Add GSM full rate codec to LCR's source repository

[lcr.git] / libgsmfr / tls / sour.c

diff --git a/libgsmfr/tls/sour.c b/libgsmfr/tls/sour.c
new file mode 100644 (file)
index 0000000..b6932e6
--- /dev/null
+++ b/libgsmfr/tls/sour.c
@@ -0,0 +1,91 @@
+/*
+ * Copyright 1996 by Jutta Degener and Carsten Bormann, Technische
+ * Universitaet Berlin.  See the accompanying file "COPYRIGHT" for
+ * details.  THERE IS ABSOLUTELY NO WARRANTY FOR THIS SOFTWARE.
+ */
+
+/*$Header*/
+
+/* Generate code to pack a bit array from a name:#bits description,
+ * WAV #49 style.
+ */
+
+#include       <stdio.h>
+#include       "taste.h"
+#include       "proto.h"
+#include       <limits.h>
+
+/* This module goes back to one Jeff Chilton used for his implementation
+ * of the #49 WAV GSM format.  (In his original patch 8, it replaced
+ * bitter.c.)
+ *
+ * In Microsoft's WAV #49 version of the GSM format, two 32 1/2
+ * byte GSM frames are packed together to make one WAV frame, and
+ * the GSM parameters are packed into bytes right-to-left rather
+ * than left-to-right.
+ *
+ * That is, where toast's GSM format writes
+ *
+ *     aaaaaabb bbbbcccc cdddddee ...
+ *     ___1____ ___2____ ___3____
+ *
+ *  for parameters a (6 bits), b (6 bits), c (5 bits), d (5 bits), e ..
+ *  the WAV format has
+ *
+ *     bbaaaaaa ccccbbbb eedddddc ...
+ *     ___1____ ___2____ ___3____
+ *
+ *  (This format looks a lot prettier if one pictures octets coming
+ *  in through a fifo queue from the left, rather than waiting in the
+ *  right-hand remainder of a C array.)
+ */
+
+#define WORD_BITS      16      /* sizeof(uword) * CHAR_BIT on the 
+                                * target architecture---if this isn't 16,
+                                * you're in trouble with this library anyway.
+                                */
+
+#define BYTE_BITS       8      /* CHAR_BIT on the target architecture---
+                                * if this isn't 8, you're in *deep* trouble.
+                                */
+
+void write_code P2((s_spex, n_spex), struct spex * s_spex, int n_spex)
+{
+       struct spex     * sp = s_spex;
+       int               n_in = 0;
+
+       printf("uword sr = 0;\n");
+
+       for (; n_spex > 0; n_spex--, sp++) {
+
+               /*      insert       old 
+                *      new var      value     unused
+                *      here  
+                *
+                *      [____________xxxxxx**********]
+                *
+                *      <----- n_in ------>
+                */
+               printf("sr = sr >> %d | %s << %d;\n",
+                       sp->varsize,
+                       sp->var, 
+                       WORD_BITS - sp->varsize);
+
+               n_in += sp->varsize;
+
+               while (n_in >= BYTE_BITS) {
+                       printf("*c++ = sr >> %d;\n",
+                               WORD_BITS - n_in);
+                       n_in -= BYTE_BITS;
+               }
+       }
+
+       while (n_in >= BYTE_BITS) {
+               printf("*c++ = sr >> %d;\n", WORD_BITS - n_in);
+               n_in -= BYTE_BITS;
+       }
+
+       if (n_in > 0) {
+               fprintf(stderr, "warning: %d bits left over\n", n_in);
+       }
+}