#include "usuals.h"
#include "httpauthd.h"

#include <syslog.h>

/* -----------------------------------------------------------------------
 * Memory Buffer
 */

/*
 * LEGEND:
 * _al: allocated
 * _dt: data
 * _rp: read/write point
 * _pp: parse/begin point
 */

void buffer_bump(ha_buffer_t* buf, int count)
{
  if(ha_buferr(buf))
    return;

  if(buf->_rp + count >= buf->_dt + buf->_al)
  {
    char* old = buf->_dt;
    int alloc = buf->_al;
    int diff;

    while((buf->_al + count) > alloc)
      alloc *= 2;

    buf->_dt = (char*)reallocf(buf->_dt, alloc * sizeof(char));
    if(!buf->_dt)
    {
      buf->_al = 0;
      buf->_rp = buf->_pp = NULL;
      ha_messagex(LOG_CRIT, "out of memory");
      return;
    }

    buf->_al = alloc;

    diff = buf->_dt - old;
    buf->_rp += diff;
    buf->_pp += diff;
  }
}

void ha_bufreset(ha_buffer_t* buf)
{
  if(!buf->_dt || buf->_al == 0)
  {
    buf->_dt = (char*)reallocf(buf->_dt, 256 * sizeof(char));
    if(!buf->_dt)
    {
      buf->_al = 0;
      buf->_rp = buf->_pp = NULL;
      ha_messagex(LOG_CRIT, "out of memory");
      return;
    }

    buf->_al = 256;
  }

  buf->_rp = buf->_dt;
  buf->_pp = buf->_dt;
}

void ha_bufinit(ha_buffer_t* buf)
{
  memset(buf, 0, sizeof(*buf));
  ha_bufreset(buf);
}

void ha_buffree(ha_buffer_t* buf)
{
  if(buf->_dt)
    free(buf->_dt);

  buf->_al = 0;
  buf->_rp = buf->_pp = NULL;
}

int ha_readline(int fd, ha_buffer_t* buf)
{
  int l;

  if(ha_buferr(buf))
    return 0;

  for(;;)
  {
    buffer_bump(buf, 1);
    l = read(fd, (void*)buf->_rp, sizeof(char));

    /* We got a character */
    if(l == 1)
    {
      /* Skip junky CRLFs */
      if(*(buf->_rp) == '\r')
      {
        *(buf->_rp) = ' ';
        continue;
      }

      /* End of line */
      else if(*(buf->_rp) == '\n')
      {
        buf->_rp++;
        break;
      }

      /* All other characters */
      else
      {
        buf->_rp++;
      }
    }

    /* If it's the end of file then return that */
    else if(l == 0)
      return 0;

    /* Transient errors */
    else if(l == -1 && (errno == EINTR || errno == EAGAIN))
      continue;

    /* Fatal errors */
    else if(l == -1)
    {
      ha_message(LOG_ERR, "couldn't read data");
      return 0;
    }
  }

  return 1;
}

char* ha_parseword(ha_buffer_t* buf, const char* delims)
{
  char* word = NULL;

  if(ha_buferr(buf))
    return NULL;

  /* Knock out any previous delims */
  while(buf->_pp < buf->_rp && strchr(delims, *(buf->_pp)))
    buf->_pp++;

  /* If at end of buffer or end of line return null */
  if(buf->_pp == buf->_rp || *(buf->_pp) == '\n')
    return NULL;

  /* We do this before we stash away a pointer */
  buffer_bump(buf, 1);

  word = buf->_pp;

  while(!strchr(delims, *(buf->_pp)))
  {
    buf->_pp++;

    /* At the end of the buffer */
    if(buf->_pp == buf->_rp)
    {
      *(buf->_rp) = 0;
      buf->_rp++;
      break;
    }

    /* At the end of a line */
    else if(*(buf->_pp) == '\n')
      break;
  }

  /* Now null terminate what we found */
  *(buf->_pp) = 0;
  buf->_pp++;

  /* We don't return empty strings */
  if(word[0] == 0)
    return NULL;

  return word;
}

char* ha_parseline(ha_buffer_t* buf, int trim)
{
  char* t;
  char* line = NULL;

  if(ha_buferr(buf))
    return NULL;

  if(trim)
  {
    /* Knock out any previous whitespace */
    while(buf->_pp < buf->_rp && isblank(*(buf->_pp)))
      buf->_pp++;
  }

  if(buf->_pp == buf->_rp)
    return NULL;

  /* We do this before we stash away a pointer */
  buffer_bump(buf, 1);

  line = buf->_pp;

  t = (char*)memchr(buf->_pp, '\n', ha_buflen(buf));
  if(t == NULL)
  {
    t = (buf->_rp);
    buf->_rp++;
  }

