Added a method to write variable sized unsigned values. Use this method for

all sorts of things in the object files. This does not only make the object
files smaller, but does also remove several limits (strings may be longer
than 255 bytes, several counters no longer have 8 or 16 bit limits).


git-svn-id: svn://svn.cc65.org/cc65/trunk@260 b7a2c559-68d2-44c3-8de9-860c34a00d81

src/od65/fileio.c

@@ -67,7 +67,7 @@ unsigned Read8 (FILE* F)
     int C = getc (F);
     if (C == EOF) {
  	Error ("Read error (file corrupt?)");
-    }		  
+    }
     return C;
 }
 
@@ -121,27 +121,35 @@ long Read32Signed (FILE* F)
 
 
 
-char* ReadStr (FILE* F, char* Str)
-/* Read a string from the file. Str must hold 256 chars at max */
+unsigned long ReadVar (FILE* F)
+/* Read a variable size value from the file */
 {
-    /* Read the length byte */
-    unsigned Len = Read8 (F);
+    /* The value was written to the file in 7 bit chunks LSB first. If there
+     * are more bytes, bit 8 is set, otherwise it is clear.
+     */
+    unsigned char C;
+    unsigned long V = 0;
+    unsigned Shift = 0;
+    do {
+	/* Read one byte */
+	C = Read8 (F);
+	/* Encode it into the target value */
+	V |= ((unsigned long)(C & 0x7F)) << Shift;
+	/* Next value */
+	Shift += 7;
+    } while (C & 0x80);
 
-    /* Read the string itself */
-    ReadData (F, Str, Len);
-
-    /* Terminate the string and return it */
-    Str [Len] = '\0';
-    return Str;
+    /* Return the value read */
+    return V;
 }
 
 
 
-char* ReadMallocedStr (FILE* F)
+char* ReadStr (FILE* F)
 /* Read a string from the file into a malloced area */
 {
-    /* Read the length byte */
-    unsigned Len = Read8 (F);
+    /* Read the length */
+    unsigned Len = ReadVar (F);
 
     /* Allocate memory */
     char* Str = xmalloc (Len + 1);
@@ -159,10 +167,10 @@ char* ReadMallocedStr (FILE* F)
 FilePos* ReadFilePos (FILE* F, FilePos* Pos)
 /* Read a file position from the file */
 {
-    /* The line number is encoded as 24 bit value to save some space */
-    Pos->Line =	Read24 (F);
-    Pos->Col  = Read8 (F);
-    Pos->Name = Read8 (F);
+    /* Read the data fields */
+    Pos->Line =	ReadVar (F);
+    Pos->Col  = ReadVar (F);
+    Pos->Name = ReadVar (F);
     return Pos;
 }