Author: Alex Gaynor <alex.gay...@gmail.com>
Branch:
Changeset: r69205:57010784af18
Date: 2014-02-18 10:33 -0800
http://bitbucket.org/pypy/pypy/changeset/57010784af18/
Log: Merged in jiaaro/pypy (pull request #204)
Implement most audioop functions
diff --git a/lib_pypy/audioop.py b/lib_pypy/audioop.py
--- a/lib_pypy/audioop.py
+++ b/lib_pypy/audioop.py
@@ -1,14 +1,20 @@
-
import struct
+import math
+from fractions import gcd
+from ctypes import create_string_buffer
class error(Exception):
pass
+# this module redefines the names of some builtins that are used
+max_ = max
+
+
def _check_size(size):
if size != 1 and size != 2 and size != 4:
- raise error("Size should be 1, 2 or 4")
+ raise error("Size should be 1, 2 or 4")
def _check_params(length, size):
@@ -17,13 +23,517 @@
raise error("not a whole number of frames")
+def _sample_count(cp, size):
+ return len(cp) / size
+
+
+def _get_samples(cp, size, signed=True):
+ for i in range(_sample_count(cp, size)):
+ yield _get_sample(cp, size, i, signed)
+
+
+def _struct_format(size, signed):
+ if size == 1:
+ return "b" if signed else "B"
+ elif size == 2:
+ return "h" if signed else "H"
+ elif size == 4:
+ return "i" if signed else "I"
+
+
+def _get_sample(cp, size, i, signed=True):
+ fmt = _struct_format(size, signed)
+ start = i * size
+ end = start + size
+ return struct.unpack_from(fmt, buffer(cp)[start:end])[0]
+
+
+def _put_sample(cp, size, i, val, signed=True):
+ fmt = _struct_format(size, signed)
+ struct.pack_into(fmt, cp, i * size, val)
+
+
+def _get_maxval(size, signed=True):
+ if signed and size == 1: return 0x7f
+ elif size == 1: return 0xff
+ elif signed and size == 2: return 0x7fff
+ elif size == 2: return 0xffff
+ elif signed and size == 4: return 0x7fffffff
+ elif size == 4: return 0xffffffff
+
+
+def _get_minval(size, signed=True):
+ if not signed: return 0
+ elif size == 1: return -0x80
+ elif size == 2: return -0x8000
+ elif size == 4: return -0x80000000
+
+
+def _get_clipfn(size, signed=True):
+ maxval = _get_maxval(size, signed)
+ minval = _get_minval(size, signed)
+ return lambda val: max_(min(val, maxval), minval)
+
+
+def _overflow(val, size, signed=True):
+ minval = _get_minval(size, signed)
+ maxval = _get_maxval(size, signed)
+ if minval <= val <= maxval:
+ return val
+
+ bits = size * 8
+ if signed:
+ offset = 2**(bits-1)
+ return ((val + offset) % (2**bits)) - offset
+ else:
+ return val % (2**bits)
+
+
def getsample(cp, size, i):
_check_params(len(cp), size)
if not (0 <= i < len(cp) / size):
raise error("Index out of range")
- if size == 1:
- return struct.unpack_from("B", buffer(cp)[i:])[0]
- elif size == 2:
- return struct.unpack_from("H", buffer(cp)[i * 2:])[0]
- elif size == 4:
- return struct.unpack_from("I", buffer(cp)[i * 4:])[0]
+ return _get_sample(cp, size, i)
+
+
+def max(cp, size):
+ _check_params(len(cp), size)
+
+ if len(cp) == 0:
+ return 0
+
+ return max_(abs(sample) for sample in _get_samples(cp, size))
+
+
+def minmax(cp, size):
+ _check_params(len(cp), size)
+
+ max_sample, min_sample = 0, 0
+ for sample in _get_samples(cp, size):
+ if sample > max_sample:
+ max_sample = sample
+ if sample < min_sample:
+ min_sample = sample
+
+ return min_sample, max_sample
+
+
+def avg(cp, size):
+ _check_params(len(cp), size)
+ sample_count = _sample_count(cp, size)
+ if sample_count == 0:
+ return 0
+ return sum(_get_samples(cp, size)) / sample_count
+
+
+def rms(cp, size):
+ _check_params(len(cp), size)
+
+ sample_count = _sample_count(cp, size)
