shell: shrink arith code; and prepare for returning text error codes
function old new delta arith 701 680 -21 Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
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Denys Vlasenko
parent
99862cbfad
commit
b771c654ca
@ -4728,9 +4728,9 @@ static NOINLINE const char *expand_one_var(char **to_be_freed_pp, char *arg, cha
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if (beg < 0) /* bash compat */
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beg = 0;
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debug_printf_varexp("from val:'%s'\n", val);
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if (len == 0 || !val || beg >= strlen(val))
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val = "";
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else {
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if (len == 0 || !val || beg >= strlen(val)) {
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val = NULL;
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} else {
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/* Paranoia. What if user entered 9999999999999
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* which fits in arith_t but not int? */
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if (len >= INT_MAX)
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@ -4742,7 +4742,7 @@ static NOINLINE const char *expand_one_var(char **to_be_freed_pp, char *arg, cha
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#endif
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{
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die_if_script("malformed ${%s:...}", var);
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val = "";
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val = NULL;
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}
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} else { /* one of "-=+?" */
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/* Standard-mandated substitution ops:
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116
shell/math.c
116
shell/math.c
@ -124,9 +124,6 @@
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#define setvar (math_hooks->setvar )
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//#define endofname (math_hooks->endofname)
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#define arith_isspace(arithval) \
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(arithval == ' ' || arithval == '\n' || arithval == '\t')
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typedef unsigned char operator;
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/* An operator's token id is a bit of a bitfield. The lower 5 bits are the
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@ -156,7 +153,7 @@ typedef unsigned char operator;
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#define TOK_REM_ASSIGN tok_decl(3,2)
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/* all assign is right associativity and precedence eq, but (7+3)<<5 > 256 */
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#define convert_prec_is_assing(prec) do { if (prec == 3) prec = 2; } while (0)
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#define convert_prec_is_assign(prec) do { if (prec == 3) prec = 2; } while (0)
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/* conditional is right associativity too */
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#define TOK_CONDITIONAL tok_decl(4,0)
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@ -223,7 +220,7 @@ tok_have_assign(operator op)
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{
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operator prec = PREC(op);
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convert_prec_is_assing(prec);
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convert_prec_is_assign(prec);
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return (prec == PREC(TOK_ASSIGN) ||
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prec == PREC_PRE || prec == PREC_POST);
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}
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@ -477,7 +474,7 @@ static const char op_tokens[] ALIGN1 = {
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0
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};
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/* ptr to ")" */
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#define endexpression (&op_tokens[sizeof(op_tokens)-7])
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#define ptr_to_rparen (&op_tokens[sizeof(op_tokens)-7])
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const char* FAST_FUNC
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endofname(const char *name)
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@ -494,32 +491,36 @@ endofname(const char *name)
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arith_t
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arith(const char *expr, int *perrcode, a_e_h_t *math_hooks)
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{
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char arithval; /* Current character under analysis */
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operator lasttok, op;
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operator prec;
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operator *stack, *stackptr;
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const char *p = endexpression;
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operator lasttok;
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int errcode;
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v_n_t *numstack, *numstackptr;
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unsigned datasizes = strlen(expr) + 2;
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const char *start_expr = expr = skip_whitespace(expr);
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unsigned expr_len = strlen(expr) + 2;
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/* Stack of integers */
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/* The proof that there can be no more than strlen(startbuf)/2+1 integers
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* in any given correct or incorrect expression is left as an exercise to
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* the reader. */
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numstackptr = numstack = alloca((datasizes / 2) * sizeof(numstack[0]));
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v_n_t *const numstack = alloca((expr_len / 2) * sizeof(numstack[0]));
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v_n_t *numstackptr = numstack;
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/* Stack of operator tokens */
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stackptr = stack = alloca(datasizes * sizeof(stack[0]));
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operator *const stack = alloca(expr_len * sizeof(stack[0]));
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operator *stackptr = stack;
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*stackptr++ = lasttok = TOK_LPAREN; /* start off with a left paren */
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*perrcode = errcode = 0;
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errcode = 0;
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while (1) {
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const char *p;
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operator op;
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operator prec;
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char arithval;
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expr = skip_whitespace(expr);
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arithval = *expr;
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if (arithval == 0) {
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if (p == endexpression) {
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if (arithval == '\0') {
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if (expr == start_expr) {
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/* Null expression. */
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return 0;
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numstack->val = 0;
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goto ret;
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}
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/* This is only reached after all tokens have been extracted from the
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@ -527,38 +528,29 @@ arith(const char *expr, int *perrcode, a_e_h_t *math_hooks)
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* are to be applied in order. At the end, there should be a final
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* result on the integer stack */
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if (expr != endexpression + 1) {
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if (expr != ptr_to_rparen + 1) {
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/* If we haven't done so already, */
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/* append a closing right paren */
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expr = endexpression;
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expr = ptr_to_rparen;
