/*

 * nghttp2 - HTTP/2 C Library

 *

 * Copyright (c) 2012 Tatsuhiro Tsujikawa

 *

 * 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 "nghttp2_helper.h"

#include <assert.h>

#include <string.h>

#include "nghttp2_net.h"

void nghttp2_put_uint16be(uint8_t *buf, uint16_t n) {

  uint16_t x = htons(n);

  memcpy(buf, &x, sizeof(uint16_t));

}

void nghttp2_put_uint32be(uint8_t *buf, uint32_t n) {

  uint32_t x = htonl(n);

  memcpy(buf, &x, sizeof(uint32_t));

}

uint16_t nghttp2_get_uint16(const uint8_t *data) {

  uint16_t n;

  memcpy(&n, data, sizeof(uint16_t));

  return ntohs(n);

}

uint32_t nghttp2_get_uint32(const uint8_t *data) {

  uint32_t n;

  memcpy(&n, data, sizeof(uint32_t));

  return ntohl(n);

}

/* Generated by gendowncasetbl.py */

const uint8_t nghttp2_downcase_tbl[] = {

  0x00 /* NUL  */, 0x01 /* SOH  */, 0x02 /* STX  */, 0x03 /* ETX  */,

  0x04 /* EOT  */, 0x05 /* ENQ  */, 0x06 /* ACK  */, 0x07 /* BEL  */,

  0x08 /* BS   */, 0x09 /* HT   */, 0x0A /* LF   */, 0x0B /* VT   */,

  0x0C /* FF   */, 0x0D /* CR   */, 0x0E /* SO   */, 0x0F /* SI   */,

  0x10 /* DLE  */, 0x11 /* DC1  */, 0x12 /* DC2  */, 0x13 /* DC3  */,

  0x14 /* DC4  */, 0x15 /* NAK  */, 0x16 /* SYN  */, 0x17 /* ETB  */,

  0x18 /* CAN  */, 0x19 /* EM   */, 0x1A /* SUB  */, 0x1B /* ESC  */,

  0x1C /* FS   */, 0x1D /* GS   */, 0x1E /* RS   */, 0x1F /* US   */,

  0x20 /* SPC  */, 0x21 /* !    */, 0x22 /* "    */, 0x23 /* #    */,

  0x24 /* $    */, 0x25 /* %    */, 0x26 /* &    */, 0x27 /* '    */,

  0x28 /* (    */, 0x29 /* )    */, 0x2A /* *    */, 0x2B /* +    */,

  0x2C /* ,    */, 0x2D /* -    */, 0x2E /* .    */, 0x2F /* /    */,

  0x30 /* 0    */, 0x31 /* 1    */, 0x32 /* 2    */, 0x33 /* 3    */,

  0x34 /* 4    */, 0x35 /* 5    */, 0x36 /* 6    */, 0x37 /* 7    */,

  0x38 /* 8    */, 0x39 /* 9    */, 0x3A /* :    */, 0x3B /* ;    */,

  0x3C /* <    */, 0x3D /* =    */, 0x3E /* >    */, 0x3F /* ?    */,

  0x40 /* @    */, 0x61 /* A    */, 0x62 /* B    */, 0x63 /* C    */,

  0x64 /* D    */, 0x65 /* E    */, 0x66 /* F    */, 0x67 /* G    */,

  0x68 /* H    */, 0x69 /* I    */, 0x6A /* J    */, 0x6B /* K    */,

  0x6C /* L    */, 0x6D /* M    */, 0x6E /* N    */, 0x6F /* O    */,

  0x70 /* P    */, 0x71 /* Q    */, 0x72 /* R    */, 0x73 /* S    */,

  0x74 /* T    */, 0x75 /* U    */, 0x76 /* V    */, 0x77 /* W    */,

  0x78 /* X    */, 0x79 /* Y    */, 0x7A /* Z    */, 0x5B /* [    */,

  0x5C /* \    */, 0x5D /* ]    */, 0x5E /* ^    */, 0x5F /* _    */,

  0x60 /* `    */, 0x61 /* a    */, 0x62 /* b    */, 0x63 /* c    */,

  0x64 /* d    */, 0x65 /* e    */, 0x66 /* f    */, 0x67 /* g    */,

  0x68 /* h    */, 0x69 /* i    */, 0x6A /* j    */, 0x6B /* k    */,

  0x6C /* l    */, 0x6D /* m    */, 0x6E /* n    */, 0x6F /* o    */,

  0x70 /* p    */, 0x71 /* q    */, 0x72 /* r    */, 0x73 /* s    */,

