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#include "sighandler.h"
#include <ctype.h>
#include <stdio.h>
/*
* Because the parser is implemented here, and doesn't take care of
* strings, character constants, or comments, we hide the { } with
* compile time constants.
*/
constexpr char left = '{';
constexpr char right = '}';
/**
** @brief Initial string to indent a line
**/
constexpr char head[] = ">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>| ";
/**
** @brief Skips any number of spaces, tabs, or newlines in @a s
**/
static
char const* skipspace(char const s[static 1]) {
while (isspace(s[0])) {
++s;
}
return s;
}
/**
** @brief Exceptional states of the parse algorithm
**/
enum state {
execution = 0, //!< Normal execution
plusL, //!< Too many left braces
plusR, //!< Too many right braces
tooDeep, //!< Nesting too deep to handle
eofOut, //!< End of output
interrupted, //!< Interrupted by a signal
};
/**
** @brief Outputs end of line and eats all subsequent spaces on input
**/
static
char const* end_line(char const s[static 1], jmp_buf jmpTarget) {
if (putchar('\n') == EOF) longjmp(jmpTarget, eofOut);
return skipspace(s);
}
/**
** @brief Keeps track of the last signal that interrupted us
**/
static sig_atomic_t volatile interrupt = 0;
static
char const* descend(char const* act,
unsigned dp[restrict static 1], // Bad
size_t len, char buffer[static len],
jmp_buf jmpTarget) {
if (dp[0]+3 > sizeof head) longjmp(jmpTarget, tooDeep);
++dp[0];/*@\label{lab:incr-rec}*/
NEW_LINE: // Loops on output
while (!act || !act[0]) { // Loops for input
if (interrupt) longjmp(jmpTarget, interrupted);
act = skipspace(fgets(buffer, len, stdin));
if (!act) { // End of stream
if (dp[0] != 1) longjmp(jmpTarget, plusL);
else goto ASCEND;
}
}
fputs(&head[sizeof head - (dp[0] + 2)], stdout); // Header
for (; act && act[0]; ++act) { // Remainder of the line
switch (act[0]) { /*@\label{lab:switch-char}*/
case left: // Descends on left brace
act = end_line(act+1, jmpTarget);
act = descend(act, dp, len, buffer, jmpTarget);/*@\label{lab:descend}*/
act = end_line(act+1, jmpTarget);
goto NEW_LINE;
case right: // Returns on right brace
if (dp[0] == 1) longjmp(jmpTarget, plusR);
else goto ASCEND;
default: // Prints char and goes on
putchar(act[0]);
}
}
goto NEW_LINE;
ASCEND:
--dp[0];/*@\label{lab:decr-rec}*/
return act;
}
constexpr unsigned maxline = 256;
void basic_blocks(void) {
char buffer[maxline];
unsigned depth = 0;
char const* format =
"All matching %0.0d'%c' '%c' pairs have been closed correctly\n";
jmp_buf jmpTarget;
switch (setjmp(jmpTarget)) {
case 0:
descend(nullptr, &depth, maxline, buffer, jmpTarget);
break;
case plusL:
format =
"Warning: %d '%c' have not been closed properly (expected '%c')\n";
break;
case plusR:
format =
"Error: closing too many (%d) '%c' parenthesis with additional '%c'\n";
break;
case tooDeep:
format =
"Error: nesting (%d) of '%c' '%c' constructs is too deep\n";
break;
case eofOut:
format =
"Error: EOF for stdout at %d open '%c', expecting same amount of '%c'\n";
break;
case interrupted:
format =
"Interrupted at level %d of '%c' '%c' nesting\n";
break;
default:;
format =
"Error: unknown error within (%d) '%c' '%c' constructs\n";
}
fflush(stdout);
fprintf(stderr, format, depth, left, right);
if (interrupt) {
SH_PRINT(stderr, interrupt,
"is somebody trying to kill us?");
raise(interrupt);
}
}
/**
** @brief A minimal signal handler
**
** After updating the signal count, for most signals this
** simply stores the signal value in "interrupt" and returns.
**/
static void signal_handler(int sig) {
sh_count(sig);
switch (sig) {
case SIGTERM: quick_exit(EXIT_FAILURE);
case SIGABRT: _Exit(EXIT_FAILURE);
#ifdef SIGCONT
// continue normal operation
case SIGCONT: return;
#endif
default:
/* reset the handling to its default */
signal(sig, SIG_DFL);
interrupt = sig;
return;
}
}
// Will point to the command-line arguments
static char** lastOpen = nullptr;
// Checks if we were in the middle of an operation
void doAtExit(void) {
if (lastOpen && lastOpen[0]) {
fprintf(stderr, "\n***********\nabnormal exit, last open file was %s\n", lastOpen[0]);
}
}
int main(int argc, char* argv[argc+1]) {
// Ensures that stdout is line buffered
if (setvbuf(stdout, nullptr, _IOLBF, maxline + sizeof head + 2)) {
fputs("we could not establish line buffering for stdout, terminating.", stderr);
return EXIT_FAILURE;
}
// Establishes exit handlers
atexit(doAtExit);
at_quick_exit(doAtExit);
// Establishes signal handlers
for (unsigned i = 1; i < sh_known; ++i)
sh_enable(i, signal_handler);
// If there are no command-line arguments, reads from stdin
lastOpen = argv;
if (argc < 2) goto RUN;
// Runs basic_blocks for each command-line argument
for (++lastOpen; lastOpen[0]; ++lastOpen) {
if (!freopen(lastOpen[0], "r", stdin)) {
perror(lastOpen[0]);
return EXIT_FAILURE;
}
printf("++++++++++ %s +++++++++++\n", lastOpen[0]);
RUN:
basic_blocks();
}
return EXIT_SUCCESS;
}
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