Commit 818336fdf4929d2ec9b376532fcdcb54b2c8641d
2000-02-13T13:36:53
Added the function FT_Read_Fields, it acts as a finite-state automata to load large TrueType tables in object structures. This is experimental, don't mess too much with it, thanks :-)
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diff --git a/src/base/ftstream.c b/src/base/ftstream.c
index 0a40fb3..90cabe4 100644
--- a/src/base/ftstream.c
+++ b/src/base/ftstream.c
@@ -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;
+ }
+
diff --git a/src/base/ftstream.h b/src/base/ftstream.h
index 944795c..58cafaa 100644
--- a/src/base/ftstream.h
+++ b/src/base/ftstream.h
@@ -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 */