  0x74 /* t    */, 0x75 /* u    */, 0x76 /* v    */, 0x77 /* w    */,

  0x78 /* x    */, 0x79 /* y    */, 0x7A /* z    */, 0x7B /* {    */,

  0x7C /* |    */, 0x7D /* }    */, 0x7E /* ~    */, 0x7F /* DEL  */,

  0x80 /* 0x80 */, 0x81 /* 0x81 */, 0x82 /* 0x82 */, 0x83 /* 0x83 */,

  0x84 /* 0x84 */, 0x85 /* 0x85 */, 0x86 /* 0x86 */, 0x87 /* 0x87 */,

  0x88 /* 0x88 */, 0x89 /* 0x89 */, 0x8A /* 0x8A */, 0x8B /* 0x8B */,

  0x8C /* 0x8C */, 0x8D /* 0x8D */, 0x8E /* 0x8E */, 0x8F /* 0x8F */,

  0x90 /* 0x90 */, 0x91 /* 0x91 */, 0x92 /* 0x92 */, 0x93 /* 0x93 */,

  0x94 /* 0x94 */, 0x95 /* 0x95 */, 0x96 /* 0x96 */, 0x97 /* 0x97 */,

  0x98 /* 0x98 */, 0x99 /* 0x99 */, 0x9A /* 0x9A */, 0x9B /* 0x9B */,

  0x9C /* 0x9C */, 0x9D /* 0x9D */, 0x9E /* 0x9E */, 0x9F /* 0x9F */,

  0xA0 /* 0xA0 */, 0xA1 /* 0xA1 */, 0xA2 /* 0xA2 */, 0xA3 /* 0xA3 */,

  0xA4 /* 0xA4 */, 0xA5 /* 0xA5 */, 0xA6 /* 0xA6 */, 0xA7 /* 0xA7 */,

  0xA8 /* 0xA8 */, 0xA9 /* 0xA9 */, 0xAA /* 0xAA */, 0xAB /* 0xAB */,

  0xAC /* 0xAC */, 0xAD /* 0xAD */, 0xAE /* 0xAE */, 0xAF /* 0xAF */,

  0xB0 /* 0xB0 */, 0xB1 /* 0xB1 */, 0xB2 /* 0xB2 */, 0xB3 /* 0xB3 */,

  0xB4 /* 0xB4 */, 0xB5 /* 0xB5 */, 0xB6 /* 0xB6 */, 0xB7 /* 0xB7 */,

  0xB8 /* 0xB8 */, 0xB9 /* 0xB9 */, 0xBA /* 0xBA */, 0xBB /* 0xBB */,

  0xBC /* 0xBC */, 0xBD /* 0xBD */, 0xBE /* 0xBE */, 0xBF /* 0xBF */,

  0xC0 /* 0xC0 */, 0xC1 /* 0xC1 */, 0xC2 /* 0xC2 */, 0xC3 /* 0xC3 */,

  0xC4 /* 0xC4 */, 0xC5 /* 0xC5 */, 0xC6 /* 0xC6 */, 0xC7 /* 0xC7 */,

  0xC8 /* 0xC8 */, 0xC9 /* 0xC9 */, 0xCA /* 0xCA */, 0xCB /* 0xCB */,

  0xCC /* 0xCC */, 0xCD /* 0xCD */, 0xCE /* 0xCE */, 0xCF /* 0xCF */,

  0xD0 /* 0xD0 */, 0xD1 /* 0xD1 */, 0xD2 /* 0xD2 */, 0xD3 /* 0xD3 */,

  0xD4 /* 0xD4 */, 0xD5 /* 0xD5 */, 0xD6 /* 0xD6 */, 0xD7 /* 0xD7 */,

  0xD8 /* 0xD8 */, 0xD9 /* 0xD9 */, 0xDA /* 0xDA */, 0xDB /* 0xDB */,

  0xDC /* 0xDC */, 0xDD /* 0xDD */, 0xDE /* 0xDE */, 0xDF /* 0xDF */,

  0xE0 /* 0xE0 */, 0xE1 /* 0xE1 */, 0xE2 /* 0xE2 */, 0xE3 /* 0xE3 */,

  0xE4 /* 0xE4 */, 0xE5 /* 0xE5 */, 0xE6 /* 0xE6 */, 0xE7 /* 0xE7 */,

  0xE8 /* 0xE8 */, 0xE9 /* 0xE9 */, 0xEA /* 0xEA */, 0xEB /* 0xEB */,

  0xEC /* 0xEC */, 0xED /* 0xED */, 0xEE /* 0xEE */, 0xEF /* 0xEF */,

  0xF0 /* 0xF0 */, 0xF1 /* 0xF1 */, 0xF2 /* 0xF2 */, 0xF3 /* 0xF3 */,

  0xF4 /* 0xF4 */, 0xF5 /* 0xF5 */, 0xF6 /* 0xF6 */, 0xF7 /* 0xF7 */,

  0xF8 /* 0xF8 */, 0xF9 /* 0xF9 */, 0xFA /* 0xFA */, 0xFB /* 0xFB */,

  0xFC /* 0xFC */, 0xFD /* 0xFD */, 0xFE /* 0xFE */, 0xFF /* 0xFF */,

};

void nghttp2_downcase(uint8_t *s, size_t len) {

  size_t i;

  for (i = 0; i < len; ++i) {

    s[i] = nghttp2_downcase_byte(s[i]);

  }

}

/*

 *   local_window_size

 *   ^  *

 *   |  *    recv_window_size

 *   |  *  * ^

 *   |  *  * |

 *  0+++++++++

 *   |  *  *   \

 *   |  *  *   | This rage is hidden in flow control.  But it must be

 *   v  *  *   / kept in order to restore it when window size is enlarged.

