111 lines
1.9 KiB
C
111 lines
1.9 KiB
C
#include <stdio.h>
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#include <ctype.h>
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#include <stdlib.h>
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#include <dlfcn.h>
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static void *funcall (char **stringp);
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static void *eval (char **stringp);
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static void *
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funcall (char **stringp)
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{
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void *args[strlen (*stringp)], **ap = args;
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void *argcookie = &args[1];
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do
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{
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/* Evaluate the next token. */
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*ap++ = eval (stringp);
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/* Whitespace is irrelevant. */
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while (isspace (**stringp))
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++*stringp;
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/* Terminate at closing paren or end of line. */
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} while (**stringp != '\0' && **stringp != ')');
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if (**stringp != '\0')
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/* Swallow closing paren. */
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++*stringp;
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/* Do it to it. */
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__builtin_return (__builtin_apply (args[0],
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&argcookie,
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(char *) ap - (char *) &args[1]));
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}
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static void *
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eval (char **stringp)
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{
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void *value;
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char *p = *stringp, c;
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/* Whitespace is irrelevant. */
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while (isspace (*p))
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++p;
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switch (*p)
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{
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case '"':
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/* String constant. */
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value = ++p;
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do
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if (*p == '\\')
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{
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switch (*strcpy (p, p + 1))
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{
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case 't':
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*p = '\t';
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break;
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case 'n':
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*p = '\n';
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break;
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}
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++p;
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}
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while (*p != '\0' && *p++ != '"');
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if (p[-1] == '"')
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p[-1] = '\0';
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break;
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case '(':
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*stringp = ++p;
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return funcall (stringp);
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default:
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/* Try to parse it as a number. */
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value = (void *) strtol (p, stringp, 0);
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if (*stringp != p)
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return value;
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/* Anything else is a symbol that produces its address. */
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value = p;
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do
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++p;
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while (*p != '\0' && !isspace (*p) && !ispunct (*p));
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c = *p;
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*p = '\0';
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value = dlsym (NULL, value);
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*p = c;
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break;
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}
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*stringp = p;
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return value;
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}
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void
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_start (void)
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{
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char *buf = NULL;
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size_t bufsz = 0;
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while (getline (&buf, &bufsz, stdin) > 0)
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{
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char *p = buf;
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eval (&p);
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}
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exit (0);
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}
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