diff options
Diffstat (limited to 'shell/math.c')
| -rw-r--r-- | shell/math.c | 81 |
1 files changed, 40 insertions, 41 deletions
diff --git a/shell/math.c b/shell/math.c index 8397157..871c06c 100644 --- a/shell/math.c +++ b/shell/math.c @@ -26,26 +26,26 @@ * Licensed under GPLv2 or later, see file LICENSE in this source tree. */ /* Copyright (c) 2001 Aaron Lehmann <aaronl@vitelus.com> - - Permission is hereby granted, free of charge, to any person obtaining - a copy of this software and associated documentation files (the - "Software"), to deal in the Software without restriction, including - without limitation the rights to use, copy, modify, merge, publish, - distribute, sublicense, and/or sell copies of the Software, and to - permit persons to whom the Software is furnished to do so, subject to - the following conditions: - - The above copyright notice and this permission notice shall be - included in all copies or substantial portions of the Software. - - THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, - EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF - MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. - IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY - CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, - TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE - SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. -*/ + * + * Permission is hereby granted, free of charge, to any person obtaining + * a copy of this software and associated documentation files (the + * "Software"), to deal in the Software without restriction, including + * without limitation the rights to use, copy, modify, merge, publish, + * distribute, sublicense, and/or sell copies of the Software, and to + * permit persons to whom the Software is furnished to do so, subject to + * the following conditions: + * + * The above copyright notice and this permission notice shall be + * included in all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. + * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY + * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, + * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE + * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + */ /* This is my infix parser/evaluator. It is optimized for size, intended * as a replacement for yacc-based parsers. However, it may well be faster @@ -60,9 +60,6 @@ * this is based (this code differs in that it applies operators immediately * to the stack instead of adding them to a queue to end up with an * expression). - * - * To use the routine, call it with an expression string and error return - * pointer */ /* @@ -250,7 +247,7 @@ typedef struct remembered_name { static arith_t FAST_FUNC evaluate_string(arith_state_t *math_state, const char *expr); -static int +static const char* arith_lookup_val(arith_state_t *math_state, v_n_t *t) { if (t->var) { @@ -264,8 +261,8 @@ arith_lookup_val(arith_state_t *math_state, v_n_t *t) */ for (cur = math_state->list_of_recursed_names; cur; cur = cur->next) { if (strcmp(cur->var, t->var) == 0) { - /* Yes. Expression recursion loop detected */ - return -5; + /* Yes */ + return "expression recursion loop detected"; } } @@ -281,7 +278,7 @@ arith_lookup_val(arith_state_t *math_state, v_n_t *t) /* pop current var name */ math_state->list_of_recursed_names = cur; - return math_state->errcode; + return math_state->errmsg; } /* treat undefined var as 0 */ t->val = 0; @@ -292,14 +289,14 @@ arith_lookup_val(arith_state_t *math_state, v_n_t *t) /* "Applying" a token means performing it on the top elements on the integer * stack. For an unary operator it will only change the top element, but a * binary operator will pop two arguments and push the result */ -static NOINLINE int +static NOINLINE const char* arith_apply(arith_state_t *math_state, operator op, v_n_t *numstack, v_n_t **numstackptr) { #define NUMPTR (*numstackptr) v_n_t *numptr_m1; arith_t numptr_val, rez; - int err; + const char *err; /* There is no operator that can work without arguments */ if (NUMPTR == numstack) @@ -399,13 +396,13 @@ arith_apply(arith_state_t *math_state, operator op, v_n_t *numstack, v_n_t **num } else if (op == TOK_EXPONENT) { arith_t c; if (numptr_val < 0) - return -3; /* exponent less than 0 */ + return "exponent less than 0"; c = 1; while (--numptr_val >= 0) c *= rez; rez = c; - } else if (numptr_val==0) /* zero divisor check */ - return -2; + } else if (numptr_val == 0) + return "divide by zero"; else if (op == TOK_DIV || op == TOK_DIV_ASSIGN) rez /= numptr_val; else if (op == TOK_REM || op == TOK_REM_ASSIGN) @@ -430,9 +427,9 @@ arith_apply(arith_state_t *math_state, operator op, v_n_t *numstack, v_n_t **num numptr_m1->val = rez; /* erase var name, it is just a number now */ numptr_m1->var = NULL; - return 0; + return NULL; err: - return -1; + return "arithmetic syntax error"; #undef NUMPTR } @@ -498,7 +495,7 @@ static arith_t FAST_FUNC evaluate_string(arith_state_t *math_state, const char *expr) { operator lasttok; - int errcode; + const char *errmsg; const char *start_expr = expr = skip_whitespace(expr); unsigned expr_len = strlen(expr) + 2; /* Stack of integers */ @@ -512,7 +509,7 @@ evaluate_string(arith_state_t *math_state, const char *expr) operator *stackptr = stack; *stackptr++ = lasttok = TOK_LPAREN; /* start off with a left paren */ - errcode = 0; + errmsg = NULL; while (1) { const char *p; @@ -548,7 +545,7 @@ evaluate_string(arith_state_t *math_state, const char *expr) } if (numstack->var) { /* expression is $((var)) only, lookup now */ - errcode = arith_lookup_val(math_state, numstack); + errmsg = arith_lookup_val(math_state, numstack); } goto ret; } @@ -663,8 +660,8 @@ evaluate_string(arith_state_t *math_state, const char *expr) break; } } - errcode = arith_apply(math_state, prev_op, numstack, &numstackptr); - if (errcode) + errmsg = arith_apply(math_state, prev_op, numstack, &numstackptr); + if (errmsg) goto ret; } if (op == TOK_RPAREN) { @@ -678,15 +675,17 @@ evaluate_string(arith_state_t *math_state, const char *expr) } /* while (1) */ err: - numstack->val = errcode = -1; + numstack->val = -1; + errmsg = "arithmetic syntax error"; ret: - math_state->errcode = errcode; + math_state->errmsg = errmsg; return numstack->val; } arith_t FAST_FUNC arith(arith_state_t *math_state, const char *expr) { + math_state->errmsg = NULL; math_state->list_of_recursed_names = NULL; return evaluate_string(math_state, expr); } |