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[woff2] Copy un-transformed tables to sfnt stream. 

Copy un-transformed tables to the sfnt stream.

* src/sfnt/sfwoff2.c: (WRITE_SFNT_BUF): New macro.
(write_buf): New function.  Extend memory of `dst' buffer and copy
bytes from `src'.
(compute_ULong_sum): New function.  Calculate checksum of table.
(reconstruct_font): Change `FT_Byte* sfnt' to `FT_Byte**
sfnt_bytes'.  This has been done because we reallocate memory to
`sfnt' multiple times, which may change the pointer value of `sfnt'.
This new pointer must be propogated back to the caller.  Same reason
for using a double pointer in `write_buf'.

* src/sfnt/woff2tags.h (WOFF2_DEFAULT_MAX_SIZE): New macro used for
overflow checking.
This commit is contained in:
Nikhil Ramakrishnan 2019-07-06 18:05:18 +05:30 committed by Werner Lemberg
parent 106bacf502
commit 81cf5326d5
3 changed files with 115 additions and 7 deletions
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19
ChangeLog
View File

@ -1,3 +1,22 @@
2019-08-27 Nikhil Ramakrishnan <ramakrishnan.nikhil@gmail.com>
[woff2] Copy un-transformed tables to sfnt stream.
Copy un-transformed tables to the sfnt stream.
* src/sfnt/sfwoff2.c: (WRITE_SFNT_BUF): New macro.
(write_buf): New function. Extend memory of `dst' buffer and copy
bytes from `src'.
(compute_ULong_sum): New function. Calculate checksum of table.
(reconstruct_font): Change `FT_Byte* sfnt' to `FT_Byte**
sfnt_bytes'. This has been done because we reallocate memory to
`sfnt' multiple times, which may change the pointer value of `sfnt'.
This new pointer must be propogated back to the caller. Same reason
for using a double pointer in `write_buf'.
* src/sfnt/woff2tags.h (WOFF2_DEFAULT_MAX_SIZE): New macro used for
overflow checking.
2019-08-27 Nikhil Ramakrishnan <ramakrishnan.nikhil@gmail.com>
[woff2] Create stream for uncompressed buffer.

