Index: libopenjpeg/openjpeg.h
===================================================================
--- libopenjpeg/openjpeg.h	(revision 338)
+++ libopenjpeg/openjpeg.h	(working copy)
@@ -311,6 +311,41 @@
 
 } opj_cparameters_t;
 
+/** Stop after tags. */
+typedef enum LIMIT_TAGS {
+	OPJ_TAG_SOC = 0x000001,	/**< start of codestream */
+	OPJ_TAG_SOT = 0x000002,	/**< start of tile-part*/
+	OPJ_TAG_SOD = 0x000004,	/**< start of data */
+	OPJ_TAG_EOC = 0x000008,	/**< end of codestream */
+	OPJ_TAG_SIZ = 0x000010,	/**< image and tile size */
+	OPJ_TAG_COD = 0x000020,	/**< coding style default */
+	OPJ_TAG_COC = 0x000040,	/**< coding style component */
+	OPJ_TAG_RGN = 0x000080,	/**< region-of-interest */
+	OPJ_TAG_QCD = 0x000100,	/**< quantization default */
+	OPJ_TAG_QCC = 0x000200,	/**< quantization component */
+	OPJ_TAG_POC = 0x000400,	/**< progression order change */
+	OPJ_TAG_TLM = 0x000800,	/**< tile-part lengths */
+	OPJ_TAG_PLM = 0x001000,	/**< packet length, main header */
+	OPJ_TAG_PLT = 0x002000,	/**< packet length, tile-part header */
+	OPJ_TAG_PPM = 0x004000,	/**< packet packet headers, main header */
+	OPJ_TAG_PPT = 0x008000,	/**< packet packet headers, tile-part header */
+	OPJ_TAG_SOP = 0x010000,	/**< SOP marker value */
+	OPJ_TAG_EPH = 0x020000,	/**< EPH marker value */
+	OPJ_TAG_CRG = 0x040000,	/**< component registration */
+	OPJ_TAG_COM = 0x080000,	/**< comment */
+#ifdef USE_JPWL
+/* UniPG>> */           
+	OPJ_TAG_EPC = 0x100000,	/**< EPC marker value (Part11) */
+	OPJ_TAG_EPB = 0x200000,	/**< EPB marker value (Part11) */
+	OPJ_TAG_ESD = 0x400000,	/**< ESD marker value (Part11) */
+	OPJ_TAG_RED = 0x800000,	/**< RED marker value (Part11) */
+#endif /* USE_JPWL */
+/* <<UniPG */
+} OPJ_LIMIT_TAGS;
+
+/** The needed tags to decode just the size of the image. */
+#define OPJ_LIMIT_FOR_SIZE (OPJ_LIMIT_TAGS)(OPJ_TAG_SOC | OPJ_TAG_SIZ )
+
 /**
 Decompression parameters
 */
@@ -330,6 +365,15 @@
 	if == 0 or not used, all the quality layers are decoded 
 	*/
 	int cp_layer;
+	/**
+	Limits the tags that are decoded.
+	This is a bitwise OR of the tags to be decoded.  If a tag is
+	encountered that isn't in the list decoding ceases and the function
+	returns.
+	if != 0 only the given tags are decoded.
+	if == 0 all tags are decoded.
+	*/
+	OPJ_LIMIT_TAGS cp_limit_tags;
 
 	/**@name command line encoder parameters (not used inside the library) */
 	/*@{*/
Index: libopenjpeg/j2k.c
===================================================================
--- libopenjpeg/j2k.c	(revision 338)
+++ libopenjpeg/j2k.c	(working copy)
@@ -1342,37 +1342,39 @@
 	int states;
 	/** action linked to the marker */
 	void (*handler) (opj_j2k_t *j2k);
+	/** The enum value used to limit decode to specific tags. */
+	OPJ_LIMIT_TAGS limit_tag;
 } opj_dec_mstabent_t;
 
