util/hexdump.c

   1 /*
   2 * Helper to hexdump a buffer
   3  *
   4  * Copyright (c) 2013 Red Hat, Inc.
   5  * Copyright (c) 2013 Gerd Hoffmann <kraxel@redhat.com>
   6  * Copyright (c) 2013 Peter Crosthwaite <peter.crosthwaite@xilinx.com>
   7  * Copyright (c) 2013 Xilinx, Inc
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2.  See
  10  * the COPYING file in the top-level directory.
  11  *
  12  * Contributions after 2012-01-13 are licensed under the terms of the
  13  * GNU GPL, version 2 or (at your option) any later version.
  14  */
  15
  16 #include "qemu/osdep.h"
  17 #include "qemu/cutils.h"
  18
  19 static inline char hexdump_nibble(unsigned x)
  20 {
  21     return (x < 10 ? '0' : 'a' - 10) + x;
  22 }
  23
  24 GString *qemu_hexdump_line(GString *str, const void *vbuf, size_t len,
  25                            size_t unit_len, size_t block_len)
  26 {
  27     const uint8_t *buf = vbuf;
  28     size_t u, b;
  29
  30     if (str == NULL) {
  31         /* Estimate the length of the output to avoid reallocs. */
  32         size_t est = len * 2;
  33         if (unit_len) {
  34             est += len / unit_len;
  35         }
  36         if (block_len) {
  37             est += len / block_len;
  38         }
  39         str = g_string_sized_new(est + 1);
  40     }
  41
  42     for (u = 0, b = 0; len; u++, b++, len--, buf++) {
  43         uint8_t c;
  44
  45         if (unit_len && u == unit_len) {
  46             g_string_append_c(str, ' ');
  47             u = 0;
  48         }
  49         if (block_len && b == block_len) {
  50             g_string_append_c(str, ' ');
  51             b = 0;
  52         }
  53
  54         c = *buf;
  55         g_string_append_c(str, hexdump_nibble(c / 16));
  56         g_string_append_c(str, hexdump_nibble(c % 16));
  57     }
  58
  59     return str;
  60 }
  61
  62 static void asciidump_line(char *line, const void *bufptr, size_t len)
  63 {
  64     const char *buf = bufptr;
  65
  66     for (size_t i = 0; i < len; i++) {
  67         char c = buf[i];
  68
  69         if (c < ' ' || c > '~') {
  70             c = '.';
  71         }
  72         *line++ = c;
  73     }
  74     *line = '\0';
  75 }
  76
  77 #define QEMU_HEXDUMP_LINE_BYTES 16
  78 #define QEMU_HEXDUMP_LINE_WIDTH \
  79     (QEMU_HEXDUMP_LINE_BYTES * 2 + QEMU_HEXDUMP_LINE_BYTES / 4)
  80
  81 void qemu_hexdump(FILE *fp, const char *prefix,
  82                   const void *bufptr, size_t size)
  83 {
  84     g_autoptr(GString) str = g_string_sized_new(QEMU_HEXDUMP_LINE_WIDTH + 1);
  85     char ascii[QEMU_HEXDUMP_LINE_BYTES + 1];
  86     size_t b, len;
  87
  88     for (b = 0; b < size; b += len) {
  89         len = MIN(size - b, QEMU_HEXDUMP_LINE_BYTES);
  90
  91         g_string_truncate(str, 0);
  92         qemu_hexdump_line(str, bufptr + b, len, 1, 4);
  93         asciidump_line(ascii, bufptr + b, len);
  94
  95         fprintf(fp, "%s: %04zx: %-*s %s\n",
  96                 prefix, b, QEMU_HEXDUMP_LINE_WIDTH, str->str, ascii);
  97     }
  98
  99 }