diff options
author | Eric Andersen <andersen@codepoet.org> | 2003-08-06 11:20:52 +0000 |
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committer | Eric Andersen <andersen@codepoet.org> | 2003-08-06 11:20:52 +0000 |
commit | 9089844382a87290143ec414cfea703bcc31e9d8 (patch) | |
tree | dd507d9dfc45625d953748ffc7c361bd1f025ca6 /libbb | |
parent | dc19af4179161bdc80ea4d382a116e916a43ac9d (diff) | |
download | busybox-w32-9089844382a87290143ec414cfea703bcc31e9d8.tar.gz busybox-w32-9089844382a87290143ec414cfea703bcc31e9d8.tar.bz2 busybox-w32-9089844382a87290143ec414cfea703bcc31e9d8.zip |
Latest dash update from vodz
Diffstat (limited to 'libbb')
-rw-r--r-- | libbb/Makefile.in | 2 | ||||
-rw-r--r-- | libbb/arith.c | 375 |
2 files changed, 1 insertions, 376 deletions
diff --git a/libbb/Makefile.in b/libbb/Makefile.in index b60adc959..0d7103ef0 100644 --- a/libbb/Makefile.in +++ b/libbb/Makefile.in | |||
@@ -24,7 +24,7 @@ LIBBB_DIR:=$(TOPDIR)libbb/ | |||
24 | endif | 24 | endif |
25 | 25 | ||
26 | LIBBB_SRC:= \ | 26 | LIBBB_SRC:= \ |
27 | arith.c bb_asprintf.c ask_confirmation.c change_identity.c chomp.c \ | 27 | bb_asprintf.c ask_confirmation.c change_identity.c chomp.c \ |
28 | compare_string_array.c concat_path_file.c copy_file.c \ | 28 | compare_string_array.c concat_path_file.c copy_file.c \ |
29 | copyfd.c correct_password.c create_icmp_socket.c \ | 29 | copyfd.c correct_password.c create_icmp_socket.c \ |
30 | create_icmp6_socket.c device_open.c dump.c error_msg.c \ | 30 | create_icmp6_socket.c device_open.c dump.c error_msg.c \ |
diff --git a/libbb/arith.c b/libbb/arith.c deleted file mode 100644 index 3e107126a..000000000 --- a/libbb/arith.c +++ /dev/null | |||
@@ -1,375 +0,0 @@ | |||
1 | /* Copyright (c) 2001 Aaron Lehmann <aaronl@vitelus.com> | ||
2 | |||
3 | Permission is hereby granted, free of charge, to any person obtaining | ||
4 | a copy of this software and associated documentation files (the | ||
5 | "Software"), to deal in the Software without restriction, including | ||
6 | without limitation the rights to use, copy, modify, merge, publish, | ||
7 | distribute, sublicense, and/or sell copies of the Software, and to | ||
8 | permit persons to whom the Software is furnished to do so, subject to | ||
9 | the following conditions: | ||
10 | |||
11 | The above copyright notice and this permission notice shall be | ||
12 | included in all copies or substantial portions of the Software. | ||
13 | |||
14 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, | ||
15 | EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF | ||
16 | MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. | ||
17 | IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY | ||
18 | CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, | ||
19 | TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE | ||
20 | SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. | ||
21 | */ | ||
22 | |||
23 | /* This is my infix parser/evaluator. It is optimized for size, intended | ||
24 | * as a replacement for yacc-based parsers. However, it may well be faster | ||
25 | * than a comparable parser writen in yacc. The supported operators are | ||
26 | * listed in #defines below. Parens, order of operations, and error handling | ||
27 | * are supported. This code is threadsafe. The exact expression format should | ||
28 | * be that which POSIX specifies for shells. */ | ||
29 | |||
