATE(s_req_http_HTT);
        break;

      case s_req_http_HTT:
        STRICT_CHECK(ch != 'P');
        UPDATE_STATE(s_req_http_HTTP);
        break;

      case s_req_http_HTTP:
        STRICT_CHECK(ch != '/');
        UPDATE_STATE(s_req_first_http_major);
        break;

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

        parser->http_major = ch - '0';
        UPDATE_STATE(s_req_http_major);
        break;

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

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

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

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

        parser->http_minor = ch - '0';
        UPDATE_STATE(s_req_http_minor);
        break;

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

        if (ch == LF) {
          UPDATE_STATE(s_header_field_start);
          break;
        }

        /* XXX allow spaces after digit? */

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

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

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

        break;
      }

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

        UPDATE_STATE(s_header_field_start);
        break;
      }

      case s_header_field_start:
      {
        if (ch == CR) {
          UPDATE_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*/
          UPDATE_STATE(s_headers_almost_done);
          REEXECUTE();
        }

        c = TOKEN(ch);

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

        MARK(header_field);

        parser->index = 0;
        UPDATE_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:
      {
        const char* start = p;
        for (; p != data + len; p++) {
          ch = *p;
          c = TOKEN(ch);

          if (!c)
            break;

          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;
          }
        }

        COUNT_HEADER_SIZE(p - start);

        if (p == data + len) {
          --p;
          break;
        }

        if (ch == ':') {
          UPDATE_STATE(s_header_value_discard_ws);
          CALLBACK_DATA(header_field);
          break;
        }

        SET_ERRNO(HPE_INVALID_HEADER_TOKEN);
        goto error;
      }

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

        if (ch == CR) {
          UPDATE_STATE(s_header_value_discard_ws_almost_done);
          break;
        }

        if (ch == LF) {
          UPDATE_STATE(s_header_value_discard_lws);
          break;
        }

        /* FALLTHROUGH */

      case s_header_value_start:
      {
        MARK(header_value);

        UPDATE_STATE(s_header_value);
        parser->index = 0;

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

            if (parser->flags & F_CONTENTLENGTH) {
              SET_ERRNO(HPE_UNEXPECTED_CONTENT_LENGTH);
              goto error;
            }

            parser->flags |= F_CONTENTLENGTH;
            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 if (c == 'u') {
              parser->header_state = h_matching_connection_upgrade;
            } else {
              parser->header_state = h_matching_connection_token;
            }
            break;

          /* Multi-value `Connection` header */
          case h_matching_connection_token_start:
            break;

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

      case s_header_value:
      {
        const char* start = p;
        enum header_states h_state = (enum header_states) parser->header_state;
        for (; p != data + len; p++) {
          ch = *p;
          if (ch == CR) {
            UPDATE_STATE(s_header_almost_done);
            parser->header_state = h_state;
            CALLBACK_DATA(header_value);
            break;
          }

          if (ch == LF) {
            UPDATE_STATE(s_header_almost_done);
            COUNT_HEADER_SIZE(p - start);
            parser->header_state = h_state;
            CALLBACK_DATA_NOADVANCE(header_value);
            REEXECUTE();
          }

          if (!lenient && !IS_HEADER_CHAR(ch)) {
            SET_ERRNO(HPE_INVALID_HEADER_TOKEN);
            goto error;
          }

          c = LOWER(ch);

          switch (h_state) {
            case h_general:
            {
              const char* p_cr;
              const char* p_lf;
              uint32_t limit = data + len - p;

              limit = MIN(limit, HTTP_MAX_HEADER_SIZE);

              p_cr = (const char*) memchr(p, CR, limit);
              p_lf = (const char*) memchr(p, LF, limit);
              if (p_cr != NULL) {
                if (p_lf != NULL && p_cr >= p_lf)
                  p = p_lf;
                else
                  p = p_cr;
              } else if (UNLIKELY(p_lf != NULL)) {
                p = p_lf;
              } else {
                p = data + len;
              }
              --p;

              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 (UNLIKELY(!IS_NUM(ch))) {
                SET_ERRNO(HPE_INVALID_CONTENT_LENGTH);
                parser->header_state = h_state;
                goto error;
              }

