issue #82 improve debugger use of variableReference

vscode-debugger/src/protocol.c

@@ -1122,3 +1122,34 @@ void vscode_string_copy(char *buf, const char *src, size_t buflen) {
   strncpy(buf, src, buflen);
   buf[buflen - 1] = 0;
 }
+
+int64_t vscode_pack(PackedInteger *pi) {
+  int64_t i = 0;
+  assert(pi->a8 <= 0xFF);
+  assert(pi->b8 <= 0xFF);
+  assert(pi->c8 <= 0xFF);
+  assert(pi->d8 <= 0xFF);
+  assert(pi->e8 <= 0xFF);
+  assert(pi->f8 <= 0xFF);
+  assert(pi->g4 <= 0x0F);
+  i |= (pi->a8 & 0xFF);
+  i |= ((int64_t)(pi->b8 & 0xFF) << 8);
+  i |= ((int64_t)(pi->c8 & 0xFF) << 16);
+  i |= ((int64_t)(pi->d8 & 0xFF) << 24);
+  i |= ((int64_t)(pi->e8 & 0xFF) << 32);
+  i |= ((int64_t)(pi->f8 & 0xFF) << 40);
+  i |= ((int64_t)(pi->g4 & 0x0F) << 48);
+  return i;
+}
+
+void vscode_unpack(int64_t i, PackedInteger *pi) {
+  int64_t mask = 0xFF;
+  pi->a8 = (unsigned int)(i & mask); mask <<= 8;
+  pi->b8 = (unsigned int)((i & mask) >> 8); mask <<= 8;
+  pi->c8 = (unsigned int)((i & mask) >> 16); mask <<= 8;
+  pi->d8 = (unsigned int)((i & mask) >> 24); mask <<= 8;
+  pi->e8 = (unsigned int)((i & mask) >> 32); mask <<= 8;
+  pi->f8 = (unsigned int)((i & mask) >> 40); mask <<= 8;
+  pi->g4 = (unsigned int)(((i & mask) >> 48) & 0x0F);
+}
+

vscode-debugger/src/protocol.h

@@ -92,6 +92,22 @@ enum {
   MAX_TOTAL_BREAKPOINTS = 20
 };
 
+/*
+The max integer that can be transferred to a Javascript number (and hence JSON
+number) is 2^53-1 which is equal to 9007199254740991. This takes up 53 bits.
+The integer 4503599627370495 takes up 52 bits - so that means 6 8-bit values and 1
+4-bit value can be accomodated.
+*/
+typedef struct {
+  unsigned int a8;
+  unsigned int b8;
+  unsigned int c8;
+  unsigned int d8;
+  unsigned int e8;
+  unsigned int f8;
+  unsigned int g4;
+} PackedInteger;
+
 typedef struct {
   int id;
   char format[TEXT_LEN];
@@ -396,5 +412,7 @@ extern void vscode_json_stringify(const char *src, char *dest, size_t len);
 
 /* guaranteed null termination */
 extern void vscode_string_copy(char *buf, const char *src, size_t buflen);
+extern int64_t vscode_pack(PackedInteger *pi);
+extern void vscode_unpack(int64_t i, PackedInteger *pi);
 
 #endif

vscode-debugger/src/testravidebug.c

@@ -102,9 +102,57 @@ int test_membuff() {
 	return 0;
 }
 
+int test_intpacking() {
+  int64_t ix = 4503599627370495;
+  int64_t i1 = 9007199254740991;
+  double d = (double) i1;
+  int64_t i2 = (int64_t) d;
+  fprintf(stderr, "%lld, %0.15f, %lld\n", i1, d, i2);
+  if (i1 != i2)
+    return 1;
+  PackedInteger pi;
+  pi.a8 = 0xFF;
+  pi.b8 = 0xFF;
+  pi.c8 = 0xFF;
+  pi.d8 = 0xFF;
+  pi.e8 = 0xFF;
+  pi.f8 = 0xFF;
+  pi.g4 = 0x0F;
+  int64_t i3 = vscode_pack(&pi);
+  d = (double) i3;
+  i2 = (int64_t) d;
+  fprintf(stderr, "%lld, %0.15f, %lld\n", i3, d, i2);
+  if (i3 != ix)
+    return 1;
+  PackedInteger p2 = { 0 };
+  vscode_unpack(i3, &p2);
+  if (memcmp(&pi, &p2, sizeof(PackedInteger)) != 0)
+    return 1;
+  fprintf(stderr, "%x %x %x %x %x %x %x\n", p2.a8, p2.b8, p2.c8, p2.d8, p2.e8, p2.f8, p2.g4);
+  pi.a8 = 127;
+  pi.b8 = 212;
+  pi.c8 = 13;
+  pi.d8 = 55;
+  pi.e8 = 220;
+  pi.f8 = 0;
+  pi.g4 = 15;
+  i3 = vscode_pack(&pi);
+  d = (double)i3;
+  i2 = (int64_t)d;
+  fprintf(stderr, "%lld, %0.15f, %lld\n", i3, d, i2);
+  if (i3 != i2)
+    return 1;
+  vscode_unpack(i3, &p2);
+  fprintf(stderr, "%u %u %u %u %u %u %u\n", p2.a8, p2.b8, p2.c8, p2.d8, p2.e8, p2.f8, p2.g4);
+  if (memcmp(&pi, &p2, sizeof(PackedInteger)) != 0)
+    return 1;
+  return 0;
+}
+
 int main(void) {
   setbuf(stdout, NULL);
   int rc = 0;
+  rc += test_intpacking();
   rc += test_initreq();
   rc += test_json_stringify();
   rc += test_membuff();