[trunk] added option to force output bit depth in opj_decompress (fixes issue 283)

1 files changed, 78 insertions, 0 deletions

diff --git a/src/bin/jp2/convert.c b/src/bin/jp2/convert.c
index 6af7b7ab..7ada9a41 100644
--- a/src/bin/jp2/convert.c
+++ b/src/bin/jp2/convert.c
@@ -67,6 +67,84 @@ static int int_floorlog2(int a) {
     return l;
 }
 
+/* Component precision scaling */
+void clip_component(opj_image_comp_t* component, OPJ_UINT32 precision)
+{
+	OPJ_SIZE_T i;
+	OPJ_SIZE_T len;
+	OPJ_UINT32 umax = (OPJ_UINT32)((OPJ_INT32)-1);
+	
+	len = (OPJ_SIZE_T)component->w * (OPJ_SIZE_T)component->h;
+	if (precision < 32) {
+		umax = (1U << precision) - 1U;
+	}
+	
+	if (component->sgnd) {
+		OPJ_INT32* l_data = component->data;
+		OPJ_INT32 max = (OPJ_INT32)(umax / 2U);
+		OPJ_INT32 min = -max - 1;
+		for (i = 0; i < len; ++i) {
+			if (l_data[i] > max) {
+				l_data[i] = max;
+			} else if (l_data[i] < min) {
+				l_data[i] = min;
+			}
+		}
+	} else {
+		OPJ_UINT32* l_data = (OPJ_UINT32*)component->data;
+		for (i = 0; i < len; ++i) {
+			if (l_data[i] > umax) {
+				l_data[i] = umax;
+			}
+		}
+	}
+	component->prec = precision;
+}
+
+/* Component precision scaling */
+void scale_component(opj_image_comp_t* component, OPJ_UINT32 precision)
+{
+	int shift;
+	OPJ_SIZE_T i;
+	OPJ_SIZE_T len;
+	
+	if (component->prec == precision) {
+		return;
+	}
+	if (component->prec < precision) {
+		shift = precision - component->prec;
+	} else {
+		shift = component->prec - precision;
+	}
+	len = (OPJ_SIZE_T)component->w * (OPJ_SIZE_T)component->h;
+	
+	if (component->sgnd) {
+		OPJ_INT32* l_data = component->data;
+		if (component->prec < precision) {
+			for (i = 0; i < len; ++i) {
+				l_data[i] <<= shift;
+			}
+		} else {
+			for (i = 0; i < len; ++i) {
+				l_data[i] >>= shift;
+			}
+		}
+	} else {
+		OPJ_UINT32* l_data = (OPJ_UINT32*)component->data;
+		if (component->prec < precision) {
+			for (i = 0; i < len; ++i) {
+				l_data[i] <<= shift;
+			}
+		} else {
+			for (i = 0; i < len; ++i) {
+				l_data[i] >>= shift;
+			}
+		}
+	}
+	component->prec = precision;
+}
+
+
 /* -->> -->> -->> -->>
 
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