Initial import of Pawn (Small 3.0)

compiler/libpc300/scexpand.c

@@ -0,0 +1,68 @@
+/* expand.c -- Byte Pair Encoding decompression */
+/* Copyright 1996 Philip Gage */
+
+/* Byte Pair Compression appeared in the September 1997
+ * issue of C/C++ Users Journal. The original source code
+ * may still be found at the web site of the magazine
+ * (www.cuj.com).
+ *
+ * The decompressor has been modified by me (Thiadmer
+ * Riemersma) to accept a string as input, instead of a
+ * complete file.
+ */
+#include <assert.h>
+#include <stdio.h>
+#include "sc.h"
+
+#define STACKSIZE 16
+
+SC_FUNC int strexpand(char *dest, unsigned char *source, int maxlen, unsigned char pairtable[128][2])
+{
+  unsigned char stack[STACKSIZE];
+  short c, top = 0;
+  int len;
+
+  assert(maxlen > 0);
+  len = 1;              /* already 1 byte for '\0' */
+  for (;;) {
+
+    /* Pop byte from stack or read byte from the input string */
+    if (top)
+      c = stack[--top];
+    else if ((c = *(unsigned char *)source++) == '\0')
+      break;
+
+    /* Push pair on stack or output byte to the output string */
+    if (c > 127) {
+      assert(top+2 <= STACKSIZE);
+      stack[top++] = pairtable[c-128][1];
+      stack[top++] = pairtable[c-128][0];
+    }
+    else {
+      len++;
+      if (maxlen > 1) { /* reserve one byte for the '\0' */
+        *dest++ = (char)c;
+        maxlen--;
+      }
+    }
+  }
+  *dest = '\0';
+  return len;           /* return number of bytes decoded */
+}
+
+#if 0 /*for testing*/
+#include "sc5.scp"
+
+int main (int argc, char **argv)
+{
+  int i;
+  char str[128];
+
+  for (i=0; i<58; i++) {
+    strexpand(str, errmsg[i], sizeof str, SCPACK_TABLE);
+    printf("%s", str);
+  } /* for */
+  return 0;
+}
+#endif
+