bc: eliminate BC_STATUS_INPUT_EOF

function                                             old     new   delta
fflush_and_check                                       -      36     +36
bc_num_a                                             445     456     +11
bc_num_ulong                                          85      95     +10
bc_vm_run                                           1978    1984      +6
bc_num_s                                             246     252      +6
bc_err_msgs                                          192     188      -4
quit                                                  38      32      -6
bc_vm_process                                        139     132      -7
bc_program_reset                                     172     159     -13
bc_parse_create                                      192     175     -17
bc_read_line                                         349     311     -38
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 4/6 up/down: 69/-85)            Total: -16 bytes
   text	   data	    bss	    dec	    hex	filename
 987844	    485	   7296	 995625	  f3129	busybox_old
 987828	    485	   7296	 995609	  f3119	busybox_unstripped

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 27 insertions, 21 deletions

diff --git a/miscutils/bc.c b/miscutils/bc.c
index c3d118417..c819decff 100644
--- a/miscutils/bc.c
+++ b/miscutils/bc.c
@@ -171,7 +171,7 @@ typedef enum BcStatus {
         BC_STATUS_SUCCESS,
 
 //      BC_STATUS_ALLOC_ERR,
-        BC_STATUS_INPUT_EOF,
+//      BC_STATUS_INPUT_EOF,
         BC_STATUS_BIN_FILE,
 //      BC_STATUS_PATH_IS_DIR,
 
@@ -240,7 +240,7 @@ typedef enum BcStatus {
 static const char *const bc_err_msgs[] = {
         NULL,
 //      "memory allocation error",
-        "I/O error",
+//      "I/O error",
         "file is not text:",
 //      "path is a directory:",
 
@@ -875,6 +875,7 @@ struct globals {
 
         smallint tty;
         smallint ttyin;
+        smallint eof;
 } FIX_ALIASING;
 #define G (*ptr_to_globals)
 #define INIT_G() do { \
@@ -1121,11 +1122,20 @@ static const char bc_lib[] = {
 };
 #endif // ENABLE_BC
 
+static void fflush_and_check(void)
+{
+        fflush_all();
+        if (ferror(stdout) || ferror(stderr))
+                bb_perror_msg_and_die("output error");
+}
+
 static void quit(void) NORETURN;
 static void quit(void)
 {
-        fflush_all();
-        exit(ferror(stdout) || ferror(stderr));
+        if (ferror(stdin))
+                bb_perror_msg_and_die("input error");
+        fflush_and_check();
+        exit(0);
 }
 
 static void bc_vec_grow(BcVec *v, size_t n)
@@ -1284,7 +1294,7 @@ static BcStatus bc_read_line(BcVec *vec, const char *prompt)
 
         bc_vec_npop(vec, vec->len);
 
-        fflush(stdout);
+        fflush_and_check();
 #if ENABLE_FEATURE_BC_SIGNALS
         if (bb_got_signal) { // ^C was pressed
  intr:
@@ -1297,15 +1307,12 @@ static BcStatus bc_read_line(BcVec *vec, const char *prompt)
 #endif
         if (G.ttyin && !G_posix)
                 fputs(prompt, stderr);
-        fflush(stderr);
+        fflush_and_check();
 
 #if ENABLE_FEATURE_BC_SIGNALS
         errno = 0;
 #endif
         do {
-                if (ferror(stdout) || ferror(stderr))
-                        bb_perror_msg_and_die("output error");
-
                 i = fgetc(stdin);
 
                 if (i == EOF) {
@@ -1318,8 +1325,12 @@ static BcStatus bc_read_line(BcVec *vec, const char *prompt)
                         }
 #endif
                         if (ferror(stdin))
-                                bb_perror_msg_and_die("input error");
-                        return BC_STATUS_INPUT_EOF;
+                                quit(); // this emits error message
+                        G.eof = 1;
+                        // Note: EOF does not append '\n', therefore:
+                        // printf 'print 123\n' | bc - works
+                        // printf 'print 123' | bc   - fails (syntax error)
+                        break;
                 }
 
                 c = (signed char) i;
@@ -3627,7 +3638,7 @@ static void bc_parse_create(BcParse *p, size_t func,
         bc_vec_init(&p->ops, sizeof(BcLexType), NULL);
 
         p->parse = parse;
-        p->auto_part = (p->nbraces = 0);
+        // p->auto_part = p->nbraces = 0; - already is
         bc_parse_updateFunc(p, func);
 }
 
@@ -6473,9 +6484,9 @@ static BcStatus bc_program_reset(BcStatus s)
         if (!s || s == BC_STATUS_EXEC_SIGNAL) {
                 if (!G.ttyin)
                         quit();
-                fflush(stdout);
+                fflush_and_check(); // make sure buffered stdout is printed
                 fputs(bc_program_ready_msg, stderr);
-                fflush(stderr);
+                fflush_and_check();
                 s = BC_STATUS_SUCCESS;
         }
 
@@ -6910,7 +6921,7 @@ static BcStatus bc_vm_process(const char *text)
 
         if (BC_PARSE_CAN_EXEC(&G.prs)) {
                 s = bc_program_exec();
-                fflush(stdout);
+                fflush_and_check();
                 if (s)
                         s = bc_vm_error(bc_program_reset(s), G.prs.l.f, 0);
         }
@@ -6961,7 +6972,7 @@ static BcStatus bc_vm_stdin(void)
         // with a backslash to the parser. The reason for that is because the parser
         // treats a backslash+newline combo as whitespace, per the bc spec. In that
         // case, and for strings and comments, the parser will expect more stuff.
-        while ((s = bc_read_line(&buf, ">>> ")) == BC_STATUS_SUCCESS) {
+        while (!G.eof && (s = bc_read_line(&buf, ">>> ")) == BC_STATUS_SUCCESS) {
 
                 char *string = buf.v;
 
@@ -7012,11 +7023,6 @@ static BcStatus bc_vm_stdin(void)
 
         if (s == BC_STATUS_BIN_FILE) s = bc_vm_error(s, G.prs.l.f, 0);
 
-        // INPUT_EOF will always happen when stdin is
-        // closed. It's not a problem in that case.
-        if (s == BC_STATUS_INPUT_EOF)
-                s = BC_STATUS_SUCCESS;
-
         if (str)
                 s = bc_vm_error(BC_STATUS_LEX_NO_STRING_END, G.prs.l.f,
                                 G.prs.l.line);