create a macro to reduce the head strain of getting the width of a type

.github/workflows/publish.yaml

@@ -9,72 +9,26 @@ on:
         description: the tag to release for
         default: ""
 jobs:
-  compile:
-    runs-on: ubuntu-latest
+  release_bin:
+    runs-on: ${{matrix.os}}
+    strategy:
+      matrix:
+        os:
+          - ubuntu-24.04
+          - ubuntu-24.04-arm
     steps:
       - uses: actions/checkout@v4
       - run: make compile
-      - uses: actions/upload-artifact@v4
-        with:
-          name: bin
-          path: bin/
-  # release_deb:
-  #   runs-on: ubuntu-latest
-  #   needs: compile
-  #   steps:
-  #     - uses: actions/download-artifact@v4
-  #       with:
-  #         name: bin
-  #         path: ${{github.workspace}}/bin
-  #     - if: ${{!env.ACT}}
-  #       uses: softprops/action-gh-release@v2
-  #       with:
-  #         tag_name: ${{github.event.release.tag_name || github.event.inputs.release_tag}}
-  #         files: bin/coinflip
-  #         fail_on_unmatched_files: true
-  #       env:
-  #         GITHUB_TOKEN: ${{secrets.GITHUB_TOKEN}}
-  #     - if: ${{env.ACT}}
-  #       uses: actions/upload-artifact@v4
-  #       with:
-  #         path: bin/coinflip
-  # release_aur-bin:
-  #   runs-on: ubuntu-latest
-  #   needs: compile
-  #   steps:
-  #     - uses: actions/download-artifact@v4
-  #       with:
-  #         name: bin
-  #         path: ${{github.workspace}}/bin
-  #     - if: ${{!env.ACT}}
-  #       uses: softprops/action-gh-release@v2
-  #       with:
-  #         tag_name: ${{github.event.release.tag_name || github.event.inputs.release_tag}}
-  #         files: bin/coinflip
-  #         fail_on_unmatched_files: true
-  #       env:
-  #         GITHUB_TOKEN: ${{secrets.GITHUB_TOKEN}}
-  #     - if: ${{env.ACT}}
-  #       uses: actions/upload-artifact@v4
-  #       with:
-  #         path: bin/coinflip
-  release_bin:
-    runs-on: ubuntu-latest
-    needs: compile
-    steps:
-      - if: ${{!env.ACT}}
-        uses: actions/download-artifact@v4
-        with:
-          name: bin
-          path: ${{github.workspace}}/bin
+      - run: echo "FNAME=coinflip-$(uname -s)-$(uname -m)" >>"$GITHUB_ENV"
+      - run: mv bin/coinflip "$FNAME"
       - uses: softprops/action-gh-release@v2
         with:
           tag_name: ${{github.event.release.tag_name || github.event.inputs.release_tag}}
-          files: bin/coinflip
+          files: ${{env.FNAME}}
           fail_on_unmatched_files: true
         env:
           GITHUB_TOKEN: ${{secrets.GITHUB_TOKEN}}
       - if: ${{env.ACT}}
         uses: actions/upload-artifact@v4
         with:
-          path: bin/coinflip
+          path: ${{env.FNAME}}

.github/workflows/validate.yaml

@@ -1,14 +0,0 @@
-name: validate
-on:
-  pull_request:
-    branches:
-      - '**'
-  push:
-    branches:
-      - '**'
-jobs:
-  compile:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4
-      - run: make compile

makefile

@@ -1,6 +1,6 @@
-CC      := x86_64-linux-gnu-gcc
-CFLAGS  := -Wall -Wextra -Wpedantic -O2 -std=gnu17
-LDFLAGS :=
+CC      ?= cc
+CFLAGS  += -Wall -Wextra -Wpedantic -O3 -MD -MP -std=gnu99 -DNDEBUG
+LDFLAGS +=
 
 SRC = $(shell find src/ -name '*.c')
 OBJ := $(patsubst src/%,obj/%,$(SRC:.c=.o))
@@ -18,7 +18,7 @@ $(BIN): $(OBJ)
 # compile .o files (w/ .d files)
 obj/%.o: src/%.c
 	@mkdir -p $(@D)
-	$(CC) -c -MD -MP $(CFLAGS) -o $@ $<
+	$(CC) -c $(CFLAGS) -o $@ $<
 
 ifneq ($(shell which bear),)
 compile_commands.json: makefile

src/main.c

@@ -1,60 +1,91 @@
-#include <features.h>
-#if _POSIX_C_SOURCE >= 199309L
-# include <bits/time.h>
-# include <errno.h>
-# include <limits.h>
-# include <stdarg.h>
-# include <stdint.h>
-# include <stdio.h>
-# include <stdlib.h>
-# include <stdnoreturn.h>
-# include <time.h>
+#include <assert.h>
+#include <errno.h>
+#include <limits.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/random.h>
+#include <time.h>
 
