/*
 * Spdylay - SPDY 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 "spdylay_frame.h"

#include <arpa/inet.h>
#include <string.h>
#include <assert.h>
#include <stdio.h>

#include "spdylay_helper.h"

#define spdylay_frame_get_nv_len(IN, LEN_SIZE)                          \
  (LEN_SIZE == 2 ? spdylay_get_uint16(IN) : spdylay_get_uint32(IN))

#define spdylay_frame_put_nv_len(OUT, VAL, LEN_SIZE)                    \
  (LEN_SIZE == 2 ?                                                      \
   spdylay_put_uint16be(OUT, VAL) : spdylay_put_uint32be(OUT, VAL))

/* Returns the number of bytes in length of name/value pair for the
   given protocol version |version|. If |version| is not supported,
   returns 0. */
static size_t spdylay_frame_get_len_size(uint16_t version)
{
  if(SPDYLAY_PROTO_SPDY2 == version) {
    return 2;
  } else if(SPDYLAY_PROTO_SPDY3 == version) {
    return 4;
  } else {
    /* Unsupported version */
    return 0;
  }
}

static uint8_t spdylay_unpack_pri(const uint8_t *data)
{
  return (data[0] >> 6) & 0x3;
}

static uint8_t* spdylay_pack_str(uint8_t *buf, const char *str, size_t len,
                                 size_t len_size)
{
  spdylay_frame_put_nv_len(buf, len, len_size);
  buf += len_size;
  memcpy(buf, str, len);
  return buf+len;
}

static void spdylay_frame_pack_ctrl_hd(uint8_t* buf, const spdylay_ctrl_hd *hd)
{
  spdylay_put_uint16be(&buf[0], hd->version);
  buf[0] |= 1 << 7;
  spdylay_put_uint16be(&buf[2], hd->type);
  spdylay_put_uint32be(&buf[4], hd->length);
  buf[4] = hd->flags;
}

static void spdylay_frame_unpack_ctrl_hd(spdylay_ctrl_hd *hd,
                                         const uint8_t* buf)
{
  hd->version = spdylay_get_uint16(buf) & SPDYLAY_VERSION_MASK;
  hd->type = spdylay_get_uint16(&buf[2]);
  hd->flags = buf[4];
  hd->length = spdylay_get_uint32(&buf[4]) & SPDYLAY_LENGTH_MASK;
}

ssize_t spdylay_frame_alloc_pack_nv(uint8_t **buf_ptr,
                                    size_t *buflen_ptr,
                                    uint8_t **nvbuf_ptr,
                                    size_t *nvbuflen_ptr,
                                    char **nv, size_t nv_offset,
                                    size_t len_size,
                                    spdylay_zlib *deflater)
{
  size_t nvspace;
  size_t maxframelen;
  ssize_t framelen;
  int r;
  nvspace = spdylay_frame_count_nv_space(nv, len_size);
  r = spdylay_reserve_buffer(nvbuf_ptr, nvbuflen_ptr, nvspace);
  if(r != 0) {
    return SPDYLAY_ERR_NOMEM;
  }
  maxframelen = nv_offset+spdylay_zlib_deflate_hd_bound(deflater, nvspace);
  r = spdylay_reserve_buffer(buf_ptr, buflen_ptr, maxframelen);
  if(r != 0) {
    return SPDYLAY_ERR_NOMEM;
  }
  spdylay_frame_pack_nv(*nvbuf_ptr, nv, len_size);
  framelen = spdylay_zlib_deflate_hd(deflater,
                                     (*buf_ptr)+nv_offset,
                                     maxframelen-nv_offset,
                                     *nvbuf_ptr, nvspace);
  if(framelen < 0) {
    return framelen;
  }
  framelen += nv_offset;
  return framelen;
}

int spdylay_frame_count_unpack_nv_space
(size_t *nvlen_ptr, size_t *buflen_ptr, const uint8_t *in, size_t inlen,
 size_t len_size)
{
  uint32_t n;
  size_t buflen = 0;
  size_t nvlen = 0;
  size_t off = 0;
  size_t i;
  if(inlen < len_size) {
    return SPDYLAY_ERR_INVALID_FRAME;
  }
  /* TODO limit n in a reasonable number */
  n = spdylay_frame_get_nv_len(in, len_size);
  off += len_size;
  for(i = 0; i < n; ++i) {
    uint32_t len;
    size_t j;
    for(j = 0; j < 2; ++j) {
      if(inlen-off < len_size) {
        return SPDYLAY_ERR_INVALID_FRAME;
      }
      len = spdylay_frame_get_nv_len(in+off, len_size);
      off += len_size;
      if(inlen-off < len) {
        return SPDYLAY_ERR_INVALID_FRAME;
      }
      buflen += len+1;
      off += len;
    }
    for(j = off, off -= len; off != j; ++off) {
      if(in[off] == '\0') {
        ++nvlen;
      }
    }
    ++nvlen;
  }
  if(inlen == off) {
    *nvlen_ptr = nvlen;
    *buflen_ptr = buflen+(nvlen*2+1)*sizeof(char*);
    return 0;
  } else {
    return SPDYLAY_ERR_INVALID_FRAME;
  }
}

