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Added the function FT_Read_Fields, it acts as a

Browse Source 
finite-state automata to load large TrueType tables
in object structures.

This is experimental, don't mess too much with it,
thanks :-)
VER-2-0-4-PATCH
David Turner 25 years ago
parent 1d1c7eb807
commit 818336fdf4
2 changed files with 224 additions and 1 deletions
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  1. 146
      src/base/ftstream.c
  2. 79
      src/base/ftstream.h

146
src/base/ftstream.c
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@ -429,3 +429,149 @@
return 0;
}
BASE_FUNC
FT_Error FT_Read_Fields( FT_Stream stream,
const FT_Frame_Field* fields,
void* structure )
{
FT_Error error;
FT_Bool frame_accessed = 0;
if (!fields || !stream)
return FT_Err_Invalid_Argument;
error = FT_Err_Ok;
do
{
FT_ULong value;
FT_Int sign_shift;
FT_Byte* p;
switch (fields->value)
{
case ft_frame_start: /* access a new frame */
{
error = FT_Access_Frame( stream, fields->offset );
if (error) goto Exit;
frame_accessed = 1;
fields++;
continue; /* loop ! */
}
case ft_frame_byte:
case ft_frame_schar: /* read a single byte */
{
value = GET_Byte();
sign_shift = 24;
break;
}
case ft_frame_short_be:
case ft_frame_ushort_be: /* read a 2-byte big-endian short */
{
value = GET_UShort();
sign_shift = 16;
break;
}
case ft_frame_short_le:
case ft_frame_ushort_le: /* read a 2-byte little-endian short */
{
char* p;
value = 0;
p = stream->cursor;
if (p+1 < stream->limit)
{
value = (FT_UShort)p[0] | ((FT_UShort)p[1] << 8);
stream->cursor += 2;
}
sign_shift = 16;
break;
}
case ft_frame_long_be:
case ft_frame_ulong_be: /* read a 4-byte big-endian long */
{
value = GET_ULong();
sign_shift = 0;
break;
}
case ft_frame_long_le:
case ft_frame_ulong_le: /* read a 4-byte little-endian long */
{
char* p;
value = 0;
p = stream->cursor;
if (p+3 < stream->limit)
{
value = (FT_ULong)p[0] |
((FT_ULong)p[1] << 8) |
((FT_ULong)p[2] << 16) |
((FT_ULong)p[3] << 24);
stream->cursor += 4;
}
sign_shift = 0;
break;
}
case ft_frame_off3_be:
case ft_frame_uoff3_be: /* read a 3-byte big-endian long */
{
value = GET_UOffset();
sign_shift = 8;
break;
}
case ft_frame_off3_le:
case ft_frame_uoff3_le: /* read a 3-byte little-endian long */
{
char* p;
value = 0;
p = stream->cursor;
if (p+3 < stream->limit)
{
value = (FT_ULong)p[0] |
((FT_ULong)p[1] << 8) |
((FT_ULong)p[2] << 16) |
((FT_ULong)p[3] << 24);
stream->cursor += 4;
}
sign_shift = 8;
break;
}
default:
/* otherwise, exit the loop */
goto Exit;
}
/* now, compute the signed value is necessary */
if (fields->value & FT_FRAME_OP_SIGNED)
value = (FT_ULong)((FT_Long)(value << sign_shift) >> sign_shift);
/* finally, store the value in the object */
p = (FT_Byte*)structure + fields->offset;
switch (fields->size)
{
case 1: *(FT_Byte*)p = (FT_Byte) value; break;
case 2: *(FT_UShort*)p = (FT_UShort)value; break;
case 4: *(FT_ULong*)p = (FT_ULong) value; break;
default: ; /* ignore !! */
}
/* go to next field */
fields++;
}
while (1);
Exit:
/* close the frame if it was opened by this read */
if (frame_accessed)
FT_Forget_Frame(stream);
return error;
}

