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Apply vodz last_patch51_2 and run through indent
This commit is contained in:
Glenn L McGrath
parent
e599b6d96e
commit
de9e803149
203
libbb/arith.c
203
libbb/arith.c
@ -26,14 +26,14 @@
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* listed in #defines below. Parens, order of operations, and error handling
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* are supported. This code is threadsafe. The exact expression format should
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* be that which POSIX specifies for shells. */
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/* The code uses a simple two-stack algorithm. See
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* http://www.onthenet.com.au/~grahamis/int2008/week02/lect02.html
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* for a detailed explaination of the infix-to-postfix algorithm on which
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* this is based (this code differs in that it applies operators immediately
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* to the stack instead of adding them to a queue to end up with an
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* expression). */
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/* To use the routine, call it with an expression string and error return
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* pointer */
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@ -140,7 +140,8 @@ typedef char operator;
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#define TOK_REM tok_decl(10,2)
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/* For now all unary operators have the same precedence, and that's used to
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* identify them as unary operators */
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* identify them as unary operators
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*/
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#define UNARYPREC 14
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#define TOK_BNOT tok_decl(UNARYPREC,0)
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#define TOK_NOT tok_decl(UNARYPREC,1)
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@ -149,75 +150,89 @@ typedef char operator;
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#define TOK_NUM tok_decl(15,0)
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#define TOK_RPAREN tok_decl(15,1)
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#define TOK_ERROR tok_decl(15,2) /* just a place-holder really */
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#define TOK_ERROR tok_decl(15,2) /* just a place-holder really */
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#define ARITH_APPLY(op) arith_apply(op, numstack, &numstackptr)
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#define NUMPTR (*numstackptr)
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/* "applying" a token means performing it on the top elements on the integer
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* stack. For a unary operator it will only change the top element, but a
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* binary operator will pop two arguments and push a result */
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static short arith_apply(operator op, long *numstack, long **numstackptr)
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* binary operator will pop two arguments and push a result
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*/
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static short arith_apply(operator op, long *numstack, long **numstackptr)
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{
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long numptr_val;
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long *NUMPTR_M1;
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if (NUMPTR == numstack) goto err; /* There is no operator that can work
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without arguments */
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/* There is no operator that can work without arguments */
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if (NUMPTR == numstack) {
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goto err;
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}
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NUMPTR_M1 = NUMPTR - 1;
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if (op == TOK_UMINUS)
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if (op == TOK_UMINUS) {
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*NUMPTR_M1 *= -1;
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else if (op == TOK_NOT)
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} else if (op == TOK_NOT) {
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*NUMPTR_M1 = !(*NUMPTR_M1);
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else if (op == TOK_BNOT)
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} else if (op == TOK_BNOT) {
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*NUMPTR_M1 = ~(*NUMPTR_M1);
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else if (op != TOK_UPLUS) {
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/* Binary operators */
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if (NUMPTR_M1 == numstack) goto err; /* ... and binary operators need two
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arguments */
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numptr_val = *--NUMPTR; /* ... and they pop one */
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NUMPTR_M1 = NUMPTR - 1;
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if (op == TOK_BOR)
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*NUMPTR_M1 |= numptr_val;
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else if (op == TOK_OR)
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*NUMPTR_M1 = numptr_val || *NUMPTR_M1;
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else if (op == TOK_BAND)
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*NUMPTR_M1 &= numptr_val;
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else if (op == TOK_AND)
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*NUMPTR_M1 = *NUMPTR_M1 && numptr_val;
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else if (op == TOK_EQ)
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*NUMPTR_M1 = (*NUMPTR_M1 == numptr_val);
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else if (op == TOK_NE)
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*NUMPTR_M1 = (*NUMPTR_M1 != numptr_val);
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else if (op == TOK_GE)
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*NUMPTR_M1 = (*NUMPTR_M1 >= numptr_val);
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else if (op == TOK_RSHIFT)
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*NUMPTR_M1 >>= numptr_val;
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else if (op == TOK_LSHIFT)
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*NUMPTR_M1 <<= numptr_val;
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else if (op == TOK_GT)
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*NUMPTR_M1 = (*NUMPTR_M1 > numptr_val);
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else if (op == TOK_LT)
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*NUMPTR_M1 = (*NUMPTR_M1 < numptr_val);
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else if (op == TOK_LE)
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*NUMPTR_M1 = (*NUMPTR_M1 <= numptr_val);
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else if (op == TOK_MUL)
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*NUMPTR_M1 *= numptr_val;
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else if (op == TOK_ADD)
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*NUMPTR_M1 += numptr_val;
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else if (op == TOK_SUB)
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*NUMPTR_M1 -= numptr_val;
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else if(numptr_val==0) /* zero divisor check */
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return -2;
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else if (op == TOK_DIV)
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*NUMPTR_M1 /= numptr_val;
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else if (op == TOK_REM)
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*NUMPTR_M1 %= numptr_val;
