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#include <stdio.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "util/versie.h"
#include "util/error.h"
#include "util/debug.h"
static void usage(FILE *f) {
fprintf(f,
"Gebruik: omd [-hV] <bestand...>\n"
"\n"
" -h Toon deze hulptekst\n"
" -V Toon versienummer\n");
}
// Returns pointer to argument array containing the file names
static char** parse_options(int argc, char **argv) {
int opt;
while ((opt = getopt(argc, argv, "hV")) != -1) {
switch (opt) {
case 'h':
usage(stdout);
exit(0);
case 'V':
drukkedoos_print_versie(stdout, "omd");
exit(0);
case '?':
usage(stderr);
exit(1);
}
}
return argv + optind;
}
static void reverse_in_place(char *buf, size_t len) {
for (size_t i = 0, j = len - 1; i < len / 2; i++, j--) {
char c = buf[i];
buf[i] = buf[j];
buf[j] = c;
}
}
static void process(const char *fname, FILE *f) {
size_t cap = 4096;
char *buffer = malloc(cap);
if (!buffer) print_error_nomem("omd");
size_t cursor = 0;
while (true) {
DEBUG("cursor=%zu\n", cursor);
// read a line
size_t linelen = 0;
while (true) {
// grow buffer when small
if (cap - cursor < 1024) {
cap *= 2;
if (cap == 0) {
fprintf(stderr, "omd: Regel te lang\n");
exit(1);
}
DEBUG("realloc to cap %zu\n", cap);
buffer = realloc(buffer, cap);
if (!buffer) print_error_nomem("omd");
}
size_t nr = fread(buffer + cursor, 1, cap - cursor, f);
DEBUG("nr=%zu\n", nr);
if (nr == 0) {
if (feof(f)) {
if (cursor == 0) return;
linelen = cursor;
break;
}
if (fname) fprintf(stderr, "omd: Fout bij lezen van bestand '%s'\n", fname);
else fprintf(stderr, "omd: Fout bij lezen van standaardinvoer\n");
exit(1);
}
char *p = memchr(buffer + cursor, '\n', nr);
cursor += nr;
if (p != NULL) {
linelen = p - buffer;
break;
}
}
DEBUG("line with len %zu (cursor=%zu)\n", linelen, cursor);
// we have a newline at cursor+linelen; print all lines that we already have in full
size_t linestart = 0;
while (true) {
reverse_in_place(buffer + linestart, linelen);
if (linestart + linelen < cap && buffer[linestart + linelen] == '\n') {
size_t nw = fwrite(buffer + linestart, 1, linelen + 1, stdout);
if (nw < linelen + 1) exit(1);
} else {
size_t nw = fwrite(buffer + linestart, 1, linelen, stdout);
if (nw < linelen) exit(1);
putchar('\n');
// no newline in the buffer but nevertheless a completed line means that input is at EOF
goto cleanup;
}
linestart += linelen + 1;
char *p = memchr(buffer + linestart, '\n', cursor - linestart);
if (p == NULL) {
DEBUG("no more newlines, moving back from %zu len %zu\n", linestart, cursor - linestart);
// move back whatever we have left
memmove(buffer, buffer + linestart, cursor - linestart);
cursor -= linestart;
break;
}
linelen = p - (buffer + linestart);
DEBUG("next line from %zu len %zu\n", linestart, linelen);
}
}
cleanup:
free(buffer);
}
int entry_omd(int argc, char **argv) {
char **args = parse_options(argc, argv);
if (*args == NULL) {
process(NULL, stdin);
} else {
while (*args != NULL) {
FILE *f = fopen(*args, "r");
if (!f) {
fprintf(stderr, "omd: Kon bestand '%s' niet openen\n", *args);
return 1;
}
process(*args, f);
fclose(f);
args++;
}
}
return 0;
}
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