--- /dev/null
+/* 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
projects / rocksndiamonds.git / blobdiff