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fix signed integer oveflow which is UB and silencing other warnings #2

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fix signed integer oveflow which is UB and silencing other warnings #2

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1 change: 1 addition & 0 deletions .gitignore
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Original file line number Diff line number Diff line change
Expand Up @@ -4,3 +4,4 @@
test
*.d
base45
.idea/
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nothing just prevent to push my ide folder

1 change: 1 addition & 0 deletions Makefile
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Expand Up @@ -14,6 +14,7 @@ INC_FLAGS :=

CPPFLAGS ?= $(INC_FLAGS) -MMD -MP


tests: all $(TARGET_TEST)
./test
for i in 1 2 3 4 5 6 7 8 9 10 11 12 13 17 19 41 42 43 103 1002 10009 100007 1000001 0; do \
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14 changes: 7 additions & 7 deletions base45.c
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Expand Up @@ -21,7 +21,7 @@

static const char BASE45_CHARSET[] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ $%*+-./:";

static char _C2I[256] = {
static unsigned char _C2I[256] = {
255,255,255,255, 255,255,255,255, 255,255,255,255, 255,255,255,255,
255,255,255,255, 255,255,255,255, 255,255,255,255, 255,255,255,255,
36, 255,255,255, 37, 38,255,255, 255,255, 39, 40, 255, 41, 42, 43,
Expand All @@ -47,7 +47,7 @@ int base45_encode(char * dst, size_t *_max_dst_len, const unsigned char * src, s
size_t out_len = 0, max_dst_len;
max_dst_len = _max_dst_len ? *_max_dst_len : src_len * 4;

for(int i = 0; i < src_len; i+=2) {
for(unsigned i = 0; i < src_len; i+=2) {
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silencing warnings about different sign

if (src_len - i > 1) {
int x = ((src[i])<<8) + src[i+1];

Expand Down Expand Up @@ -88,7 +88,7 @@ int base45_encode(char * dst, size_t *_max_dst_len, const unsigned char * src, s
return 0;
}

int base45_decode(unsigned char * dst, size_t * _max_dst_len, const char * src, size_t src_len) {
int base45_decode(unsigned char * dst, size_t * _max_dst_len, const char *src, size_t src_len) {
size_t out_len = 0, max_dst_len;
max_dst_len = _max_dst_len ? *_max_dst_len : src_len;

Expand All @@ -101,19 +101,19 @@ int base45_decode(unsigned char * dst, size_t * _max_dst_len, const char * src,
if (src_len == 0)
src_len = strlen(src);

for(int i = 0; i < src_len; i+=3) {
for(unsigned i = 0; i < src_len; i+=3) {
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silencing warnings about different sign

int x,a,b;

if (src_len - i < 2)
return -1;
return -1;

if ((255 == (a = _C2I[src[i]])) || (255 == (b = _C2I[src[i+1]])))
if ((255 == (a = _C2I[(unsigned char)src[i]])) || (255 == (b = _C2I[(unsigned char)src[i+1]])))
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unsigned integer overflow is well defined, so this cast silence other useless warnings

return -1;

x = a + 45 * b;

if (src_len - i >= 3) {
if (255 == (a = _C2I[src[i+2]]))
if (255 == (a = _C2I[(unsigned char)src[i+2]]))
return -1;

x += a * 45 * 45;
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4 changes: 2 additions & 2 deletions test.c
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Expand Up @@ -21,7 +21,7 @@ void check(char * in, char * out) {
assert(0 == bcmp(dec,in,dlen));

printf("base64(\"%s\") -> \"%s\"\n", (char*)dec, enc);
};
}
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C standards doesn't allow ; after function definitions


int main(int argc, char **argv) {
check("Hello!!","%69 VD92EX0");
Expand All @@ -30,4 +30,4 @@ int main(int argc, char **argv) {
check("COVID-19","-M8*+A%R81A6");
check("2021 Digital Green Certificates for travel",
"NF6OF6P34SED-EDAECS34ZKE1$CO345$CBWER.CGPC7WE.OEX.CBJEKWEKEC: C");
};
}
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C standards doesn't allow ; after function definitions

1 change: 0 additions & 1 deletion test.d
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@@ -1,3 +1,2 @@
test.o: test.c base45.h

base45.h: