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;
+    }
+
+}