[util] Add graph library

Add a library for drawing horizontal and vertical bar graphs (thanks to
@somospocos for contributing!)

util/graph.py

@@ -0,0 +1,111 @@
+MAX_PERCENTS = 100.
+
+class Bar(object):
+    """superclass"""
+    bars = None
+
+    def __init__(self, value):
+        """
+            Args:
+
+                value (float): value between 0. and 100. meaning percents
+        """
+        self.value = value
+
+class HBar(Bar):
+    """horizontal bar (1 char)"""
+    bars = [
+        u"\u2581",
+        u"\u2582",
+        u"\u2583",
+        u"\u2584",
+        u"\u2585",
+        u"\u2586",
+        u"\u2587",
+        u"\u2588"
+    ]
+
+    def __init__(self, value):
+        """
+            Args:
+
+                value (float): value between 0. and 100. meaning percents
+        """
+        super(HBar, self).__init__(value)
+        self.step = MAX_PERCENTS / len(HBar.bars)
+
+    def get_char(self):
+        """
+            Decide which char to draw
+
+            Return: str
+        """
+        for i in range(len(HBar.bars)):
+            left = i * self.step
+            right = (i + 1) * self.step
+            if left <= self.value < right:
+                return self.bars[i]
+        return self.bars[-1]
+
+def hbar(value):
+    """wrapper function"""
+    return HBar(value).get_char()
+
+
+class VBar(Bar):
+    """vertical bar (can be more than 1 char)"""
+    bars = [
+        u"\u258f",
+        u"\u258e",
+        u"\u258d",
+        u"\u258c",
+        u"\u258b",
+        u"\u258a",
+        u"\u2589",
+        u"\u2588"
+    ]
+
+    def __init__(self, value, width=1):
+        """
+            Args:
+
+                value (float): value between 0. and 100. meaning percents
+
+                width (int): width
+        """
+        super(VBar, self).__init__(value)
+        self.step = MAX_PERCENTS / (len(VBar.bars) * width)
+        self.width = width
+
+    def get_chars(self):
+        """
+            Decide which char to draw
+
+            Return: str
+        """
+        if self.value == 100:
+            return self.bars[-1] * self.width
+        if self.width == 1:
+            for i in range(len(VBar.bars)):
+                left = i * self.step
+                right = (i + 1) * self.step
+                if left <= self.value < right:
+                    return self.bars[i]
+        else:
+            full_parts = int(self.value // (self.step * len(Vbar.bars)))
+            remainder = self.value - full_parts * self.step * CHARS
+            empty_parts = self.width - full_parts
+            if remainder >= 0:
+                empty_parts -= 1
+            part_vbar = VBar(remainder * self.width)  # scale to width
+            chars = self.bars[-1] * full_parts
+            chars += part_vbar.get_chars()
+            chars += " " * empty_parts
+            return chars
+
+
+def vbar(value, width):
+    """wrapper function"""
+    return VBar(value, width).get_chars()
+
+# vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4