int spdylay_frame_unpack_nv(char ***nv_ptr, const uint8_t *in, size_t inlen,
                            size_t len_size)
{
  size_t nvlen, buflen;
  int r;
  size_t i;
  char *buf, **index, *data;
  uint32_t n;
  r = spdylay_frame_count_unpack_nv_space(&nvlen, &buflen, in, inlen, len_size);
  if(r != 0) {
    return r;
  }
  buf = malloc(buflen);
  if(buf == NULL) {
    return SPDYLAY_ERR_NOMEM;
  }
  index = (char**)buf;
  data = buf+(nvlen*2+1)*sizeof(char*);
  n = spdylay_frame_get_nv_len(in, len_size);
  in += len_size;
  for(i = 0; i < n; ++i) {
    uint32_t len;
    char *name, *val;
    char *stop;
    len = spdylay_frame_get_nv_len(in, len_size);
    in += len_size;
    name = data;
    memcpy(data, in, len);
    data += len;
    *data = '\0';
    ++data;
    in += len;

    len = spdylay_frame_get_nv_len(in, len_size);
    in += len_size;
    val = data;
    memcpy(data, in, len);

    for(stop = data+len; data != stop; ++data) {
      if(*data == '\0') {
        *index++ = name;
        *index++ = val;
        val = data+1;
      }
    }
    *data = '\0';
    ++data;
    in += len;

    *index++ = name;
    *index++ = val;
  }
  *index = NULL;
  assert((size_t)((char*)index - buf) == (nvlen*2)*sizeof(char*));
  *nv_ptr = (char**)buf;
  return 0;
}

int spdylay_frame_alloc_unpack_nv(char ***nv_ptr,
                                  spdylay_buffer *inflatebuf,
                                  uint8_t **nvbuf_ptr,
                                  size_t *nvbuflen_ptr,
                                  const uint8_t *in, size_t inlen,
                                  size_t len_size,
                                  spdylay_zlib *inflater)
{
  ssize_t nvspace;
  int r;
  nvspace = spdylay_zlib_inflate_hd(inflater, inflatebuf, in, inlen);
  if(nvspace < 0) {
    return nvspace;
  } else {
    r = spdylay_reserve_buffer(nvbuf_ptr, nvbuflen_ptr, nvspace);
    if(r != 0) {
      return SPDYLAY_ERR_NOMEM;
    }
    spdylay_buffer_serialize(inflatebuf, *nvbuf_ptr);
    r = spdylay_frame_unpack_nv(nv_ptr, *nvbuf_ptr, nvspace, len_size);
    return r;
  }
}

size_t spdylay_frame_count_nv_space(char **nv, size_t len_size)
{
  size_t sum = len_size;
  int i;
  const char *prev = "";
  size_t prevlen = 0;
  for(i = 0; nv[i]; i += 2) {
    const char *key = nv[i];
    const char *val = nv[i+1];
    size_t keylen = strlen(key);
    size_t vallen = strlen(val);
    if(prevlen == keylen && memcmp(prev, key, keylen) == 0) {
      /* Join previous value, with NULL character */
      sum += vallen+1;
    } else {
      prev = key;
      prevlen = keylen;
      /* SPDY NV header does not include terminating NULL byte */
      sum += keylen+vallen+len_size*2;
    }
  }
  return sum;
}

ssize_t spdylay_frame_pack_nv(uint8_t *buf, char **nv, size_t len_size)
{
  int i;
  uint8_t *bufp = buf+len_size;
  uint32_t num_nv = 0;
  /* TODO Join values with same keys, using '\0' as a delimiter */
  const char *prev = "";
  uint8_t *prev_vallen_buf = NULL;
  uint32_t prev_vallen = 0;
  for(i = 0; nv[i]; i += 2) {
    const char *key = nv[i];
    const char *val = nv[i+1];
    size_t keylen = strlen(key);
    size_t vallen = strlen(val);
    if(strcmp(prev, key) == 0) {
      prev_vallen += vallen+1;
      spdylay_frame_put_nv_len(prev_vallen_buf, prev_vallen, len_size);
      *bufp = '\0';
      ++bufp;
      memcpy(bufp, val, vallen);
      bufp += vallen;
    } else {
      ++num_nv;
      bufp = spdylay_pack_str(bufp, key, keylen, len_size);
      prev = key;
      prev_vallen_buf = bufp;
      prev_vallen = vallen;
      bufp = spdylay_pack_str(bufp, val, vallen, len_size);
    }
  }
  spdylay_frame_put_nv_len(buf, num_nv, len_size);
  return bufp-buf;
}

