Fix writing of character data to v5 MAT file

As reported by #251

src/mat5.c

@@ -262,7 +262,7 @@ GetTypeBufSize(matvar_t *matvar, size_t *size)
  break;
  }
  case MAT_C_CHAR:
- if ( MAT_T_UINT8 == matvar->data_type || MAT_T_INT8 == matvar->data_type )
+ if ( MAT_T_INT8 == matvar->data_type )
  err = Mul(&data_bytes, nelems, Mat_SizeOf(MAT_T_UINT16));
  else
  err = Mul(&data_bytes, nelems, Mat_SizeOf(matvar->data_type));
@@ -876,6 +876,56 @@ WriteCompressedCharData(mat_t *mat, z_streamp z, void *data, size_t N, enum mati
  } while ( z->avail_out == 0 );
  }
  break;
+ case MAT_T_INT8: {
+ mat_uint8_t *ptr;
+ mat_uint16_t c;
+ int i;
+
+ /* Matlab can't read MAT_C_CHAR as uint8, needs uint16 */
+ data_size = 2;
+ data_tag[0] = MAT_T_UINT16;
+ data_tag[1] = N * data_size;
+ z->next_in = ZLIB_BYTE_PTR(data_tag);
+ z->avail_in = 8;
+ do {
+ z->next_out = buf;
+ z->avail_out = buf_size;
+ deflate(z, Z_NO_FLUSH);
+ byteswritten += fwrite(buf, 1, buf_size - z->avail_out, (FILE *)mat->fp);
+ } while ( z->avail_out == 0 );
+
+ /* exit early if this is an empty data */
+ if ( NULL == data || N < 1 )
+ break;
+
+ z->next_in = (Bytef *)data;
+ z->avail_in = data_size * N;
+ ptr = (mat_uint8_t *)data;
+ for ( i = 0; i < N; i++ ) {
+ c = (mat_uint16_t) * (char *)ptr;
+ z->next_in = ZLIB_BYTE_PTR(&c);
+ z->avail_in = 2;
+ do {
+ z->next_out = buf;
+ z->avail_out = buf_size;
+ deflate(z, Z_NO_FLUSH);
+ byteswritten += fwrite(buf, 1, buf_size - z->avail_out, (FILE *)mat->fp);
+ } while ( z->avail_out == 0 );
+ ptr++;
+ }
+ /* Add/Compress padding to pad to 8-byte boundary */
+ if ( N * data_size % 8 ) {
+ z->next_in = pad;
+ z->avail_in = 8 - (N * data_size % 8);
+ do {
+ z->next_out = buf;
+ z->avail_out = buf_size;
+ deflate(z, Z_NO_FLUSH);
+ byteswritten += fwrite(buf, 1, buf_size - z->avail_out, (FILE *)mat->fp);
+ } while ( z->avail_out == 0 );
+ }
+ break;
+ }
  case MAT_T_UNKNOWN:
  /* Sometimes empty char data will have MAT_T_UNKNOWN, so just write a data tag */
  data_tag[0] = MAT_T_UINT16;
@@ -1018,7 +1068,7 @@ ReadNextCell(mat_t *mat, matvar_t *matvar)
  mat_uint32_t nBytes;
  mat_uint32_t array_flags;
 
- memset(&uncomp_buf, 0, sizeof(uncomp_buf));
+ memset(uncomp_buf, 0, sizeof(uncomp_buf));
  for ( i = 0; i < nelems; i++ ) {
  cells[i] = Mat_VarCalloc();
  if ( NULL == cells[i] ) {
@@ -1394,7 +1444,7 @@ ReadNextStructField(mat_t *mat, matvar_t *matvar)
  mat_uint32_t uncomp_buf[16];
  mat_uint32_t array_flags, len, fieldname_size;
 
- memset(&uncomp_buf, 0, sizeof(uncomp_buf));
+ memset(uncomp_buf, 0, sizeof(uncomp_buf));
  /* Field name length */
  err = Inflate(mat, matvar->internal->z, uncomp_buf, 8, &bytesread);
  if ( err ) {
@@ -2265,7 +2315,7 @@ WriteCompressedTypeArrayFlags(mat_t *mat, matvar_t *matvar, z_streamp z)
  return byteswritten;
  }
 
- memset(&uncomp_buf, 0, sizeof(uncomp_buf));
+ memset(uncomp_buf, 0, sizeof(uncomp_buf));
  /* Array Flags */
  array_flags = matvar->class_type & CLASS_TYPE_MASK;
  if ( matvar->isComplex )
@@ -2346,7 +2396,7 @@ WriteCompressedType(mat_t *mat, matvar_t *matvar, z_streamp z)
  return byteswritten;
  }
 
