From: Brian Foley <bpfoley@google.com>
Date: Thu, 5 Sep 2019 08:46:22 +0000 (+0200)
Subject: dc: execute shouldn't pop if stack head is not a string
X-Git-Tag: 1_31_1~9
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=4699b932446f809d747d97f8e24b5d48608f7276;p=oweals%2Fbusybox.git

dc: execute shouldn't pop if stack head is not a string

This matches the behaviour of both GNU dc (as specified in
its man page), and BSD dc (where stack_popstring() pops
only if the head is a string.)

Add a couple of tests to verify this behavior.

function                                             old     new   delta
zxc_vm_process                                      6882    6884      +2

Signed-off-by: Brian Foley <bpfoley@google.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
---

diff --git a/miscutils/bc.c b/miscutils/bc.c
index aba51e5f8..9a9880706 100644
--- a/miscutils/bc.c
+++ b/miscutils/bc.c
@@ -6521,7 +6521,7 @@ static BC_STATUS zdc_program_execStr(char *code, size_t *bgn, bool cond)
 			if (s || !BC_PROG_STR(n)) goto exit;
 			sidx = n->rdx;
 		} else
-			goto exit;
+			goto exit_nopop;
 	}
 
 	fidx = sidx + BC_PROG_REQ_FUNCS;
@@ -6561,6 +6561,7 @@ static BC_STATUS zdc_program_execStr(char *code, size_t *bgn, bool cond)
 	RETURN_STATUS(BC_STATUS_SUCCESS);
  exit:
 	bc_vec_pop(&G.prog.results);
+ exit_nopop:
 	RETURN_STATUS(s);
 }
 #define zdc_program_execStr(...) (zdc_program_execStr(__VA_ARGS__) COMMA_SUCCESS)
diff --git a/testsuite/dc.tests b/testsuite/dc.tests
index 8c3af4156..f74e3f0f5 100755
--- a/testsuite/dc.tests
+++ b/testsuite/dc.tests
@@ -44,6 +44,16 @@ testing "dc complex without spaces (multiple args)" \
 optional FEATURE_DC_BIG
 # All tests below depend on FEATURE_DC_BIG
 
+testing "dc: x should execute strings" \
+	"dc -e'[40 2 +] x f'" \
+	"42\n" \
+	"" ""
+
+testing "dc: x should not execute or pop non-strings" \
+	"dc -e'42 x f'" \
+	"42\n" \
+	"" ""
+
 testing "dc read" \
 	"dc -finput" \
 	"2\n9\n1\n" \