-noreturn static inline void error(char* fmt, ...) {
-	va_list args;
-	va_start(args, fmt);
-	vfprintf(stderr, fmt, args);
-	va_end(args);
-	exit(1);
+#define error(ret, s, ...)                             \
+	do {                                               \
+		fprintf(stderr, (s)__VA_OPT__(, __VA_ARGS__)); \
+		exit(ret);                                     \
+	} while (0)
+
+#define WIDTHOF(x) (sizeof(x) * 8)
+
+typedef unsigned long long ull;
+
+typedef struct dynrdat {
+	size_t cap;
+	ull dat[];
+} dynrdat;
+
+dynrdat* rdat = NULL;
+
+static inline ull pow2_ceil(ull x) {
+	x -= !!x; // if x=0, remains 0; else x -= 1
+	return 1ULL << (WIDTHOF(ull) - __builtin_clzll(x | 1));
+}
+
+static void quit(void) {
+	free(rdat);
 }
 
 int main(int argc, char** argv) {
-	// set the seed to the number of seconds xor with nanoseconds
-	{
-		struct timespec ts;
-		clock_gettime(CLOCK_MONOTONIC, &ts);
-		srand((uint32_t)(ts.tv_nsec ^ ts.tv_sec)); // combine seconds and nanoseconds
-	}
+	// return the result if no input
+	if (argc <= 1) return printf("%s\n", (clock() & 1) ? "heads" : "tails");
+	atexit(quit);
 
-	// just print whether it's heads or tails
-	if (argc == 1) {
-		printf("%s\n", (rand() & 1) ? "heads" : "tails");
-		return 0;
-	}
-
-	// if we have input; perform coin flips for those times
-	for (uint32_t i = 1; i < (unsigned)argc; ++i) {
-		int n = 0;           // contains the random data
-		uint64_t headsc = 0; // amount of heads
-		uint64_t tailsc = 0; // amount of tails
-
-		// get the integer from the string, return 1 if an error occurred
+	// loop through arguments
+	for (unsigned i = 1; i < (unsigned)argc; ++i) {
+		// parse the argument
 		errno = 0;
-		long const c = strtol(argv[i], NULL, 10);
-		if (errno == EINVAL) error("syntax error for string: %s\n", argv[i]);
-		if (c < 1 || c > (LONG_MAX - 1)) error("count may only be in between 1 and %l. Received %l\n", LONG_MAX, c);
+		ull c = strtoull(argv[i], NULL, 10);
+		if (errno != 0) error(errno, "parse error for string: '%s'\n", argv[i]);
+
+		// acquire random data (compiler will optimize MOD and DIV away since they're both base-2 constant values)
+		int mod = c % WIDTHOF(ull); // get the remainder of the available random bits
+		c = c / WIDTHOF(ull);       // compute our "word count"
+
+		// dynamically scale the array to our needs, ensuring 2^n scaling
+		size_t cap = pow2_ceil(c + !!mod);
+		if (!rdat || rdat->cap < cap) {
+			void* ptr = realloc(rdat, sizeof(dynrdat) + sizeof(ull) * cap);
+			if (!ptr) error(1, "insufficient memory\n", );
+
+			rdat = ptr;
+			rdat->cap = cap;
+		}
+
+		// populate the array with random data
+		if (getrandom(rdat->dat, (c + !!mod) * sizeof(ull), 0) < 0)
+			error(1, "failed to acquire random data!\n", );
 
 		// perform for the input count
-		for (long j = 0; j < c; ++j) {
-			if (n == 0) n = rand();                // get a new random number if the random data ran out
-			(void)((n & 1) ? headsc++ : tailsc++); // increment the correct counter
-			n >>= 1;                               // shift the random integer right by 1
+		ull headsc = 0; // amount of heads
+		ull tailsc = 0; // amount of tails
+
+		// loop through how many full words there are available
+		ull* n = rdat->dat; // initialize the pointer to the start of our random data
+		for (; n < (rdat->dat + c); n++) {
+			int cnt = __builtin_popcountll(*n); // counts the set bits
+			headsc += cnt;
+			tailsc += WIDTHOF(ull) - cnt;
+		}
+
+		// if there is a remainder, use the last N to get this
+		if (mod) {
+			ull msk = (1 << mod) - 1; // get a mask with the set word size
+			int cnt = __builtin_popcountll(*n & msk);
+			headsc += cnt;
+			tailsc += mod - cnt;
 		}
 
 		// print the results of this cycle
-		printf("results:\n heads: %lu\n tails: %lu\n", headsc, tailsc);
+		printf("results:\n heads: %llu\n tails: %llu\n", headsc, tailsc);
 	}
+
+	return 0;
 }
-#else
-# error "platform unsupported"
-#endif