 *   recv_reduction

 *   (+ for negative direction)

 *

 *   recv_window_size could be negative if we decrease

 *   local_window_size more than recv_window_size:

 *

 *   local_window_size

 *   ^  *

 *   |  *

 *   |  *

 *   0++++++++

 *   |  *    ^ recv_window_size (negative)

 *   |  *    |

 *   v  *  *

 *   recv_reduction

 */

int nghttp2_adjust_local_window_size(int32_t *local_window_size_ptr,

                                     int32_t *recv_window_size_ptr,

                                     int32_t *recv_reduction_ptr,

                                     int32_t *delta_ptr) {

  if (*delta_ptr > 0) {

    int32_t recv_reduction_delta;

    int32_t delta;

    int32_t new_recv_window_size =

      nghttp2_max_int32(0, *recv_window_size_ptr) - *delta_ptr;

    if (new_recv_window_size >= 0) {

      *recv_window_size_ptr = new_recv_window_size;

      return 0;

    }

    delta = -new_recv_window_size;

    /* The delta size is strictly more than received bytes. Increase

       local_window_size by that difference |delta|. */

    if (*local_window_size_ptr > NGHTTP2_MAX_WINDOW_SIZE - delta) {

      return NGHTTP2_ERR_FLOW_CONTROL;

    }

    *local_window_size_ptr += delta;

    /* If there is recv_reduction due to earlier window_size

       reduction, we have to adjust it too. */

    recv_reduction_delta = nghttp2_min_int32(*recv_reduction_ptr, delta);

    *recv_reduction_ptr -= recv_reduction_delta;

    if (*recv_window_size_ptr < 0) {

      *recv_window_size_ptr += recv_reduction_delta;

    } else {

      /* If *recv_window_size_ptr > 0, then those bytes are going to

         be returned to the remote peer (by WINDOW_UPDATE with the

         adjusted *delta_ptr), so it is effectively 0 now.  We set to

         *recv_reduction_delta, because caller does not take into

         account it in *delta_ptr. */

      *recv_window_size_ptr = recv_reduction_delta;

    }

    /* recv_reduction_delta must be paid from *delta_ptr, since it was

       added in window size reduction (see below). */

    *delta_ptr -= recv_reduction_delta;

    return 0;

  }

  if (*local_window_size_ptr + *delta_ptr < 0 ||

      *recv_window_size_ptr < INT32_MIN - *delta_ptr ||

      *recv_reduction_ptr > INT32_MAX + *delta_ptr) {

    return NGHTTP2_ERR_FLOW_CONTROL;

  }

  /* Decreasing local window size. Note that we achieve this without

     noticing to the remote peer. To do this, we cut

     recv_window_size by -delta. This means that we don't send

     WINDOW_UPDATE for -delta bytes. */

  *local_window_size_ptr += *delta_ptr;

  *recv_window_size_ptr += *delta_ptr;

  *recv_reduction_ptr -= *delta_ptr;

  *delta_ptr = 0;

  return 0;

}

int nghttp2_increase_local_window_size(int32_t *local_window_size_ptr,

                                       int32_t *recv_window_size_ptr,

                                       int32_t *recv_reduction_ptr,

                                       int32_t *delta_ptr) {

  int32_t recv_reduction_delta;

  int32_t delta;

  delta = *delta_ptr;

  assert(delta >= 0);

  /* The delta size is strictly more than received bytes. Increase

     local_window_size by that difference |delta|. */

  if (*local_window_size_ptr > NGHTTP2_MAX_WINDOW_SIZE - delta) {

    return NGHTTP2_ERR_FLOW_CONTROL;

  }

  *local_window_size_ptr += delta;

  /* If there is recv_reduction due to earlier window_size

     reduction, we have to adjust it too. */

  recv_reduction_delta = nghttp2_min_int32(*recv_reduction_ptr, delta);

  *recv_reduction_ptr -= recv_reduction_delta;

  *recv_window_size_ptr += recv_reduction_delta;

  /* recv_reduction_delta must be paid from *delta_ptr, since it was

     added in window size reduction (see below). */

  *delta_ptr -= recv_reduction_delta;

  return 0;

}

int nghttp2_should_send_window_update(int32_t local_window_size,

                                      int32_t recv_window_size) {

  return recv_window_size > 0 && recv_window_size >= local_window_size / 2;

