From 952c31861914a60c6a0aa8378ca06dc844245b4f Mon Sep 17 00:00:00 2001
From: John Breaux <JohnBreaux@my.unt.edu>
Date: Fri, 22 Apr 2022 21:12:22 -0500
Subject: [PATCH] read_input: - Clarify what each regex does by assigning rule
 numbers - Properly handle commented-out lines in input files - Properly scope
 several vars which were in too broad a scope - Rewrite string-to-vector<int>
 to use regex to parse malformed input - Remove dependency on sstream.

---
 src/read_input.cpp | 68 ++++++++++++++++++++++------------------------
 1 file changed, 32 insertions(+), 36 deletions(-)

diff --git a/src/read_input.cpp b/src/read_input.cpp
index 1c6744b..0fc4b58 100644
--- a/src/read_input.cpp
+++ b/src/read_input.cpp
@@ -1,54 +1,58 @@
 //TODO: Include C file IO header (stdio.h? Whatever it is)
 #include <iostream>
-#include <sstream>
 #include <fstream>
 #include <string>
 #include <vector>
 #include <regex>
 #include "graph.hpp"
 
-#define MAX_LINE_LEN 1024
+#define MAX_INT_LEN 16
 
-// Vector of regices
+// Vector of regices, in order of precedence. Earlier entries will be checked before later entries.
 std::vector<std::regex> patterns = {
-    //* A line starting with a % is a comment, and should be skipped
-    //* A blank line should be skipped
-    //* A line starting with `num_processes=` contains the number of processes
-    std::regex("^.*(num_processes)\\s*=\\s*(\\d+).*"),
-    //* A line starting with `num_resources=` contains the number of resources
-    std::regex("^.*(num_resources)\\s*=\\s*(\\d+)"),
-    //* A line containing comma-separated values should be returned as-is, for manual disassembly
-    std::regex("^([\\-0-9, ]+)")}; // matches comma-separated space-separated signed decimal integers
+   //* Rule 1: A line starting with a % is a comment, and should not be parsed
+   std::regex("^\\s*(%)"),
+   //* Rule 2: A line starting with `num_processes=` contains the number of processes
+   std::regex("^.*(num_processes)\\s*=\\s*(\\d+).*"),
+   //* Rule 3: A line starting with `num_resources=` contains the number of resources
+   std::regex("^.*(num_resources)\\s*=\\s*(\\d+)"),
+   //* Rule 4: A line containing only comma-separated values should be captured completely
+   std::regex("^([\\-0-9, ]+)") // matches comma-separated space-separated signed decimal integers
+};
 
 // convert comma-separated string s to vector<int>
 std::vector<int> stovi (const std::string &s);
 
 // TODO: Implement reading from a file
 void graph::read(std::string filename) {
-   printf("graph::read(%s)\n", filename.c_str());
 
    // Open file with name filename as read-only
    std::fstream f; f.open(filename, f.in);
-
    // TODO: Check for file IO errors (I might have a solution for that in another project)
-   std::string line; // Lines can be no more than 1KB in size, a sensible limitation
+
 
    while (!f.eof()) {
+      // acquire a line
+      std::string line;
       std::getline (f, line);
 
-      std::smatch res;
       // Iterate over each pattern, and grab the associated data
       for (auto pattern: patterns) {
+         std::smatch res;
          if (std::regex_search (line, res, pattern)) {
             // get the pattern type, value
             std::string type = res.format("$1"), value = res.format("$2");
-
             // Handle the pattern
-            //   If num_processes= matched, assign value to num_processes
+            //   Rule 1: If line is a comment, ignore it and move on
+            if (type == "%"); else
+
+            //   Rule 2: If num_processes= matched, assign value to num_processes
             if (type == "num_processes") { num_processes = std::stoi(value); } else
-            //   If num_resources= matched, assign value to num_resources
+
+            //   Rule 3: If num_resources= matched, assign value to num_resources
             if (type == "num_resources") { num_resources = std::stoi(value); } else
-            //   If this line is a comma-separated list of numbers,
+
+            //   Rule 4: If this line is a comma-separated list of numbers,
             //     and this is the first match, assign it to resource counts
             if (!resource_counts.size()) { resource_counts = stovi(type);    } else
             //     and this is a subsequent match, push it onto the matrix
@@ -64,24 +68,16 @@ void graph::read(std::string filename) {
    f.close();
    // TODO: Check for file IO errors (Shouldn't be any)
 
-   // print information about the graph
-   printf("np: %d\tnr: %d\n", num_processes, num_resources);
-   printf("resource_counts:\n"); for (auto e: resource_counts) printf("%d\t", e); printf("\n");
-   printf("matrix:\n"); for (auto x: matrix.data) {for (auto y: x) printf("%d\t", y); printf("\n");}
    return;
 }
 
 std::vector<int> stovi (const std::string &s) {
-   std::stringstream ss(s);
-   printf("%s\n", s.c_str());
-   size_t idx = 0;
-   std::vector<int> vi;
-   // reserve enough space for an entire string of one-character ints
-   vi.reserve((s.length()+1)/2);
-   while (!ss.eof()) {
-      char integer[16]; // "    -WXXXYYYZZZ,"
-      ss.getline(integer, 16, ',');
-      vi.push_back(atoi( (const char* ) &integer));
-   }
-   return vi;
-}
+   // Create the number classifier
+   std::regex breaker("[0-9]+");
+   std::sregex_token_iterator first{s.begin(), s.end(), breaker, 0}, last;
+   // Match the numbers
+   std::vector<int> res;
+   for (auto i = first; i != last; ++i) res.push_back(atoi(i->str().c_str()));
+   // give the numbers back
+   return res;
+}
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