1 files changed, 159 insertions, 0 deletions
diff --git a/src/cumsum.c b/src/cumsum.c
new file mode 100644
index 0000000..5648661
--- /dev/null
+++ b/src/cumsum.c
@@ -0,0 +1,159 @@
+/*
+ * 
+ */
+
+
+#include "cumsum.h"
+
+/*
+ * Global configuration variables. These are set based on command-line
+ * arguments, and read-only beyond that point.
+ */
+static bool ARG_FP_INPUT = false;
+static bool ARG_UINT_INPUT = false;
+static bool ARG_HELP = false;
+
+static int parse_options(int argc, char*const* argv) {
+  int arg_index = 0;
+  int arg;
+  bool error = false;
+
+  while ((arg = getopt(argc, argv, "frhu")) != -1) {
+    switch (arg) {
+      case 'f':
+        ARG_FP_INPUT = true;
+        break;
+      case 'u':
+        ARG_UINT_INPUT = true;
+      case 'h':
+        ARG_HELP = true;
+        break;
+      case '?':
+        if (isprint(optopt)) {
+          fprintf(stderr, "Unknown option `-%c`.\n", optopt);
+        } else {
+          fprintf(stderr, "Unknown option character `\\x%x`.\n", optopt);
+        }
+        error = true;
+        break;
+      default:
+        error = true;
+        break;
+    }
+  }
+
+  if (ARG_UINT_INPUT && ARG_FP_INPUT) {
+    fprintf(stderr, "Error: the -u and -f flags are mutually exclusive.\n");
+    error = true;
+  }
+
+  if (!error) {
+    arg_index = optind;
+  }
+
+  return arg_index;
+}
+
+static void help() {
+  fprintf(stderr, "Usage:\ncumsum [-f|-u] [filename]\n");
+}
+
+void print_sum(Number sum) {
+  if (ARG_FP_INPUT) {
+    fprintf(stdout, "%lf\n", sum.d);
+  } else if (ARG_UINT_INPUT) {
+    fprintf(stdout, "%ld\n", sum.u);
+  } else {
+    fprintf(stdout, "%ld\n", sum.i);
+  }
+}
+
+static int read_data_fp(FILE *file, Number *num) {
+  double val;
+  while (fscanf(file, "%lf ", &val) != EOF) {
+    num->d += val;
+  }
+
+  return 1;
+}
+
+static int read_data_int(FILE *file, Number *num) {
+  int64_t val;
+  while (fscanf(file, "%ld ", &val) != EOF) {
+    num->i += val;
+  }
+
+  return 1;
+}
+
+static int read_data_uint(FILE *file, Number *num) {
+  uint64_t val;
+  while (fscanf(file, "%ld ", &val) != EOF) {
+    num->u += val;
+  }
+
+  return 1;
+}
+
+static int process_data(FILE *file) {
+  int rc = 1;
+  
+  Number sum = {};
+
+  /* FIXME: this could probably use a type-based macro to collapse the 
+            if statements into a single macro call
+   */
+  if (ARG_FP_INPUT) {
+    rc = read_data_fp(file, &sum);
+  } else if (ARG_UINT_INPUT) {
+    rc = read_data_uint(file, &sum);
+  } else {
+    rc = read_data_int(file, &sum);
+  }
+
+  if (rc) {
+    print_sum(sum);
+  }
+
+process_data_end:
+  return rc;
+}
+
+
+int main(int argc, char **argv) {
+  int rc = EXIT_SUCCESS;
+  int file_index = 0;
+  if (!(file_index = parse_options(argc, argv))) {
+    help();
+    rc = EXIT_FAILURE;
+    goto program_exit;
+  }
+
+  /* if the -h argument is supplied, print usage and exit successfully */
+  if (ARG_HELP) {
+    help();
+    goto program_exit;
+  }
+
+  /* open the input file, if one is specified, otherwise default to stdin */
+  FILE *input_file;
+  if (file_index < argc && strcmp(argv[file_index], "-") != 0) {
+    if (!(input_file = fopen(argv[file_index], "r"))) {
+      fprintf(stderr, "Error: Unable to open input file %s\n", argv[file_index]);
+      rc = EXIT_FAILURE;
+      goto program_exit;
+    }
+  } else {
+    input_file = stdin;
+  }
+
+  if (!process_data(input_file)) {
+    rc = EXIT_FAILURE;
+  }
+
+close_file:
+  fclose(input_file);
+
+program_exit:
+  exit(rc);
+}