}

const char *nghttp2_strerror(int error_code) {

  switch (error_code) {

  case 0:

    return "Success";

  case NGHTTP2_ERR_INVALID_ARGUMENT:

    return "Invalid argument";

  case NGHTTP2_ERR_BUFFER_ERROR:

    return "Out of buffer space";

  case NGHTTP2_ERR_UNSUPPORTED_VERSION:

    return "Unsupported SPDY version";

  case NGHTTP2_ERR_WOULDBLOCK:

    return "Operation would block";

  case NGHTTP2_ERR_PROTO:

    return "Protocol error";

  case NGHTTP2_ERR_INVALID_FRAME:

    return "Invalid frame octets";

  case NGHTTP2_ERR_EOF:

    return "EOF";

  case NGHTTP2_ERR_DEFERRED:

    return "Data transfer deferred";

  case NGHTTP2_ERR_STREAM_ID_NOT_AVAILABLE:

    return "No more Stream ID available";

  case NGHTTP2_ERR_STREAM_CLOSED:

    return "Stream was already closed or invalid";

  case NGHTTP2_ERR_STREAM_CLOSING:

    return "Stream is closing";

  case NGHTTP2_ERR_STREAM_SHUT_WR:

    return "The transmission is not allowed for this stream";

  case NGHTTP2_ERR_INVALID_STREAM_ID:

    return "Stream ID is invalid";

  case NGHTTP2_ERR_INVALID_STREAM_STATE:

    return "Invalid stream state";

  case NGHTTP2_ERR_DEFERRED_DATA_EXIST:

    return "Another DATA frame has already been deferred";

  case NGHTTP2_ERR_START_STREAM_NOT_ALLOWED:

    return "request HEADERS is not allowed";

  case NGHTTP2_ERR_GOAWAY_ALREADY_SENT:

    return "GOAWAY has already been sent";

  case NGHTTP2_ERR_INVALID_HEADER_BLOCK:

    return "Invalid header block";

  case NGHTTP2_ERR_INVALID_STATE:

    return "Invalid state";

  case NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE:

    return "The user callback function failed due to the temporal error";

  case NGHTTP2_ERR_FRAME_SIZE_ERROR:

    return "The length of the frame is invalid";

  case NGHTTP2_ERR_HEADER_COMP:

    return "Header compression/decompression error";

  case NGHTTP2_ERR_FLOW_CONTROL:

    return "Flow control error";

  case NGHTTP2_ERR_INSUFF_BUFSIZE:

    return "Insufficient buffer size given to function";

  case NGHTTP2_ERR_PAUSE:

    return "Callback was paused by the application";

  case NGHTTP2_ERR_TOO_MANY_INFLIGHT_SETTINGS:

    return "Too many inflight SETTINGS";

  case NGHTTP2_ERR_PUSH_DISABLED:

    return "Server push is disabled by peer";

  case NGHTTP2_ERR_DATA_EXIST:

    return "DATA or HEADERS frame has already been submitted for the stream";

  case NGHTTP2_ERR_SESSION_CLOSING:

    return "The current session is closing";

  case NGHTTP2_ERR_HTTP_HEADER:

    return "Invalid HTTP header field was received";

  case NGHTTP2_ERR_HTTP_MESSAGING:

    return "Violation in HTTP messaging rule";

  case NGHTTP2_ERR_REFUSED_STREAM:

    return "Stream was refused";

  case NGHTTP2_ERR_INTERNAL:

    return "Internal error";

  case NGHTTP2_ERR_CANCEL:

    return "Cancel";

  case NGHTTP2_ERR_SETTINGS_EXPECTED:

    return "When a local endpoint expects to receive SETTINGS frame, it "

           "receives an other type of frame";

  case NGHTTP2_ERR_NOMEM:

    return "Out of memory";

  case NGHTTP2_ERR_CALLBACK_FAILURE:

    return "The user callback function failed";

  case NGHTTP2_ERR_BAD_CLIENT_MAGIC:

    return "Received bad client magic byte string";

  case NGHTTP2_ERR_FLOODED:

    return "Flooding was detected in this HTTP/2 session, and it must be "

           "closed";

  case NGHTTP2_ERR_TOO_MANY_SETTINGS:

    return "SETTINGS frame contained more than the maximum allowed entries";

  case NGHTTP2_ERR_TOO_MANY_CONTINUATIONS:

    return "Too many CONTINUATION frames following a HEADER frame";

  default:

    return "Unknown error code";

