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128 lines
2.4 KiB
C
128 lines
2.4 KiB
C
/* radare - LGPL - Copyright 2014-2015 - pancake */
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#include <r_util.h>
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/* dex/dwarf uleb128 implementation */
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R_API const ut8 *r_uleb128(const ut8 *data, int datalen, ut64 *v) {
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ut8 c;
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ut64 s, sum = 0;
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const ut8 *data_end;
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if (v) *v = 0LL;
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if (datalen == ST32_MAX) {
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// WARNING; possible overflow
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datalen = 0xffff;
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}
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if (datalen < 0) {
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return NULL;
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}
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data_end = data + datalen;
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if (data && datalen > 0) {
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if (*data) {
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for (s = 0; data < data_end; s += 7) {
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c = *(data++) & 0xff;
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sum |= ((ut32) (c & 0x7f) << s);
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if (!(c & 0x80)) break;
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}
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} else {
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data++;
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}
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}
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if (v) *v = sum;
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return data;
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}
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/* data is the char array containing the uleb number
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* datalen will point (if not NULL) to the length of the uleb number
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* v (if not NULL) will point to the data's value (if fitting the size of an ut64)
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*/
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R_API const ut8 *r_uleb128_decode(const ut8 *data, int *datalen, ut64 *v) {
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ut8 c = 0xff;
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ut64 s = 0, sum = 0, l = 0;
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if (data && *data) {
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do {
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c = *(data++) & 0xff;
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sum |= ((ut32) (c&0x7f) << s);
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s += 7;
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l++;
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} while (c & 0x80);
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}
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if (v) *v = sum;
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if (datalen) *datalen = l;
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return data;
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}
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R_API const ut8 *r_uleb128_encode(const ut64 s, int *len) {
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ut8 c = 0;
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int l = 0;
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ut8 *otarget = NULL, *target = NULL;
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ut64 source = s;
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do {
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l++;
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if (!(otarget = realloc (otarget, l))) {
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l = 0;
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break;
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}
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target = otarget+l-1;
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c = 0; //May not be necessary
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c = source & 0x7f;
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source >>= 7;
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if (source) c |= 0x80;
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*(target) = c;
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} while (source);
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if (len) *len = l;
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return otarget;
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}
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R_API const ut8 *r_leb128(const ut8 *data, st64 *v) {
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ut8 c = 0;
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st64 s = 0, sum = 0;
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if (data) {
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for (s = 0; *data;) {
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c = *(data++) & 0x0ff;
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sum |= ((st64) (c & 0x7f) << s);
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s += 7;
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if (!(c & 0x80)) break;
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}
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}
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if ((s < (8 * sizeof (sum))) && (c & 0x40)) {
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sum |= -((st64)1 << s);
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}
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if (v) *v = sum;
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return data;
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}
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//API borrowed from frida
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#define G_GINT64_CONSTANT(val) (val##L)
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R_API st64 r_sleb128(const ut8 **data, const ut8 *end) {
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const ut8 *p = *data;
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st64 result = 0;
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int offset = 0;
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ut8 value;
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do {
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st64 chunk;
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value = *p;
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chunk = value & 0x7f;
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result |= (chunk << offset);
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offset += 7;
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}
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while (*p++ & 0x80);
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if ((value & 0x40) != 0) {
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result |= G_GINT64_CONSTANT (-1) << offset;
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}
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*data = p;
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return result;
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}
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#if 0
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main() {
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ut32 n;
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ut8 *buf = "\x10\x02\x90\x88";
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r_uleb128 (buf, &n);
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printf ("n = %d\n", n);
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}
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#endif
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