From 7113f02ae87482211aec5046f9ac46c3cc9ad017 Mon Sep 17 00:00:00 2001
From: Florian Jung <flo@thinkpad.(none)>
Date: Wed, 29 Dec 2010 16:55:25 +0100
Subject: Initial commit

---
 synth/readwave.cpp | 137 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 137 insertions(+)
 create mode 100644 synth/readwave.cpp

(limited to 'synth/readwave.cpp')

diff --git a/synth/readwave.cpp b/synth/readwave.cpp
new file mode 100644
index 0000000..08106ca
--- /dev/null
+++ b/synth/readwave.cpp
@@ -0,0 +1,137 @@
+#include <string>
+#include <cstring>
+
+#include "readwave.h"
+#include "util.h"
+#include "fixed.h"
+
+using namespace std;
+
+
+unsigned long int le_dword(unsigned char *b)
+{
+	return b[0]+256*b[1]+256*256*b[2]+256*256*256*b[3];
+}
+unsigned int le_word(unsigned char *b)
+{
+	return b[0]+256*b[1];
+}
+
+signed int le_sword(unsigned char *b)
+{
+	int x=le_word(b);
+	if (x & (1<<15) )
+		return - ((~(x-1))&0xFFFF);
+	else
+		return x;
+}
+
+void safe_fread(void* buf, int size, int n, FILE* f)
+{
+	int x=fread(buf,size,n,f);
+	
+	if (x!=n)
+		throw string("got end-of-file or error while reading from file");
+}
+
+void read_wave(const char *fn, custom_wave_t *result)
+{
+	try
+	{
+		int fmt=0, chans=0, sr=0, bits=0, bytes=0, filelen=0;
+		unsigned char buf[100];
+
+		FILE *f=fopen(fn,"r");
+		if (f==NULL)
+			throw string("could not open file");
+		
+		safe_fread(buf, 1, 12, f);
+		
+		if ((memcmp(buf,"RIFF",4)==0) && (memcmp(buf+8,"WAVE",4)==0))
+		{
+			filelen=le_dword(buf+4);
+			
+			while (!feof(f))
+			{
+				int chunklen;
+				
+				safe_fread(buf,1,8,f); //read chunk name and chunk size
+				
+				if (memcmp(buf,"fmt ",4)==0) //it's the fmt-chunk!
+				{
+					chunklen=le_dword(buf+4);
+					safe_fread(buf,1,chunklen,f);
+					
+					fmt=le_word(buf); //should be 1 for PCM
+					chans=le_word(buf+2); //number of channels
+					sr=le_dword(buf+4); //sampling rate
+					bits=le_word(buf+14); //bits per sample (8 or 16)
+					
+					if (fmt!=1)
+						throw string("invalid format, expected PCM");
+					
+					if ((bits!=8) && (bits!=16))
+						throw string("invalid format, expected 8 or 16 bits");
+					
+					if (chans==0)
+						throw string("invalid format, n_channels may not be zero");
+					
+					if (chans>=2)
+						output_note("NOTE: wavefile '"+string(fn)+"' is multichannel, using the left\nchannel and ignoring the rest...");			
+					
+					if (sr==0)
+						throw string("sampling rate may not be zero");
+						
+				}
+				else if (memcmp(buf,"data",4)==0) //it's the data-chunk!
+				{
+					chunklen=le_dword(buf+4);
+					
+					if (sr==0)
+						throw string("found data chunk before the fmt chunk");
+					
+					if (bits==8)
+						bytes=1;
+					else if (bits==16)
+						bytes=2;
+
+					int n_samples=chunklen/(bytes * chans);
+					
+					result->samp_rate=fixed_t(sr)<<SCALE;
+					result->wave_len=n_samples;
+					result->wave=new fixed_t[n_samples];
+					
+					double sample;
+					for (int i=0;i<n_samples;i++)
+					{
+						if (feof(f))
+							throw string("unexpected end-of-file");
+							
+						safe_fread(buf,1,bytes*chans,f);
+						if (bits==8)
+							sample=(buf[0]-128)/128.0;
+						else
+							sample=le_sword(buf)/double(1<<15);
+						
+						result->wave[i]=sample*ONE;
+					}
+					break;
+				}
+				else //unknown chunk, skip it
+				{
+					chunklen=le_dword(buf+4);
+					safe_fread(buf,1,chunklen,f);
+				}
+			}
+		}
+		else
+		{
+			//not a valid wave file!
+			throw string("not a valid RIFF-WAVE file");
+		}
+	}
+	catch (string err)
+	{
+		output_warning("ERROR: could not read '"+string(fn)+"': "+err+"\n  a default waveform (sine) will be loaded");
+	}
+}
-- 
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