1/* XzIn.c - Xz input
22009-06-19 : Igor Pavlov : Public domain */
3
4#include <string.h>
5
6#include "7zCrc.h"
7#include "CpuArch.h"
8#include "Xz.h"
9
10SRes Xz_ReadHeader(CXzStreamFlags *p, ISeqInStream *inStream)
11{
12  Byte sig[XZ_STREAM_HEADER_SIZE];
13  RINOK(SeqInStream_Read2(inStream, sig, XZ_STREAM_HEADER_SIZE, SZ_ERROR_NO_ARCHIVE));
14  if (memcmp(sig, XZ_SIG, XZ_SIG_SIZE) != 0)
15    return SZ_ERROR_NO_ARCHIVE;
16  return Xz_ParseHeader(p, sig);
17}
18
19#define READ_VARINT_AND_CHECK(buf, pos, size, res) \
20  { unsigned s = Xz_ReadVarInt(buf + pos, size - pos, res); \
21  if (s == 0) return SZ_ERROR_ARCHIVE; pos += s; }
22
23SRes XzBlock_ReadHeader(CXzBlock *p, ISeqInStream *inStream, Bool *isIndex, UInt32 *headerSizeRes)
24{
25  Byte header[XZ_BLOCK_HEADER_SIZE_MAX];
26  unsigned headerSize;
27  *headerSizeRes = 0;
28  RINOK(SeqInStream_ReadByte(inStream, &header[0]));
29  headerSize = ((unsigned)header[0] << 2) + 4;
30  if (headerSize == 0)
31  {
32    *headerSizeRes = 1;
33    *isIndex = True;
34    return SZ_OK;
35  }
36
37  *isIndex = False;
38  *headerSizeRes = headerSize;
39  RINOK(SeqInStream_Read(inStream, header + 1, headerSize - 1));
40  return XzBlock_Parse(p, header);
41}
42
43#define ADD_SIZE_CHECH(size, val) \
44  { UInt64 newSize = size + (val); if (newSize < size) return XZ_SIZE_OVERFLOW; size = newSize; }
45
46UInt64 Xz_GetUnpackSize(const CXzStream *p)
47{
48  UInt64 size = 0;
49  size_t i;
50  for (i = 0; i < p->numBlocks; i++)
51    ADD_SIZE_CHECH(size, p->blocks[i].unpackSize);
52  return size;
53}
54
55UInt64 Xz_GetPackSize(const CXzStream *p)
56{
57  UInt64 size = 0;
58  size_t i;
59  for (i = 0; i < p->numBlocks; i++)
60    ADD_SIZE_CHECH(size, (p->blocks[i].totalSize + 3) & ~(UInt64)3);
61  return size;
62}
63
64/*
65SRes XzBlock_ReadFooter(CXzBlock *p, CXzStreamFlags f, ISeqInStream *inStream)
66{
67  return SeqInStream_Read(inStream, p->check, XzFlags_GetCheckSize(f));
68}
69*/
70
71static SRes Xz_ReadIndex2(CXzStream *p, const Byte *buf, size_t size, ISzAlloc *alloc)
72{
73  size_t i, numBlocks, crcStartPos, pos = 1;
74  UInt32 crc;
75
76  if (size < 5 || buf[0] != 0)
77    return SZ_ERROR_ARCHIVE;
78
79  size -= 4;
80  crc = CrcCalc(buf, size);
81  if (crc != GetUi32(buf + size))
82    return SZ_ERROR_ARCHIVE;
83
84  {
85    UInt64 numBlocks64;
86    READ_VARINT_AND_CHECK(buf, pos, size, &numBlocks64);
87    numBlocks = (size_t)numBlocks64;
88    if (numBlocks != numBlocks64 || numBlocks * 2 > size)
89      return SZ_ERROR_ARCHIVE;
90  }
91
92  crcStartPos = pos;
93  Xz_Free(p, alloc);
94  if (numBlocks != 0)
95  {
96    p->numBlocks = numBlocks;
97    p->numBlocksAllocated = numBlocks;
98    p->blocks = alloc->Alloc(alloc, sizeof(CXzBlockSizes) * numBlocks);
99    if (p->blocks == 0)
100      return SZ_ERROR_MEM;
101    for (i = 0; i < numBlocks; i++)
102    {
103      CXzBlockSizes *block = &p->blocks[i];
104      READ_VARINT_AND_CHECK(buf, pos, size, &block->totalSize);
105      READ_VARINT_AND_CHECK(buf, pos, size, &block->unpackSize);
106      if (block->totalSize == 0)