  }

}

static const uint8_t VALID_HD_NAME_CHARS[256] = {

  ['!'] = 1, ['#'] = 1, ['$'] = 1, ['%'] = 1, ['&'] = 1, ['\''] = 1, ['*'] = 1,

  ['+'] = 1, ['-'] = 1, ['.'] = 1, ['0'] = 1, ['1'] = 1, ['2'] = 1,  ['3'] = 1,

  ['4'] = 1, ['5'] = 1, ['6'] = 1, ['7'] = 1, ['8'] = 1, ['9'] = 1,  ['A'] = 2,

  ['B'] = 2, ['C'] = 2, ['D'] = 2, ['E'] = 2, ['F'] = 2, ['G'] = 2,  ['H'] = 2,

  ['I'] = 2, ['J'] = 2, ['K'] = 2, ['L'] = 2, ['M'] = 2, ['N'] = 2,  ['O'] = 2,

  ['P'] = 2, ['Q'] = 2, ['R'] = 2, ['S'] = 2, ['T'] = 2, ['U'] = 2,  ['V'] = 2,

  ['W'] = 2, ['X'] = 2, ['Y'] = 2, ['Z'] = 2, ['^'] = 1, ['_'] = 1,  ['`'] = 1,

  ['a'] = 1, ['b'] = 1, ['c'] = 1, ['d'] = 1, ['e'] = 1, ['f'] = 1,  ['g'] = 1,

  ['h'] = 1, ['i'] = 1, ['j'] = 1, ['k'] = 1, ['l'] = 1, ['m'] = 1,  ['n'] = 1,

  ['o'] = 1, ['p'] = 1, ['q'] = 1, ['r'] = 1, ['s'] = 1, ['t'] = 1,  ['u'] = 1,

  ['v'] = 1, ['w'] = 1, ['x'] = 1, ['y'] = 1, ['z'] = 1, ['|'] = 1,  ['~'] = 1,

};

int nghttp2_check_header_name(const uint8_t *name, size_t len) {

  const uint8_t *last;

  if (len == 0) {

    return 0;

  }

  if (*name == ':') {

    if (len == 1) {

      return 0;

    }

    ++name;

    --len;

  }

  for (last = name + len; name != last; ++name) {

    if (VALID_HD_NAME_CHARS[*name] != 1) {

      return 0;

    }

  }

  return 1;

}

int nghttp2_check_nonempty_header_name(const uint8_t *name, size_t len) {

  const uint8_t *last;

  int rv;

  for (last = name + len; name != last; ++name) {

    rv = VALID_HD_NAME_CHARS[*name];

    if (rv != 1) {

      return rv;

    }

  }

  return 1;