  *t = 0;
  buf->_pp = t + 1;

  if(trim)
  {
    while(t > line && isspace(*(--t)))
      *t = 0;
  }

  /* We don't return empty strings */
  if(line[0] == 0)
    return NULL;

  return line;
}

void ha_bufnext(ha_buffer_t* buf)
{
  buffer_bump(buf, 1);

  if(!ha_buferr(buf))
  {
    buf->_rp++;
    buf->_pp = buf->_rp;
    *(buf->_rp) = 0;
  }
}

void ha_bufcat(ha_buffer_t* buf, ...)
{
  const char* str;
  va_list ap;

  va_start(ap, buf);

  while((str = va_arg(ap, char*)) != NULL)
  {
    int len = strlen(str);

    buffer_bump(buf, len);

    if(ha_buferr(buf))
      return;

    /* _rpoint points to teh null */
    strcpy(buf->_rp, str);
    buf->_rp += len;
  }
}

void* ha_bufmalloc(ha_buffer_t* buf, size_t sz)
{
  void* ret;

  ha_bufnext(buf);
  buffer_bump(buf, sz);
  buf->_rp += sz;

  if(ha_buferr(buf))
    return NULL;

  ret = (void*)ha_bufdata(buf);
  ha_bufnext(buf);

  return ret;
}

/*
 * Portions Copyright (c) 1995 by International Business Machines, Inc.
 *
 * International Business Machines, Inc. (hereinafter called IBM) grants
 * permission under its copyrights to use, copy, modify, and distribute this
 * Software with or without fee, provided that the above copyright notice and
 * all paragraphs of this notice appear in all copies, and that the name of IBM
 * not be used in connection with the marketing of any product incorporating
 * the Software or modifications thereof, without specific, written prior
 * permission.
 *
 * To the extent it has a right to do so, IBM grants an immunity from suit
 * under its patents, if any, for the use, sale or manufacture of products to
 * the extent that such products are used for performing Domain Name System
 * dynamic updates in TCP/IP networks by means of the Software.  No immunity is
 * granted for any product per se or for any other function of any product.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", AND IBM DISCLAIMS ALL WARRANTIES,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 * PARTICULAR PURPOSE.  IN NO EVENT SHALL IBM BE LIABLE FOR ANY SPECIAL,
 * DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE, EVEN
 * IF IBM IS APPRISED OF THE POSSIBILITY OF SUCH DAMAGES.
 */

static const char BASE64C[] =
        "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
static const char PAD64C = '=';

void ha_bufenc64(ha_buffer_t* buf, const char* src, int len)
{
  unsigned char input[3];
  unsigned char output[4];
  size_t i;

  if(len == -1)
    len = strlen(src);

  while(2 < len)
  {
    input[0] = *src++;
    input[1] = *src++;
    input[2] = *src++;
    len -= 3;

    output[0] = input[0] >> 2;
    output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
    output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
    output[3] = input[2] & 0x3f;

    buffer_bump(buf, 5);

    if(ha_buferr(buf))
      return;

    *(buf->_rp++) = BASE64C[output[0]];
    *(buf->_rp++) = BASE64C[output[1]];
    *(buf->_rp++) = BASE64C[output[2]];
    *(buf->_rp++) = BASE64C[output[3]];
  }

  /* Now we worry about padding. */
  if(0 != len)
   {
    /* Get what's left. */
    input[0] = input[1] = input[2] = '\0';
    for(i = 0; i < len; i++)
      input[i] = *src++;

    output[0] = input[0] >> 2;
    output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
    output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);

    buffer_bump(buf, 5);

    if(ha_buferr(buf))
      return;

    *(buf->_rp++) = BASE64C[output[0]];
    *(buf->_rp++) = BASE64C[output[1]];
    if(len == 1)
      *(buf->_rp++) = PAD64C;
    else
      *(buf->_rp++) = BASE64C[output[2]];
    *(buf->_rp++) = PAD64C;
  }

  *(buf->_rp++) = '\0';
}

void ha_bufdec64(ha_buffer_t* buf, const char* src)
{
  int state;
  int ch;
  char* pos;

  state = 0;

  while((ch = *src++) != '\0')
  {
    if(isspace(ch))        /* Skip whitespace anywhere. */
      continue;

    if(ch == PAD64C)
      break;

    pos = strchr(BASE64C, ch);
    if(pos == 0)           /* A non-base64 character. */
      break;

    buffer_bump(buf, 3);

    if(ha_buferr(buf))
      return;

    switch(state)
    {
    case 0:
      *(buf->_rp++) = (pos - BASE64C) << 2;
      state = 1;
      break;

    case 1:
      *(buf->_rp++) |= (pos - BASE64C) >> 4;
      *(buf->_rp) = ((pos - BASE64C) & 0x0f) << 4;
      state = 2;
      break;

    case 2:
      *(buf->_rp++) |= (pos - BASE64C) >> 2;
      *(buf->_rp) = ((pos - BASE64C) & 0x03) << 6;
      state = 3;
      break;

    case 3:
      *(buf->_rp++) |= (pos - BASE64C);
      state = 0;
      break;
    };

    /* TODO: Validate ending and return error if invalid somehow */
  }

  *(buf->_rp++) = '\0';
}