79
src/base/ftstream.h
Unescape View File

@ -3,6 +3,77 @@
#include <ftobjs.h>
/* format of an 8-bit frame_op value = [ xxxxx | e | s ] */
/* where s is set to 1 when the value is signed.. */
/* where e is set to 1 when the value is little-endian */
/* xxxxx is a command */
#define FT_FRAME_OP_SHIFT 2
#define FT_FRAME_OP_SIGNED 1
#define FT_FRAME_OP_LITTLE 2
#define FT_FRAME_OP_COMMAND(x) (x >> FT_FRAME_OP_SHIFT)
#define FT_MAKE_FRAME_OP( command, little, sign ) \
((command << FT_FRAME_OP_SHIFT) | (little << 1) | sign)
#define FT_FRAME_OP_END 0
#define FT_FRAME_OP_START 1 /* start a new frame */
#define FT_FRAME_OP_BYTE 2 /* read 1-byte value */
#define FT_FRAME_OP_SHORT 3 /* read 2-byte value */
#define FT_FRAME_OP_LONG 4 /* read 4-byte value */
#define FT_FRAME_OP_OFF3 5 /* read 3-byte value */
typedef enum FT_Frame_Op_
{
ft_frame_end = 0,
ft_frame_start = FT_MAKE_FRAME_OP( FT_FRAME_OP_START, 0, 0 ),
ft_frame_byte = FT_MAKE_FRAME_OP( FT_FRAME_OP_BYTE, 0, 0 ),
ft_frame_schar = FT_MAKE_FRAME_OP( FT_FRAME_OP_BYTE, 0, 1 ),
ft_frame_ushort_be = FT_MAKE_FRAME_OP( FT_FRAME_OP_SHORT, 0, 0 ),
ft_frame_short_be = FT_MAKE_FRAME_OP( FT_FRAME_OP_SHORT, 0, 1 ),
ft_frame_ushort_le = FT_MAKE_FRAME_OP( FT_FRAME_OP_SHORT, 1, 0 ),
ft_frame_short_le = FT_MAKE_FRAME_OP( FT_FRAME_OP_SHORT, 1, 1 ),
ft_frame_ulong_be = FT_MAKE_FRAME_OP( FT_FRAME_OP_LONG, 0, 0 ),
ft_frame_ulong_le = FT_MAKE_FRAME_OP( FT_FRAME_OP_LONG, 0, 1 ),
ft_frame_long_be = FT_MAKE_FRAME_OP( FT_FRAME_OP_LONG, 1, 0 ),
ft_frame_long_le = FT_MAKE_FRAME_OP( FT_FRAME_OP_LONG, 1, 1 ),
ft_frame_uoff3_be = FT_MAKE_FRAME_OP( FT_FRAME_OP_OFF3, 0, 0 ),
ft_frame_uoff3_le = FT_MAKE_FRAME_OP( FT_FRAME_OP_OFF3, 0, 1 ),
ft_frame_off3_be = FT_MAKE_FRAME_OP( FT_FRAME_OP_OFF3, 1, 0 ),
ft_frame_off3_le = FT_MAKE_FRAME_OP( FT_FRAME_OP_OFF3, 1, 1 ),
} FT_Frame_Op;
typedef struct FT_Frame_Field_
{
FT_Frame_Op value;
char size;
FT_UShort offset;
} FT_Frame_Field;
/* make-up a FT_Frame_Field out of a structure type and a field name */
#define FT_FIELD_REF(s,f) (((s*)0)->f)
#define FT_FRAME_FIELD( frame_op, struct_type, field ) \
{ \
frame_op, \
sizeof(FT_FIELD_REF(struct_type,field)), \
(FT_UShort)(char*)&FT_FIELD_REF(struct_type,field) }
#define FT_MAKE_EMPTY_FIELD( frame_op ) { frame_op, 0, 0 }
#define FT_FRAME_LONG(s,f) FT_FRAME_FIELD( ft_frame_long_be, s, f )
#define FT_FRAME_ULONG(s,f) FT_FRAME_FIELD( ft_frame_ulong_be, s, f )
#define FT_FRAME_SHORT(s,f) FT_FRAME_FIELD( ft_frame_short_be, s, f )
#define FT_FRAME_USHORT(s,f) FT_FRAME_FIELD( ft_frame_ushort_be, s, f )
#define FT_FRAME_BYTE(s,f) FT_FRAME_FIELD( ft_frame_byte, s, f )
#define FT_FRAME_CHAR(s,f) FT_FRAME_FIELD( ft_frame_schar, s, f )
/*************************************************************************/
/* */
@ -134,6 +205,11 @@
FT_Long FT_Read_Long( FT_Stream stream,
FT_Error* error );
BASE_DEF
FT_Error FT_Read_Fields( FT_Stream stream,
const FT_Frame_Field* fields,
void* structure );
#define USE_Stream( resource, stream ) \
FT_SET_ERROR( FT_Open_Stream( resource, stream ) )
@ -173,6 +249,7 @@
(FT_Char*)buffer, \
count ) )
#define READ_Fields( fields, object ) \
((error = FT_Read_Fields( stream, fields, object )) != FT_Err_Ok)
#endif /* FTIO_H */

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