+ if sample_count == 0:
+ return 0
+
+ sum_squares = sum(sample**2 for sample in _get_samples(cp, size))
+ return int(math.sqrt(sum_squares / sample_count))
+
+
+def _sum2(cp1, cp2, length):
+ size = 2
+ total = 0
+ for i in range(length):
+ total += getsample(cp1, size, i) * getsample(cp2, size, i)
+ return total
+
+
+def findfit(cp1, cp2):
+ size = 2
+
+ if len(cp1) % 2 != 0 or len(cp2) % 2 != 0:
+ raise error("Strings should be even-sized")
+
+ if len(cp1) < len(cp2):
+ raise error("First sample should be longer")
+
+ len1 = _sample_count(cp1, size)
+ len2 = _sample_count(cp2, size)
+
+ sum_ri_2 = _sum2(cp2, cp2, len2)
+ sum_aij_2 = _sum2(cp1, cp1, len2)
+ sum_aij_ri = _sum2(cp1, cp2, len2)
+
+ result = (sum_ri_2 * sum_aij_2 - sum_aij_ri * sum_aij_ri) / sum_aij_2
+
+ best_result = result
+ best_i = 0
+
+ for i in range(1, len1 - len2 + 1):
+ aj_m1 = _get_sample(cp1, size, i - 1)
+ aj_lm1 = _get_sample(cp1, size, i + len2 - 1)
+
+ sum_aij_2 += aj_lm1**2 - aj_m1**2
+ sum_aij_ri = _sum2(buffer(cp1)[i*size:], cp2, len2)
+
+ result = (sum_ri_2 * sum_aij_2 - sum_aij_ri * sum_aij_ri) / sum_aij_2
+
+ if result < best_result:
+ best_result = result
+ best_i = i
+
+ factor = _sum2(buffer(cp1)[best_i*size:], cp2, len2) / sum_ri_2
+
+ return best_i, factor
+
+
+def findfactor(cp1, cp2):
+ size = 2
+
+ if len(cp1) % 2 != 0:
+ raise error("Strings should be even-sized")
+
+ if len(cp1) != len(cp2):
+ raise error("Samples should be same size")
+
+ sample_count = _sample_count(cp1, size)
+
+ sum_ri_2 = _sum2(cp2, cp2, sample_count)
+ sum_aij_ri = _sum2(cp1, cp2, sample_count)
+
+ return sum_aij_ri / sum_ri_2
+
+
+def findmax(cp, len2):
+ size = 2
+ sample_count = _sample_count(cp, size)
+
+ if len(cp) % 2 != 0:
+ raise error("Strings should be even-sized")
+
+ if len2 < 0 or sample_count < len2:
+ raise error("Input sample should be longer")
+
+ if sample_count == 0:
+ return 0
+
+ result = _sum2(cp, cp, len2)
+ best_result = result
+ best_i = 0
+
+ for i in range(1, sample_count - len2 + 1):
+ sample_leaving_window = getsample(cp, size, i - 1)
+ sample_entering_window = getsample(cp, size, i + len2 - 1)
+
+ result -= sample_leaving_window**2
+ result += sample_entering_window**2
+
+ if result > best_result:
+ best_result = result
+ best_i = i
+
+ return best_i
+
+
+def avgpp(cp, size):
+ _check_params(len(cp), size)
+ sample_count = _sample_count(cp, size)
+
+ prevextremevalid = False
+ avg = 0
+ nextreme = 0
+
+ prevval = getsample(cp, size, 0)
+ val = getsample(cp, size, 1)
+
+ prevdiff = val - prevval
+
+ for i in range(1, sample_count):
+ val = getsample(cp, size, i)
+ diff = val - prevval
+
+ if diff * prevdiff < 0:
+ if prevextremevalid:
+ avg += abs(prevval - prevextreme)
+ nextreme += 1
+
+ prevextremevalid = True
+ prevextreme = prevval
+
+ prevval = val
+ if diff != 0:
+ prevdiff = diff
+
+ if nextreme == 0:
+ return 0
+
+ return avg / nextreme
+
+
+def maxpp(cp, size):
+ _check_params(len(cp), size)
+ sample_count = _sample_count(cp, size)
+
+ prevextremevalid = False
+ max = 0
+
+ prevval = getsample(cp, size, 0)
+ val = getsample(cp, size, 1)
+
+ prevdiff = val - prevval
+
+ for i in range(1, sample_count):
+ val = getsample(cp, size, i)
+ diff = val - prevval
+
+ if diff * prevdiff < 0:
+ if prevextremevalid:
+ extremediff = abs(prevval - prevextreme)
+ if extremediff > max:
+ max = extremediff
+ prevextremevalid = True
+ prevextreme = prevval
+
+ prevval = val
+ if diff != 0:
+ prevdiff = diff
+
+ return max
+
+
+def cross(cp, size):