30 | /* The code uses a simple two-stack algorithm. See | ||
31 | * http://www.onthenet.com.au/~grahamis/int2008/week02/lect02.html | ||
32 | * for a detailed explaination of the infix-to-postfix algorithm on which | ||
33 | * this is based (this code differs in that it applies operators immediately | ||
34 | * to the stack instead of adding them to a queue to end up with an | ||
35 | * expression). */ | ||
36 | |||
37 | /* To use the routine, call it with an expression string and error return | ||
38 | * pointer */ | ||
39 | |||
40 | /* | ||
41 | * Aug 24, 2001 Manuel Novoa III | ||
42 | * | ||
43 | * Reduced the generated code size by about 30% (i386) and fixed several bugs. | ||
44 | * | ||
45 | * 1) In arith_apply(): | ||
46 | * a) Cached values of *numptr and &(numptr[-1]). | ||
47 | * b) Removed redundant test for zero denominator. | ||
48 | * | ||
49 | * 2) In arith(): | ||
50 | * a) Eliminated redundant code for processing operator tokens by moving | ||
51 | * to a table-based implementation. Also folded handling of parens | ||
52 | * into the table. | ||
53 | * b) Combined all 3 loops which called arith_apply to reduce generated | ||
54 | * code size at the cost of speed. | ||
55 | * | ||
56 | * 3) The following expressions were treated as valid by the original code: | ||
57 | * 1() , 0! , 1 ( *3 ) . | ||
58 | * These bugs have been fixed by internally enclosing the expression in | ||
59 | * parens and then checking that all binary ops and right parens are | ||
60 | * preceded by a valid expression (NUM_TOKEN). | ||
61 | * | ||
62 | * Note: It may be desireable to replace Aaron's test for whitespace with | ||
63 | * ctype's isspace() if it is used by another busybox applet or if additional | ||
64 | * whitespace chars should be considered. Look below the "#include"s for a | ||
65 | * precompiler test. | ||
66 | */ | ||
67 | |||
68 | /* | ||
69 | * Aug 26, 2001 Manuel Novoa III | ||
70 | * | ||
71 | * Return 0 for null expressions. Pointed out by vodz. | ||
72 | * | ||
73 | * Merge in Aaron's comments previously posted to the busybox list, | ||
74 | * modified slightly to take account of my changes to the code. | ||
75 | * | ||
76 | * TODO: May want to allow access to variables in the arith code. | ||
77 | * This would: | ||
78 | * 1) allow us to evaluate $A as 0 if A isn't set (although this | ||
79 | * would require changes to ash.c too). | ||
80 | * 2) allow us to write expressions as $(( A + 2 )). | ||
81 | * This could be done using a callback function passed to the | ||
82 | * arith() function of by requiring such a function with fixed | ||
83 | * name as an extern. | ||
84 | */ | ||
85 | |||
86 | #include <stdlib.h> | ||
87 | #include <string.h> | ||
88 | #include <ctype.h> | ||
89 | #include "libbb.h" | ||
90 | |||
91 | /* | ||
92 | * Use "#if 1" below for Aaron's original test for whitespace. | ||
93 | * Use "#if 0" for ctype's isspace(). | ||
94 | * */ | ||
95 | #if 1 | ||
96 | #undef isspace | ||
97 | #define isspace(arithval) \ | ||
98 | (arithval == ' ' || arithval == '\n' || arithval == '\t') | ||
99 | #endif | ||
100 | |||
101 | typedef char operator; | ||
102 | |||
103 | /* An operator's token id is a bit of a bitfield. The lower 5 bits are the | ||
104 | * precedence, and high 3 are an ID unique accross operators of that | ||
105 | * precedence. The ID portion is so that multiple operators can have the | ||
106 | * same precedence, ensuring that the leftmost one is evaluated first. | ||
