mpw/mpw/environ.cpp

/* Generated by re2c 0.13.5 on Sat May 18 16:26:02 2013 */
#include <string>
#include <unordered_map>

#include <cstdio>

/*
 * #...comment
 * var=value
 * where value may contain $var and ${var} interpolations.
 *
 */

namespace MPW {
std::string EvalString(std::string &s, std::unordered_map<std::string, std::string> &env)
{

	std::string rv;
	const char *cp = s.c_str();
	const char *marker = NULL;

	while (*cp)
	{
		const char *begin = cp;

		
	{
		char yych;

		yych = (char)*cp;
		switch (yych) {
		case '\n':	goto yy5;
		case '$':	goto yy2;
		default:	goto yy4;
		}
yy2:
		yych = (char)*(marker = ++cp);
		switch (yych) {
		case '0':
		case '1':
		case '2':
		case '3':
		case '4':
		case '5':
		case '6':
		case '7':
		case '8':
		case '9':
		case 'A':
		case 'B':
		case 'C':
		case 'D':
		case 'E':
		case 'F':
		case 'G':
		case 'H':
		case 'I':
		case 'J':
		case 'K':
		case 'L':
		case 'M':
		case 'N':
		case 'O':
		case 'P':
		case 'Q':
		case 'R':
		case 'S':
		case 'T':
		case 'U':
		case 'V':
		case 'W':
		case 'X':
		case 'Y':
		case 'Z':
		case '_':
		case 'a':
		case 'b':
		case 'c':
		case 'd':
		case 'e':
		case 'f':
		case 'g':
		case 'h':
		case 'i':
		case 'j':
		case 'k':
		case 'l':
		case 'm':
		case 'n':
		case 'o':
		case 'p':
		case 'q':
		case 'r':
		case 's':
		case 't':
		case 'u':
		case 'v':
		case 'w':
		case 'x':
		case 'y':
		case 'z':	goto yy9;
		case '{':	goto yy7;
		default:	goto yy3;
		}
yy3:
		{
			rv.push_back(*begin);
			continue;
		}
yy4:
		yych = (char)*++cp;
		goto yy3;
yy5:
		++cp;
		{
			break;
		}
yy7:
		yych = (char)*++cp;
		switch (yych) {
		case '}':	goto yy8;
		default:	goto yy13;
		}
yy8:
		cp = marker;
		goto yy3;
yy9:
		++cp;
		yych = (char)*cp;
		switch (yych) {
		case '0':
		case '1':
		case '2':
		case '3':
		case '4':
		case '5':
		case '6':
		case '7':
		case '8':
		case '9':
		case 'A':
		case 'B':
		case 'C':
		case 'D':
		case 'E':
		case 'F':
		case 'G':
		case 'H':
		case 'I':
		case 'J':
		case 'K':
		case 'L':
		case 'M':
		case 'N':
		case 'O':
		case 'P':
		case 'Q':
		case 'R':
		case 'S':
		case 'T':
		case 'U':
		case 'V':
		case 'W':
		case 'X':
		case 'Y':
		case 'Z':
		case '_':
		case 'a':
		case 'b':
		case 'c':
		case 'd':
		case 'e':
		case 'f':
		case 'g':
		case 'h':
		case 'i':
		case 'j':
		case 'k':
		case 'l':
		case 'm':
		case 'n':
		case 'o':
		case 'p':
		case 'q':
		case 'r':
		case 's':
		case 't':
		case 'u':
		case 'v':
		case 'w':
		case 'x':
		case 'y':
		case 'z':	goto yy9;
		default:	goto yy11;
		}
yy11:
		{
			std::string tmp(begin + 1, cp);

			// lookup value...
			// append to rv.
			auto iter = env.find(tmp);
			if (iter != env.end())
			{
				rv.append(iter->second);
			}
			continue;
		}
yy12:
		++cp;
		yych = (char)*cp;
yy13:
		switch (yych) {
		case '0':
		case '1':
		case '2':
		case '3':
		case '4':
		case '5':
		case '6':
		case '7':
		case '8':
		case '9':
		case 'A':
		case 'B':
		case 'C':
		case 'D':
		case 'E':
		case 'F':
		case 'G':
		case 'H':
		case 'I':
		case 'J':
		case 'K':
		case 'L':
		case 'M':
		case 'N':
		case 'O':
		case 'P':
		case 'Q':
		case 'R':
		case 'S':
		case 'T':
		case 'U':
		case 'V':
		case 'W':
		case 'X':
		case 'Y':
		case 'Z':
		case '_':
		case 'a':
		case 'b':
		case 'c':
		case 'd':
		case 'e':
		case 'f':
		case 'g':
		case 'h':
		case 'i':
		case 'j':
		case 'k':
		case 'l':
		case 'm':
		case 'n':
		case 'o':
		case 'p':
		case 'q':
		case 'r':
		case 's':
		case 't':
		case 'u':
		case 'v':
		case 'w':
		case 'x':
		case 'y':
		case 'z':	goto yy12;
		case '}':	goto yy14;
		default:	goto yy8;
		}
yy14:
		++cp;
		{
		
			std::string tmp(begin + 2, cp - 1);

			auto iter = env.find(tmp);
			if (iter != env.end())
			{
				rv.append(iter->second);
			}
			continue;
		}
	}


	}

	return rv;
}


void LoadEnvironment(std::string &envfile, std::unordered_map<std::string, std::string> &env)
{

	FILE *fp;


	fp = fopen(envfile.c_str(), "r");

	if (!fp) return;

	for (;;)
	{
		char *begin;
		char *end;
		char *iter;

		size_t length;		

		begin = fgetln(fp, &length);
		if (!begin) break; // eof or error.

		if (!length) continue;
		if (begin[0] == '#') continue;

		while (length && isspace(begin[length - 1])) --length;
		if (!length) continue;

		// key=value

		// ehh, this could really check for [A-Za-z0-9_]+ '='

		end = begin + length;
		iter = std::find(begin, end, '=');

		if (iter == end || iter == begin)
		{
			fprintf(stderr, "Invalid Environment entry: %.*s\n", length, begin);
			continue;
		}

		std::string key(begin, iter);
		std::string value(iter + 1, end);

		value = EvalString(value, env);

		//fprintf(stdout, "%s = %s\n", key.c_str(), value.c_str());

		// todo -- does this replace an existing value?
		env.emplace(key, value);
	}

	fclose(fp);
}

}