text: /*
   * QEMU Block driver for DMG images
   *
   * Copyright (c) 2004 Johannes E. Schindelin
   *
   * 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 "qemu-common.h"
  #include "block_int.h"
  #include "bswap.h"
  #include <zlib.h>
  
  typedef struct BDRVDMGState {
      int fd;
  
      /* each chunk contains a certain number of sectors,
       * offsets[i] is the offset in the .dmg file,
       * lengths[i] is the length of the compressed chunk,
       * sectors[i] is the sector beginning at offsets[i],
       * sectorcounts[i] is the number of sectors in that chunk,
       * the sectors array is ordered
       * 0<=i<n_chunks */
  
      uint32_t n_chunks;
      uint32_t* types;
      uint64_t* offsets;
      uint64_t* lengths;
      uint64_t* sectors;
      uint64_t* sectorcounts;
      uint32_t current_chunk;
      uint8_t *compressed_chunk;
      uint8_t *uncompressed_chunk;
      z_stream zstream;
  } BDRVDMGState;
  
  static int dmg_probe(const uint8_t *buf, int buf_size, const char *filename)
  {
      int len=strlen(filename);
      if(len>4 && !strcmp(filename+len-4,".dmg"))
  	return 2;
      return 0;
  }
  
  static off_t read_off(int fd)
  {
  	uint64_t buffer;
  	if(qemu_read_ok(fd,&buffer,8)<0)
  		return 0;
  	return be64_to_cpu(buffer);
  }
  
  static off_t read_uint32(int fd)
  {
  	uint32_t buffer;
  	if(qemu_read_ok(fd,&buffer,4)<0)
  		return 0;
  	return be32_to_cpu(buffer);
  }
  
  static int dmg_open(BlockDriverState *bs, const char *filename, int flags)
  {
      BDRVDMGState *s = bs->opaque;
      off_t info_begin,info_end,last_in_offset,last_out_offset;
      uint32_t count;
      uint32_t max_compressed_size=1,max_sectors_per_chunk=1,i;
  
      s->fd = open(filename, O_RDONLY | O_BINARY);
      if (s->fd < 0)
          return -errno;
      bs->read_only = 1;
      s->n_chunks = 0;
      s->offsets = s->lengths = s->sectors = s->sectorcounts = 0;
  
      /* read offset of info blocks */
      if(lseek(s->fd,-0x1d8,SEEK_END)<0) {
  dmg_close:
  	close(s->fd);
  	/* open raw instead */
  	bs->drv=&bdrv_raw;
  	return bs->drv->bdrv_open(bs, filename, flags);
      }
      info_begin=read_off(s->fd);
      if(info_begin==0)
  	goto dmg_close;
      if(lseek(s->fd,info_begin,SEEK_SET)<0)
  	goto dmg_close;
      if(read_uint32(s->fd)!=0x100)
  	goto dmg_close;
      if((count = read_uint32(s->fd))==0)
  	goto dmg_close;
      info_end = info_begin+count;
      if(lseek(s->fd,0xf8,SEEK_CUR)<0)
  	goto dmg_close;
  
      /* read offsets */
      last_in_offset = last_out_offset = 0;
      while(lseek(s->fd,0,SEEK_CUR)<info_end) {
          uint32_t type;
  
  	count = read_uint32(s->fd);
  	if(count==0)
  	    goto dmg_close;
  	type = read_uint32(s->fd);
  	if(type!=0x6d697368 || count<244)
  	    lseek(s->fd,count-4,SEEK_CUR);
  	else {
  	    int new_size, chunk_count;
  	    if(lseek(s->fd,200,SEEK_CUR)<0)
  	        goto dmg_close;
  	    chunk_count = (count-204)/40;
  	    new_size = sizeof(uint64_t) * (s->n_chunks + chunk_count);
  	    s->types = qemu_realloc(s->types, new_size/2);
  	    s->offsets = qemu_realloc(s->offsets, new_size);
  	    s->lengths = qemu_realloc(s->lengths, new_size);
  	    s->sectors = qemu_realloc(s->sectors, new_size);
  	    s->sectorcounts = qemu_realloc(s->sectorcounts, new_size);
  
  	    for(i=s->n_chunks;i<s->n_chunks+chunk_count;i++) {
  		s->types[i] = read_uint32(s->fd);
  		if(s->types[i]!=0x80000005 && s->types[i]!=1 && s->types[i]!=2) {
  		    if(s->types[i]==0xffffffff) {
  			last_in_offset = s->offsets[i-1]+s->lengths[i-1];
  			last_out_offset = s->sectors[i-1]+s->sectorcounts[i-1];
  		    }
  		    chunk_count--;
  		    i--;
  		    if(lseek(s->fd,36,SEEK_CUR)<0)
  			goto dmg_close;
  		    continue;
  		}
  		read_uint32(s->fd);
  		s->sectors[i] = last_out_offset+read_off(s->fd);
  		s->sectorcounts[i] = read_off(s->fd);
  		s->offsets[i] = last_in_offset+read_off(s->fd);
  		s->lengths[i] = read_off(s->fd);
  		if(s->lengths[i]>max_compressed_size)
  		    max_compressed_size = s->lengths[i];
  		if(s->sectorcounts[i]>max_sectors_per_chunk)
  		    max_sectors_per_chunk = s->sectorcounts[i];
  	    }
  	    s->n_chunks+=chunk_count;
  	}
      }
  