 opj_dec_mstabent_t j2k_dec_mstab[] = {
-  {J2K_MS_SOC, J2K_STATE_MHSOC, j2k_read_soc},
-  {J2K_MS_SOT, J2K_STATE_MH | J2K_STATE_TPHSOT, j2k_read_sot},
-  {J2K_MS_SOD, J2K_STATE_TPH, j2k_read_sod},
-  {J2K_MS_EOC, J2K_STATE_TPHSOT, j2k_read_eoc},
-  {J2K_MS_SIZ, J2K_STATE_MHSIZ, j2k_read_siz},
-  {J2K_MS_COD, J2K_STATE_MH | J2K_STATE_TPH, j2k_read_cod},
-  {J2K_MS_COC, J2K_STATE_MH | J2K_STATE_TPH, j2k_read_coc},
-  {J2K_MS_RGN, J2K_STATE_MH | J2K_STATE_TPH, j2k_read_rgn},
-  {J2K_MS_QCD, J2K_STATE_MH | J2K_STATE_TPH, j2k_read_qcd},
-  {J2K_MS_QCC, J2K_STATE_MH | J2K_STATE_TPH, j2k_read_qcc},
-  {J2K_MS_POC, J2K_STATE_MH | J2K_STATE_TPH, j2k_read_poc},
-  {J2K_MS_TLM, J2K_STATE_MH, j2k_read_tlm},
-  {J2K_MS_PLM, J2K_STATE_MH, j2k_read_plm},
-  {J2K_MS_PLT, J2K_STATE_TPH, j2k_read_plt},
-  {J2K_MS_PPM, J2K_STATE_MH, j2k_read_ppm},
-  {J2K_MS_PPT, J2K_STATE_TPH, j2k_read_ppt},
-  {J2K_MS_SOP, 0, 0},
-  {J2K_MS_CRG, J2K_STATE_MH, j2k_read_crg},
-  {J2K_MS_COM, J2K_STATE_MH | J2K_STATE_TPH, j2k_read_com},
+  {J2K_MS_SOC, J2K_STATE_MHSOC, j2k_read_soc, OPJ_TAG_SOC},
+  {J2K_MS_SOT, J2K_STATE_MH | J2K_STATE_TPHSOT, j2k_read_sot, OPJ_TAG_SOT},
+  {J2K_MS_SOD, J2K_STATE_TPH, j2k_read_sod, OPJ_TAG_SOD},
+  {J2K_MS_EOC, J2K_STATE_TPHSOT, j2k_read_eoc, OPJ_TAG_EOC},
+  {J2K_MS_SIZ, J2K_STATE_MHSIZ, j2k_read_siz, OPJ_TAG_SIZ},
+  {J2K_MS_COD, J2K_STATE_MH | J2K_STATE_TPH, j2k_read_cod, OPJ_TAG_COD},
+  {J2K_MS_COC, J2K_STATE_MH | J2K_STATE_TPH, j2k_read_coc, OPJ_TAG_COC},
+  {J2K_MS_RGN, J2K_STATE_MH | J2K_STATE_TPH, j2k_read_rgn, OPJ_TAG_RGN},
+  {J2K_MS_QCD, J2K_STATE_MH | J2K_STATE_TPH, j2k_read_qcd, OPJ_TAG_QCD},
+  {J2K_MS_QCC, J2K_STATE_MH | J2K_STATE_TPH, j2k_read_qcc, OPJ_TAG_QCC},
+  {J2K_MS_POC, J2K_STATE_MH | J2K_STATE_TPH, j2k_read_poc, OPJ_TAG_POC},
+  {J2K_MS_TLM, J2K_STATE_MH, j2k_read_tlm, OPJ_TAG_TLM},
+  {J2K_MS_PLM, J2K_STATE_MH, j2k_read_plm, OPJ_TAG_PLM},
+  {J2K_MS_PLT, J2K_STATE_TPH, j2k_read_plt, OPJ_TAG_PLT},
+  {J2K_MS_PPM, J2K_STATE_MH, j2k_read_ppm, OPJ_TAG_PPM},
+  {J2K_MS_PPT, J2K_STATE_TPH, j2k_read_ppt, OPJ_TAG_PPT},
+  {J2K_MS_SOP, 0, 0, OPJ_TAG_SOP},
+  {J2K_MS_CRG, J2K_STATE_MH, j2k_read_crg, OPJ_TAG_CRG},
+  {J2K_MS_COM, J2K_STATE_MH | J2K_STATE_TPH, j2k_read_com, OPJ_TAG_COM},
 /* UniPG>> */
 #ifdef USE_JPWL
-  {J2K_MS_EPC, J2K_STATE_MH | J2K_STATE_TPH, j2k_read_epc},
-  {J2K_MS_EPB, J2K_STATE_MH | J2K_STATE_TPH, j2k_read_epb},
-  {J2K_MS_ESD, J2K_STATE_MH | J2K_STATE_TPH, j2k_read_esd},
-  {J2K_MS_RED, J2K_STATE_MH | J2K_STATE_TPH, j2k_read_red},
+  {J2K_MS_EPC, J2K_STATE_MH | J2K_STATE_TPH, j2k_read_epc, OPJ_TAG_EPC},
+  {J2K_MS_EPB, J2K_STATE_MH | J2K_STATE_TPH, j2k_read_epb, OPJ_TAG_EPB},
+  {J2K_MS_ESD, J2K_STATE_MH | J2K_STATE_TPH, j2k_read_esd, OPJ_TAG_ESD},
+  {J2K_MS_RED, J2K_STATE_MH | J2K_STATE_TPH, j2k_read_red, OPJ_TAG_RED},
 #endif /* USE_JPWL */
 /* <<UniPG */
-  {0, J2K_STATE_MH | J2K_STATE_TPH, j2k_read_unk}
+  {0, J2K_STATE_MH | J2K_STATE_TPH, j2k_read_unk, -1}
 };
 
 static void j2k_read_unk(opj_j2k_t *j2k) {
@@ -1522,6 +1524,7 @@
 		opj_cp_t *cp = (opj_cp_t*)opj_malloc(sizeof(opj_cp_t));
 		cp->reduce = parameters->cp_reduce;	
 		cp->layer = parameters->cp_layer;
+		cp->limit_tags = parameters->cp_limit_tags;
 /* UniPG>> */
 #ifdef USE_JPWL
 		cp->correct = parameters->jpwl_correct;
@@ -1599,6 +1602,12 @@
 			opj_event_msg(cinfo, EVT_ERROR, "%.8x: unexpected marker %x\n", cio_tell(cio) - 2, id);
 			return 0;
 		}
+		/* If a partial decode is requested, stop if the current tag
+		 * isn't in the list.
+		 */
+		if (j2k->cp->limit_tags && !(j2k->cp->limit_tags & e->limit_tag)) {
+			return image;
+		}
 		if (e->handler) {
 			(*e->handler)(j2k);
 		}
Index: libopenjpeg/j2k.h
===================================================================
--- libopenjpeg/j2k.h	(revision 338)
+++ libopenjpeg/j2k.h	(working copy)
@@ -197,6 +197,8 @@
 	int reduce;
 	/** if != 0, then only the first "layer" layers are decoded; if == 0 or not used, all the quality layers are decoded */
 	int layer;
+	/** if != 0, then only decode specific tags, abort on any other; if == 0 decode all tags */
+	OPJ_LIMIT_TAGS limit_tags;
 	/** 0 = no index || 1 = index */
 	int index_on;
 	/** XTOsiz */