Windows: BUFR decoding

src/grib_accessor_class_bufr_data_array.c

@@ -606,7 +606,7 @@ static grib_darray* decode_double_array(grib_context* c,unsigned char* data,long
 {
     grib_darray* ret=NULL;
     int j;
-    unsigned long lval;
+    size_t lval;
     int localReference,localWidth,modifiedWidth,modifiedReference;
     double modifiedFactor,dval;
     int bufr_multi_element_constant_arrays = c->bufr_multi_element_constant_arrays;
@@ -627,7 +627,7 @@ static grib_darray* decode_double_array(grib_context* c,unsigned char* data,long
         *err=0;
         return ret;
     }
-    lval=grib_decode_unsigned_long(data,pos,modifiedWidth);
+    lval=grib_decode_size_t(data,pos,modifiedWidth);
     localReference=(long)lval+modifiedReference;
     localWidth=grib_decode_unsigned_long(data,pos,6);
     grib_context_log(c, GRIB_LOG_DEBUG,"BUFR data decoding: \tlocalWidth=%ld",localWidth);
@@ -644,7 +644,7 @@ static grib_darray* decode_double_array(grib_context* c,unsigned char* data,long
             return ret;
         }
         for (j=0;j<self->numberOfSubsets;j++) {
-            lval=grib_decode_unsigned_long(data,pos,localWidth);
+            lval=grib_decode_size_t(data,pos,localWidth);
             if (grib_is_all_bits_one(lval,localWidth) && canBeMissing) {
                 dval=GRIB_MISSING_DOUBLE;
             } else {
@@ -1012,7 +1012,7 @@ static double decode_double_value(grib_context* c,unsigned char* data,long* pos,
         bufr_descriptor* bd,int canBeMissing,
         grib_accessor_bufr_data_array* self,int* err)
 {
-    unsigned long lval;
+    size_t lval;
     int modifiedWidth,modifiedReference;
     double modifiedFactor;
     double dval=0;
@@ -1026,7 +1026,7 @@ static double decode_double_value(grib_context* c,unsigned char* data,long* pos,
     CHECK_END_DATA_RETURN(c, self, modifiedWidth, 0);
     if (*err) {*err=0; return GRIB_MISSING_DOUBLE;}
 
-    lval=grib_decode_unsigned_long(data,pos,modifiedWidth);
+    lval=grib_decode_size_t(data,pos,modifiedWidth);
     if (grib_is_all_bits_one(lval,modifiedWidth) && canBeMissing) {
         dval=GRIB_MISSING_DOUBLE;
     } else {

src/grib_api_prototypes.h

@@ -1552,6 +1552,7 @@ int grib_encode_string(unsigned char *bitStream, long *bitOffset, size_t numberO
 char *grib_decode_string(const unsigned char *bitStream, long *bitOffset, size_t numberOfCharacters, char *string);
 unsigned long grib_decode_unsigned_long(const unsigned char *p, long *bitp, long nbits);
 int grib_encode_unsigned_long(unsigned char *p, unsigned long val, long *bitp, long nbits);
+size_t grib_decode_size_t(const unsigned char* p, long* bitp, long nbits);
 int grib_encode_unsigned_longb(unsigned char *p, unsigned long val, long *bitp, long nb);
 
 /* grib_bits_any_endian_simple.c */

src/grib_bits.c

@@ -33,6 +33,7 @@ long GRIB_MASK = -1;       /* Mask of sword bits */
 static const unsigned long dmasks[] = { 0xFF, 0xFE, 0xFC, 0xF8, 0xF0, 0xE0, 0xC0, 0x80, 0x00, };
 
 static const int max_nbits = sizeof(unsigned long)*8;
+static const int max_nbits_size_t = sizeof(size_t)*8;
 
 unsigned long grib_decode_unsigned_byte_long(const unsigned char* p, long o, int l)
 {

src/grib_bits_any_endian.c

@@ -298,6 +298,73 @@ int grib_encode_unsigned_long(unsigned char* p, unsigned long val ,long *bitp, l
     return GRIB_SUCCESS;
 }
 
+/*
+ * Note: On x64 Micrsoft Windows a "long" is 32 bits but "size_t" is 64 bits
+ */
+#define BIT_MASK_SIZE_T(x) \
+        (((x) == max_nbits_size_t) ? \
+                (size_t) -1UL : (1UL << (x)) - 1)
+
+size_t grib_decode_size_t(const unsigned char* p, long *bitp, long nbits)
+{
+    size_t ret = 0;
+    long oc = *bitp / 8;
+    size_t mask = 0;
+    long pi = 0;
+    int usefulBitsInByte = 0;
+    long bitsToRead = 0;
+
+    if (nbits == 0) return 0;
+
+    if (nbits > max_nbits_size_t)
+    {
+        int bits = nbits;
+        int mod = bits % max_nbits_size_t;
+
+        if (mod != 0)
+        {
+            int e = grib_decode_size_t(p, bitp, mod);
+            Assert(e == 0);
+            bits -= mod;
+        }
+
+        while (bits > max_nbits_size_t)
+        {
+            int e = grib_decode_size_t(p, bitp, max_nbits_size_t);
+            Assert(e == 0);
+            bits -= max_nbits_size_t;
+        }
+
+        return grib_decode_size_t(p, bitp, bits);
+    }
+
+    mask = BIT_MASK_SIZE_T(nbits);
+    /* pi: position of bitp in p[]. >>3 == /8 */
+    pi = oc;
+    /* number of useful bits in current byte */
+    usefulBitsInByte = 8 - (*bitp & 7);
+    /* read at least enough bits (byte by byte) from input */
+    bitsToRead = nbits;
+    while (bitsToRead > 0) {
+        ret <<= 8;
+        /*   ret += p[pi];     */
+        DebugAssert((ret & p[pi]) == 0);
+        ret = ret | p[pi];
+        pi++;
+        bitsToRead -= usefulBitsInByte;
+        usefulBitsInByte = 8;
+    }
+    *bitp += nbits;
+
+    /* bitsToRead might now be negative (too many bits read) */
+    /* remove those which are too much */
+    ret >>= -1 * bitsToRead;
+    /* remove leading bits (from previous value) */
+    ret &= mask;
+
+    return ret;
+}
+
 int grib_encode_unsigned_longb(unsigned char* p, unsigned long val ,long *bitp, long nb)
 {
     long  i = 0;