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#define _POSIX_C_SOURCE 200809L
#define _XOPEN_SOURCE 500
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <ctype.h>
static bool valid_char(int c)
{
return isprint(c) || c == ' ' || c == '\t';
}
static size_t g_min_len = 4;
static char g_offset_format = -1;
static char *g_buf = NULL;
static void strings(FILE *file)
{
size_t buf_offset = 0;
int c;
while ((c = fgetc(file)) != EOF)
{
if (valid_char(c))
{
if (buf_offset < g_min_len - 1)
{
g_buf[buf_offset] = c;
buf_offset++;
}
else
{
switch (g_offset_format)
{
case 'd': printf("%7ld ", ftell(file) - g_min_len); break;
case 'o': printf("%7lo ", ftell(file) - g_min_len); break;
case 'x': printf("%7lx ", ftell(file) - g_min_len); break;
}
fwrite(g_buf, sizeof(char), buf_offset, stdout);
buf_offset = 0;
fputc(c, stdout);
int c2;
while ((c2 = fgetc(file)) != EOF && valid_char(c2))
fputc(c2, stdout);
fputc('\n', stdout);
}
}
else
buf_offset = 0;
}
}
int main(int argc, char **argv)
{
int option;
while ((option = getopt(argc, argv, "an:t:")) != -1)
{
switch (option)
{
case 'a':
break;
case 'n':
sscanf(optarg, "%lu", &g_min_len);
break;
case 't':
g_offset_format = optarg[0];
break;
}
}
g_buf = malloc(sizeof(char) * g_min_len);
if (g_buf == NULL)
exit(1);
if (optind == argc)
{
strings(stdin);
free(g_buf);
return 0;
}
for (; optind < argc; optind++)
{
FILE *file = fopen(argv[optind], "r");
if (file == NULL)
continue;
strings(file);
fclose(file);
}
free(g_buf);
return 0;
}
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