107        return SZ_ERROR_ARCHIVE;
108    }
109  }
110  while ((pos & 3) != 0)
111    if (buf[pos++] != 0)
112      return SZ_ERROR_ARCHIVE;
113  return (pos == size) ? SZ_OK : SZ_ERROR_ARCHIVE;
114}
115
116static SRes Xz_ReadIndex(CXzStream *p, ILookInStream *stream, UInt64 indexSize, ISzAlloc *alloc)
117{
118  SRes res;
119  size_t size;
120  Byte *buf;
121  if (indexSize > ((UInt32)1 << 31))
122    return SZ_ERROR_UNSUPPORTED;
123  size = (size_t)indexSize;
124  if (size != indexSize)
125    return SZ_ERROR_UNSUPPORTED;
126  buf = alloc->Alloc(alloc, size);
127  if (buf == 0)
128    return SZ_ERROR_MEM;
129  res = LookInStream_Read2(stream, buf, size, SZ_ERROR_UNSUPPORTED);
130  if (res == SZ_OK)
131    res = Xz_ReadIndex2(p, buf, size, alloc);
132  alloc->Free(alloc, buf);
133  return res;
134}
135
136static SRes SeekFromCur(ILookInStream *inStream, Int64 *res)
137{
138  return inStream->Seek(inStream, res, SZ_SEEK_CUR);
139}
140
141static SRes Xz_ReadBackward(CXzStream *p, ILookInStream *stream, Int64 *startOffset, ISzAlloc *alloc)
142{
143  UInt64 indexSize;
144  Byte buf[XZ_STREAM_FOOTER_SIZE];
145
146  if ((*startOffset & 3) != 0 || *startOffset < XZ_STREAM_FOOTER_SIZE)
147    return SZ_ERROR_NO_ARCHIVE;
148  *startOffset = -XZ_STREAM_FOOTER_SIZE;
149  RINOK(SeekFromCur(stream, startOffset));
150
151  RINOK(LookInStream_Read2(stream, buf, XZ_STREAM_FOOTER_SIZE, SZ_ERROR_NO_ARCHIVE));
152
153  if (memcmp(buf + 10, XZ_FOOTER_SIG, XZ_FOOTER_SIG_SIZE) != 0)
154  {
155    Int64 i = 0;
156    *startOffset += XZ_STREAM_FOOTER_SIZE;
157    for (;;)
158    {
159      int j;
160      size_t processedSize;
161      #define TEMP_BUF_SIZE (1 << 10)
162      Byte tempBuf[TEMP_BUF_SIZE];
163      if (*startOffset < XZ_STREAM_FOOTER_SIZE || i > (1 << 16))
164        return SZ_ERROR_NO_ARCHIVE;
165      processedSize = (*startOffset > TEMP_BUF_SIZE) ? TEMP_BUF_SIZE : (size_t)*startOffset;
166      i += processedSize;
167      *startOffset = -(Int64)processedSize;
168      RINOK(SeekFromCur(stream, startOffset));
169      RINOK(LookInStream_Read2(stream, tempBuf, processedSize, SZ_ERROR_NO_ARCHIVE));
170      for (j = (int)processedSize; j >= 0; j--)
171        if (tempBuf[j -1] != 0)
172          break;
173      if (j != 0)
174      {
175        if ((j & 3) != 0)
176          return SZ_ERROR_NO_ARCHIVE;
177        *startOffset += j;
178        if (*startOffset < XZ_STREAM_FOOTER_SIZE)
179          return SZ_ERROR_NO_ARCHIVE;
180        *startOffset -= XZ_STREAM_FOOTER_SIZE;
181        RINOK(stream->Seek(stream, startOffset, SZ_SEEK_SET));
182        RINOK(LookInStream_Read2(stream, buf, XZ_STREAM_FOOTER_SIZE, SZ_ERROR_NO_ARCHIVE));
183        if (memcmp(buf + 10, XZ_FOOTER_SIG, XZ_FOOTER_SIG_SIZE) != 0)
184          return SZ_ERROR_NO_ARCHIVE;
185        break;
186      }
187    }
188  }
189
190  p->flags = (CXzStreamFlags)GetBe16(buf + 8);
191
192  if (!XzFlags_IsSupported(p->flags))
193    return SZ_ERROR_UNSUPPORTED;
194
195  if (GetUi32(buf) != CrcCalc(buf + 4, 6))
196    return SZ_ERROR_ARCHIVE;
197