- memset(&uncomp_buf, 0, sizeof(uncomp_buf));
+ memset(uncomp_buf, 0, sizeof(uncomp_buf));
  err = Mat_MulDims(matvar, &nelems);
  if ( err ) {
  Mat_Critical("Integer multiplication overflow");
@@ -2525,7 +2575,7 @@ WriteCompressedCellArrayField(mat_t *mat, matvar_t *matvar, z_streamp z)
  if ( NULL == matvar || NULL == mat || NULL == z )
  return 0;
 
- memset(&uncomp_buf, 0, sizeof(uncomp_buf));
+ memset(uncomp_buf, 0, sizeof(uncomp_buf));
  uncomp_buf[0] = MAT_T_MATRIX;
  if ( MAT_C_EMPTY != matvar->class_type ) {
  int err = GetCellArrayFieldBufSize(matvar, &field_buf_size);
@@ -2659,7 +2709,7 @@ WriteCompressedStructField(mat_t *mat, matvar_t *matvar, z_streamp z)
  return byteswritten;
  }
 
- memset(&uncomp_buf, 0, sizeof(uncomp_buf));
+ memset(uncomp_buf, 0, sizeof(uncomp_buf));
  uncomp_buf[0] = MAT_T_MATRIX;
  if ( MAT_C_EMPTY != matvar->class_type ) {
  int err = GetStructFieldBufSize(matvar, &field_buf_size);
@@ -2788,7 +2838,7 @@ Mat_WriteCompressedEmptyVariable5(mat_t *mat, const char *name, int rank, const
  /* Array Flags */
  array_flags = MAT_C_DOUBLE;
 
- memset(&uncomp_buf, 0, sizeof(uncomp_buf));
+ memset(uncomp_buf, 0, sizeof(uncomp_buf));
  uncomp_buf[0] = MAT_T_MATRIX;
  err = GetEmptyMatrixMaxBufSize(name, rank, &empty_matrix_max_buf_size);
  if ( err || empty_matrix_max_buf_size > UINT32_MAX )
@@ -5015,7 +5065,7 @@ Mat_VarWrite5(mat_t *mat, matvar_t *matvar, int compress)
  if ( matvar->class_type == MAT_C_SPARSE )
  nzmax = ((mat_sparse_t *)matvar->data)->nzmax;
 
- memset(&uncomp_buf, 0, sizeof(uncomp_buf));
+ memset(uncomp_buf, 0, sizeof(uncomp_buf));
  uncomp_buf[0] = MAT_T_MATRIX;
  err = GetMatrixMaxBufSize(matvar, &matrix_max_buf_size);
  if ( err ) {
@@ -5119,20 +5169,15 @@ Mat_VarWrite5(mat_t *mat, matvar_t *matvar, int compress)
  err = deflate(z, Z_FINISH);
  fwrite(comp_buf, 1, buf_size * sizeof(*comp_buf) - z->avail_out, (FILE *)mat->fp);
  } while ( err != Z_STREAM_END && z->avail_out == 0 );
-#if 0
- if ( byteswritten % 8 )
- for ( i = 0; i < 8-(byteswritten % 8); i++ )
- fwrite(&pad1,1,1,(FILE*)mat->fp);
-#endif
  (void)deflateEnd(z);
  free(z);
 #endif
  }
  end = ftello((FILE *)mat->fp);
  if ( start != -1L && end != -1L ) {
- nBytes = (int)(end - start);
- (void)fseeko((FILE *)mat->fp, (mat_off_t) - (nBytes + 4), SEEK_CUR);
- fwrite(&nBytes, 4, 1, (FILE *)mat->fp);
+ const mat_uint32_t _nBytes = (mat_uint32_t)(end - start);
+ (void)fseeko((FILE *)mat->fp, start - 4, SEEK_SET);
+ fwrite(&_nBytes, 4, 1, (FILE *)mat->fp);
  (void)fseeko((FILE *)mat->fp, end, SEEK_SET);
  } else {
  Mat_Critical("Couldn't determine file position");
@@ -5187,7 +5232,7 @@ Mat_VarReadNextInfo5(mat_t *mat)
  mat_uint32_t uncomp_buf[16];
  size_t bytesread = 0;
 
- memset(&uncomp_buf, 0, sizeof(uncomp_buf));
+ memset(uncomp_buf, 0, sizeof(uncomp_buf));
  matvar = Mat_VarCalloc();
  if ( NULL == matvar ) {
  Mat_Critical("Couldn't allocate memory");