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/* and let the loop process it. */
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continue;
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}
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/* At this point, we're done with the expression. */
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if (numstackptr != numstack + 1) {
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/* ... but if there isn't, it's bad */
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err:
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*perrcode = -1;
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return *perrcode;
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goto err;
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}
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if (numstack->var) {
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/* expression is $((var)) only, lookup now */
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errcode = arith_lookup_val(numstack, math_hooks);
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}
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ret:
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*perrcode = errcode;
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return numstack->val;
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goto ret;
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}
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/* Continue processing the expression. */
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if (arith_isspace(arithval)) {
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/* Skip whitespace */
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goto prologue;
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}
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p = endofname(expr);
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if (p != expr) {
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size_t var_name_size = (p-expr) + 1; /* trailing zero */
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/* Name */
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size_t var_name_size = (p-expr) + 1; /* +1 for NUL */
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numstackptr->var = alloca(var_name_size);
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safe_strncpy(numstackptr->var, expr, var_name_size);
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expr = p;
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@ -568,36 +560,37 @@ arith(const char *expr, int *perrcode, a_e_h_t *math_hooks)
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lasttok = TOK_NUM;
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continue;
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}
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if (isdigit(arithval)) {
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/* Number */
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numstackptr->var = NULL;
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errno = 0;
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/* call strtoul[l]: */
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numstackptr->val = strto_arith_t(expr, (char**) &expr, 0);
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if (errno)
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numstackptr->val = 0; /* bash compat */
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goto num;
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}
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for (p = op_tokens; ; p++) {
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const char *o;
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if (*p == 0) {
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/* strange operator not found */
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goto err;
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}
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for (o = expr; *p && *o == *p; p++)
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o++;
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if (!*p) {
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/* found */
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expr = o - 1;
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/* Should be an operator */
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p = op_tokens;
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while (1) {
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const char *e = expr;
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/* Compare expr to current op_tokens[] element */
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while (*p && *e == *p)
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p++, e++;
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if (*p == '\0') { /* match: operator is found */
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expr = e;
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break;
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}
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/* skip tail uncompared token */
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/* Go to next element of op_tokens[] */
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while (*p)
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p++;
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/* skip zero delim */
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p++;
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p += 2; /* skip NUL and TOK_foo bytes */
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if (*p == '\0') /* no next element, operator not found */
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goto err;
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}
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op = p[1];
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op = p[1]; /* fetch TOK_foo value */
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/* NB: expr now points past the operator */
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/* post grammar: a++ reduce to num */
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if (lasttok == TOK_POST_INC || lasttok == TOK_POST_DEC)
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@ -651,13 +644,12 @@ arith(const char *expr, int *perrcode, a_e_h_t *math_hooks)
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/* Any operator directly after a */
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lasttok = TOK_NUM;
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/* close paren should consider itself binary */
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goto prologue;
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goto next;
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}
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} else {
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operator prev_prec = PREC(stackptr[-1]);
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convert_prec_is_assing(prec);
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convert_prec_is_assing(prev_prec);
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convert_prec_is_assign(prec);
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convert_prec_is_assign(prev_prec);
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if (prev_prec < prec)
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break;
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/* check right assoc */
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@ -665,7 +657,8 @@ arith(const char *expr, int *perrcode, a_e_h_t *math_hooks)
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break;
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}
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errcode = arith_apply(*--stackptr, numstack, &numstackptr, math_hooks);
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if (errcode) goto ret;
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if (errcode)
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goto ret;
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}
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if (op == TOK_RPAREN) {
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goto err;
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@ -674,9 +667,14 @@ arith(const char *expr, int *perrcode, a_e_h_t *math_hooks)
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/* Push this operator to the stack and remember it. */
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*stackptr++ = lasttok = op;
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prologue:
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++expr;
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} /* while */
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next: ;
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} /* while (1) */
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err:
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numstack->val = errcode = -1;
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ret:
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*perrcode = errcode;
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return numstack->val;
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}
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/*
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