}

static const uint8_t VALID_HD_VALUE_CHARS[256] = {

  ['\t'] = 1, [' '] = 1,  ['!'] = 1,  ['"'] = 1,  ['#'] = 1,  ['$'] = 1,

  ['%'] = 1,  ['&'] = 1,  ['\''] = 1, ['('] = 1,  [')'] = 1,  ['*'] = 1,

  ['+'] = 1,  [','] = 1,  ['-'] = 1,  ['.'] = 1,  ['/'] = 1,  ['0'] = 1,

  ['1'] = 1,  ['2'] = 1,  ['3'] = 1,  ['4'] = 1,  ['5'] = 1,  ['6'] = 1,

  ['7'] = 1,  ['8'] = 1,  ['9'] = 1,  [':'] = 1,  [';'] = 1,  ['<'] = 1,

  ['='] = 1,  ['>'] = 1,  ['?'] = 1,  ['@'] = 1,  ['A'] = 1,  ['B'] = 1,

  ['C'] = 1,  ['D'] = 1,  ['E'] = 1,  ['F'] = 1,  ['G'] = 1,  ['H'] = 1,

  ['I'] = 1,  ['J'] = 1,  ['K'] = 1,  ['L'] = 1,  ['M'] = 1,  ['N'] = 1,

  ['O'] = 1,  ['P'] = 1,  ['Q'] = 1,  ['R'] = 1,  ['S'] = 1,  ['T'] = 1,

  ['U'] = 1,  ['V'] = 1,  ['W'] = 1,  ['X'] = 1,  ['Y'] = 1,  ['Z'] = 1,

  ['['] = 1,  ['\\'] = 1, [']'] = 1,  ['^'] = 1,  ['_'] = 1,  ['`'] = 1,

  ['a'] = 1,  ['b'] = 1,  ['c'] = 1,  ['d'] = 1,  ['e'] = 1,  ['f'] = 1,

  ['g'] = 1,  ['h'] = 1,  ['i'] = 1,  ['j'] = 1,  ['k'] = 1,  ['l'] = 1,

  ['m'] = 1,  ['n'] = 1,  ['o'] = 1,  ['p'] = 1,  ['q'] = 1,  ['r'] = 1,

  ['s'] = 1,  ['t'] = 1,  ['u'] = 1,  ['v'] = 1,  ['w'] = 1,  ['x'] = 1,

  ['y'] = 1,  ['z'] = 1,  ['{'] = 1,  ['|'] = 1,  ['}'] = 1,  ['~'] = 1,

  [0x80] = 1, [0x81] = 1, [0x82] = 1, [0x83] = 1, [0x84] = 1, [0x85] = 1,

  [0x86] = 1, [0x87] = 1, [0x88] = 1, [0x89] = 1, [0x8A] = 1, [0x8B] = 1,

  [0x8C] = 1, [0x8D] = 1, [0x8E] = 1, [0x8F] = 1, [0x90] = 1, [0x91] = 1,

  [0x92] = 1, [0x93] = 1, [0x94] = 1, [0x95] = 1, [0x96] = 1, [0x97] = 1,

  [0x98] = 1, [0x99] = 1, [0x9A] = 1, [0x9B] = 1, [0x9C] = 1, [0x9D] = 1,

  [0x9E] = 1, [0x9F] = 1, [0xA0] = 1, [0xA1] = 1, [0xA2] = 1, [0xA3] = 1,

  [0xA4] = 1, [0xA5] = 1, [0xA6] = 1, [0xA7] = 1, [0xA8] = 1, [0xA9] = 1,

  [0xAA] = 1, [0xAB] = 1, [0xAC] = 1, [0xAD] = 1, [0xAE] = 1, [0xAF] = 1,

  [0xB0] = 1, [0xB1] = 1, [0xB2] = 1, [0xB3] = 1, [0xB4] = 1, [0xB5] = 1,

  [0xB6] = 1, [0xB7] = 1, [0xB8] = 1, [0xB9] = 1, [0xBA] = 1, [0xBB] = 1,

  [0xBC] = 1, [0xBD] = 1, [0xBE] = 1, [0xBF] = 1, [0xC0] = 1, [0xC1] = 1,

  [0xC2] = 1, [0xC3] = 1, [0xC4] = 1, [0xC5] = 1, [0xC6] = 1, [0xC7] = 1,

  [0xC8] = 1, [0xC9] = 1, [0xCA] = 1, [0xCB] = 1, [0xCC] = 1, [0xCD] = 1,

  [0xCE] = 1, [0xCF] = 1, [0xD0] = 1, [0xD1] = 1, [0xD2] = 1, [0xD3] = 1,

  [0xD4] = 1, [0xD5] = 1, [0xD6] = 1, [0xD7] = 1, [0xD8] = 1, [0xD9] = 1,

  [0xDA] = 1, [0xDB] = 1, [0xDC] = 1, [0xDD] = 1, [0xDE] = 1, [0xDF] = 1,

  [0xE0] = 1, [0xE1] = 1, [0xE2] = 1, [0xE3] = 1, [0xE4] = 1, [0xE5] = 1,

  [0xE6] = 1, [0xE7] = 1, [0xE8] = 1, [0xE9] = 1, [0xEA] = 1, [0xEB] = 1,

  [0xEC] = 1, [0xED] = 1, [0xEE] = 1, [0xEF] = 1, [0xF0] = 1, [0xF1] = 1,

  [0xF2] = 1, [0xF3] = 1, [0xF4] = 1, [0xF5] = 1, [0xF6] = 1, [0xF7] = 1,

  [0xF8] = 1, [0xF9] = 1, [0xFA] = 1, [0xFB] = 1, [0xFC] = 1, [0xFD] = 1,

  [0xFE] = 1, [0xFF] = 1,

};

int nghttp2_check_header_value(const uint8_t *value, size_t len) {

  const uint8_t *last;

  for (last = value + len; value != last; ++value) {

    if (!VALID_HD_VALUE_CHARS[*value]) {

      return 0;

    }

  }

  return 1;

}

int nghttp2_check_header_value_rfc9113(const uint8_t *value, size_t len) {

  if (len == 0) {

    return 1;

  }

  if (*value == ' ' || *value == '\t' || *(value + len - 1) == ' ' ||

      *(value + len - 1) == '\t') {

    return 0;

  }

  return nghttp2_check_header_value(value, len);

}

static const uint8_t VALID_METHOD_CHARS[256] = {

  ['!'] = 1, ['#'] = 1, ['$'] = 1, ['%'] = 1, ['&'] = 1, ['\''] = 1, ['*'] = 1,

  ['+'] = 1, ['-'] = 1, ['.'] = 1, ['0'] = 1, ['1'] = 1, ['2'] = 1,  ['3'] = 1,

  ['4'] = 1, ['5'] = 1, ['6'] = 1, ['7'] = 1, ['8'] = 1, ['9'] = 1,  ['A'] = 1,

  ['B'] = 1, ['C'] = 1, ['D'] = 1, ['E'] = 1, ['F'] = 1, ['G'] = 1,  ['H'] = 1,

  ['I'] = 1, ['J'] = 1, ['K'] = 1, ['L'] = 1, ['M'] = 1, ['N'] = 1,  ['O'] = 1,

  ['P'] = 1, ['Q'] = 1, ['R'] = 1, ['S'] = 1, ['T'] = 1, ['U'] = 1,  ['V'] = 1,

  ['W'] = 1, ['X'] = 1, ['Y'] = 1, ['Z'] = 1, ['^'] = 1, ['_'] = 1,  ['`'] = 1,

  ['a'] = 1, ['b'] = 1, ['c'] = 1, ['d'] = 1, ['e'] = 1, ['f'] = 1,  ['g'] = 1,

  ['h'] = 1, ['i'] = 1, ['j'] = 1, ['k'] = 1, ['l'] = 1, ['m'] = 1,  ['n'] = 1,

  ['o'] = 1, ['p'] = 1, ['q'] = 1, ['r'] = 1, ['s'] = 1, ['t'] = 1,  ['u'] = 1,

  ['v'] = 1, ['w'] = 1, ['x'] = 1, ['y'] = 1, ['z'] = 1, ['|'] = 1,  ['~'] = 1,

};

int nghttp2_check_method(const uint8_t *value, size_t len) {

  const uint8_t *last;

  if (len == 0) {

    return 0;

  }

  for (last = value + len; value != last; ++value) {

    if (!VALID_METHOD_CHARS[*value]) {

      return 0;

