From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Serge Petrenko Subject: [PATCH v3 2/6] decimal: fix encoding numbers with positive exponent. Date: Tue, 20 Aug 2019 20:10:00 +0300 Message-Id: In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit To: vdavydov.dev@gmail.com, kostja@tarantool.org Cc: tarantool-patches@freelists.org, Serge Petrenko List-ID: When a number having a positive exponent is encoded, the internal decPackedFromNumber function returns a negative scale, which differs from the scale, returned by decimal_scale(). This leads to errors in decoding. Account for negative scale in decimal_pack() and decimal_unpack(). Follow-up #692 --- src/lib/core/decimal.c | 42 ++++++++++++++++++++++++++++++++-------- test/unit/decimal.c | 15 ++++++++++++-- test/unit/decimal.result | 11 ++++++++--- 3 files changed, 55 insertions(+), 13 deletions(-) diff --git a/src/lib/core/decimal.c b/src/lib/core/decimal.c index e141a91f8..356acf6f2 100644 --- a/src/lib/core/decimal.c +++ b/src/lib/core/decimal.c @@ -33,6 +33,7 @@ #include "third_party/decNumber/decContext.h" #include "third_party/decNumber/decPacked.h" #include "lib/core/tt_static.h" +#include "lib/msgpuck/msgpuck.h" #include #include #include /* DBL_DIG */ @@ -339,20 +340,27 @@ decimal_sqrt(decimal_t *res, const decimal_t *lhs) uint32_t decimal_len(const decimal_t *dec) { - /* 1 + ceil((digits + 1) / 2) */ - return 2 + dec->digits / 2; + uint32_t sizeof_scale = dec->exponent > 0 ? mp_sizeof_int(-dec->exponent) : + mp_sizeof_uint(-dec->exponent); + /* sizeof_scale + ceil((digits + 1) / 2) */ + return sizeof_scale + 1 + dec->digits / 2; } char * decimal_pack(char *data, const decimal_t *dec) { uint32_t len = decimal_len(dec); - *data++ = decimal_scale(dec); - len--; + char *svp = data; + /* encode scale */ + if (dec->exponent > 0) { + data = mp_encode_int(data, -dec->exponent); + } else { + data = mp_encode_uint(data, -dec->exponent); + } + len -= data - svp; int32_t scale; char *tmp = (char *)decPackedFromNumber((uint8_t *)data, len, &scale, dec); assert(tmp == data); - assert(scale == (int32_t)decimal_scale(dec)); (void)tmp; data += len; return data; @@ -361,12 +369,30 @@ decimal_pack(char *data, const decimal_t *dec) decimal_t * decimal_unpack(const char **data, uint32_t len, decimal_t *dec) { - int32_t scale = *((*data)++); - len--; + int32_t scale; + const char *svp = *data; + if (mp_typeof(**data) == MP_UINT) { + scale = mp_decode_uint(data); + } else if (mp_typeof(**data) == MP_INT) { + scale = mp_decode_int(data); + } else { + return NULL; + } + /* + * scale = -exponent. The exponent should be in range + * [-DECIMAL_MAX_DIGITS; DECIMAL_MAX_DIGITS) + */ + if (scale > DECIMAL_MAX_DIGITS || + scale <= -DECIMAL_MAX_DIGITS) { + *data = svp; + return NULL; + } + + len -= *data - svp; decimal_t *res = decPackedToNumber((uint8_t *)*data, len, &scale, dec); if (res) *data += len; else - (*data)--; + *data = svp; return res; } diff --git a/test/unit/decimal.c b/test/unit/decimal.c index b587e1f14..b55333ed7 100644 --- a/test/unit/decimal.c +++ b/test/unit/decimal.c @@ -91,7 +91,7 @@ char buf[32]; static int test_pack_unpack(void) { - plan(146); + plan(151); test_decpack("0"); test_decpack("-0"); @@ -112,13 +112,24 @@ test_pack_unpack(void) test_decpack("99999999999999999999999999999999999999"); test_decpack("-99999999999999999999999999999999999999"); + /* Check correct encoding of positive exponent numbers. */ + decimal_t dec, d1; + decimal_from_string(&dec, "1e10"); + uint32_t l1 = decimal_len(&dec); + ok(l1 == 2, "decimal_len() is small for positive exponent decimal"); + char *b1 = decimal_pack(buf, &dec); + is(b1, buf + l1, "positive exponent decimal length"); + const char *b2 = buf; + is(decimal_unpack(&b2, l1, &d1), &d1, "decimal_unpack() of a positive exponent decimal"); + is(b1, b2, "decimal_unpack uses every byte packed by decimal_pack"); + is(decimal_compare(&dec, &d1), 0, "positive exponent number is packed/unpacked correctly"); + /* Pack an invalid decimal. */ char *b = buf; *b++ = 1; *b++ = '\xab'; *b++ = '\xcd'; const char *bb = buf; - decimal_t dec; is(decimal_unpack(&bb, 3, &dec), NULL, "unpack malformed decimal fails"); is(bb, buf, "decode malformed decimal preserves buffer position"); diff --git a/test/unit/decimal.result b/test/unit/decimal.result index 1c72cdfab..2dd91af49 100644 --- a/test/unit/decimal.result +++ b/test/unit/decimal.result @@ -277,7 +277,7 @@ ok 275 - decimal_from_string(-1) ok 276 - decimal_log10(-1) - error on wrong operands. ok 277 - decimal_from_string(-10) ok 278 - decimal_sqrt(-10) - error on wrong operands. - 1..146 + 1..151 ok 1 - decimal_len(0) ok 2 - decimal_len(0) == len(decimal_pack(0) ok 3 - decimal_unpack(decimal_pack(0)) @@ -422,6 +422,11 @@ ok 278 - decimal_sqrt(-10) - error on wrong operands. ok 142 - decimal_unpack(decimal_pack(-99999999999999999999999999999999999999)) scale ok 143 - decimal_unpack(decimal_pack(-99999999999999999999999999999999999999)) precision ok 144 - str(decimal_unpack(decimal_pack(-99999999999999999999999999999999999999)) == -99999999999999999999999999999999999999 - ok 145 - unpack malformed decimal fails - ok 146 - decode malformed decimal preserves buffer position + ok 145 - decimal_len() is small for positive exponent decimal + ok 146 - positive exponent decimal length + ok 147 - decimal_unpack() of a positive exponent decimal + ok 148 - decimal_unpack uses every byte packed by decimal_pack + ok 149 - positive exponent number is packed/unpacked correctly + ok 150 - unpack malformed decimal fails + ok 151 - decode malformed decimal preserves buffer position ok 279 - subtests -- 2.20.1 (Apple Git-117)