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authorakr <akr@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2013-06-06 21:20:04 +0000
committerakr <akr@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2013-06-06 21:20:04 +0000
commitc9c67d2fe0d8d502d444c477d3272c4092513a53 (patch)
tree81a21632cffe836b8e768ed733eedcbfd999426a /bignum.c
parent64ed7df5434bc2978d5a92a1e750bab39b11edfa (diff)
* bignum.c (rb_int_import): New function.
(int_import_push_bits): Ditto. * internal.h (rb_int_import): Declared. * pack.c (pack_unpack): Use rb_int_import for BER compressed integer. git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41111 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Diffstat (limited to 'bignum.c')
-rw-r--r--bignum.c155
1 files changed, 154 insertions, 1 deletions
diff --git a/bignum.c b/bignum.c
index 41e4fdd551..1cedb8b171 100644
--- a/bignum.c
+++ b/bignum.c
@@ -607,7 +607,7 @@ rb_int_export(VALUE val, int *signp, void *bufarg, size_t *countp, int wordorder
#ifdef WORDS_BIGENDIAN
endian = 1;
#else
- endian = 0;
+ endian = -1;
#endif
}
@@ -770,6 +770,159 @@ rb_int_export(VALUE val, int *signp, void *bufarg, size_t *countp, int wordorder
#undef TAKE_LOWBITS
}
+static inline void
+int_import_push_bits(int data, int numbits, BDIGIT_DBL *ddp, int *numbits_in_dd_p, BDIGIT **dpp)
+{
+ (*ddp) |= ((BDIGIT_DBL)data) << (*numbits_in_dd_p);
+ *numbits_in_dd_p += numbits;
+ while (SIZEOF_BDIGITS*CHAR_BIT <= *numbits_in_dd_p) {
+ *(*dpp)++ = (*ddp) & (((BDIGIT_DBL)1 << (SIZEOF_BDIGITS*CHAR_BIT))-1);
+ *ddp >>= SIZEOF_BDIGITS*CHAR_BIT;
+ *numbits_in_dd_p -= SIZEOF_BDIGITS*CHAR_BIT;
+ }
+}
+
+/*
+ * Import an integer into a buffer.
+ *
+ * [sign] signedness of the value.
+ * -1 for non-positive. 0 or 1 for non-negative.
+ * [bufarg] buffer to import.
+ * [wordcount] the size of given buffer as number of words.
+ * [wordorder] order of words: 1 for most significant word first. -1 for least significant word first.
+ * [wordsize] the size of word as number of bytes.
+ * [endian] order of bytes in a word: 1 for most significant byte first. -1 for least significant byte first. 0 for native endian.
+ * [nails] number of padding bits in a word. Most significant nails bits of each word are filled by zero.
+ *
+ * This function returns the imported integer as Fixnum or Bignum.
+ */
+VALUE
+rb_int_import(int sign, const void *bufarg, size_t wordcount, int wordorder, size_t wordsize, int endian, size_t nails)
+{
+ VALUE num_bits, num_bdigits;
+ VALUE result;
+ const unsigned char *buf = bufarg;
+
+ BDIGIT *dp;
+ BDIGIT *de;
+
+ int word_num_partialbits;
+ size_t word_num_fullbytes;
+
+ ssize_t word_step;
+ size_t byte_start;
+ int byte_step;
+
+ const unsigned char *bytep, *wordp, *last_wordp;
+ size_t index_in_word;
+ BDIGIT_DBL dd;
+ int numbits_in_dd;
+
+ if (sign != 1 && sign != 0 && sign != -1)
