nixpkgs/pkgs/build-support/cc-wrapper/expand-response-params.c

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#include <assert.h>
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef struct { char *data; size_t len, cap; } String;
void resize(String *s, size_t len) {
s->len = len;
if (s->cap < s->len) {
s->cap = s->len * 2;
s->data = (char *)realloc(s->data, s->cap);
assert(s->data);
}
}
void append(String *s, const char *data, size_t len) {
resize(s, s->len + len);
memcpy(s->data + s->len - len, data, len);
}
typedef enum { space = 0, other = 1, backslash = 2, apostrophe = 3, quotation_mark = 4 } CharClass;
typedef enum { outside, unq, unq_esc, sq, sq_esc, dq, dq_esc } State;
// current State -> CharClass -> next State
const State transitions[][5] = {
[outside] = {outside, unq, unq_esc, sq, dq},
[unq] = {outside, unq, unq_esc, sq, dq},
[unq_esc] = {unq, unq, unq, unq, unq},
[sq] = {sq, sq, sq_esc, unq, sq},
[sq_esc] = {sq, sq, sq, sq, sq},
[dq] = {dq, dq, dq_esc, dq, unq},
[dq_esc] = {dq, dq, dq, dq, dq},
};
CharClass charClass(int c) {
return c == '\\' ? backslash : c == '\'' ? apostrophe : c == '"' ? quotation_mark :
isspace(c) ? space : other;
}
// expandArg writes NULL-terminated expansions of `arg', a NULL-terminated
// string, to stdout. If arg does not begin with `@' or does not refer to a
// file, it is written as is. Otherwise the contents of the file are
// recursively expanded. On unexpected EOF in malformed response files an
// incomplete final argument is written, even if it is empty, to parse like GCC.
void expandArg(String *arg) {
FILE *f;
if (arg->data[0] != '@' || !(f = fopen(&arg->data[1], "r"))) {
fwrite(arg->data, 1, arg->len, stdout);
return;
}
resize(arg, 0);
State cur = outside;
int c;
do {
c = fgetc(f);
State next = transitions[cur][charClass(c)];
if ((cur == unq && next == outside) || (cur != outside && c == EOF)) {
append(arg, "", 1);
expandArg(arg);
resize(arg, 0);
} else if (cur == unq_esc || cur == sq_esc || cur == dq_esc ||
(cur == outside ? next == unq : cur == next)) {
char s = c;
append(arg, &s, 1);
}
cur = next;
} while (c != EOF);
fclose(f);
}
int main(int argc, char **argv) {
String arg = { 0 };
while (*++argv) {
resize(&arg, 0);
append(&arg, *argv, strlen(*argv) + 1);
expandArg(&arg);
}
free(arg.data);
return EXIT_SUCCESS;
}