X-Git-Url: https://git.artsoft.org/?a=blobdiff_plain;f=src%2Fgame_em%2Fulaw_generate.c;fp=src%2Fgame_em%2Fulaw_generate.c;h=05ab83e989cde14b74e2a3c32cb66e37112f4653;hb=2b65ec99f743dde3ee41083cf89623d4d9b8740e;hp=0000000000000000000000000000000000000000;hpb=b7c0e8ca1c06e1d54714b382d6b92f4ff2d47af7;p=rocksndiamonds.git

diff --git a/src/game_em/ulaw_generate.c b/src/game_em/ulaw_generate.c
new file mode 100644
index 00000000..05ab83e9
--- /dev/null
+++ b/src/game_em/ulaw_generate.c
@@ -0,0 +1,181 @@
+/* 2000-08-10T04:29:10Z
+ *
+ * generate ulaw<->linear conversion tables to be included
+ * directly in emerald mine source
+ */
+
+#include "../libgame/platform.h"
+
+
+#if defined(TARGET_X11)
+
+#if defined(PLATFORM_LINUX) || defined(PLATFORM_BSD)
+
+#include <stdio.h>
+
+int calc_ulaw_to_linear(unsigned char);
+unsigned char calc_linear_to_ulaw(int);
+
+int buffer[65536];
+
+#if 0
+
+void print_buffer(int *buffer, int count)
+{
+	int i,j;
+	j = 0;
+	for(i = 0; i < count;) {
+		if(j > 80) { j=0; printf("\n"); }
+		if(j == 0) printf("\t");
+		j += printf("%d", buffer[i]);
+		j += printf("%s", ++i == count ? "" : ",");
+	}
+	if(j) printf("\n");
+}
+int main_OLD(void)
+{
+	int i;
+	printf("/* THIS FILE AUTOMATICALLY GENERATED */\n");
+	printf("\n#if defined(LINUX) || defined(BSD)\n");
+	printf("\n/* convert from 8 bit ulaw to signed 16 bit linear */\n");
+	printf("const short ulaw_to_linear[256] = {\n");
+	for(i = 0; i < 256; i++) {
+		buffer[i] = calc_ulaw_to_linear(i);
+	}
+	print_buffer(buffer, 256);
+	printf("};\n");
+	printf("\n/* convert from signed 16 bit linear to 8 bit ulaw */\n");
+	printf("const unsigned char linear_to_ulaw[65536] = {\n");
+	for(i = -32768; i < 32768; i++) {
+		buffer[i + 32768] = calc_linear_to_ulaw(i);
+	}
+	print_buffer(buffer, 65536);
+	printf("};\n");
+	printf("\n#endif /* defined(LINUX) || defined(BSD) */\n");
+	return(0);
+}
+
+#endif
+
+/* convert from 8 bit ulaw to signed 16 bit linear */
+short ulaw_to_linear[256];
+
+/* convert from signed 16 bit linear to 8 bit ulaw */
+unsigned char linear_to_ulaw[65536];
+
+void ulaw_generate()
+{
+  int i;
+
+  for(i = 0; i < 256; i++)
+    ulaw_to_linear[i] = calc_ulaw_to_linear(i);
+
+  for(i = -32768; i < 32768; i++)
+    linear_to_ulaw[i + 32768] = calc_linear_to_ulaw(i);
+}
+
+/*
+** This routine converts from ulaw to 16 bit linear.
+**
+** Craig Reese: IDA/Supercomputing Research Center
+** 29 September 1989
+**
+** References:
+** 1) CCITT Recommendation G.711  (very difficult to follow)
+** 2) MIL-STD-188-113,"Interoperability and Performance Standards
+**     for Analog-to_Digital Conversion Techniques,"
+**     17 February 1987
+**
+** Input: 8 bit ulaw sample
+** Output: signed 16 bit linear sample
+*/
+
+int calc_ulaw_to_linear(unsigned char ulawbyte)
+{
+	static int exp_lut[8] = { 0, 132, 396, 924, 1980, 4092, 8316, 16764 };
+	int sign, exponent, mantissa, sample;
+
+	ulawbyte = ~ ulawbyte;
+	sign = ( ulawbyte & 0x80 );
+	exponent = ( ulawbyte >> 4 ) & 0x07;
+	mantissa = ulawbyte & 0x0F;
+	sample = exp_lut[exponent] + ( mantissa << ( exponent + 3 ) );
+	if (sign != 0)
+		sample = -sample;
+
+	return(sample);
+}
+
+/*
+** This routine converts from linear to ulaw.
+**
+** Craig Reese: IDA/Supercomputing Research Center
+** Joe Campbell: Department of Defense
+** 29 September 1989
+**
+** References:
+** 1) CCITT Recommendation G.711  (very difficult to follow)
+** 2) "A New Digital Technique for Implementation of Any
+**     Continuous PCM Companding Law," Villeret, Michel,
+**     et al. 1973 IEEE Int. Conf. on Communications, Vol 1,
+**     1973, pg. 11.12-11.17
+** 3) MIL-STD-188-113,"Interoperability and Performance Standards
+**     for Analog-to_Digital Conversion Techniques,"
+**     17 February 1987
+**
+** Input: Signed 16 bit linear sample
+** Output: 8 bit ulaw sample
+*/
+
+#define ZEROTRAP    /* turn on the trap as per the MIL-STD */
+#define BIAS 0x84   /* define the add-in bias for 16 bit samples */
+#define CLIP 32635
+
+unsigned char calc_linear_to_ulaw(int sample)
+{
+	static int exp_lut[256] =
+	{
+		0,0,1,1,2,2,2,2,3,3,3,3,3,3,3,3,
+		4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,
+		5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
+		5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
+		6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
+		6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
+		6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
+		6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
+		7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+		7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+		7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+		7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+		7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+		7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+		7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+		7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7
+	};
+
+	int sign, exponent, mantissa;
+	unsigned char ulawbyte;
+
+/* Get the sample into sign-magnitude. */
+	sign = (sample >> 8) & 0x80; /* set aside the sign */
+	if (sign != 0)
+		sample = -sample; /* get magnitude */
+	if (sample > CLIP)
+		sample = CLIP; /* clip the magnitude */
+
+/* Convert from 16 bit linear to ulaw. */
+	sample = sample + BIAS;
+	exponent = exp_lut[( sample >> 7 ) & 0xFF];
+	mantissa = ( sample >> ( exponent + 3 ) ) & 0x0F;
+	ulawbyte = ~ ( sign | ( exponent << 4 ) | mantissa );
+#ifdef ZEROTRAP
+	if (ulawbyte == 0)
+		ulawbyte = 0x02; /* optional CCITT trap */
+#endif
+
+	return(ulawbyte);
+}
+
+#endif /* defined(PLATFORM_LINUX) || defined(PLATFORM_BSD) */
+
+#endif