    }

  }

  return 1;

}

static const uint8_t VALID_PATH_CHARS[256] = {

  ['!'] = 1,  ['"'] = 1,  ['#'] = 1,  ['$'] = 1,  ['%'] = 1,  ['&'] = 1,

  ['\''] = 1, ['('] = 1,  [')'] = 1,  ['*'] = 1,  ['+'] = 1,  [','] = 1,

  ['-'] = 1,  ['.'] = 1,  ['/'] = 1,  ['0'] = 1,  ['1'] = 1,  ['2'] = 1,

  ['3'] = 1,  ['4'] = 1,  ['5'] = 1,  ['6'] = 1,  ['7'] = 1,  ['8'] = 1,

  ['9'] = 1,  [':'] = 1,  [';'] = 1,  ['<'] = 1,  ['='] = 1,  ['>'] = 1,

  ['?'] = 1,  ['@'] = 1,  ['A'] = 1,  ['B'] = 1,  ['C'] = 1,  ['D'] = 1,

  ['E'] = 1,  ['F'] = 1,  ['G'] = 1,  ['H'] = 1,  ['I'] = 1,  ['J'] = 1,

  ['K'] = 1,  ['L'] = 1,  ['M'] = 1,  ['N'] = 1,  ['O'] = 1,  ['P'] = 1,

  ['Q'] = 1,  ['R'] = 1,  ['S'] = 1,  ['T'] = 1,  ['U'] = 1,  ['V'] = 1,

  ['W'] = 1,  ['X'] = 1,  ['Y'] = 1,  ['Z'] = 1,  ['['] = 1,  ['\\'] = 1,

  [']'] = 1,  ['^'] = 1,  ['_'] = 1,  ['`'] = 1,  ['a'] = 1,  ['b'] = 1,

  ['c'] = 1,  ['d'] = 1,  ['e'] = 1,  ['f'] = 1,  ['g'] = 1,  ['h'] = 1,

  ['i'] = 1,  ['j'] = 1,  ['k'] = 1,  ['l'] = 1,  ['m'] = 1,  ['n'] = 1,

  ['o'] = 1,  ['p'] = 1,  ['q'] = 1,  ['r'] = 1,  ['s'] = 1,  ['t'] = 1,

  ['u'] = 1,  ['v'] = 1,  ['w'] = 1,  ['x'] = 1,  ['y'] = 1,  ['z'] = 1,

  ['{'] = 1,  ['|'] = 1,  ['}'] = 1,  ['~'] = 1,  [0x80] = 1, [0x81] = 1,

  [0x82] = 1, [0x83] = 1, [0x84] = 1, [0x85] = 1, [0x86] = 1, [0x87] = 1,

  [0x88] = 1, [0x89] = 1, [0x8A] = 1, [0x8B] = 1, [0x8C] = 1, [0x8D] = 1,

  [0x8E] = 1, [0x8F] = 1, [0x90] = 1, [0x91] = 1, [0x92] = 1, [0x93] = 1,

  [0x94] = 1, [0x95] = 1, [0x96] = 1, [0x97] = 1, [0x98] = 1, [0x99] = 1,

  [0x9A] = 1, [0x9B] = 1, [0x9C] = 1, [0x9D] = 1, [0x9E] = 1, [0x9F] = 1,

  [0xA0] = 1, [0xA1] = 1, [0xA2] = 1, [0xA3] = 1, [0xA4] = 1, [0xA5] = 1,

  [0xA6] = 1, [0xA7] = 1, [0xA8] = 1, [0xA9] = 1, [0xAA] = 1, [0xAB] = 1,

  [0xAC] = 1, [0xAD] = 1, [0xAE] = 1, [0xAF] = 1, [0xB0] = 1, [0xB1] = 1,

  [0xB2] = 1, [0xB3] = 1, [0xB4] = 1, [0xB5] = 1, [0xB6] = 1, [0xB7] = 1,

  [0xB8] = 1, [0xB9] = 1, [0xBA] = 1, [0xBB] = 1, [0xBC] = 1, [0xBD] = 1,

  [0xBE] = 1, [0xBF] = 1, [0xC0] = 1, [0xC1] = 1, [0xC2] = 1, [0xC3] = 1,

  [0xC4] = 1, [0xC5] = 1, [0xC6] = 1, [0xC7] = 1, [0xC8] = 1, [0xC9] = 1,

  [0xCA] = 1, [0xCB] = 1, [0xCC] = 1, [0xCD] = 1, [0xCE] = 1, [0xCF] = 1,

  [0xD0] = 1, [0xD1] = 1, [0xD2] = 1, [0xD3] = 1, [0xD4] = 1, [0xD5] = 1,

  [0xD6] = 1, [0xD7] = 1, [0xD8] = 1, [0xD9] = 1, [0xDA] = 1, [0xDB] = 1,

  [0xDC] = 1, [0xDD] = 1, [0xDE] = 1, [0xDF] = 1, [0xE0] = 1, [0xE1] = 1,

  [0xE2] = 1, [0xE3] = 1, [0xE4] = 1, [0xE5] = 1, [0xE6] = 1, [0xE7] = 1,

  [0xE8] = 1, [0xE9] = 1, [0xEA] = 1, [0xEB] = 1, [0xEC] = 1, [0xED] = 1,

  [0xEE] = 1, [0xEF] = 1, [0xF0] = 1, [0xF1] = 1, [0xF2] = 1, [0xF3] = 1,

  [0xF4] = 1, [0xF5] = 1, [0xF6] = 1, [0xF7] = 1, [0xF8] = 1, [0xF9] = 1,