int spdylay_frame_is_ctrl_frame(uint8_t first_byte)
{
  return first_byte & 0x80;
}

void spdylay_frame_nv_del(char **nv)
{
  free(nv);
}

char** spdylay_frame_nv_copy(const char **nv)
{
  int i;
  char *buf;
  char **index, *data;
  size_t buflen = 0;
  for(i = 0; nv[i]; ++i) {
    buflen += strlen(nv[i])+1;
  }
  buflen += (i+1)*sizeof(char*);
  buf = malloc(buflen);
  if(buf == NULL) {
    return NULL;
  }
  index = (char**)buf;
  data = buf+(i+1)*sizeof(char*);

  for(i = 0; nv[i]; ++i) {
    size_t len = strlen(nv[i])+1;
    memcpy(data, nv[i], len);
    *index++ = data;
    data += len;
  }
  *index = NULL;
  return (char**)buf;
}

static int spdylay_string_compar(const void *lhs, const void *rhs)
{
  return strcmp(*(char **)lhs, *(char **)rhs);
}

void spdylay_frame_nv_sort(char **nv)
{
  int n;
  for(n = 0; nv[n]; ++n);
  qsort(nv, n/2, 2*sizeof(char*), spdylay_string_compar);
}

void spdylay_frame_nv_downcase(char **nv)
{
  int i, j;
  for(i = 0; nv[i]; i += 2) {
    for(j = 0; nv[i][j] != '\0'; ++j) {
      if('A' <= nv[i][j] && nv[i][j] <= 'Z') {
        nv[i][j] += 'a'-'A';
      }
    }
  }
}

char** spdylay_frame_nv_norm_copy(const char **nv)
{
  char **nv_copy;
  nv_copy = spdylay_frame_nv_copy(nv);
  if(nv_copy != NULL) {
    spdylay_frame_nv_downcase(nv_copy);
    spdylay_frame_nv_sort(nv_copy);
  }
  return nv_copy;
}

/* Table to translate SPDY/3 header names to SPDY/2. */
static char *spdylay_nv_3to2[] = {
  ":host", "host",
  ":method", "method",
  ":path", "url",
  ":scheme", "scheme",
  ":status", "status",
  ":version", "version",
  NULL
};

void spdylay_frame_nv_3to2(char **nv)
{
  int i, j;
  for(i = 0; nv[i]; i += 2) {
    for(j = 0; spdylay_nv_3to2[j]; j += 2) {
      if(strcmp(nv[i], spdylay_nv_3to2[j]) == 0) {
        nv[i] = spdylay_nv_3to2[j+1];
        break;
      }
    }
  }
}

void spdylay_frame_nv_2to3(char **nv)
{
  int i, j;
  for(i = 0; nv[i]; i += 2) {
    for(j = 0; spdylay_nv_3to2[j]; j += 2) {
      if(strcmp(nv[i], spdylay_nv_3to2[j+1]) == 0) {
        nv[i] = spdylay_nv_3to2[j];
        break;
      }
    }
  }
}

void spdylay_frame_syn_stream_init(spdylay_syn_stream *frame,
                                   uint16_t version, uint8_t flags,
                                   int32_t stream_id, int32_t assoc_stream_id,
                                   uint8_t pri, char **nv)
{
  memset(frame, 0, sizeof(spdylay_syn_stream));
  frame->hd.version = version;
  frame->hd.type = SPDYLAY_SYN_STREAM;
  frame->hd.flags = flags;
  frame->stream_id = stream_id;
  frame->assoc_stream_id = assoc_stream_id;
  frame->pri = pri;
  frame->nv = nv;
}

void spdylay_frame_syn_stream_free(spdylay_syn_stream *frame)
{
  spdylay_frame_nv_del(frame->nv);
}

void spdylay_frame_syn_reply_init(spdylay_syn_reply *frame,
                                  uint16_t version, uint8_t flags,
                                  int32_t stream_id, char **nv)
{
  memset(frame, 0, sizeof(spdylay_syn_reply));
  frame->hd.version = version;
  frame->hd.type = SPDYLAY_SYN_REPLY;
  frame->hd.flags = flags;
  frame->stream_id = stream_id;
  frame->nv = nv;
}

void spdylay_frame_syn_reply_free(spdylay_syn_reply *frame)
{
  spdylay_frame_nv_del(frame->nv);
}

void spdylay_frame_ping_init(spdylay_ping *frame,
                             uint16_t version, uint32_t unique_id)
{
  memset(frame, 0, sizeof(spdylay_ping));
  frame->hd.version = version;
  frame->hd.type = SPDYLAY_PING;
  frame->hd.flags = SPDYLAY_CTRL_FLAG_NONE;
  frame->hd.length = 4;
  frame->unique_id = unique_id;
}