100
src/sfnt/sfwoff2.c
View File

@ -64,6 +64,8 @@
\
} while ( 0 )
#define WRITE_SFNT_BUF( buf, s ) \
write_buf( &sfnt, &dest_offset, buf, s, memory )
static void
stream_close( FT_Stream stream )
@ -182,6 +184,41 @@
}
static FT_Error
write_buf( FT_Byte** dst_bytes,
FT_ULong* offset,
FT_Byte* src,
FT_ULong size,
FT_Memory memory )
{
FT_Error error = FT_Err_Ok;
/* We are reallocating memory for `dst', so its pointer may change. */
FT_Byte* dst = *dst_bytes;
/* Check if we are within limits. */
if( ( *offset + size ) > WOFF2_DEFAULT_MAX_SIZE )
return FT_THROW( Array_Too_Large );
/* DEBUG - Remove later */
FT_TRACE2(( "Reallocating %lu to %lu.\n", *offset, (*offset + size) ));
/* Reallocate `dst'. */
if ( FT_REALLOC( dst,
(FT_ULong)(*offset),
(FT_ULong)(*offset + size ) ) )
goto Exit;
/* Copy data. */
ft_memcpy( dst + *offset, src, size );
*offset += size;
/* Set pointer of `dst' to its correct value. */
*dst_bytes = dst;
Exit:
return error;
}
static FT_Offset
CollectionHeaderSize( FT_ULong header_version,
FT_UShort num_fonts )
@ -216,6 +253,32 @@
return offset;
}
static FT_Long
compute_ULong_sum( FT_Byte* buf,
FT_ULong size )
{
FT_ULong checksum = 0;
FT_ULong aligned_size = size & ~3;
FT_ULong i;
FT_ULong v;
for( i = 0; i < aligned_size; i += 4 )
{
checksum += ( buf[i] << 24 ) | ( buf[i+1] << 16 ) |
( buf[i+2] << 8 ) | ( buf[i+3] << 0 );
}
/* If size is not aligned to 4, treat as if it is padded with 0s */
if( size != aligned_size )
{
v = 0;
for( i = aligned_size ; i < size; ++i )
v |= buf[i] << ( 24 - 8 * ( i & 3 ) );
checksum += v;
}
return checksum;
}
static FT_Error
woff2_uncompress( FT_Byte* dst,
@ -293,15 +356,17 @@
FT_ULong transformed_buf_size,
WOFF2_Table* indices,
WOFF2_Header woff2,
FT_Byte* sfnt,
FT_Byte** sfnt_bytes,
FT_Memory memory )
{
FT_Error error = FT_Err_Ok;
FT_Stream stream = NULL;
FT_Byte* buf_cursor = NULL;
/* We are reallocating memory for `sfnt', so its pointer may change. */
FT_Byte* sfnt = *sfnt_bytes;
/* We're writing only one face per call, so initial offset is fixed. */
FT_ULong dst_offset = 12;
FT_UShort num_tables = woff2->num_tables;
FT_ULong dest_offset = 12 + num_tables * 16UL;
FT_ULong checksum = 0;
FT_ULong loca_checksum = 0;
@ -333,7 +398,6 @@
}
}
FT_UNUSED( dst_offset );
FT_UNUSED( loca_checksum );
FT_UNUSED( checksum );
@ -351,12 +415,14 @@
WOFF2_TableRec table = *( indices[nn] );
/* DEBUG - Remove later */
FT_TRACE2(( "Seeking to %d with table size %d.\n", table.src_offset, table.src_length ));
FT_TRACE2(( "Seeking to %d with table size %d.\n",
table.src_offset, table.src_length ));
FT_TRACE2(( "Table tag: %c%c%c%c.\n",
(FT_Char)( table.Tag >> 24 ),
(FT_Char)( table.Tag >> 16 ),
(FT_Char)( table.Tag >> 8 ),
(FT_Char)( table.Tag ) ));
if ( FT_STREAM_SEEK( table.src_offset ) )
return FT_THROW( Invalid_Table );
@ -370,6 +436,7 @@
return FT_THROW( Invalid_Table );
}
checksum = 0;
if( ( table.flags & WOFF2_FLAGS_TRANSFORM ) != WOFF2_FLAGS_TRANSFORM )
{
/* Check if `head' is atleast 12 bytes. */
@ -377,12 +444,30 @@
{
if( table.src_length < 12 )
return FT_THROW( Invalid_Table );
buf_cursor = transformed_buf + table.src_offset + 8;
WRITE_ULONG( buf_cursor, 0 );
}
table.dst_offset = dest_offset;
checksum = compute_ULong_sum( transformed_buf + table.src_offset,
table.src_length );
/* DEBUG - Remove later */
FT_TRACE2(( "Checksum = %u\n", checksum ));
if( WRITE_SFNT_BUF( transformed_buf + table.src_offset,
table.src_length ) )
return FT_THROW( Invalid_Table );
}
else{
/* DEBUG - Remove later */
FT_TRACE2(( "This table has xform.\n" ));
/* TODO reconstruct transformed font tables! */
}
}
/* TODO reconstruct the font tables! */
/* Set pointer of sfnt stream to its correct value. */
*sfnt_bytes = sfnt;
return FT_Err_Ok;
}
@ -793,7 +878,7 @@
/* TODO Write table entries. */
reconstruct_font( uncompressed_buf, woff2.uncompressed_size,
indices, &woff2, sfnt, memory );
indices, &woff2, &sfnt, memory );
error = FT_THROW( Unimplemented_Feature );
/* DEBUG - Remove later */
@ -821,6 +906,7 @@
#undef ROUND4
#undef WRITE_USHORT
#undef WRITE_ULONG
#undef WRITE_SFNT_BUF
/* END */

3
src/sfnt/woff2tags.h
View File

@ -33,6 +33,9 @@ FT_BEGIN_HEADER
#define WOFF2_SFNT_HEADER_SIZE 12
#define WOFF2_SFNT_ENTRY_SIZE 16
/* Suggested max size for output. */
#define WOFF2_DEFAULT_MAX_SIZE 30 * 1024 * 1024
FT_LOCAL( FT_ULong )
woff2_known_tags( FT_Byte index );