fumiama/base16384
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修复整数溢出

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fumiama
2021-10-29 00:11:36 +08:00
parent b499fd74ff
commit 1b636bf2ae
5 changed files with 46 additions and 51 deletions
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41
32/base14.c
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@@ -6,9 +6,9 @@
//#define DEBUG
LENDAT* encode(const uint8_t* data, const uint32_t len) {
LENDAT* encode(const uint8_t* data, const int32_t len) {
LENDAT* encd = (LENDAT*)malloc(sizeof(LENDAT));
uint32_t outlen = len / 7 * 8;
int32_t outlen = len / 7 * 8;
uint8_t offset = len % 7;
switch(offset) { //算上偏移标志字符占用的2字节
case 0: break;
@@ -27,7 +27,7 @@ LENDAT* encode(const uint8_t* data, const uint32_t len) {
encd->len = outlen;
uint32_t* vals = (uint32_t*)(encd->data);
uint32_t n = 0;
uint32_t i = 0;
int32_t i = 0;
for(; i <= len - 7; i += 7) {
register uint32_t sum = 0x0000003f & ((uint32_t)data[i] >> 2);
sum |= (((uint32_t)data[i + 1] << 6) | (data[i] << 14)) & 0x0000ff00;
@@ -48,28 +48,25 @@ LENDAT* encode(const uint8_t* data, const uint32_t len) {
printf("n: %u, add sum: %08x\n", n, sum);
#endif
}
if(offset > 0) {
uint8_t o = offset;
if(o--) {
register uint32_t sum = 0x0000003f & (data[i] >> 2);
sum |= ((uint32_t)data[i] << 14) & 0x0000c000;
if(offset > 1) {
if(o--) {
sum |= ((uint32_t)data[i + 1] << 6) & 0x00003f00;
sum |= ((uint32_t)data[i + 1] << 20) & 0x00300000;
if(offset > 2) {
if(o--) {
sum |= ((uint32_t)data[i + 2] << 12) & 0x000f0000;
sum |= ((uint32_t)data[i + 2] << 28) & 0xf0000000;
if(offset == 2) {
sum += 0x004e004e;
vals[n++] = sum;
}
if(offset > 3) {
if(o--) {
sum |= ((uint32_t)data[i + 3] << 20) & 0x0f000000;
sum += 0x004e004e;
vals[n++] = sum;
sum = (((uint32_t)data[i + 3] << 2)) & 0x0000003c;
if(offset > 4) {
if(o--) {
sum |= (((uint32_t)data[i + 4] >> 6)) & 0x00000003;
sum |= ((uint32_t)data[i + 4] << 10) & 0x0000fc00;
if(offset > 5) {
if(o--) {
sum |= ((uint32_t)data[i + 5] << 2) & 0x00000300;
sum |= ((uint32_t)data[i + 5] << 16) & 0x003f0000;
}
@@ -85,9 +82,9 @@ LENDAT* encode(const uint8_t* data, const uint32_t len) {
return encd;
}
LENDAT* decode(const uint8_t* data, const uint32_t len) {
LENDAT* decode(const uint8_t* data, const int32_t len) {
LENDAT* decd = (LENDAT*)malloc(sizeof(LENDAT));
uint32_t outlen = len;
int32_t outlen = len;
uint8_t offset = 0;
if(data[len-2] == '=') {
offset = data[len-1];
@@ -107,7 +104,7 @@ LENDAT* decode(const uint8_t* data, const uint32_t len) {
decd->len = outlen;
uint32_t* vals = (uint32_t*)data;
uint32_t n = 0;
uint32_t i = 0;
int32_t i = 0;
for(; i <= outlen - 7; n++) { //n实际每次自增2
register uint32_t sum = vals[n++];
sum -= 0x004e004e;
@@ -122,23 +119,23 @@ LENDAT* decode(const uint8_t* data, const uint32_t len) {
decd->data[i++] = ((sum & 0x00000300) >> 2) | ((sum & 0x003f0000) >> 16);
decd->data[i++] = ((sum & 0xff000000) >> 24);
}
if(offset > 0) {
if(offset--) {
register uint32_t sum = vals[n++];
sum -= 0x0000004e;
decd->data[i++] = ((sum & 0x0000003f) << 2) | ((sum & 0x0000c000) >> 14);
if(offset > 1) {
if(offset--) {
sum -= 0x004e0000;
decd->data[i++] = ((sum & 0x00003f00) >> 6) | ((sum & 0x00300000) >> 20);
if(offset > 2) {
if(offset--) {
decd->data[i++] = ((sum & 0x000f0000) >> 12) | ((sum & 0xf0000000) >> 28);
if(offset > 3) {
if(offset--) {
decd->data[i++] = (sum & 0x0f000000) >> 20;
sum = vals[n];
sum -= 0x0000004e;
decd->data[i++] |= (sum & 0x0000003c) >> 2;
if(offset > 4) {
if(offset--) {
decd->data[i++] = ((sum & 0x00000003) << 6) | ((sum & 0x0000fc00) >> 10);
if(offset > 5) {
if(offset--) {
sum -= 0x004e0000;
decd->data[i] = ((sum & 0x00000300) >> 2) | ((sum & 0x003f0000) >> 16);
}