198  indexSize = ((UInt64)GetUi32(buf + 4) + 1) << 2;
199
200  *startOffset = -(Int64)(indexSize + XZ_STREAM_FOOTER_SIZE);
201  RINOK(SeekFromCur(stream, startOffset));
202
203  RINOK(Xz_ReadIndex(p, stream, indexSize, alloc));
204
205  {
206    UInt64 totalSize = Xz_GetPackSize(p);
207    UInt64 sum = XZ_STREAM_HEADER_SIZE + totalSize + indexSize;
208    if (totalSize == XZ_SIZE_OVERFLOW ||
209      sum >= ((UInt64)1 << 63) ||
210      totalSize >= ((UInt64)1 << 63))
211      return SZ_ERROR_ARCHIVE;
212    *startOffset = -(Int64)sum;
213    RINOK(SeekFromCur(stream, startOffset));
214  }
215  {
216    CXzStreamFlags headerFlags;
217    CSecToRead secToRead;
218    SecToRead_CreateVTable(&secToRead);
219    secToRead.realStream = stream;
220
221    RINOK(Xz_ReadHeader(&headerFlags, &secToRead.s));
222    return (p->flags == headerFlags) ? SZ_OK : SZ_ERROR_ARCHIVE;
223  }
224}
225
226
227/* ---------- Xz Streams ---------- */
228
229void Xzs_Construct(CXzs *p)
230{
231  p->num = p->numAllocated = 0;
232  p->streams = 0;
233}
234
235void Xzs_Free(CXzs *p, ISzAlloc *alloc)
236{
237  size_t i;
238  for (i = 0; i < p->num; i++)
239    Xz_Free(&p->streams[i], alloc);
240  alloc->Free(alloc, p->streams);
241  p->num = p->numAllocated = 0;
242  p->streams = 0;
243}
244
245UInt64 Xzs_GetNumBlocks(const CXzs *p)
246{
247  UInt64 num = 0;
248  size_t i;
249  for (i = 0; i < p->num; i++)
250    num += p->streams[i].numBlocks;
251  return num;
252}
253
254UInt64 Xzs_GetUnpackSize(const CXzs *p)
255{
256  UInt64 size = 0;
257  size_t i;
258  for (i = 0; i < p->num; i++)
259    ADD_SIZE_CHECH(size, Xz_GetUnpackSize(&p->streams[i]));
260  return size;
261}
262
263/*
264UInt64 Xzs_GetPackSize(const CXzs *p)
265{
266  UInt64 size = 0;
267  size_t i;
268  for (i = 0; i < p->num; i++)
269    ADD_SIZE_CHECH(size, Xz_GetTotalSize(&p->streams[i]));
270  return size;
271}
272*/
273
274SRes Xzs_ReadBackward(CXzs *p, ILookInStream *stream, Int64 *startOffset, ICompressProgress *progress, ISzAlloc *alloc)
275{
276  Int64 endOffset = 0;
277  RINOK(stream->Seek(stream, &endOffset, SZ_SEEK_END));
278  *startOffset = endOffset;
279  for (;;)
280  {
281    CXzStream st;
282    SRes res;
283    Xz_Construct(&st);
284    res = Xz_ReadBackward(&st, stream, startOffset, alloc);
285    st.startOffset = *startOffset;
286    RINOK(res);
287    if (p->num == p->numAllocated)
288    {
289      size_t newNum = p->num + p->num / 4 + 1;
290      Byte *data = (Byte *)alloc->Alloc(alloc, newNum * sizeof(CXzStream));
291      if (data == 0)
292        return SZ_ERROR_MEM;
293      p->numAllocated = newNum;
294      memcpy(data, p->streams, p->num * sizeof(CXzStream));
295      alloc->Free(alloc, p->streams);
296      p->streams = (CXzStream *)data;
297    }
298    p->streams[p->num++] = st;
299    if (*startOffset == 0)
300      break;
301    RINOK(stream->Seek(stream, startOffset, SZ_SEEK_SET));
302    if (progress && progress->Progress(progress, endOffset - *startOffset, (UInt64)(Int64)-1) != SZ_OK)
303      return SZ_ERROR_PROGRESS;
304  }
305  return SZ_OK;
306}
307