chan_dahdi: fix lower bound check with -ve integer conversion from a float

Lower bound of a 16bit signed int is -32768 not -32767

(closes issue ASTERISK-21744)

Reported by: alecdavis
Tested by: alecdavis
alecdavis (license 585)
........

Merged revisions 387297 from http://svn.asterisk.org/svn/asterisk/branches/1.8


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/11@387298 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_dahdi.c

@@ -5127,9 +5127,12 @@ static void fill_txgain(struct dahdi_gains *g, float gain, float drc, int law)
 				if (drc) {
 					k = drc_sample(k, drc);
 				}
-				k = (float)k*linear_gain;
-				if (k > 32767) k = 32767;
-				if (k < -32767) k = -32767;
+				k = (float)k * linear_gain;
+				if (k > 32767) {
+					k = 32767;
+				} else if (k < -32768) {
+					k = -32768;
+				}
 				g->txgain[j] = AST_LIN2A(k);
 			} else {
 				g->txgain[j] = j;
@@ -5143,9 +5146,12 @@ static void fill_txgain(struct dahdi_gains *g, float gain, float drc, int law)
 				if (drc) {
 					k = drc_sample(k, drc);
 				}
-				k = (float)k*linear_gain;
-				if (k > 32767) k = 32767;
-				if (k < -32767) k = -32767;
+				k = (float)k * linear_gain;
+				if (k > 32767) {
+					k = 32767;
+				} else if (k < -32768) {
+					k = -32768;
+				}
 				g->txgain[j] = AST_LIN2MU(k);
 
 			} else {
@@ -5170,9 +5176,12 @@ static void fill_rxgain(struct dahdi_gains *g, float gain, float drc, int law)
 				if (drc) {
 					k = drc_sample(k, drc);
 				}
-				k = (float)k*linear_gain;
-				if (k > 32767) k = 32767;
-				if (k < -32767) k = -32767;
+				k = (float)k * linear_gain;
+				if (k > 32767) {
+					k = 32767;
+				} else if (k < -32768) {
+					k = -32768;
+				}
 				g->rxgain[j] = AST_LIN2A(k);
 			} else {
 				g->rxgain[j] = j;
@@ -5186,9 +5195,12 @@ static void fill_rxgain(struct dahdi_gains *g, float gain, float drc, int law)
 				if (drc) {
 					k = drc_sample(k, drc);
 				}
-				k = (float)k*linear_gain;
-				if (k > 32767) k = 32767;
-				if (k < -32767) k = -32767;
+				k = (float)k * linear_gain;
+				if (k > 32767) {
+					k = 32767;
+				} else if (k < -32768) {
+					k = -32768;
+				}
 				g->rxgain[j] = AST_LIN2MU(k);
 			} else {
 				g->rxgain[j] = j;