import errno
import fnmatch
import os
import sys

# Avoid "maximum recursion depth exceeded" errors
sys.setrecursionlimit(10000)

def clamp(v, eps = 0.000001):
    """Round values close to zero to zero."""
    if abs(v) < eps:
        return 0.0
    else:
        return v

def find_filenames_sub(path, pattern):
    try:
        for fn in os.listdir(path):
            for p in find_filenames_sub(os.path.join(path, fn), pattern):
                yield p
    except OSError, e:
        if e.errno != errno.ENOTDIR:
            raise
        if fnmatch.fnmatch(path, pattern):
            yield path

def find_filenames(path, pattern):
    try:
        for fn in os.listdir(path):
            for p in find_filenames_sub(os.path.join(path, fn), pattern):
                yield p
    except OSError, e:
        if e.errno != errno.ENOTDIR:
            raise
        # At the top level we don't require a pattern match.
        yield path

def find_files_or_stdin(paths, pattern):
    if not paths:
        yield None, sys.stdin
    else:
        for path in paths:
            for filename in find_filenames(path, pattern):
                f = open(filename)
                yield filename, f
                f.close()