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// re2c $INPUT -o $OUTPUT --loop-switch -i
#include <assert.h>
#include <stdio.h>
#include <string.h>
#define SIZE 4096
typedef struct {
FILE *file;
char buf[SIZE + 1], *lim, *cur, *mar, *tok;
int eof;
} Input;
static int fill(Input *in)
{
if (in->eof) {
return 1;
}
const size_t free = in->tok - in->buf;
if (free < 1) {
return 2;
}
memmove(in->buf, in->tok, in->lim - in->tok);
in->lim -= free;
in->cur -= free;
in->mar -= free;
in->tok -= free;
in->lim += fread(in->lim, 1, free, in->file);
in->lim[0] = 0;
in->eof |= in->lim < in->buf + SIZE;
return 0;
}
static void init(Input *in, FILE *file)
{
in->file = file;
in->cur = in->mar = in->tok = in->lim = in->buf + SIZE;
in->eof = 0;
fill(in);
}
static int lex(Input *in)
{
int count = 0;
loop:
in->tok = in->cur;
/*!re2c
re2c:eof = 0;
re2c:api:style = free-form;
re2c:define:YYCTYPE = char;
re2c:define:YYCURSOR = in->cur;
re2c:define:YYMARKER = in->mar;
re2c:define:YYLIMIT = in->lim;
re2c:define:YYFILL = "fill(in) == 0";
* { return -1; }
$ { return count; }
['] ([^'\\] | [\\][^])* ['] { ++count; goto loop; }
[ ]+ { goto loop; }
*/
}
int main()
{
const char *fname = "input";
const char str[] = "'qu\0tes' 'are' 'fine: \\'' ";
FILE *f;
Input in;
// prepare input file: a few times the size of the buffer,
// containing strings with zeroes and escaped quotes
f = fopen(fname, "w");
for (int i = 0; i < SIZE; ++i) {
fwrite(str, 1, sizeof(str) - 1, f);
}
fclose(f);
f = fopen(fname, "r");
init(&in, f);
assert(lex(&in) == SIZE * 3);
fclose(f);
remove(fname);
return 0;
}
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