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/* xxd.c - hexdump.
*
* Copyright 2015 The Android Open Source Project
*
* No obvious standard, output looks like:
* 0000000: 4c69 6e75 7820 7665 7273 696f 6e20 332e Linux version 3.
USE_XXD(NEWTOY(xxd, ">1c#<1>4096=16l#g#<1=2prs#[!rs]", TOYFLAG_USR|TOYFLAG_BIN))
config XXD
bool "xxd"
default y
help
usage: xxd [-c n] [-g n] [-l n] [-p] [-r] [-s n] [file]
Hexdump a file to stdout. If no file is listed, copy from stdin.
Filename "-" is a synonym for stdin.
-c n Show n bytes per line (default 16).
-g n Group bytes by adding a ' ' every n bytes (default 2).
-l n Limit of n bytes before stopping (default is no limit).
-p Plain hexdump (30 bytes/line, no grouping).
-r Reverse operation: turn a hexdump into a binary file.
-s n Skip to offset n.
*/
#define FOR_xxd
#include "toys.h"
GLOBALS(
long s;
long g;
long l;
long c;
)
static void do_xxd(int fd, char *name)
{
long long pos = 0;
long long limit = TT.l;
int i, len, space;
if (toys.optflags&FLAG_s) {
xlseek(fd, TT.s, SEEK_SET);
pos = TT.s;
if (limit) limit += TT.s;
}
while (0<(len = readall(fd, toybuf,
(limit && limit-pos<TT.c)?limit-pos:TT.c))) {
if (!(toys.optflags&FLAG_p)) printf("%08llx: ", pos);
pos += len;
space = 2*TT.c+TT.c/TT.g+1;
for (i=0; i<len;) {
space -= printf("%02x", toybuf[i]);
if (!(++i%TT.g)) {
putchar(' ');
space--;
}
}
if (!(toys.optflags&FLAG_p)) {
printf("%*s", space, "");
for (i=0; i<len; i++)
putchar((toybuf[i]>=' ' && toybuf[i]<='~') ? toybuf[i] : '.');
}
putchar('\n');
}
if (len<0) perror_exit("read");
}
static int dehex(char ch)
{
if (ch >= '0' && ch <= '9') return ch - '0';
if (ch >= 'a' && ch <= 'f') return ch - 'a' + 10;
if (ch >= 'A' && ch <= 'F') return ch - 'a' + 10;
return (ch == '\n') ? -2 : -1;
}
static void do_xxd_reverse(int fd, char *name)
{
FILE *fp = xfdopen(fd, "r");
while (!feof(fp)) {
int col = 0;
int tmp;
// Each line of a non-plain hexdump starts with an offset/address.
if (!(toys.optflags&FLAG_p)) {
long long pos;
if (fscanf(fp, "%llx: ", &pos) == 1) {
if (fseek(stdout, pos, SEEK_SET) != 0) {
// TODO: just write out zeros if non-seekable?
perror_exit("%s: seek failed", name);
}
}
}
// A plain hexdump can have as many bytes per line as you like,
// but a non-plain hexdump assumes garbage after it's seen the
// specified number of bytes.
while (toys.optflags&FLAG_p || col < TT.c) {
int n1, n2;
// If we're at EOF or EOL or we read some non-hex...
if ((n1 = n2 = dehex(fgetc(fp))) < 0 || (n2 = dehex(fgetc(fp))) < 0) {
// If we're at EOL, start on that line.
if (n1 == -2 || n2 == -2) continue;
// Otherwise, skip to the next line.
break;
}
fputc((n1 << 4) | (n2 & 0xf), stdout);
col++;
// Is there any grouping going on? Ignore a single space.
tmp = fgetc(fp);
if (tmp != ' ') ungetc(tmp, fp);
}
// Skip anything else on this line (such as the ASCII dump).
while ((tmp = fgetc(fp)) != EOF && tmp != '\n')
;
}
if (ferror(fp)) perror_msg_raw(name);
fclose(fp);
}
void xxd_main(void)
{
// Plain style is 30 bytes/line, no grouping.
if (toys.optflags&FLAG_p) TT.c = TT.g = 30;
loopfiles(toys.optargs, toys.optflags&FLAG_r ? do_xxd_reverse : do_xxd);
}
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