void spdylay_frame_ping_free(spdylay_ping *frame)
{}

void spdylay_frame_goaway_init(spdylay_goaway *frame,
                               uint16_t version, int32_t last_good_stream_id,
                               uint32_t status_code)
{
  memset(frame, 0, sizeof(spdylay_goaway));
  frame->hd.version = version;
  frame->hd.type = SPDYLAY_GOAWAY;
  if(version == SPDYLAY_PROTO_SPDY2) {
    frame->hd.length = 4;
  } else if(version == SPDYLAY_PROTO_SPDY3) {
    frame->hd.length = 8;
    frame->status_code = status_code;
  } else {
    frame->hd.length = 0;
  }
  frame->last_good_stream_id = last_good_stream_id;
}

void spdylay_frame_goaway_free(spdylay_goaway *frame)
{}

void spdylay_frame_headers_init(spdylay_headers *frame,
                                uint16_t version, uint8_t flags,
                                int32_t stream_id, char **nv)
{
  memset(frame, 0, sizeof(spdylay_headers));
  frame->hd.version = version;
  frame->hd.type = SPDYLAY_HEADERS;
  frame->hd.flags = flags;
  frame->stream_id = stream_id;
  frame->nv = nv;
}

void spdylay_frame_headers_free(spdylay_headers *frame)
{
  spdylay_frame_nv_del(frame->nv);
}

void spdylay_frame_rst_stream_init(spdylay_rst_stream *frame,
                                   uint16_t version,
                                   int32_t stream_id, uint32_t status_code)
{
  memset(frame, 0, sizeof(spdylay_rst_stream));
  frame->hd.version = version;
  frame->hd.type = SPDYLAY_RST_STREAM;
  frame->hd.flags = 0;
  frame->hd.length = 8;
  frame->stream_id = stream_id;
  frame->status_code = status_code;
}

void spdylay_frame_rst_stream_free(spdylay_rst_stream *frame)
{}

void spdylay_frame_window_update_init(spdylay_window_update *frame,
                                      uint16_t version,
                                      int32_t stream_id,
                                      int32_t delta_window_size)
{
  memset(frame, 0, sizeof(spdylay_window_update));
  frame->hd.version = version;
  frame->hd.type = SPDYLAY_WINDOW_UPDATE;
  frame->hd.flags = 0;
  frame->hd.length = 8;
  frame->stream_id = stream_id;
  frame->delta_window_size = delta_window_size;
}

void spdylay_frame_window_update_free(spdylay_window_update *frame)
{}

void spdylay_frame_settings_init(spdylay_settings *frame,
                                 uint16_t version, uint8_t flags,
                                 spdylay_settings_entry *iv, size_t niv)
{
  memset(frame, 0, sizeof(spdylay_settings));
  frame->hd.version = version;
  frame->hd.type = SPDYLAY_SETTINGS;
  frame->hd.flags = flags;
  frame->hd.length = 4+niv*8;
  frame->niv = niv;
  frame->iv = iv;
}

void spdylay_frame_settings_free(spdylay_settings *frame)
{
  free(frame->iv);
}

void spdylay_frame_data_init(spdylay_data *frame, int32_t stream_id,
                             uint8_t flags,
                             const spdylay_data_provider *data_prd)
{
  memset(frame, 0, sizeof(spdylay_data));
  frame->stream_id = stream_id;
  frame->flags = flags;
  frame->data_prd = *data_prd;
}

void spdylay_frame_data_free(spdylay_data *frame)
{}

#define SPDYLAY_SYN_STREAM_NV_OFFSET 18

ssize_t spdylay_frame_pack_syn_stream(uint8_t **buf_ptr,
                                      size_t *buflen_ptr,
                                      uint8_t **nvbuf_ptr,
                                      size_t *nvbuflen_ptr,
                                      spdylay_syn_stream *frame,
                                      spdylay_zlib *deflater)
{
  ssize_t framelen;
  size_t len_size = spdylay_frame_get_len_size(frame->hd.version);
  if(len_size == 0) {
    return SPDYLAY_ERR_UNSUPPORTED_VERSION;
  }
  framelen = spdylay_frame_alloc_pack_nv(buf_ptr, buflen_ptr,
                                         nvbuf_ptr, nvbuflen_ptr,
                                         frame->nv,
                                         SPDYLAY_SYN_STREAM_NV_OFFSET,
                                         len_size,
                                         deflater);
  if(framelen < 0) {
    return framelen;
  }
  frame->hd.length = framelen-SPDYLAY_FRAME_HEAD_LENGTH;
  memset(*buf_ptr, 0, SPDYLAY_SYN_STREAM_NV_OFFSET);
  /* pack ctrl header after length is determined */
  spdylay_frame_pack_ctrl_hd(*buf_ptr, &frame->hd);
  spdylay_put_uint32be(&(*buf_ptr)[8], frame->stream_id);
  spdylay_put_uint32be(&(*buf_ptr)[12], frame->assoc_stream_id);
  (*buf_ptr)[16] = (frame->pri << 6);
  if(frame->hd.version == SPDYLAY_PROTO_SPDY3) {
    (*buf_ptr)[17] = frame->slot;
  }
  return framelen;
}

