From efcf811633c15c1ed6e42dec964483a72b247770 Mon Sep 17 00:00:00 2001
From: Karchnu <karchnu@karchnu.fr>
Date: Mon, 5 Dec 2022 03:31:47 +0100
Subject: [PATCH] Distort: add distortion to a WAV music input.

---
 c/distort.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)
 create mode 100644 c/distort.c

diff --git a/c/distort.c b/c/distort.c
new file mode 100644
index 0000000..d9a386a
--- /dev/null
+++ b/c/distort.c
@@ -0,0 +1,50 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#include <sndfile.h>
+
+#define BUFFER_LEN  1024
+
+int main(int argc, char **argv) {
+	int    distortionLevel;
+	SNDFILE *infile, *outfile;
+	SF_INFO sfinfo;
+	double buffer[BUFFER_LEN];
+
+	// Check for distortion level argument
+	if (argc < 2) {
+		printf("Usage: %s distortion_level\n", argv[0]);
+		return 1;
+	}
+	distortionLevel = atoi(argv[1]);
+
+	// Open standard input as input file
+	if (!(infile = sf_open_fd(0, SFM_READ, &sfinfo, 0))) {
+		printf("Error: could not open standard input\n");
+		return 1;
+	}
+
+	// Open standard output as output file
+	if (!(outfile = sf_open_fd(1, SFM_WRITE, &sfinfo, 0))) {
+		printf("Error: could not open standard output\n");
+		return 1;
+	}
+
+	// Read and process data
+	while (sf_read_double(infile, buffer, BUFFER_LEN) > 0) {
+		for (int i=0; i<BUFFER_LEN; i++) {
+			// Add distortion to the sample
+			buffer[i] = buffer[i] * (1.0 + (distortionLevel/100.0) * sin(2.0 * M_PI * buffer[i]));
+		}
+
+		// Write the processed sample to the output file
+		sf_write_double(outfile, buffer, BUFFER_LEN);
+	}
+
+	// Close files
+	sf_close(infile);
+	sf_close(outfile);
+
+	return 0;
+}