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

              /* Overflow? Test against a conservative limit for simplicity. */
              if (UNLIKELY((ULLONG_MAX - 10) / 10 < parser->content_length)) {
                SET_ERRNO(HPE_INVALID_CONTENT_LENGTH);
                parser->header_state = h_state;
                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]) {
                h_state = h_general;
              } else if (parser->index == sizeof(CHUNKED)-2) {
                h_state = h_transfer_encoding_chunked;
              }
              break;

            case h_matching_connection_token_start:
              /* looking for 'Connection: keep-alive' */
              if (c == 'k') {
                h_state = h_matching_connection_keep_alive;
              /* looking for 'Connection: close' */
              } else if (c == 'c') {
                h_state = h_matching_connection_close;
              } else if (c == 'u') {
                h_state = h_matching_connection_upgrade;
              } else if (STRICT_TOKEN(c)) {
                h_state = h_matching_connection_token;
              } else if (c == ' ' || c == '\t') {
                /* Skip lws */
              } else {
                h_state = h_general;
              }
              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]) {
                h_state = h_matching_connection_token;
              } else if (parser->index == sizeof(KEEP_ALIVE)-2) {
                h_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]) {
                h_state = h_matching_connection_token;
              } else if (parser->index == sizeof(CLOSE)-2) {
                h_state = h_connection_close;
              }
              break;

            /* looking for 'Connection: upgrade' */
            case h_matching_connection_upgrade:
              parser->index++;
              if (parser->index > sizeof(UPGRADE) - 1 ||
                  c != UPGRADE[parser->index]) {
                h_state = h_matching_connection_token;
              } else if (parser->index == sizeof(UPGRADE)-2) {
                h_state = h_connection_upgrade;
              }
              break;

            case h_matching_connection_token:
              if (ch == ',') {
                h_state = h_matching_connection_token_start;
                parser->index = 0;
              }
              break;

            case h_transfer_encoding_chunked:
              if (ch != ' ') h_state = h_general;
              break;

            case h_connection_keep_alive:
            case h_connection_close:
            case h_connection_upgrade:
              if (ch == ',') {
                if (h_state == h_connection_keep_alive) {
                  parser->flags |= F_CONNECTION_KEEP_ALIVE;
                } else if (h_state == h_connection_close) {
                  parser->flags |= F_CONNECTION_CLOSE;
                } else if (h_state == h_connection_upgrade) {
                  parser->flags |= F_CONNECTION_UPGRADE;
                }
                h_state = h_matching_connection_token_start;
                parser->index = 0;
              } else if (ch != ' ') {
                h_state = h_matching_connection_token;
              }
              break;

            default:
              UPDATE_STATE(s_header_value);
              h_state = h_general;
              break;
          }
        }
        parser->header_state = h_state;

        COUNT_HEADER_SIZE(p - start);

        if (p == data + len)
          --p;
        break;
      }

      case s_header_almost_done:
      {
        if (UNLIKELY(ch != LF)) {
          SET_ERRNO(HPE_LF_EXPECTED);
          goto error;
        }

        UPDATE_STATE(s_header_value_lws);
        break;
      }

      case s_header_value_lws:
      {
        if (ch == ' ' || ch == '\t') {
          UPDATE_STATE(s_header_value_start);
          REEXECUTE();
        }

        /* finished the header */
        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;
          case h_connection_upgrade:
            parser->flags |= F_CONNECTION_UPGRADE;
            break;
          default:
            break;
        }

        UPDATE_STATE(s_header_field_start);
        REEXECUTE();
      }

      case s_header_value_discard_ws_almost_done:
      {
        STRICT_CHECK(ch != LF);
        UPDATE_STATE(s_header_value_discard_lws);
        break;
      }

      case s_header_value_discard_lws:
      {
        if (ch == ' ' || ch == '\t') {
          UPDATE_STATE(s_header_value_discard_ws);
          break;
        } else {
          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_connection_upgrade:
              parser->flags |= F_CONNECTION_UPGRADE;
              break;
            case h_transfer_encoding_chunked:
              parser->flags |= F_CHUNKED;
              break;
            default:
              break;
          }

          /* header value was empty */
          MARK(header_value);
          UPDATE_STATE(s_header_field_start);
          CALLBACK_DATA_NOADVANCE(header_value);
          REEXECUTE();
        }
      }

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

        if (parser->flags & F_TRAILING) {
          /* End of a chunked request */
          UPDATE_STATE(s_message_done);
          CALLBACK_NOTIFY_NOADVANCE(chunk_complete);
          REEXECUTE();
        }