int spdylay_frame_unpack_syn_stream(spdylay_syn_stream *frame,
                                    spdylay_buffer *inflatebuf,
                                    uint8_t **nvbuf_ptr,
                                    size_t *nvbuflen_ptr,
                                    const uint8_t *head, size_t headlen,
                                    const uint8_t *payload, size_t payloadlen,
                                    spdylay_zlib *inflater)
{
  int r;
  size_t len_size;
  if(payloadlen < 12) {
    return SPDYLAY_ERR_INVALID_FRAME;
  }
  spdylay_frame_unpack_ctrl_hd(&frame->hd, head);
  len_size = spdylay_frame_get_len_size(frame->hd.version);
  if(len_size == 0) {
    return SPDYLAY_ERR_UNSUPPORTED_VERSION;
  }
  frame->stream_id = spdylay_get_uint32(payload) & SPDYLAY_STREAM_ID_MASK;
  frame->assoc_stream_id =
    spdylay_get_uint32(payload+4) & SPDYLAY_STREAM_ID_MASK;
  frame->pri = spdylay_unpack_pri(payload+8);
  if(frame->hd.version == SPDYLAY_PROTO_SPDY3) {
    frame->slot = payload[9];
  } else {
    frame->slot = 0;
  }
  r = spdylay_frame_alloc_unpack_nv(&frame->nv, inflatebuf,
                                    nvbuf_ptr, nvbuflen_ptr,
                                    payload+10, payloadlen-10,
                                    len_size,
                                    inflater);
  return r;
}

#define SPDYLAY_SPDY2_SYN_REPLY_NV_OFFSET 14
#define SPDYLAY_SPDY3_SYN_REPLY_NV_OFFSET 12

ssize_t spdylay_frame_pack_syn_reply(uint8_t **buf_ptr,
                                     size_t *buflen_ptr,
                                     uint8_t **nvbuf_ptr,
                                     size_t *nvbuflen_ptr,
                                     spdylay_syn_reply *frame,
                                     spdylay_zlib *deflater)
{
  ssize_t framelen;
  size_t len_size;
  size_t nv_offset;
  len_size = spdylay_frame_get_len_size(frame->hd.version);
  if(len_size == 0) {
    return SPDYLAY_ERR_UNSUPPORTED_VERSION;
  }
  nv_offset = frame->hd.version == SPDYLAY_PROTO_SPDY2 ?
    SPDYLAY_SPDY2_SYN_REPLY_NV_OFFSET : SPDYLAY_SPDY3_SYN_REPLY_NV_OFFSET;

  framelen = spdylay_frame_alloc_pack_nv(buf_ptr, buflen_ptr,
                                         nvbuf_ptr, nvbuflen_ptr,
                                         frame->nv, nv_offset,
                                         len_size, deflater);
  if(framelen < 0) {
    return framelen;
  }
  frame->hd.length = framelen-SPDYLAY_FRAME_HEAD_LENGTH;
  memset(*buf_ptr, 0, nv_offset);
  spdylay_frame_pack_ctrl_hd(*buf_ptr, &frame->hd);
  spdylay_put_uint32be(&(*buf_ptr)[8], frame->stream_id);
  return framelen;
}

int spdylay_frame_unpack_syn_reply(spdylay_syn_reply *frame,
                                   spdylay_buffer *inflatebuf,
                                   uint8_t **nvbuf_ptr,
                                   size_t *nvbuflen_ptr,
                                   const uint8_t *head, size_t headlen,
                                   const uint8_t *payload, size_t payloadlen,
                                   spdylay_zlib *inflater)
{
  int r;
  size_t len_size;
  size_t nv_offset;
  if(payloadlen < 8) {
    return SPDYLAY_ERR_INVALID_FRAME;
  }
  spdylay_frame_unpack_ctrl_hd(&frame->hd, head);
  len_size = spdylay_frame_get_len_size(frame->hd.version);
  if(len_size == 0) {
    return SPDYLAY_ERR_UNSUPPORTED_VERSION;
  }
  nv_offset = frame->hd.version == SPDYLAY_PROTO_SPDY2 ? 6 : 4;
  frame->stream_id = spdylay_get_uint32(payload) & SPDYLAY_STREAM_ID_MASK;
  r = spdylay_frame_alloc_unpack_nv(&frame->nv, inflatebuf,
                                    nvbuf_ptr, nvbuflen_ptr,
                                    payload+nv_offset, payloadlen-nv_offset,
                                    len_size, inflater);
  return r;
}