  [0xFA] = 1, [0xFB] = 1, [0xFC] = 1, [0xFD] = 1, [0xFE] = 1, [0xFF] = 1,

};

int nghttp2_check_path(const uint8_t *value, size_t len) {

  const uint8_t *last;

  for (last = value + len; value != last; ++value) {

    if (!VALID_PATH_CHARS[*value]) {

      return 0;

    }

  }

  return 1;

}

static const uint8_t VALID_AUTHORITY_CHARS[256] = {

  ['!'] = 1, ['$'] = 1, ['%'] = 1, ['&'] = 1, ['\''] = 1, ['('] = 1, [')'] = 1,

  ['*'] = 1, ['+'] = 1, [','] = 1, ['-'] = 1, ['.'] = 1,  ['0'] = 1, ['1'] = 1,

  ['2'] = 1, ['3'] = 1, ['4'] = 1, ['5'] = 1, ['6'] = 1,  ['7'] = 1, ['8'] = 1,

  ['9'] = 1, [':'] = 1, [';'] = 1, ['='] = 1, ['@'] = 1,  ['A'] = 1, ['B'] = 1,

  ['C'] = 1, ['D'] = 1, ['E'] = 1, ['F'] = 1, ['G'] = 1,  ['H'] = 1, ['I'] = 1,

  ['J'] = 1, ['K'] = 1, ['L'] = 1, ['M'] = 1, ['N'] = 1,  ['O'] = 1, ['P'] = 1,

  ['Q'] = 1, ['R'] = 1, ['S'] = 1, ['T'] = 1, ['U'] = 1,  ['V'] = 1, ['W'] = 1,

  ['X'] = 1, ['Y'] = 1, ['Z'] = 1, ['['] = 1, [']'] = 1,  ['_'] = 1, ['a'] = 1,

  ['b'] = 1, ['c'] = 1, ['d'] = 1, ['e'] = 1, ['f'] = 1,  ['g'] = 1, ['h'] = 1,

  ['i'] = 1, ['j'] = 1, ['k'] = 1, ['l'] = 1, ['m'] = 1,  ['n'] = 1, ['o'] = 1,

  ['p'] = 1, ['q'] = 1, ['r'] = 1, ['s'] = 1, ['t'] = 1,  ['u'] = 1, ['v'] = 1,

  ['w'] = 1, ['x'] = 1, ['y'] = 1, ['z'] = 1, ['~'] = 1,

};

int nghttp2_check_authority(const uint8_t *value, size_t len) {

  const uint8_t *last;

  for (last = value + len; value != last; ++value) {

    if (!VALID_AUTHORITY_CHARS[*value]) {

      return 0;

    }

  }

  return 1;

}

uint8_t *nghttp2_cpymem(uint8_t *dest, const void *src, size_t len) {

  if (len == 0) {

    return dest;

  }

  memcpy(dest, src, len);

  return dest + len;

}

const char *nghttp2_http2_strerror(uint32_t error_code) {

  switch (error_code) {

  case NGHTTP2_NO_ERROR:

    return "NO_ERROR";

  case NGHTTP2_PROTOCOL_ERROR:

    return "PROTOCOL_ERROR";

  case NGHTTP2_INTERNAL_ERROR:

    return "INTERNAL_ERROR";

  case NGHTTP2_FLOW_CONTROL_ERROR:

    return "FLOW_CONTROL_ERROR";

  case NGHTTP2_SETTINGS_TIMEOUT:

    return "SETTINGS_TIMEOUT";

  case NGHTTP2_STREAM_CLOSED:

    return "STREAM_CLOSED";

  case NGHTTP2_FRAME_SIZE_ERROR:

    return "FRAME_SIZE_ERROR";

  case NGHTTP2_REFUSED_STREAM:

    return "REFUSED_STREAM";

  case NGHTTP2_CANCEL:

    return "CANCEL";

  case NGHTTP2_COMPRESSION_ERROR:

    return "COMPRESSION_ERROR";

  case NGHTTP2_CONNECT_ERROR:

    return "CONNECT_ERROR";

  case NGHTTP2_ENHANCE_YOUR_CALM:

    return "ENHANCE_YOUR_CALM";

  case NGHTTP2_INADEQUATE_SECURITY:

    return "INADEQUATE_SECURITY";

  case NGHTTP2_HTTP_1_1_REQUIRED:

    return "HTTP_1_1_REQUIRED";

  default:

    return "unknown";

  }

}