107 | * Consider * and /. */ | ||
108 | |||
109 | #define tok_decl(prec,id) (((id)<<5)|(prec)) | ||
110 | #define PREC(op) ((op)&0x1F) | ||
111 | |||
112 | #define TOK_LPAREN tok_decl(0,0) | ||
113 | |||
114 | #define TOK_OR tok_decl(1,0) | ||
115 | |||
116 | #define TOK_AND tok_decl(2,0) | ||
117 | |||
118 | #define TOK_BOR tok_decl(3,0) | ||
119 | |||
120 | #define TOK_BXOR tok_decl(4,0) | ||
121 | |||
122 | #define TOK_BAND tok_decl(5,0) | ||
123 | |||
124 | #define TOK_EQ tok_decl(6,0) | ||
125 | #define TOK_NE tok_decl(6,1) | ||
126 | |||
127 | #define TOK_LT tok_decl(7,0) | ||
128 | #define TOK_GT tok_decl(7,1) | ||
129 | #define TOK_GE tok_decl(7,2) | ||
130 | #define TOK_LE tok_decl(7,3) | ||
131 | |||
132 | #define TOK_LSHIFT tok_decl(8,0) | ||
133 | #define TOK_RSHIFT tok_decl(8,1) | ||
134 | |||
135 | #define TOK_ADD tok_decl(9,0) | ||
136 | #define TOK_SUB tok_decl(9,1) | ||
137 | |||
138 | #define TOK_MUL tok_decl(10,0) | ||
139 | #define TOK_DIV tok_decl(10,1) | ||
140 | #define TOK_REM tok_decl(10,2) | ||
141 | |||
142 | /* For now all unary operators have the same precedence, and that's used to | ||
143 | * identify them as unary operators */ | ||
144 | #define UNARYPREC 14 | ||
145 | #define TOK_BNOT tok_decl(UNARYPREC,0) | ||
146 | #define TOK_NOT tok_decl(UNARYPREC,1) | ||
147 | #define TOK_UMINUS tok_decl(UNARYPREC,2) | ||
148 | #define TOK_UPLUS tok_decl(UNARYPREC,3) | ||
149 | |||
150 | #define TOK_NUM tok_decl(15,0) | ||
151 | #define TOK_RPAREN tok_decl(15,1) | ||
152 | #define TOK_ERROR tok_decl(15,2) /* just a place-holder really */ | ||
153 | |||
154 | #define ARITH_APPLY(op) arith_apply(op, numstack, &numstackptr) | ||
155 | #define NUMPTR (*numstackptr) | ||
156 | |||
157 | /* "applying" a token means performing it on the top elements on the integer | ||
158 | * stack. For a unary operator it will only change the top element, but a | ||
159 | * binary operator will pop two arguments and push a result */ | ||
160 | static short arith_apply(operator op, long *numstack, long **numstackptr) | ||
161 | { | ||
162 | long numptr_val; | ||
163 | long *NUMPTR_M1; | ||
164 | |||
165 | if (NUMPTR == numstack) goto err; /* There is no operator that can work | ||
166 | without arguments */ | ||
167 | NUMPTR_M1 = NUMPTR - 1; | ||
168 | if (op == TOK_UMINUS) | ||
169 | *NUMPTR_M1 *= -1; | ||
170 | else if (op == TOK_NOT) | ||
171 | *NUMPTR_M1 = !(*NUMPTR_M1); | ||
172 | else if (op == TOK_BNOT) | ||
173 | *NUMPTR_M1 = ~(*NUMPTR_M1); | ||
174 | else if (op != TOK_UPLUS) { | ||
175 | /* Binary operators */ | ||
176 | if (NUMPTR_M1 == numstack) goto err; /* ... and binary operators need two | ||
177 | arguments */ | ||
178 | numptr_val = *--NUMPTR; /* ... and they pop one */ | ||
179 | NUMPTR_M1 = NUMPTR - 1; | ||
180 | if (op == TOK_BOR) | ||
181 | *NUMPTR_M1 |= numptr_val; | ||
182 | else if (op == TOK_OR) | ||
183 | *NUMPTR_M1 = numptr_val || *NUMPTR_M1; | ||
184 | else if (op == TOK_BAND) | ||
185 | *NUMPTR_M1 &= numptr_val; | ||
186 | else if (op == TOK_AND) | ||
187 | *NUMPTR_M1 = *NUMPTR_M1 && numptr_val; | ||
188 | else if (op == TOK_EQ) | ||
189 | *NUMPTR_M1 = (*NUMPTR_M1 == numptr_val); | ||
190 | else if (op == TOK_NE) | ||
191 | *NUMPTR_M1 = (*NUMPTR_M1 != numptr_val); | ||
192 | else if (op == TOK_GE) | ||
193 | *NUMPTR_M1 = (*NUMPTR_M1 >= numptr_val); | ||
194 | else if (op == TOK_RSHIFT) | ||
195 | *NUMPTR_M1 >>= numptr_val; | ||
196 | else if (op == TOK_LSHIFT) | ||