ssize_t spdylay_frame_pack_ping(uint8_t **buf_ptr, size_t *buflen_ptr,
                                spdylay_ping *frame)
{
  ssize_t framelen = 12;
  int r;
  r = spdylay_reserve_buffer(buf_ptr, buflen_ptr, framelen);
  if(r != 0) {
    return r;
  }
  memset(*buf_ptr, 0, framelen);
  spdylay_frame_pack_ctrl_hd(*buf_ptr, &frame->hd);
  spdylay_put_uint32be(&(*buf_ptr)[8], frame->unique_id);
  return framelen;
}

int spdylay_frame_unpack_ping(spdylay_ping *frame,
                              const uint8_t *head, size_t headlen,
                              const uint8_t *payload, size_t payloadlen)
{
  if(payloadlen != 4) {
    return SPDYLAY_ERR_INVALID_FRAME;
  }
  spdylay_frame_unpack_ctrl_hd(&frame->hd, head);
  frame->unique_id = spdylay_get_uint32(payload);
  return 0;
}

ssize_t spdylay_frame_pack_goaway(uint8_t **buf_ptr, size_t *buflen_ptr,
                                  spdylay_goaway *frame)
{
  ssize_t framelen;
  int r;
  if(frame->hd.version == SPDYLAY_PROTO_SPDY2) {
    framelen = 12;
  } else if(frame->hd.version == SPDYLAY_PROTO_SPDY3) {
    framelen = 16;
  } else {
    return SPDYLAY_ERR_UNSUPPORTED_VERSION;
  }
  r = spdylay_reserve_buffer(buf_ptr, buflen_ptr, framelen);
  if(r != 0) {
    return r;
  }
  memset(*buf_ptr, 0, framelen);
  spdylay_frame_pack_ctrl_hd(*buf_ptr, &frame->hd);
  spdylay_put_uint32be(&(*buf_ptr)[8], frame->last_good_stream_id);
  if(frame->hd.version == SPDYLAY_PROTO_SPDY3) {
    spdylay_put_uint32be(&(*buf_ptr)[12], frame->status_code);
  }
  return framelen;
}

int spdylay_frame_unpack_goaway(spdylay_goaway *frame,
                                const uint8_t *head, size_t headlen,
                                const uint8_t *payload, size_t payloadlen)
{
  spdylay_frame_unpack_ctrl_hd(&frame->hd, head);
  if(frame->hd.version == SPDYLAY_PROTO_SPDY2) {
    if(payloadlen != 4) {
      return SPDYLAY_ERR_INVALID_FRAME;
    }
  } else if(frame->hd.version == SPDYLAY_PROTO_SPDY3) {
    if(payloadlen != 8) {
      return SPDYLAY_ERR_INVALID_FRAME;
    }
  } else {
    return SPDYLAY_ERR_UNSUPPORTED_VERSION;
  }
  frame->last_good_stream_id = spdylay_get_uint32(payload) &
    SPDYLAY_STREAM_ID_MASK;
  if(frame->hd.version == SPDYLAY_PROTO_SPDY3) {
    frame->status_code = spdylay_get_uint32(payload+4);
  } else {
    frame->status_code = 0;
  }
  return 0;
}

#define SPDYLAY_SPDY2_HEADERS_NV_OFFSET 14
#define SPDYLAY_SPDY3_HEADERS_NV_OFFSET 12

ssize_t spdylay_frame_pack_headers(uint8_t **buf_ptr, size_t *buflen_ptr,
                                   uint8_t **nvbuf_ptr, size_t *nvbuflen_ptr,
                                   spdylay_headers *frame,
                                   spdylay_zlib *deflater)
{
  ssize_t framelen;
  size_t len_size;
  size_t nv_offset;
  len_size = spdylay_frame_get_len_size(frame->hd.version);
  if(len_size == 0) {
    return SPDYLAY_ERR_UNSUPPORTED_VERSION;
  }
  nv_offset = frame->hd.version == SPDYLAY_PROTO_SPDY2 ?
    SPDYLAY_SPDY2_HEADERS_NV_OFFSET : SPDYLAY_SPDY3_HEADERS_NV_OFFSET;
  framelen = spdylay_frame_alloc_pack_nv(buf_ptr, buflen_ptr,
                                         nvbuf_ptr, nvbuflen_ptr,
                                         frame->nv, nv_offset,
                                         len_size, deflater);
  if(framelen < 0) {
    return framelen;
  }
  frame->hd.length = framelen-SPDYLAY_FRAME_HEAD_LENGTH;
  memset(*buf_ptr, 0, nv_offset);
  spdylay_frame_pack_ctrl_hd(*buf_ptr, &frame->hd);
  spdylay_put_uint32be(&(*buf_ptr)[8], frame->stream_id);
  return framelen;
}