+ rb_raise(rb_eArgError, "unexpected sign: %d", sign);
+ if (wordorder != 1 && wordorder != -1)
+ rb_raise(rb_eArgError, "unexpected wordorder: %d", wordorder);
+ if (endian != 1 && endian != -1 && endian != 0)
+ rb_raise(rb_eArgError, "unexpected endian: %d", endian);
+ if (wordsize == 0)
+ rb_raise(rb_eArgError, "invalid wordsize: %"PRI_SIZE_PREFIX"u", wordsize);
+ if (SSIZE_MAX < wordsize)
+ rb_raise(rb_eArgError, "too big wordsize: %"PRI_SIZE_PREFIX"u", wordsize);
+ if (SIZE_MAX / wordsize < wordcount)
+ rb_raise(rb_eArgError, "too big wordcount * wordsize: %"PRI_SIZE_PREFIX"u * %"PRI_SIZE_PREFIX"u", wordcount, wordsize);
+ if (wordsize <= nails / CHAR_BIT)
+ rb_raise(rb_eArgError, "too big nails: %"PRI_SIZE_PREFIX"u", nails);
+
+ if (endian == 0) {
+#ifdef WORDS_BIGENDIAN
+ endian = 1;
+#else
+ endian = -1;
+#endif
+ }
+
+ /*
+ * num_bits = (wordsize * CHAR_BIT - nails) * count
+ * num_bdigits = (num_bits + SIZEOF_BDIGITS*CHAR_BIT - 1) / (SIZEOF_BDIGITS*CHAR_BIT)
+ */
+ num_bits = SIZE2NUM(wordsize);
+ num_bits = rb_funcall(num_bits, '*', 1, LONG2FIX(CHAR_BIT));
+ num_bits = rb_funcall(num_bits, '-', 1, SIZE2NUM(nails));
+ num_bits = rb_funcall(num_bits, '*', 1, SIZE2NUM(wordcount));
+
+ if (num_bits == LONG2FIX(0))
+ return LONG2FIX(0);
+
+ num_bdigits = rb_funcall(num_bits, '+', 1, LONG2FIX(SIZEOF_BDIGITS*CHAR_BIT-1));
+ num_bdigits = rb_funcall(num_bdigits, '/', 1, LONG2FIX(SIZEOF_BDIGITS*CHAR_BIT));
+
+ result = bignew(NUM2LONG(num_bdigits), 0 <= sign);
+
+ dp = BDIGITS(result);
+ de = dp + RBIGNUM_LEN(result);
+
+ word_num_partialbits = CHAR_BIT - (int)(nails % CHAR_BIT);
+ if (word_num_partialbits == CHAR_BIT)
+ word_num_partialbits = 0;
+ word_num_fullbytes = wordsize - (nails / CHAR_BIT);
+ if (word_num_partialbits != 0) {
+ word_num_fullbytes--;
+ }
+
+ if (wordorder == 1) {
+ word_step = -(ssize_t)wordsize;
+ wordp = buf + wordsize*(wordcount-1);
+ last_wordp = buf;
+ }
+ else {
+ word_step = wordsize;
+ wordp = buf;
+ last_wordp = buf + wordsize*(wordcount-1);
+ }
+
+ if (endian == 1) {
+ byte_step = -1;
+ byte_start = wordsize-1;
+ }
+ else {
+ byte_step = 1;
+ byte_start = 0;
+ }
+
+ dd = 0;
+ numbits_in_dd = 0;
+
+#define PUSH_BITS(data, numbits) \
+ int_import_push_bits(data, numbits, &dd, &numbits_in_dd, &dp)
+
+ while (1) {
+ index_in_word = 0;
+ bytep = wordp + byte_start;
+ while (index_in_word < word_num_fullbytes) {
+ PUSH_BITS(*bytep, CHAR_BIT);
+ bytep += byte_step;
+ index_in_word++;
+ }
+ if (word_num_partialbits) {
+ PUSH_BITS(*bytep & ((1 << word_num_partialbits) - 1), word_num_partialbits);
+ bytep += byte_step;
+ index_in_word++;
+ }
+
+ if (wordp == last_wordp)
+ break;
+
+ wordp += word_step;
+ }
+ if (dd)
+ *dp++ = dd;
+ while (dp < de)
+ *dp++ = 0;
+
+ return bignorm(result);
+#undef PUSH_BITS
+}
+
#define QUAD_SIZE 8
#if SIZEOF_LONG_LONG == QUAD_SIZE && SIZEOF_BDIGITS*2 == SIZEOF_LONG_LONG