/* <!-- copyright */
/*
 * aria2 - a simple utility for downloading files faster
 *
 * Copyright (C) 2006 Tatsuhiro Tsujikawa
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
/* copyright --> */
#include "ChunkedEncoding.h"
#include "DlAbortEx.h"
#include "message.h"
#include <string.h>
#include <strings.h>
#include <errno.h>

#define MAX_BUFSIZE (1024*1024)

ChunkedEncoding::ChunkedEncoding() {
  strbufSize = 4096;
  strbuf = new char[strbufSize];
  strbuf[0] = '\0';
  state = READ_SIZE;
  chunkSize = 0;
}

ChunkedEncoding::~ChunkedEncoding() {
  if(strbuf != NULL) {
    delete [] strbuf;
  }
}

void ChunkedEncoding::init() {
}

bool ChunkedEncoding::finished() {
  return state == FINISH ? true : false;
}

void ChunkedEncoding::end() {}

void ChunkedEncoding::inflate(char* outbuf, int& outlen, const char* inbuf, int inlen) {
  addBuffer(inbuf, inlen);
  char* p = strbuf;
  int clen = 0;
  while(1) {
    if(state == READ_SIZE) {
      if(readChunkSize(&p) == 0) {
	if(chunkSize == 0) {
	  state = FINISH;
	} else {
	  state = READ_DATA;
	}
      } else {
	// chunk size is not fully received.
	break;
      }
    } else if(state == READ_DATA) {
      if(readData(&p, outbuf, clen, outlen) == 0) {
	state = READ_SIZE;
      } else {
	break;
      }
    } else {
      break;
    }
    // Was all bytes in strbuf examined?
    if(strbuf+strlen(strbuf) <= p) {
      break;
    }
  }
  if(strbuf+strlen(strbuf) <= p) {
    // make strbuf NULL-string 
    strbuf[0] = '\0';
  } else {
    // copy string between [p, strbuf+strlen(strbuf)+1], +1 is for NULL
    // character.
    char* temp = new char[strbufSize];
    memcpy(temp, p, strbuf+strlen(strbuf)-p+1);
    delete [] strbuf;
    strbuf = temp;
  }
  outlen = clen;
}

int ChunkedEncoding::readData(char** pp, char* buf, int& len, int maxlen) {
  if(buf+len == buf+maxlen) {
    return -1;
  }
  if(chunkSize == 0) {
    return readDataEOL(pp);
  }
  int wsize;
  if(strlen(*pp) < (unsigned long int)chunkSize) {
    wsize = strlen(*pp) <= (unsigned int)maxlen-len ? strlen(*pp) : maxlen-len;
  } else {
    wsize = chunkSize <= maxlen-len ? chunkSize : maxlen-len;
  }
  memcpy(buf+len, *pp, wsize);
  chunkSize -= wsize;
  len += wsize;
  *pp += wsize;

  if(chunkSize == 0) {
    return readDataEOL(pp);
  } else {
    return -1;
  }
}

int ChunkedEncoding::readDataEOL(char** pp) {
  if(strstr(*pp, "\r\n") == *pp) {
    *pp += 2;
    return 0;
  } else if(strlen(*pp) < 2) {
    return -1;
  } else {
    throw new DlAbortEx(EX_INVALID_CHUNK_SIZE);
  }  
}

// strbuf is NULL terminated string, and inlen is strlen(strbuf).
// therefore, strbuf[inlen] = '\0'
int ChunkedEncoding::readChunkSize(char** pp) {
  // we read chunk-size from *pp
  char* p = strstr(*pp, "\r\n");
  // \r\n is not found. Return -1
  if(p == NULL) {
    return -1;
  }
  // We ignore chunk-extension
  char* exsp = index(*pp, ';');
  if(exsp == NULL) {
    exsp = p;
  }
  // TODO check invalid characters in buffer
  chunkSize = strtol(*pp, NULL, 16);
  if(chunkSize < 0) {
    throw new DlAbortEx(EX_INVALID_CHUNK_SIZE);
  } else if(errno == ERANGE && (chunkSize == LONG_MAX || chunkSize == LONG_MIN)) {
    throw new DlAbortEx(strerror(errno));
  }
  *pp = p+2;

  return 0;
}

void ChunkedEncoding::addBuffer(const char* inbuf, int inlen) {
  if(strlen(strbuf)+inlen >= (unsigned int)strbufSize) {
    if(strlen(strbuf)+inlen+1 > MAX_BUFSIZE) {
      throw new DlAbortEx(EX_TOO_LARGE_CHUNK, strlen(strbuf)+inlen+1);
    }
    strbufSize = strlen(strbuf)+inlen+1;
    char* temp = new char[strbufSize];
    memcpy(temp, strbuf, strlen(strbuf)+1);
    delete [] strbuf;
    strbuf = temp;
  }
  int origlen = strlen(strbuf);
  memcpy(strbuf+origlen, inbuf, inlen);
  strbuf[origlen+inlen] = '\0';
}