1 files changed, 96 insertions, 0 deletions
diff --git a/lib/util.cc b/lib/util.cc
new file mode 100644
index 0000000..4bbe6f3
--- a/dev/null
+++ b/lib/util.cc
@@ -0,0 +1,96 @@
+#include <midillo/util.h>
+#include <midillo/exception.h>
+
+namespace midillo {
+
+    unsigned long read32(istream& s) {
+	unsigned long rv = 0;
+	for(int t=0;t<4;++t) {
+	    rv<<=8;
+	    rv|=0xFF&s.get();
+	    if(!s.good())
+		throw exception_input_error(CODEPOINT,"Input error");
+	}
+	return rv;
+    }
+
+    unsigned int read16(istream& s) {
+	unsigned int rv = 0;
+	for(int t=0;t<2;++t) {
+	    rv<<=8;
+	    rv|=0xFF&s.get();
+	    if(!s.good())
+		throw exception_input_error(CODEPOINT,"Input error");
+	}
+	return rv;
+    }
+
+    unsigned long readVL(istream& s) {
+	unsigned long rv=s.get();
+	if(!s.good())
+	    throw exception_input_error(CODEPOINT,"Error reading VLQ");
+	int b;
+	if(rv&0x80) {
+	    rv&=0x7F;
+	    do {
+		rv = (rv<<7)|( (b=s.get())&0x7F );
+		if(!s.good())
+		    throw exception_input_error(CODEPOINT,"Error reading VLQ");
+	    }while(b&0x80);
+	}
+	return rv;
+    }
+
+    void write32(ostream& s,unsigned long d) {
+	for(int t=3;t>=0;--t) {
+	    s.put(((const char*)&d)[t]);
+	    if(!s.good())
+		throw exception_output_error(CODEPOINT,"Output error");
+	}
+    }
+
+    void write16(ostream& s,unsigned int d) {
+	for(int t=1;t>=0;--t) {
+	    s.put(((const char*)&d)[t]);
+	    if(!s.good())
+		throw exception_output_error(CODEPOINT,"Output error");
+	}
+    }
+
+    void writeVL(ostream& s,unsigned long d) {
+	// TODO: I don't think this is perfectly written code
+	unsigned long tmp = d&0x7F;
+	while(d>>=7) {
+	    tmp<<=8;
+	    tmp |=((d&0x7F)|0x80);
+	}
+	for(;;) {
+	    s.put(tmp&0xFF);
+	    if(!s.good())
+		throw exception_output_error(CODEPOINT,"Error writing VLQ");
+	    if(tmp&0x80)
+		tmp>>=8;
+	    else
+		break;
+	}
+    }
+
+    unsigned long calcVLsize(unsigned long d) {
+	unsigned long rv = 0;
+	// TODO: imperfect code revisited
+	unsigned long tmp = d&0x7F;
+	while(d>>=7) {
+	    tmp<<=8;
+	    tmp |=((d&0x7F)|0x80);
+	}
+	for(;;) {
+	    ++rv;
+	    if(tmp&0x80)
+		tmp>>=8;
+	    else
+		break;
+	}
+	return rv;
+    }
+
+}