зеркало из https://github.com/github/putty.git
88 строки
3.3 KiB
C
88 строки
3.3 KiB
C
/*
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* Coroutine mechanics used in PuTTY's SSH code.
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*/
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#ifndef PUTTY_SSHCR_H
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#define PUTTY_SSHCR_H
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/*
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* If these macros look impenetrable to you, you might find it helpful
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* to read
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*
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* https://www.chiark.greenend.org.uk/~sgtatham/coroutines.html
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*
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* which explains the theory behind these macros.
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*
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* In particular, if you are getting `case expression not constant'
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* errors when building with MS Visual Studio, this is because MS's
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* Edit and Continue debugging feature causes their compiler to
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* violate ANSI C. To disable Edit and Continue debugging:
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*
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* - right-click ssh.c in the FileView
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* - click Settings
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* - select the C/C++ tab and the General category
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* - under `Debug info:', select anything _other_ than `Program
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* Database for Edit and Continue'.
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*/
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#define crBegin(v) do { int *crLine = &v; switch(v) { case 0:
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#define crBeginState crBegin(s->crLine)
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#define crStateP(t, v) \
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struct t *s; \
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if (!(v)) { s = (v) = snew(struct t); s->crLine = 0; } \
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s = (v);
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#define crState(t) crStateP(t, ssh->t)
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#define crFinish(z) } *crLine = 0; return (z); } while (0)
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#define crFinishV } *crLine = 0; return; } while (0)
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#define crFinishFreed(z) } return (z); } while (0)
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#define crFinishFreedV } return; } while (0)
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#define crFinishFree(z) } sfree(s); return (z); } while (0)
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#define crFinishFreeV } sfree(s); return; } while (0)
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#define crReturn(z) \
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do {\
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*crLine =__LINE__; return (z); case __LINE__:;\
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} while (0)
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#define crReturnV \
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do {\
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*crLine=__LINE__; return; case __LINE__:;\
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} while (0)
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#define crStop(z) do{ *crLine = 0; return (z); }while(0)
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#define crStopV do{ *crLine = 0; return; }while(0)
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/*
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* The crMaybeWaitUntil macros could have been more easily written in
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* terms of the simple crReturn above, by writing things like
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*
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* while (!condition) { crReturn(whatever); }
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*
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* (or do-while in the case of crWaitUntil). But it's better to do it
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* directly by writing _once_ to crLine before first testing the
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* condition, because this way it's robust against the condition check
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* potentially freeing the entire coroutine state structure as a side
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* effect (as long as it also evaluates false if it does that),
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* because we don't write into crLine between the condition evaluating
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* to false and the 'return' statement.
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*/
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#define crMaybeWaitUntil(c) \
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do { \
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*crLine =__LINE__; \
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case __LINE__: if (!(c)) return 0; \
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} while (0)
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#define crMaybeWaitUntilV(c) \
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do { \
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*crLine =__LINE__; \
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case __LINE__: if (!(c)) return; \
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} while (0)
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#define crWaitUntil(c) \
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do { \
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*crLine =__LINE__; return; \
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case __LINE__: if (!(c)) return 0; \
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} while (0)
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#define crWaitUntilV(c) \
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do { \
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*crLine =__LINE__; return; \
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case __LINE__: if (!(c)) return; \
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} while (0)
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#endif /* PUTTY_SSHCR_H */
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