int spdylay_frame_unpack_headers(spdylay_headers *frame,
                                 spdylay_buffer *inflatebuf,
                                 uint8_t **nvbuf_ptr,
                                 size_t *nvbuflen_ptr,
                                 const uint8_t *head, size_t headlen,
                                 const uint8_t *payload, size_t payloadlen,
                                 spdylay_zlib *inflater)
{
  int r;
  size_t len_size;
  size_t nv_offset;
  if(payloadlen < 8) {
    return SPDYLAY_ERR_INVALID_FRAME;
  }
  spdylay_frame_unpack_ctrl_hd(&frame->hd, head);
  len_size = spdylay_frame_get_len_size(frame->hd.version);
  if(len_size == 0) {
    return SPDYLAY_ERR_UNSUPPORTED_VERSION;
  }
  nv_offset = frame->hd.version == SPDYLAY_PROTO_SPDY2 ? 6 : 4;
  frame->stream_id = spdylay_get_uint32(payload) & SPDYLAY_STREAM_ID_MASK;
  r = spdylay_frame_alloc_unpack_nv(&frame->nv, inflatebuf,
                                    nvbuf_ptr, nvbuflen_ptr,
                                    payload+nv_offset, payloadlen-nv_offset,
                                    len_size, inflater);
  return r;
}

ssize_t spdylay_frame_pack_rst_stream(uint8_t **buf_ptr, size_t *buflen_ptr,
                                      spdylay_rst_stream *frame)
{
  ssize_t framelen = 16;
  int r;
  r = spdylay_reserve_buffer(buf_ptr, buflen_ptr, framelen);
  if(r != 0) {
    return r;
  }
  memset(*buf_ptr, 0, framelen);
  spdylay_frame_pack_ctrl_hd(*buf_ptr, &frame->hd);
  spdylay_put_uint32be(&(*buf_ptr)[8], frame->stream_id);
  spdylay_put_uint32be(&(*buf_ptr)[12], frame->status_code);
  return framelen;
}

int spdylay_frame_unpack_rst_stream(spdylay_rst_stream *frame,
                                    const uint8_t *head, size_t headlen,
                                    const uint8_t *payload, size_t payloadlen)
{
  if(payloadlen != 8) {
    return SPDYLAY_ERR_INVALID_FRAME;
  }
  spdylay_frame_unpack_ctrl_hd(&frame->hd, head);
  frame->stream_id = spdylay_get_uint32(payload) & SPDYLAY_STREAM_ID_MASK;
  frame->status_code = spdylay_get_uint32(payload+4);
  return 0;
}

ssize_t spdylay_frame_pack_window_update(uint8_t **buf_ptr, size_t *buflen_ptr,
                                         spdylay_window_update *frame)
{
  ssize_t framelen = 16;
  int r;
  r = spdylay_reserve_buffer(buf_ptr, buflen_ptr, framelen);
  if(r != 0) {
    return r;
  }
  memset(*buf_ptr, 0, framelen);
  spdylay_frame_pack_ctrl_hd(*buf_ptr, &frame->hd);
  spdylay_put_uint32be(&(*buf_ptr)[8], frame->stream_id);
  spdylay_put_uint32be(&(*buf_ptr)[12], frame->delta_window_size);
  return framelen;
}

int spdylay_frame_unpack_window_update(spdylay_window_update *frame,
                                       const uint8_t *head, size_t headlen,
                                       const uint8_t *payload,
                                       size_t payloadlen)
{
  if(payloadlen != 8) {
    return SPDYLAY_ERR_INVALID_FRAME;
  }
  spdylay_frame_unpack_ctrl_hd(&frame->hd, head);
  frame->stream_id = spdylay_get_uint32(payload) & SPDYLAY_STREAM_ID_MASK;
  frame->delta_window_size = spdylay_get_uint32(&payload[4]) &
    SPDYLAY_DELTA_WINDOW_SIZE_MASK;
  return 0;
}

