Fix: string and floats conversion fixes (#117)

* fix wide to C string conversion truncation indic.

In case of SQLWCHAR to SQLCHAR conversion the truncation indication
was wrongly signaled (the conversion was performed correctly, though).
This happened because of the wrong number of bytes compared against
available buffer: the SQLWCHAR string space instead of the (correct)
converted equivalent.

* added unit test for the fix

* fix: consider val 0 on dbl to float range check

- double zero will be less than FLT_MIN and still a valid float;
- double zero to integers conversions consider this case already and are
not affected.

(cherry picked from commit f6669dd)

Author: bpintea

driver/convert.c

@@ -1332,9 +1332,11 @@ SQLRETURN sql2c_double(esodbc_rec_st *arec, esodbc_rec_st *irec,
 
 		case SQL_C_FLOAT:
 			REJECT_IF_NULL_DEST_BUFF(stmt, data_ptr);
-			udbl = dbl < 0 ? -dbl : dbl;
-			if (udbl < FLT_MIN || FLT_MAX < udbl) {
-				REJECT_AS_OOR(stmt, dbl, /* is fixed */FALSE, SQLREAL);
+			if (dbl) {
+				udbl = dbl < 0 ? -dbl : dbl;
+				if (udbl < FLT_MIN || FLT_MAX < udbl) {
+					REJECT_AS_OOR(stmt, dbl, /* is fixed */FALSE, SQLREAL);
+				}
 			}
 			*(SQLREAL *)data_ptr = (SQLREAL)dbl;
 			write_out_octets(octet_len_ptr, sizeof(SQLREAL), irec);
@@ -1382,15 +1384,38 @@ static SQLRETURN wstr_to_cstr(esodbc_rec_st *arec, esodbc_rec_st *irec,
 
 	gd_offset_apply(stmt, &xstr);
 
+	assert(xstr.w.str[xstr.w.cnt] == L'\0');
+	/* how much space would the converted string take? */
+	in_bytes = WCS2U8(xstr.w.str, (int)xstr.w.cnt + 1, NULL, 0);
+	if (in_bytes <= 0) {
+		ERRNH(stmt, "failed to convert wchar* to char* for string `"
+			LWPDL "`.", LWSTR(&xstr.w));
+		RET_HDIAGS(stmt, SQL_STATE_22018);
+	}
+	/* out length needs to be provided with no (potential) truncation. */
+	if (octet_len_ptr) {
+		/* chars_0 accounts for 0-terminator, so WCS2U8 will count that in
+		 * the output as well => trim it, since we must not count it when
+		 * indicating the length to the application */
+		out_bytes = in_bytes - 1;
+		write_out_octets(octet_len_ptr, out_bytes, irec);
+	} else {
+		DBGH(stmt, "REC@0x%p, NULL octet_len_ptr.", arec);
+	}
+
 	if (data_ptr) {
 		charp = (char *)data_ptr;
 
-		in_bytes = (int)buff_octet_size((xstr.w.cnt + 1) * sizeof(SQLWCHAR),
-				sizeof(SQLCHAR), arec, irec, &state);
+		/* calculate how much of original data could possibly be copied in
+		 * provided buffer; this will be given as a limitation to W-to-C
+		 * conversion function. */
+		in_bytes = (int)buff_octet_size(in_bytes, sizeof(SQLCHAR), arec, irec,
+				&state);
 		/* trim the original string until it fits in output buffer, with given
 		 * length limitation */
 		for (c = (int)xstr.w.cnt + 1; 0 < c; c --) {
 			out_bytes = WCS2U8(xstr.w.str, c, charp, in_bytes);
+			/* if user gives 0 as buffer size, out_bytes will also be 0 */
 			if (out_bytes <= 0) {
 				if (WCS2U8_BUFF_INSUFFICIENT) {
 					continue;
@@ -1404,10 +1429,7 @@ static SQLRETURN wstr_to_cstr(esodbc_rec_st *arec, esodbc_rec_st *irec,
 			}
 		}
 
-		/* if 0's present => 0 < out_bytes */
-		assert(xstr.w.str[xstr.w.cnt] == L'\0');
 		assert(0 < out_bytes);
-		/* if user gives 0 as buffer size, out_bytes will also be 0 */
 		if (charp[out_bytes - 1]) {
 			/* ran out of buffer => not 0-terminated and truncated already */
 			charp[out_bytes - 1] = 0;
@@ -1418,30 +1440,12 @@ static SQLRETURN wstr_to_cstr(esodbc_rec_st *arec, esodbc_rec_st *irec,
 		/* only update offset if data is copied out */
 		gd_offset_update(stmt, xstr.w.cnt, c);
 
-		DBGH(stmt, "REC@0x%p, data_ptr@0x%p, copied %zd bytes: `" LWPD "`.",
+		DBGH(stmt, "REC@0x%p, data_ptr@0x%p, copied %d bytes: `" LCPD "`.",
 			arec, data_ptr, out_bytes, charp);
 	} else {
 		DBGH(stmt, "REC@0x%p, NULL data_ptr.", arec);
 	}
 