197 | *NUMPTR_M1 <<= numptr_val; | ||
198 | else if (op == TOK_GT) | ||
199 | *NUMPTR_M1 = (*NUMPTR_M1 > numptr_val); | ||
200 | else if (op == TOK_LT) | ||
201 | *NUMPTR_M1 = (*NUMPTR_M1 < numptr_val); | ||
202 | else if (op == TOK_LE) | ||
203 | *NUMPTR_M1 = (*NUMPTR_M1 <= numptr_val); | ||
204 | else if (op == TOK_MUL) | ||
205 | *NUMPTR_M1 *= numptr_val; | ||
206 | else if (op == TOK_ADD) | ||
207 | *NUMPTR_M1 += numptr_val; | ||
208 | else if (op == TOK_SUB) | ||
209 | *NUMPTR_M1 -= numptr_val; | ||
210 | else if(numptr_val==0) /* zero divisor check */ | ||
211 | return -2; | ||
212 | else if (op == TOK_DIV) | ||
213 | *NUMPTR_M1 /= numptr_val; | ||
214 | else if (op == TOK_REM) | ||
215 | *NUMPTR_M1 %= numptr_val; | ||
216 | /* WARNING!!! WARNING!!! WARNING!!! */ | ||
217 | /* Any new operators should be added BEFORE the zero divisor check! */ | ||
218 | } | ||
219 | return 0; | ||
220 | err: return(-1); | ||
221 | } | ||
222 | |||
223 | static const char endexpression[] = ")"; | ||
224 | |||
225 | /* + and - (in that order) must be last */ | ||
226 | static const char op_char[] = "!<>=|&*/%~()+-"; | ||
227 | static const char op_token[] = { | ||
228 | /* paired with equal */ | ||
229 | TOK_NE, TOK_LE, TOK_GE, | ||
230 | /* paired with self -- note: ! is special-cased below*/ | ||
231 | TOK_ERROR, TOK_LSHIFT, TOK_RSHIFT, TOK_EQ, TOK_OR, TOK_AND, | ||
232 | /* singles */ | ||
233 | TOK_NOT, TOK_LT, TOK_GT, TOK_ERROR, TOK_BOR, TOK_BAND, | ||
234 | TOK_MUL, TOK_DIV, TOK_REM, TOK_BNOT, TOK_LPAREN, TOK_RPAREN, | ||
235 | TOK_ADD, TOK_SUB, TOK_UPLUS, TOK_UMINUS | ||
236 | }; | ||
237 | |||
238 | #define NUM_PAIR_EQUAL 3 | ||
239 | #define NUM_PAIR_SAME 6 | ||
240 | |||
241 | extern long arith (const char *expr, int *errcode) | ||
242 | { | ||
243 | register char arithval; /* Current character under analysis */ | ||
244 | operator lasttok, op; | ||
245 | unsigned char prec; | ||
246 | |||
247 | const char *p = endexpression; | ||
248 | |||
249 | size_t datasizes = strlen(expr) + 2; | ||
250 | |||
251 | /* Stack of integers */ | ||
252 | /* The proof that there can be no more than strlen(startbuf)/2+1 integers | ||
253 | * in any given correct or incorrect expression is left as an excersize to | ||
254 | * the reader. */ | ||
255 | long *numstack = alloca(((datasizes)/2)*sizeof(long)), | ||
256 | *numstackptr = numstack; | ||
257 | /* Stack of operator tokens */ | ||
258 | operator *stack = alloca((datasizes) * sizeof(operator)), | ||
259 | *stackptr = stack; | ||
260 | |||
261 | *numstack = 0; | ||
262 | *stackptr++ = lasttok = TOK_LPAREN; /* start off with a left paren */ | ||
263 | |||
264 | loop: | ||
265 | if ((arithval = *expr) == 0) { | ||
266 | if (p == endexpression) { /* Null expression. */ | ||
267 | *errcode = 0; | ||
268 | return *numstack; | ||
269 | } | ||
270 | |||
271 | /* This is only reached after all tokens have been extracted from the | ||
272 | * input stream. If there are still tokens on the operator stack, they | ||
273 | * are to be applied in order. At the end, there should be a final | ||
274 | * result on the integer stack */ | ||
275 | |||
276 | if (expr != endexpression + 1) { /* If we haven't done so already, */ | ||
277 | expr = endexpression; /* append a closing right paren */ | ||
278 | goto loop; /* and let the loop process it. */ | ||
279 | } | ||
280 | /* At this point, we're done with the expression. */ | ||
281 | if (numstackptr != numstack+1) {/* ... but if there isn't, it's bad */ | ||
282 | err: | ||
283 | return (*errcode = -1); | ||
284 | /* NOTREACHED */ | ||
285 | } | ||
286 | return *numstack; | ||
287 | } else { | ||
288 | /* Continue processing the expression. */ | ||
289 | if (isspace(arithval)) { | ||
290 | goto prologue; /* Skip whitespace */ | ||
291 | } | ||
292 | if ((unsigned)arithval-'0' <= 9) /* isdigit */ { | ||
293 | *numstackptr++ = strtol(expr, (char **) &expr, 10); | ||
294 | lasttok = TOK_NUM; | ||
295 | goto loop; | ||
296 | } | ||
297 | #if 1 | ||
298 | if ((p = strchr(op_char, arithval)) == NULL) { | ||
299 | goto err; | ||
300 | } | ||
301 | #else | ||
302 | for ( p=op_char ; *p != arithval ; p++ ) { | ||
303 | if (!*p) { | ||
304 | goto err; | ||
305 | } | ||
306 | } | ||
307 | #endif | ||
308 | p = op_token + (int)(p - op_char); | ||
309 | ++expr; | ||
310 | if ((p >= op_token + NUM_PAIR_EQUAL) || (*expr != '=')) { | ||
311 | p += NUM_PAIR_EQUAL; | ||
312 | if ((p >= op_token + NUM_PAIR_SAME + NUM_PAIR_EQUAL) | ||
313 | || (*expr != arithval) || (arithval == '!')) { | ||
314 | --expr; | ||
315 | if (arithval == '=') { /* single = */ | ||
316 | goto err; | ||
317 | } | ||
318 | p += NUM_PAIR_SAME; | ||
319 | /* Plus and minus are binary (not unary) _only_ if the last | ||
320 | * token was as number, or a right paren (which pretends to be | ||
321 | * a number, since it evaluates to one). Think about it. | ||
322 | * It makes sense. */ | ||
323 | if ((lasttok != TOK_NUM) | ||
324 | && (p >= op_token + NUM_PAIR_SAME + NUM_PAIR_EQUAL | ||
325 | + sizeof(op_char) - 2)) { | ||
326 | p += 2; /* Unary plus or minus */ | ||
327 | } | ||
328 | } | ||
329 | } | ||
330 | op = *p; | ||
331 | |||
332 | /* We don't want a unary operator to cause recursive descent on the | ||
333 | * stack, because there can be many in a row and it could cause an | ||
334 | * operator to be evaluated before its argument is pushed onto the | ||
335 | * integer stack. */ | ||
336 | /* But for binary operators, "apply" everything on the operator | ||
337 | * stack until we find an operator with a lesser priority than the | ||
338 | * one we have just extracted. */ | ||
339 | /* Left paren is given the lowest priority so it will never be | ||
340 | * "applied" in this way */ | ||
341 | prec = PREC(op); | ||
342 | if ((prec > 0) && (prec != UNARYPREC)) { /* not left paren or unary */ | ||
343 | if (lasttok != TOK_NUM) { /* binary op must be preceded by a num */ | ||
344 | goto err; | ||
345 | } | ||
346 | while (stackptr != stack) { | ||
347 | if (op == TOK_RPAREN) { | ||
348 | /* The algorithm employed here is simple: while we don't | ||
349 | * hit an open paren nor the bottom of the stack, pop | ||
350 | * tokens and apply them */ | ||
351 | if (stackptr[-1] == TOK_LPAREN) { | ||
352 | --stackptr; | ||
353 | lasttok = TOK_NUM; /* Any operator directly after a */ | ||
354 | /* close paren should consider itself binary */ | ||
355 | goto prologue; | ||
356 | } | ||
357 | } else if (PREC(stackptr[-1]) < prec) { | ||
358 | break; | ||
359 | } | ||
360 | *errcode = ARITH_APPLY(*--stackptr); | ||
361 | if(*errcode) return *errcode; | ||
362 | } | ||
363 | if (op == TOK_RPAREN) { | ||
364 | goto err; | ||
365 | } | ||
366 | } | ||
367 | |||
368 | /* Push this operator to the stack and remember it. */ | ||
369 | *stackptr++ = lasttok = op; | ||
370 | |||
371 | prologue: | ||
372 | ++expr; | ||
373 | goto loop; | ||
374 | } | ||
375 | } | ||