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* fix undefined behavior in strto* via FILE buffer pointer abuseRich Felker2018-09-151-2/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | in order to produce FILE objects to pass to the intscan/floatscan backends without any (prohibitively costly) extra buffering layer, the strto* functions set the FILE's rend (read end) buffer pointer to an invalid value at the end of the address space, or SIZE_MAX/2 past the beginning of the string. this led to undefined behavior comparing and subtracting the end pointer with the buffer position pointer (rpos). the comparison issue is easily eliminated by using != instead of <. however the subtractions require nontrivial changes: previously, f->shcnt stored the count that would have been read if consuming the whole buffer, which required an end pointer for the buffer. the purpose for this was that it allowed reading it and adding rpos-rend at any time to get the actual count so far, and required no adjustment at the time of __shgetc (actual function call) since the call would only happen when reaching the end of the buffer. to get rid of the dependency on rend, instead offset shcnt by buf-rpos (start of buffer) at the time of last __shlim/__shgetc call. this makes for slightly more work in __shgetc the function, but for the inline macro it's still just as easy to compute the current count. since the scan helper interfaces used here are a big hack, comments are added to document their contracts and what's going on with their implementations.
* apply hidden visibility to various remaining internal interfacesRich Felker2018-09-121-2/+2
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* fix broken shgetc limiter logic (wasn't working)Rich Felker2012-04-161-1/+1
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* use macros instead of inline functions in shgetc.hRich Felker2012-04-131-20/+4
| | | | | | at -Os optimization level, gcc refuses to inline these functions even though the inlined code would roughly the same size as the function call, and much faster. the easy solution is to make them into macros.
* add "scan helper getc" and rework strtod, etc. to use itRich Felker2012-04-101-0/+25
the immediate benefit is a significant debloating of the float parsing code by moving the responsibility for keeping track of the number of characters read to a different module. by linking shgetc with the stdio buffer logic, counting logic is defered to buffer refill time, keeping the calls to shgetc fast and light. in the future, shgetc will also be useful for integrating the new float code with scanf, which needs to not only count the characters consumed, but also limit the number of characters read based on field width specifiers. shgetc may also become a useful tool for simplifying the integer parsing code.