        /* Cannot use chunked encoding and a content-length header together
           per the HTTP specification. */
        if ((parser->flags & F_CHUNKED) &&
            (parser->flags & F_CONTENTLENGTH)) {
          SET_ERRNO(HPE_UNEXPECTED_CONTENT_LENGTH);
          goto error;
        }

        UPDATE_STATE(s_headers_done);

        /* Set this here so that on_headers_complete() callbacks can see it */
        parser->upgrade =
          ((parser->flags & (F_UPGRADE | F_CONNECTION_UPGRADE)) ==
           (F_UPGRADE | F_CONNECTION_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 2:
              parser->upgrade = 1;

            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);
        }

        REEXECUTE();
      }

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

        parser->nread = 0;

        hasBody = parser->flags & F_CHUNKED ||
          (parser->content_length > 0 && parser->content_length != ULLONG_MAX);
        if (parser->upgrade && (parser->method == HTTP_CONNECT ||
                                (parser->flags & F_SKIPBODY) || !hasBody)) {
          /* Exit, the rest of the message is in a different protocol. */
          UPDATE_STATE(NEW_MESSAGE());
          CALLBACK_NOTIFY(message_complete);
          RETURN((p - data) + 1);
        }

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

        break;
      }

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

        break;

      case s_message_done:
        UPDATE_STATE(NEW_MESSAGE());
        CALLBACK_NOTIFY(message_complete);
        if (parser->upgrade) {
          /* Exit, the rest of the message is in a different protocol. */
          RETURN((p - data) + 1);
        }
        break;

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

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

        parser->content_length = unhex_val;
        UPDATE_STATE(s_chunk_size);
        break;
      }

      case s_chunk_size:
      {
        uint64_t t;

        assert(parser->flags & F_CHUNKED);

        if (ch == CR) {
          UPDATE_STATE(s_chunk_size_almost_done);
          break;
        }

        unhex_val = unhex[(unsigned char)ch];

        if (unhex_val == -1) {
          if (ch == ';' || ch == ' ') {
            UPDATE_STATE(s_chunk_parameters);
            break;
          }

          SET_ERRNO(HPE_INVALID_CHUNK_SIZE);
          goto error;
        }

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

        /* Overflow? Test against a conservative limit for simplicity. */
        if (UNLIKELY((ULLONG_MAX - 16) / 16 < parser->content_length)) {
          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) {
          UPDATE_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;
          UPDATE_STATE(s_header_field_start);
        } else {
          UPDATE_STATE(s_chunk_data);
        }
        CALLBACK_NOTIFY(chunk_header);
        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) {
          UPDATE_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);
        UPDATE_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;
        UPDATE_STATE(s_chunk_size_start);
        CALLBACK_NOTIFY(chunk_complete);
        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) +
          (status_mark ? 1 : 0)) <= 1);

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

  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 (const 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 (const 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 ELEM_AT(method_strings, m, "<unknown>");
}


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;
}

void
http_parser_settings_init(http_parser_settings *settings)
{
  memset(settings, 0, sizeof(*settings));
}

const char *
http_errno_name(enum http_errno err) {
  assert(((uint32_t) err) < ARRAY_SIZE(http_strerror_tab));
  return http_strerror_tab[err].name;
}

const char *
http_errno_description(enum http_errno err) {
  assert(((uint32_t) err) < ARRAY_SIZE(http_strerror_tab));
  return http_strerror_tab[err].description;
}

static enum http_host_state
http_parse_host_char(enum http_host_state s, const char ch) {
  switch(s) {
    case s_http_userinfo:
    case s_http_userinfo_start:
      if (ch == '@') {
        return s_http_host_start;
      }

      if (IS_USERINFO_CHAR(ch)) {
        return s_http_userinfo;
      }
      break;

    case s_http_host_start:
      if (ch == '[') {
        return s_http_host_v6_start;
      }

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

      break;

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

    /* FALLTHROUGH */
    case s_http_host_v6_end:
      if (ch == ':') {
        return s_http_host_port_start;
      }

      break;

    case s_http_host_v6:
      if (ch == ']') {
        return s_http_host_v6_end;
      }

    /* FALLTHROUGH */
    case s_http_host_v6_start:
      if (IS_HEX(ch) || ch == ':' || ch == '.') {
        return s_http_host_v6;
      }

      if (s == s_http_host_v6 && ch == '%') {
        return s_http_host_v6_zone_start;
      }
      break;

    case s_http_host_v6_zone:
      if (ch == ']') {
        return s_http_host_v6_end;
      }

    /* FALLTHROUGH */
    case s_http_host_v6_zone_start:
      /* RFC 6874 Zone ID consists of 1*( unreserved / pct-encoded) */
      if (IS_ALPHANUM(ch) || ch == '%' || ch == '.' || ch == '-' || ch == '_' ||
          ch == '~') {
        return s_http_host_v6_zone;
      }
      break;

    case s_http_host_port:
    case s_http_host_port_start:
      if (IS_NUM(ch)) {
        return s_http_host_port;
      }

      break;

    default:
      break;
  }
  return s_http_host_dead;
}

static int
http_parse_host(const char * buf, struct http_parser_url *u, int found_at) {
  enum http_host_state s;

  const char *p;
  uint32_t buflen = u->field_data[UF_HOST].off + u->field_data[UF_HOST].len;

  assert(u->field_set & (1 << UF_HOST));

  u->field_data[UF_HOST].len = 0;

  s = found_at ? s_http_userinfo_start : s_http_host_start;

  for (p = buf + u->field_data[UF_HOST].off; p < buf + buflen; p++) {
    enum http_host_state new_s = http_parse_host_char(s, *p);

    if (new_s == s_http_host_dead) {
      return 1;
    }

    switch(new_s) {
      case s_http_host:
        if (s != s_http_host) {
          u->field_data[UF_HOST].off = p - buf;
        }
        u->field_data[UF_HOST].len++;
        break;

      case s_http_host_v6:
        if (s != s_http_host_v6) {
          u->field_data[UF_HOST].off = p - buf;
        }
        u->field_data[UF_HOST].len++;
        break;

      case s_http_host_v6_zone_start:
      case s_http_host_v6_zone:
        u->field_data[UF_HOST].len++;
        break;

      case s_http_host_port:
        if (s != s_http_host_port) {
          u->field_data[UF_PORT].off = p - buf;
          u->field_data[UF_PORT].len = 0;
          u->field_set |= (1 << UF_PORT);
        }
        u->field_data[UF_PORT].len++;
        break;

      case s_http_userinfo:
        if (s != s_http_userinfo) {
          u->field_data[UF_USERINFO].off = p - buf ;
          u->field_data[UF_USERINFO].len = 0;
          u->field_set |= (1 << UF_USERINFO);
        }
        u->field_data[UF_USERINFO].len++;
        break;

      default:
        break;
    }
    s = new_s;
  }

  /* Make sure we don't end somewhere unexpected */
  switch (s) {
    case s_http_host_start:
    case s_http_host_v6_start:
    case s_http_host_v6:
    case s_http_host_v6_zone_start:
    case s_http_host_v6_zone:
    case s_http_host_port_start:
    case s_http_userinfo:
    case s_http_userinfo_start:
      return 1;
    default:
      break;
  }

  return 0;
}

void
http_parser_url_init(struct http_parser_url *u) {
  memset(u, 0, sizeof(*u));
}

int
http_parser_parse_url(const char *buf, uint32_t buflen, int is_connect,
                      struct http_parser_url *u)
{
  enum state s;
  const char *p;
  enum http_parser_url_fields uf, old_uf;
  int found_at = 0;

  u->port = u->field_set = 0;
  s = is_connect ? s_req_server_start : s_req_spaces_before_url;
  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_server_start:
      case s_req_query_string_start:
      case s_req_fragment_start:
        continue;

      case s_req_schema:
        uf = UF_SCHEMA;
        break;

      case s_req_server_with_at:
        found_at = 1;

      /* FALLTROUGH */
      case s_req_server:
        uf = UF_HOST;
        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;
  }

  /* host must be present if there is a schema */
  /* parsing http:///toto will fail */
  if ((u->field_set & (1 << UF_SCHEMA)) &&
      (u->field_set & (1 << UF_HOST)) == 0) {
    return 1;
  }

  if (u->field_set & (1 << UF_HOST)) {
    if (http_parse_host(buf, u, found_at) != 0) {
      return 1;
    }
  }

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

  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");
  }
}

int
http_body_is_final(const struct http_parser *parser) {
    return parser->state == s_message_done;
}

unsigned long
http_parser_version(void) {
  return HTTP_PARSER_VERSION_MAJOR * 0x10000 |
         HTTP_PARSER_VERSION_MINOR * 0x00100 |
         HTTP_PARSER_VERSION_PATCH * 0x00001;
}