This repository holds the code for csize, a program that measures the size of C programs. See the csize man page for a detailed discussion of the measures, their definitions, and their pitfalls. No complexity measures are computed.
The measures are purely syntactical; the program has no understanding of the C grammar. Measures such as declaration or executable statement counts require an understanding of the semantics of C. Although these measures would be valuable, computing them would require the scanner to differentiate between /identifiers/ and /type names/; i.e., csize would need the type system from a C compiler. See p. 234 of Kernighan and Ritchie, 2nd edn., 2nd paragraph, 2nd-to-last sentence.
The scanner-generator flex is required; see the INSTALL file for the exact version that is required. I use flex to generate a scanner that recognizes tokens from the C language. The scanner is arguably underutilized. However, I much prefer using flex because I think it makes the code which I must write far simpler to maintain. The code size is hardly a problem, and I don't think that I can generate a scanner that runs faster than a flex scanner. The file scan.l holds the source used by flex to generate the scanner for C. The old unix utility lex will not work; it complains about the file: "scan.l", line 401: (Error) Too many right contexts If you simply remove the first token ("auto"), then lex dumps core on my machine. Neither behavior is acceptable and I refuse to code around bugs in lex when flex is available, reliable, and free.
The foundation for this code was a rudimentary C parser distributed originally by Jeff Lee (see README attached below). The scan.h file in this distribution was actually generated by yacc from that grammar.
----- Begin: README from Jeff Lee
The files in this directory contain the ANSI C grammar from the April 30, 1985 draft of the proposed standard. This copy also incorporates all bug fixes I have seen since the last two postings. With a little work this grammar can be made to parse the C that most of us know and love (sort of).
There is one bug fix to the grammar that is in this posting. On line 295 of gram.y it previously read declaration_specifiers instead of type_specifier_list as it does now. I believe the folks at the ANSI committee made a mistake since if you replace the line with what the original read you will end up with 16 shift/reduce errors and 2 reduce/reduce errors (the good ones). As it is, it only has 1 shift/reduce error that occurs on the if/else construct. YACC creates the correct parser and I don't want to ugly my grammar up.
Anyway, all cumquats unite and generate this sucker. Then just sit and play with it. Remember, the grammar accepts things like
"Hello, world"++;
--1.23456;
*'a'
but this is not a bug, but simply a shuffling of the checking into the semantic analysis. If you want to hack it up to do lvalue and rvalue checking, I'm sure the ANSI committee would be glad to have your changes. Don't send'em to me though. I don't want'em. Wear this in good health.
Jeff Lee gatech!jeff jeff@gatech jeff%[email protected]
----- End: README from Jeff Lee