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#include "user.h"
static const char HEX[] = "0123456789abcdef";
static void put_hex8(unsigned char byte)
{
char digits[2] = { HEX[byte >> 4], HEX[byte & 15] };
(void)sys_write(1, digits, 2);
}
static void put_hex32(unsigned long value)
{
char digits[8];
for (int nibble = 0; nibble < 8; nibble++)
digits[nibble] = HEX[(value >> ((7 - nibble) * 4)) & 15];
(void)sys_write(1, digits, 8);
}
#define PAGE 256
#define COLS 16
void _start(const char* arg, unsigned long arglen)
{
char name[64];
if (arglen > 0 && arglen < 64)
{
for (unsigned long i = 0; i < arglen; i++)
name[i] = arg[i];
name[arglen] = 0;
}
else
{
put("hexview, type a filename\nfile: ");
(void)read_line(name, 64);
put("\n");
}
long size = sys_fs_size(name);
if (size < 0)
{
put("no such file\n");
sys_exit(1);
}
unsigned long offset = 0;
char buffer[PAGE];
for (;;)
{
long count = sys_fs_read(name, offset, buffer, PAGE);
put("--- ");
put(name);
put(" @ 0x");
put_hex32(offset);
put(" / 0x");
put_hex32((unsigned long)size);
put(" ---\n");
for (long row = 0; row < count; row += COLS)
{
put_hex32(offset + (unsigned long)row);
put(": ");
for (int column = 0; column < COLS; column++)
{
if (row + column < count)
{
put_hex8((unsigned char)buffer[row + column]);
(void)sys_write(1, " ", 1);
}
else
put(" ");
}
put(" ");
for (int column = 0; column < COLS && row + column < count; column++)
{
char character = buffer[row + column];
if (character >= 32 && character < 127)
(void)sys_write(1, &character, 1);
else
(void)sys_write(1, ".", 1);
}
put("\n");
}
put("[n]ext [p]rev [q]uit (or up/down arrows) > ");
char key = (char)get_char();
if (key == 27) // ESC
{
(void)get_char();
char final = (char)get_char();
if (final == 'A')
key = 'p';
else if (final == 'B')
key = 'n';
}
put("\n");
if (key == 'q')
break;
if (key == 'n' && offset + PAGE < (unsigned long)size)
offset += PAGE;
if (key == 'p' && offset >= PAGE)
offset -= PAGE;
}
sys_exit(0);
}
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