57 lines
1.2 KiB
C
57 lines
1.2 KiB
C
#include <stddef.h>
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#include "psargs.h"
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/* Test string containing { c, '\0' } without iteration.
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* Theoretically saves a little bit of time compared to strcmp(3). */
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#define SCMPFLAT(a, b) (*(a) != '\0' && *((a)+1) == '\0' && *(a) == (b))
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int
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check_arg(char **args, char l, char r){
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enum {
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UNINITIALIZED = 0,
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NORMAL = 1,
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INLPAREN = 2
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} s;
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int terms;
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for(s = UNINITIALIZED, terms = 0; *args != NULL; ++args)
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switch(s){
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case UNINITIALIZED: case NORMAL:
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if(SCMPFLAT(*args, l))
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s = INLPAREN;
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else
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return 0; /* syntax error */
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break;
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default: /* >= INLPAREN */
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/* decrement s if on an rparen, increment if on lparen
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* increment terms if on an rparen */
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if(args[0][1] == '\0'){
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s += (args[0][0] == l) - (args[0][0] == r);
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terms += (args[0][0] == r && s == NORMAL);
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}
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break;
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}
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/* make sure nothing's open */
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return terms * (s == NORMAL);
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}
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char **
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corresponding_arg(char **arg, char l, char r){
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size_t p;
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for(p = 1; p > 0;){
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++arg;
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/* branching here potentially saves a comparison.
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* this seems like the most optimal way to do this,
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* maybe it isn't, i don't care too much */
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if(SCMPFLAT(*arg, l))
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++p;
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else if(SCMPFLAT(*arg, r))
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--p;
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}
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return arg;
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}
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