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/* WARNING!!! WARNING!!! WARNING!!! */
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/* Any new operators should be added BEFORE the zero divisor check! */
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} else if (op != TOK_UPLUS) {
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/* Binary operators */
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/* ... and binary operators need two arguments */
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if (NUMPTR_M1 == numstack) {
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goto err;
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}
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/* ... and they pop one */
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numptr_val = *--NUMPTR;
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NUMPTR_M1 = NUMPTR - 1;
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if (op == TOK_BOR) {
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*NUMPTR_M1 |= numptr_val;
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} else if (op == TOK_OR) {
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*NUMPTR_M1 = numptr_val || *NUMPTR_M1;
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} else if (op == TOK_BAND) {
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*NUMPTR_M1 &= numptr_val;
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} else if (op == TOK_AND) {
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*NUMPTR_M1 = *NUMPTR_M1 && numptr_val;
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} else if (op == TOK_EQ) {
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*NUMPTR_M1 = (*NUMPTR_M1 == numptr_val);
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} else if (op == TOK_NE) {
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*NUMPTR_M1 = (*NUMPTR_M1 != numptr_val);
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} else if (op == TOK_GE) {
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*NUMPTR_M1 = (*NUMPTR_M1 >= numptr_val);
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} else if (op == TOK_RSHIFT) {
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*NUMPTR_M1 >>= numptr_val;
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} else if (op == TOK_LSHIFT) {
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*NUMPTR_M1 <<= numptr_val;
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} else if (op == TOK_GT) {
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*NUMPTR_M1 = (*NUMPTR_M1 > numptr_val);
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} else if (op == TOK_LT) {
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*NUMPTR_M1 = (*NUMPTR_M1 < numptr_val);
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} else if (op == TOK_LE) {
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*NUMPTR_M1 = (*NUMPTR_M1 <= numptr_val);
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} else if (op == TOK_MUL) {
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*NUMPTR_M1 *= numptr_val;
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} else if (op == TOK_ADD) {
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*NUMPTR_M1 += numptr_val;
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} else if (op == TOK_SUB) {
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*NUMPTR_M1 -= numptr_val;
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}
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/* zero divisor check */
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else if (numptr_val == 0) {
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return -2;
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} else if (op == TOK_DIV) {
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*NUMPTR_M1 /= numptr_val;
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} else if (op == TOK_REM) {
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*NUMPTR_M1 %= numptr_val;
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}
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/* WARNING!!! WARNING!!! WARNING!!! */
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/* Any new operators should be added BEFORE the zero divisor check! */
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}
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return 0;
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err: return(-1);
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err:
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return (-1);
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}
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static const char endexpression[] = ")";
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@ -227,7 +242,7 @@ static const char op_char[] = "!<>=|&*/%~()+-";
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static const char op_token[] = {
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/* paired with equal */
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TOK_NE, TOK_LE, TOK_GE,
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/* paired with self -- note: ! is special-cased below*/
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/* paired with self -- note: ! is special-cased below */
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TOK_ERROR, TOK_LSHIFT, TOK_RSHIFT, TOK_EQ, TOK_OR, TOK_AND,
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/* singles */
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TOK_NOT, TOK_LT, TOK_GT, TOK_ERROR, TOK_BOR, TOK_BAND,
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@ -238,31 +253,32 @@ static const char op_token[] = {
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#define NUM_PAIR_EQUAL 3
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#define NUM_PAIR_SAME 6
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extern long arith (const char *expr, int *errcode)
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extern long arith(const char *expr, int *errcode)
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{
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register char arithval; /* Current character under analysis */
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operator lasttok, op;
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register char arithval; /* Current character under analysis */
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operator lasttok, op;
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unsigned char prec;
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const char *p = endexpression;
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size_t datasizes = strlen(expr);
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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 excersize to
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* the reader. */
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long *numstack = alloca((datasizes/2)*sizeof(long)),
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*numstackptr = numstack;
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long *numstack = alloca(((datasizes + 1) / 2) * sizeof(long));
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long *numstackptr = numstack;
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/* Stack of operator tokens */
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operator *stack = alloca((datasizes+1) * sizeof(operator)),
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*stackptr = stack;
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operator * stack = alloca((datasizes + 1) * sizeof(operator));
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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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/* start off with a left paren */
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*stackptr++ = lasttok = TOK_LPAREN;
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loop:
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loop:
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if ((arithval = *expr) == 0) {
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if (p == endexpression) { /* Null expression. */
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/* Null expression. */
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if (p == endexpression) {
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return (*errcode = 0);
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}