-	/* if length needs to be given, calculate it (not truncated) & converted */
-	if (octet_len_ptr) {
-		out_bytes = (size_t)WCS2U8(xstr.w.str, (int)xstr.w.cnt + 1, NULL, 0);
-		if (out_bytes <= 0) {
-			ERRNH(stmt, "failed to convert wchar* to char* for string `"
-				LWPDL "`.", LWSTR(&xstr.w));
-			RET_HDIAGS(stmt, SQL_STATE_22018);
-		} else {
-			/* chars_0 accounts for 0-terminator, so WCS2U8 will count that in
-			 * the output as well => trim it, since we must not count it when
-			 * indicating the length to the application */
-			out_bytes --;
-		}
-		write_out_octets(octet_len_ptr, out_bytes, irec);
-	} else {
-		DBGH(stmt, "REC@0x%p, NULL octet_len_ptr.", arec);
-	}
-
 	if (state != SQL_STATE_00000) {
 		RET_HDIAGS(stmt, state);
 	}

driver/queries.c

@@ -773,7 +773,7 @@ SQLRETURN copy_one_row(esodbc_stmt_st *stmt, SQLULEN pos)
 			case UJT_Long:
 			case UJT_LongLong:
 				ll = UJNumericLongLong(obj);
-				DBGH(stmt, "value [%zd, %d] is numeric: %lld.", rowno, i + 1,
+				DBGH(stmt, "value [%zd, %d] is integer: %lld.", rowno, i + 1,
 					ll);
 				ret = sql2c_longlong(arec, irec, pos, ll);
 				break;

test/test_conversion_sql2c_floats.cc

@@ -333,6 +333,39 @@ TEST_F(ConvertSQL2C_Floats, Float2Long) {
 }
 
 
+TEST_F(ConvertSQL2C_Floats, Double_zero2Float) {
+
+#undef SQL_RAW
+#undef SQL_VAL
+#undef SQL
+#define SQL_RAW 0.0
+#define SQL_VAL STR(SQL_RAW)
+#define SQL "CAST(" SQL_VAL " AS DOUBLE)"
+
+  const char json_answer[] = "\
+{\
+  \"columns\": [\
+    {\"name\": \"" SQL "\", \"type\": \"double\"}\
+  ],\
+  \"rows\": [\
+    [" SQL_VAL "]\
+  ]\
+}\
+";
+  prepareStatement(json_answer);
+
+  SQLREAL val;
+  ret = SQLBindCol(stmt, /*col#*/1, SQL_C_FLOAT, &val, sizeof(val), &ind_len);
+  ASSERT_TRUE(SQL_SUCCEEDED(ret));
+
+  ret = SQLFetch(stmt);
+  ASSERT_TRUE(SQL_SUCCEEDED(ret));
+
+  EXPECT_EQ(ind_len, sizeof(val));
+  EXPECT_LE(SQL_RAW, val);
+}
+
+
 TEST_F(ConvertSQL2C_Floats, Double2Float) {
 
 #undef SQL_RAW

test/test_conversion_sql2c_string.cc

@@ -45,6 +45,7 @@ TEST_F(ConvertSQL2C_String, String2Char) {
 
   ret = SQLFetch(stmt);
   ASSERT_TRUE(SQL_SUCCEEDED(ret));
+  assertState(L"00000");
 
   EXPECT_EQ(ind_len, sizeof(SQL_VAL) - /*\0*/1);
   EXPECT_STREQ((char/*4gtest*/*)buff, SQL_VAL);
@@ -114,6 +115,38 @@ TEST_F(ConvertSQL2C_String, String2Char_zero_copy) {
 }
 
 
+TEST_F(ConvertSQL2C_String, String2Char_truncate) {
+
+#undef SQL_VAL
+#undef SQL
+#define SQL_VAL "abcdef"
+#define SQL "CAST(" SQL_VAL " AS TEXT)"
+
+  const char json_answer[] = "\
+{\
+  \"columns\": [\
+    {\"name\": \"" SQL "\", \"type\": \"text\"}\
+  ],\
+  \"rows\": [\
+    [\"" SQL_VAL "\"]\
+  ]\
+}\
+";
+  prepareStatement(json_answer);
+
+  SQLCHAR buff[(sizeof(SQL_VAL) - 1)/2 + 1];
+  ret = SQLBindCol(stmt, /*col#*/1, SQL_C_CHAR, &buff, sizeof(buff), &ind_len);
+  ASSERT_TRUE(SQL_SUCCEEDED(ret));
+
+  ret = SQLFetch(stmt);
+  ASSERT_TRUE(SQL_SUCCEEDED(ret));
+  assertState(L"01004");
+
+  EXPECT_EQ(ind_len, sizeof(SQL_VAL) - /*\0*/1);
+  EXPECT_STREQ((char/*4gtest*/*)buff, "abc");
+}
+
+
 TEST_F(ConvertSQL2C_String, String2SLong) {
 
 #undef SQL_RAW