39 lines
1.9 KiB
Diff
39 lines
1.9 KiB
Diff
|
--- jdhuff.c
|
||
|
|
+++ jdhuff.c
|
||
|
|
@@ -649,3 +649,35 @@
|
||
|
|
entropy->dc_derived_tbls[i] = entropy->ac_derived_tbls[i] = NULL;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
+/*
|
||
|
|
+ * BEWARE OF KLUDGE: This subroutine is a hack for decoding illegal JPEG-in-
|
||
|
|
+ * TIFF encapsulations produced by Microsoft's Wang Imaging
|
||
|
|
+ * for Windows application with the public-domain TIFF Library. Based upon an
|
||
|
|
+ * examination of selected output files, this program apparently divides a JPEG
|
||
|
|
+ * bit-stream into consecutive horizontal TIFF "strips", such that the JPEG
|
||
|
|
+ * encoder's/decoder's DC coefficients for each image component are reset before
|
||
|
|
+ * each "strip". Moreover, a "strip" is not necessarily encoded in a multiple
|
||
|
|
+ * of 8 bits, so one must sometimes discard 1-7 bits at the end of each "strip"
|
||
|
|
+ * for alignment to the next input-Byte storage boundary. IJG JPEG Library
|
||
|
|
+ * decoder state is not normally exposed to client applications, so this sub-
|
||
|
|
+ * routine provides the TIFF Library with a "hook" to make these corrections.
|
||
|
|
+ * It should be called after "jpeg_start_decompress()" and before
|
||
|
|
+ * "jpeg_finish_decompress()", just before decoding each "strip" using
|
||
|
|
+ * "jpeg_read_raw_data()" or "jpeg_read_scanlines()".
|
||
|
|
+ *
|
||
|
|
+ * This kludge is not sanctioned or supported by the Independent JPEG Group, and
|
||
|
|
+ * future changes to the IJG JPEG Library might invalidate it. Do not send bug
|
||
|
|
+ * reports about this code to IJG developers. Instead, contact the author for
|
||
|
|
+ * advice: Scott B. Marovich <marovich@hpl.hp.com>, Hewlett-Packard Labs, 6/01.
|
||
|
|
+ */
|
||
|
|
+GLOBAL(void)
|
||
|
|
+jpeg_reset_huff_decode (register j_decompress_ptr cinfo,register float *refbw)
|
||
|
|
+{ register huff_entropy_ptr entropy = (huff_entropy_ptr)cinfo->entropy;
|
||
|
|
+ register int ci = 0;
|
||
|
|
+
|
||
|
|
+ /* Re-initialize DC predictions */
|
||
|
|
+ do entropy->saved.last_dc_val[ci] = -refbw[ci << 1];
|
||
|
|
+ while (++ci < cinfo->comps_in_scan);
|
||
|
|
+ /* Discard encoded input bits, up to the next Byte boundary */
|
||
|
|
+ entropy->bitstate.bits_left &= ~7;
|
||
|
|
+}
|