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Rewrite substr() to properly clamp its argument ranges and handle negative start arguments as offset-from-end values

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andy
2007-04-02 18:28:38 +00:00
parent 38b9a874e0
commit 9d68727a84
1 changed files with 15 additions and 8 deletions
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23
simgear/nasal/lib.c
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@@ -128,14 +128,21 @@ static naRef f_cmp(naContext c, naRef me, int argc, naRef* args)
static naRef f_substr(naContext c, naRef me, int argc, naRef* args)
{
naRef src = argc > 1 ? args[0] : naNil();
naRef startR = argc > 1 ? naNumValue(args[1]) : naNil();
naRef lenR = argc > 2 ? naNumValue(args[2]) : naNil();
int start, len;
if(!naIsString(src) || naIsNil(startR)) ARGERR();
start = (int)startR.num;
len = naIsNil(lenR) ? (naStr_len(src) - start) : (int)lenR.num;
if(len < 0) ARGERR();
int start, len, srclen;
naRef src = argc > 0 ? args[0] : naNil();
naRef startr = argc > 1 ? naNumValue(args[1]) : naNil();
naRef lenr = argc > 2 ? naNumValue(args[2]) : naNil();
if(!naIsString(src)) ARGERR();
if(naIsNil(startr) || !naIsNum(startr)) ARGERR();
if(!naIsNil(lenr) && !naIsNum(lenr)) ARGERR();
srclen = naStr_len(src);
start = (int)startr.num;
len = naIsNum(lenr) ? (int)lenr.num : (srclen - start);
if(start < 0) start += srclen;
if(start < 0) start = len = 0;
if(start >= srclen) start = len = 0;
if(len < 0) len = 0;
if(len > srclen - start) len = srclen - start;
return naStr_substr(naNewString(c), src, start, len);
}