diff options
Diffstat (limited to 'src/skaembutils/s6-expr.c')
| -rw-r--r-- | src/skaembutils/s6-expr.c | 205 |
1 files changed, 0 insertions, 205 deletions
diff --git a/src/skaembutils/s6-expr.c b/src/skaembutils/s6-expr.c deleted file mode 100644 index 91be041..0000000 --- a/src/skaembutils/s6-expr.c +++ /dev/null @@ -1,205 +0,0 @@ -/* ISC license. */ - -#include <string.h> -#include <skalibs/allreadwrite.h> -#include <skalibs/types.h> -#include <skalibs/strerr.h> - -#define USAGE "s6-expr arithmetic expression" -#define bail() strerr_dief1x(2, "invalid expression") - -enum expr_opnum_e -{ - T_DATA, - T_AND, - T_OR, - T_LEFTP, - T_RIGHTP, - T_EQUAL, - T_NEQUAL, - T_GREATER, - T_GREATERE, - T_LESSER, - T_LESSERE, - T_PLUS, - T_MINUS, - T_TIMES, - T_DIV, - T_MOD -} ; - -struct expr_token_s -{ - char const *string ; - enum expr_opnum_e op ; - unsigned int type ; -} ; - -struct expr_node_s -{ - enum expr_opnum_e op ; - unsigned int type ; - unsigned int arg1 ; - unsigned int arg2 ; - long data ; -} ; - -static unsigned int expr_lex (struct expr_node_s *tree, char const *const *argv) -{ - static struct expr_token_s const tokens[16] = - { - { "+", T_PLUS, 3 }, - { "-", T_MINUS, 3 }, - { "*", T_TIMES, 2 }, - { "/", T_DIV, 2 }, - { "%", T_MOD, 2 }, - { "(", T_LEFTP, 7 }, - { ")", T_RIGHTP, 8 }, - { "=", T_EQUAL, 4 }, - { "!=", T_NEQUAL, 4 }, - { "<", T_LESSER, 4 }, - { "<=", T_LESSERE, 4 }, - { ">", T_GREATER, 4 }, - { ">=", T_GREATERE, 4 }, - { "|", T_OR, 6 }, - { "&", T_AND, 5 }, - { 0, 0, 0 } - } ; - unsigned int pos = 0 ; - - for (; argv[pos] ; pos++) - { - unsigned int i = 0 ; - for (i = 0 ; tokens[i].string ; i++) - if (!strcmp(argv[pos], tokens[i].string)) - { - tree[pos].op = tokens[i].op ; - tree[pos].type = tokens[i].type ; - break ; - } - if (!tokens[i].string) - { - tree[pos].op = T_DATA ; - tree[pos].type = 0 ; - if (!long_scan(argv[pos], &tree[pos].data)) bail() ; - } - } - return pos ; -} - -static void expr_reduce (struct expr_node_s *tree, unsigned int *stack, unsigned int *sp, unsigned int type) -{ - if (tree[stack[*sp-1]].type == type) - { - tree[stack[*sp-1]].arg1 = stack[*sp-2] ; - tree[stack[*sp-1]].arg2 = stack[*sp] ; - stack[*sp-2] = stack[*sp-1] ; - *sp -= 2 ; - } - tree[stack[*sp]].type = type + 7 ; -} - -static unsigned int expr_parse (struct expr_node_s *tree, unsigned int n) -{ - static char const table[9][15] = - { - "xsssssssxzzzzzz", - "xxxxxxxx!zzzzzz", - "mxxxxxxxMszzzzz", - "mxxxxxxxMaszzzz", - "mxxxxxxxMacszzz", - "mxxxxxxxMacAszz", - "mxxxxxxxMacAOsz", - "xsssssssxzzzzzz", - "mxxxxxxxMacAOEs" - } ; - unsigned int stack[n] ; - unsigned int sp = 0, pos = 0 ; - char cont = 1 ; - stack[0] = n + 1 ; - tree[n].type = 8 ; /* add ) for the final reduce */ - tree[n+1].type = 1 ; /* add EOF */ - while (cont) - { - switch (table[tree[pos].type][tree[stack[sp]].type]) - { - case 'x' : bail() ; - case '!' : cont = 0 ; break ; - case 's' : stack[++sp] = pos++ ; break ; - case 'M' : - if (tree[stack[sp-2]].type != 7) bail() ; - stack[sp-2] = stack[sp-1] ; - sp -= 2 ; - case 'm' : expr_reduce(tree, stack, &sp, 2) ; break ; - case 'a' : expr_reduce(tree, stack, &sp, 3) ; break ; - case 'c' : expr_reduce(tree, stack, &sp, 4) ; break ; - case 'A' : expr_reduce(tree, stack, &sp, 5) ; break ; - case 'O' : expr_reduce(tree, stack, &sp, 6) ; break ; - case 'E' : tree[stack[sp]].type = 14 ; break ; - case 'z' : - default : strerr_dief1x(101, "internal error in parse, please submit a bug-report.") ; /* can't happen */ - } - } - if (sp != 2) bail() ; - return stack[1] ; -} - -static long expr_run (struct expr_node_s const *tree, unsigned int root) -{ - switch (tree[root].op) - { - case T_DATA : - return tree[root].data ; - case T_OR : - { - long r = expr_run(tree, tree[root].arg1) ; - return r ? r : expr_run(tree, tree[root].arg2) ; - } - case T_AND : - { - long r = expr_run(tree, tree[root].arg1) ; - return r ? expr_run(tree, tree[root].arg2) ? r : 0 : 0 ; - } - case T_EQUAL : - return expr_run(tree, tree[root].arg1) == expr_run(tree, tree[root].arg2) ; - case T_NEQUAL : - return expr_run(tree, tree[root].arg1) != expr_run(tree, tree[root].arg2) ; - case T_GREATER : - return expr_run(tree, tree[root].arg1) > expr_run(tree, tree[root].arg2) ; - case T_GREATERE : - return expr_run(tree, tree[root].arg1) >= expr_run(tree, tree[root].arg2) ; - case T_LESSER : - return expr_run(tree, tree[root].arg1) < expr_run(tree, tree[root].arg2) ; - case T_LESSERE : - return expr_run(tree, tree[root].arg1) <= expr_run(tree, tree[root].arg2) ; - case T_PLUS : - return expr_run(tree, tree[root].arg1) + expr_run(tree, tree[root].arg2) ; - case T_MINUS : - return expr_run(tree, tree[root].arg1) - expr_run(tree, tree[root].arg2) ; - case T_TIMES : - return expr_run(tree, tree[root].arg1) * expr_run(tree, tree[root].arg2) ; - case T_DIV : - return expr_run(tree, tree[root].arg1) / expr_run(tree, tree[root].arg2) ; - case T_MOD : - return expr_run(tree, tree[root].arg1) % expr_run(tree, tree[root].arg2) ; - default : strerr_dief1x(101, "internal error in expr_run, please submit a bug-report") ; - } -} - -int main (int argc, char const *const *argv) -{ - char fmt[LONG_FMT] ; - long val ; - size_t len ; - PROG = "s6-expr" ; - if (argc <= 1) return 2 ; - { - struct expr_node_s tree[argc + 1] ; - val = expr_run(tree, expr_parse(tree, expr_lex(tree, argv+1))) ; - } - len = long_fmt(fmt, val) ; - fmt[len++] = '\n' ; - if (allwrite(1, fmt, len) < len) - strerr_diefu1sys(111, "write to stdout") ; - return !val ; -} |