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@ -271,23 +287,25 @@ extern long arith (const char *expr, int *errcode)
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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) { /* If we haven't done so already, */
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if (expr != endexpression + 1) { /* If we haven't done so already, */
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expr = endexpression; /* append a closing right paren */
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goto loop; /* and let the loop process it. */
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goto loop; /* and let the loop process it. */
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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) {/* ... but if there isn't, it's bad */
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err:
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if (numstackptr != numstack + 1) { /* ... but if there isn't, it's bad */
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err:
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return (*errcode = -1);
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/* NOTREACHED */
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}
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return *numstack;
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} else {
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/* Continue processing the expression. */
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/* Skip whitespace */
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if (isspace(arithval)) {
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goto prologue; /* Skip whitespace */
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goto prologue;
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}
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if ((unsigned)arithval-'0' <= 9) /* isdigit */ {
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/* isdigit ? */
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if ((unsigned) arithval - '0' <= 9) {
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*numstackptr++ = strtol(expr, (char **) &expr, 10);
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lasttok = TOK_NUM;
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goto loop;
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@ -297,20 +315,21 @@ extern long arith (const char *expr, int *errcode)
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goto err;
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}
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#else
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for ( p=op_char ; *p != arithval ; p++ ) {
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for (p = op_char; *p != arithval; p++) {
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if (!*p) {
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goto err;
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}
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}
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#endif
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p = op_token + (int)(p - op_char);
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p = op_token + (int) (p - op_char);
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++expr;
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if ((p >= op_token + NUM_PAIR_EQUAL) || (*expr != '=')) {
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p += NUM_PAIR_EQUAL;
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if ((p >= op_token + NUM_PAIR_SAME + NUM_PAIR_EQUAL)
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|| (*expr != arithval) || (arithval == '!')) {
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--expr;
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if (arithval == '=') { /* single = */
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/* single = */
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if (arithval == '=') {
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goto err;
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}
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p += NUM_PAIR_SAME;
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@ -319,9 +338,11 @@ extern long arith (const char *expr, int *errcode)
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* a number, since it evaluates to one). Think about it.
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* It makes sense. */
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if ((lasttok != TOK_NUM)
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&& (p >= op_token + NUM_PAIR_SAME + NUM_PAIR_EQUAL
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+ sizeof(op_char) - 2)) {
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p += 2; /* Unary plus or minus */
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&& (p >=
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(op_token + NUM_PAIR_SAME + NUM_PAIR_EQUAL +
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sizeof(op_char) - 2))) {
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/* Unary plus or minus */
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p += 2;
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}
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}
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}
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@ -337,8 +358,11 @@ extern long arith (const char *expr, int *errcode)
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/* Left paren is given the lowest priority so it will never be
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* "applied" in this way */
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prec = PREC(op);
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if ((prec > 0) && (prec != UNARYPREC)) { /* not left paren or unary */
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if (lasttok != TOK_NUM) { /* binary op must be preceded by a num */
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/* not left paren or unary */
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if ((prec > 0) && (prec != UNARYPREC)) {
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/* binary op must be preceded by a num */
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if (lasttok != TOK_NUM) {
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goto err;
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}
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while (stackptr != stack) {
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@ -348,15 +372,20 @@ extern long arith (const char *expr, int *errcode)
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* tokens and apply them */
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if (stackptr[-1] == TOK_LPAREN) {
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--stackptr;
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lasttok = TOK_NUM; /* Any operator directly after a */
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/* close paren should consider itself binary */
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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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}
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} else if (PREC(stackptr[-1]) < prec) {
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break;
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}
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*errcode = ARITH_APPLY(*--stackptr);
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if(*errcode) return *errcode;
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if (*errcode) {
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return *errcode;
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}
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}
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if (op == TOK_RPAREN) {
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goto err;
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@ -366,7 +395,7 @@ extern long arith (const char *expr, int *errcode)
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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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prologue:
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++expr;
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goto loop;
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}
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