ssize_t spdylay_frame_pack_settings(uint8_t **buf_ptr, size_t *buflen_ptr,
                                    spdylay_settings *frame)
{
  ssize_t framelen = SPDYLAY_FRAME_HEAD_LENGTH+frame->hd.length;
  size_t i;
  int r;
  if(frame->hd.version != SPDYLAY_PROTO_SPDY2 &&
     frame->hd.version != SPDYLAY_PROTO_SPDY3) {
    return SPDYLAY_ERR_UNSUPPORTED_VERSION;
  }
  r = spdylay_reserve_buffer(buf_ptr, buflen_ptr, framelen);
  if(r != 0) {
    return r;
  }
  memset(*buf_ptr, 0, framelen);
  spdylay_frame_pack_ctrl_hd(*buf_ptr, &frame->hd);
  spdylay_put_uint32be(&(*buf_ptr)[8], frame->niv);
  if(frame->hd.version == SPDYLAY_PROTO_SPDY2) {
    for(i = 0; i < frame->niv; ++i) {
      int off = i*8;
      /* spdy/2 spec says ID is network byte order, but publicly
         deployed server sends little endian host byte order. */
      char *id_ptr = (char*)(&frame->iv[i].settings_id);
#ifdef WORDS_BIGENDIAN
      (*buf_ptr)[12+off] = id_ptr[3];
      (*buf_ptr)[12+off+1] = id_ptr[2];
      (*buf_ptr)[12+off+2] = id_ptr[1];
#else /* !WORDS_BIGENDIAN */
      memcpy(&(*buf_ptr)[12+off], id_ptr, 3);
#endif /* !WORDS_BIGENDIAN */
      (*buf_ptr)[15+off] = frame->iv[i].flags;
      spdylay_put_uint32be(&(*buf_ptr)[16+off], frame->iv[i].value);
    }
  } else {
    for(i = 0; i < frame->niv; ++i) {
      int off = i*8;
      spdylay_put_uint32be(&(*buf_ptr)[12+off], frame->iv[i].settings_id);
      (*buf_ptr)[12+off] = frame->iv[i].flags;
      spdylay_put_uint32be(&(*buf_ptr)[16+off], frame->iv[i].value);
    }
  }
  return framelen;
}

int spdylay_frame_unpack_settings(spdylay_settings *frame,
                                  const uint8_t *head, size_t headlen,
                                  const uint8_t *payload, size_t payloadlen)
{
  size_t i;
  if(payloadlen < 4) {
    return SPDYLAY_ERR_INVALID_FRAME;
  }
  spdylay_frame_unpack_ctrl_hd(&frame->hd, head);
  if(frame->hd.version != SPDYLAY_PROTO_SPDY2 &&
     frame->hd.version != SPDYLAY_PROTO_SPDY3) {
    return SPDYLAY_ERR_UNSUPPORTED_VERSION;
  }
  frame->niv = spdylay_get_uint32(payload);
  if(payloadlen != 4+frame->niv*8) {
    return SPDYLAY_ERR_INVALID_FRAME;
  }
  frame->iv = malloc(frame->niv*sizeof(spdylay_settings_entry));
  if(frame->iv == NULL) {
    return SPDYLAY_ERR_NOMEM;
  }
  if(frame->hd.version == SPDYLAY_PROTO_SPDY2) {
    for(i = 0; i < frame->niv; ++i) {
      size_t off = i*8;
      /* ID is little endian. See comments in
         spdylay_frame_pack_settings(). */
      frame->iv[i].settings_id = 0;
#ifdef WORDS_BIGENDIAN
      *(char*)(&frame->iv[i].settings_id[1]) = &payload[4+off+2];
      *(char*)(&frame->iv[i].settings_id[2]) = &payload[4+off+1];
      *(char*)(&frame->iv[i].settings_id[3]) = &payload[4+off+0];
#else /* !WORDS_BIGENDIAN */
      memcpy(&frame->iv[i].settings_id, &payload[4+off], 3);
#endif /* !WORDS_BIGENDIAN */
      frame->iv[i].flags = payload[7+off];
      frame->iv[i].value = spdylay_get_uint32(&payload[8+off]);
    }
  } else {
    for(i = 0; i < frame->niv; ++i) {
      size_t off = i*8;
      frame->iv[i].settings_id = spdylay_get_uint32(&payload[4+off]) &
        SPDYLAY_SETTINGS_ID_MASK;
      frame->iv[i].flags = payload[4+off];
      frame->iv[i].value = spdylay_get_uint32(&payload[8+off]);
    }
  }
  return 0;
}

spdylay_settings_entry* spdylay_frame_iv_copy(const spdylay_settings_entry *iv,
                                              size_t niv)
{
  spdylay_settings_entry *iv_copy;
  size_t len = niv*sizeof(spdylay_settings_entry);
  iv_copy = malloc(len);
  if(iv_copy == NULL) {
    return NULL;
  }
  memcpy(iv_copy, iv, len);
  return iv_copy;
}

static int spdylay_settings_entry_compar(const void *lhs, const void *rhs)
{
  return ((spdylay_settings_entry *)lhs)->settings_id
    -((spdylay_settings_entry *)rhs)->settings_id;
}

void spdylay_frame_iv_sort(spdylay_settings_entry *iv, size_t niv)
{
  qsort(iv, niv, sizeof(spdylay_settings_entry), spdylay_settings_entry_compar);
}