      /* initialize zlib engine */
      s->compressed_chunk = qemu_malloc(max_compressed_size+1);
      s->uncompressed_chunk = qemu_malloc(512*max_sectors_per_chunk);
      if(inflateInit(&s->zstream) != Z_OK)
  	goto dmg_close;
  
      s->current_chunk = s->n_chunks;
  
      return 0;
  }
  
  static inline int is_sector_in_chunk(BDRVDMGState* s,
  		uint32_t chunk_num,int sector_num)
  {
      if(chunk_num>=s->n_chunks || s->sectors[chunk_num]>sector_num ||
  	    s->sectors[chunk_num]+s->sectorcounts[chunk_num]<=sector_num)
  	return 0;
      else
  	return -1;
  }
  
  static inline uint32_t search_chunk(BDRVDMGState* s,int sector_num)
  {
      /* binary search */
      uint32_t chunk1=0,chunk2=s->n_chunks,chunk3;
      while(chunk1!=chunk2) {
  	chunk3 = (chunk1+chunk2)/2;
  	if(s->sectors[chunk3]>sector_num)
  	    chunk2 = chunk3;
  	else if(s->sectors[chunk3]+s->sectorcounts[chunk3]>sector_num)
  	    return chunk3;
  	else
  	    chunk1 = chunk3;
      }
      return s->n_chunks; /* error */
  }
  
  static inline int dmg_read_chunk(BDRVDMGState *s,int sector_num)
  {
      if(!is_sector_in_chunk(s,s->current_chunk,sector_num)) {
  	int ret;
  	uint32_t chunk = search_chunk(s,sector_num);
  
  	if(chunk>=s->n_chunks)
  	    return -1;
  
  	s->current_chunk = s->n_chunks;
  	switch(s->types[chunk]) {
  	case 0x80000005: { /* zlib compressed */
  	    ret = lseek(s->fd, s->offsets[chunk], SEEK_SET);
  	    if(ret<0)
  		return -1;
  
  	    /* we need to buffer, because only the chunk as whole can be
  	     * inflated. */
  	    ret = qemu_read_ok(s->fd, s->compressed_chunk, s->lengths[chunk]);
  	    if (ret < 0)
  	        return -1;
  
  	    s->zstream.next_in = s->compressed_chunk;
  	    s->zstream.avail_in = s->lengths[chunk];
  	    s->zstream.next_out = s->uncompressed_chunk;
  	    s->zstream.avail_out = 512*s->sectorcounts[chunk];
  	    ret = inflateReset(&s->zstream);
  	    if(ret != Z_OK)
  		return -1;
  	    ret = inflate(&s->zstream, Z_FINISH);
  	    if(ret != Z_STREAM_END || s->zstream.total_out != 512*s->sectorcounts[chunk])
  		return -1;
  	    break; }
  	case 1: /* copy */
  	    ret = qemu_read_ok(s->fd, s->uncompressed_chunk, s->lengths[chunk]);
  	    if (ret < 0)
  		return -1;
  	    break;
  	case 2: /* zero */
  	    memset(s->uncompressed_chunk, 0, 512*s->sectorcounts[chunk]);
  	    break;
  	}
  	s->current_chunk = chunk;
      }
      return 0;
  }
  
  static int dmg_read(BlockDriverState *bs, int64_t sector_num,
                      uint8_t *buf, int nb_sectors)
  {
      BDRVDMGState *s = bs->opaque;
      int i;
  
      for(i=0;i<nb_sectors;i++) {
  	uint32_t sector_offset_in_chunk;
  	if(dmg_read_chunk(s, sector_num+i) != 0)
  	    return -1;
  	sector_offset_in_chunk = sector_num+i-s->sectors[s->current_chunk];
  	memcpy(buf+i*512,s->uncompressed_chunk+sector_offset_in_chunk*512,512);
      }
      return 0;
  }
  
  static void dmg_close(BlockDriverState *bs)
  {
      BDRVDMGState *s = bs->opaque;
      close(s->fd);
      if(s->n_chunks>0) {
  	free(s->types);
  	free(s->offsets);
  	free(s->lengths);
  	free(s->sectors);
  	free(s->sectorcounts);
      }
      free(s->compressed_chunk);
      free(s->uncompressed_chunk);
      inflateEnd(&s->zstream);
  }
  
  BlockDriver bdrv_dmg = {
      "dmg",
      sizeof(BDRVDMGState),
      dmg_probe,
      dmg_open,
      dmg_read,
      NULL,
      dmg_close,
  };
  