+ _check_params(len(cp), size)
+
+ crossings = 0
+ last_sample = 0
+ for sample in _get_samples(cp, size):
+ if sample <= 0 < last_sample or sample >= 0 > last_sample:
+ crossings += 1
+ last_sample = sample
+
+ return crossings
+
+
+def mul(cp, size, factor):
+ _check_params(len(cp), size)
+ clip = _get_clipfn(size)
+
+ result = create_string_buffer(len(cp))
+
+ for i, sample in enumerate(_get_samples(cp, size)):
+ sample = clip(int(sample * factor))
+ _put_sample(result, size, i, sample)
+
+ return result.raw
+
+
+def tomono(cp, size, fac1, fac2):
+ _check_params(len(cp), size)
+ clip = _get_clipfn(size)
+
+ sample_count = _sample_count(cp, size)
+
+ result = create_string_buffer(len(cp) / 2)
+
+ for i in range(0, sample_count, 2):
+ l_sample = getsample(cp, size, i)
+ r_sample = getsample(cp, size, i + 1)
+
+ sample = (l_sample * fac1) + (r_sample * fac2)
+ sample = clip(sample)
+
+ _put_sample(result, size, i / 2, sample)
+
+ return result.raw
+
+
+def tostereo(cp, size, fac1, fac2):
+ _check_params(len(cp), size)
+
+ sample_count = _sample_count(cp, size)
+
+ result = create_string_buffer(len(cp) * 2)
+ clip = _get_clipfn(size)
+
+ for i in range(sample_count):
+ sample = _get_sample(cp, size, i)
+
+ l_sample = clip(sample * fac1)
+ r_sample = clip(sample * fac2)
+
+ _put_sample(result, size, i * 2, l_sample)
+ _put_sample(result, size, i * 2 + 1, r_sample)
+
+ return result.raw
+
+
+def add(cp1, cp2, size):
+ _check_params(len(cp1), size)
+ maxval = _get_maxval(size)
+
+ if len(cp1) != len(cp2):
+ raise error("Lengths should be the same")
+
+ clip = _get_clipfn(size)
+ sample_count = _sample_count(cp1, size)
+ result = create_string_buffer(len(cp1))
+
+ for i in range(sample_count):
+ sample1 = getsample(cp1, size, i)
+ sample2 = getsample(cp2, size, i)
+
+ sample = clip(sample1 + sample2)
+
+ _put_sample(result, size, i, sample)
+
+ return result.raw
+
+
+def bias(cp, size, bias):
+ _check_params(len(cp), size)
+
+ result = create_string_buffer(len(cp))
+
+ for i, sample in enumerate(_get_samples(cp, size)):
+ sample = _overflow(sample + bias, size)
+ _put_sample(result, size, i, sample)
+
+ return result.raw
+
+
+def reverse(cp, size):
+ _check_params(len(cp), size)
+ sample_count = _sample_count(cp, size)
+
+ result = create_string_buffer(len(cp))
+ for i, sample in enumerate(_get_samples(cp, size)):
+ _put_sample(result, size, sample_count - i - 1, sample)
+
+ return result.raw
+
+
+def lin2lin(cp, size, size2):
+ _check_params(len(cp), size)
+ _check_size(size2)
+
+ if size == size2:
+ return cp
+
+ new_len = (len(cp) / size) * size2
+
+ result = create_string_buffer(new_len)
+
+ for i in range(_sample_count(cp, size)):
+ sample = _get_sample(cp, size, i)
+ if size < size2:
+ sample = sample << (4 * size2 / size)
+ elif size > size2:
+ sample = sample >> (4 * size / size2)
+
+ sample = _overflow(sample, size2)
+
+ _put_sample(result, size2, i, sample)
+
+ return result.raw
+
+
+def ratecv(cp, size, nchannels, inrate, outrate, state, weightA=1, weightB=0):
+ _check_params(len(cp), size)
+ if nchannels < 1:
+ raise error("# of channels should be >= 1")
+
+ bytes_per_frame = size * nchannels
+ frame_count = len(cp) / bytes_per_frame
+
+ if bytes_per_frame / nchannels != size:
+ raise OverflowError("width * nchannels too big for a C int")
+
+ if weightA < 1 or weightB < 0:
+ raise error("weightA should be >= 1, weightB should be >= 0")
+
+ if len(cp) % bytes_per_frame != 0:
+ raise error("not a whole number of frames")
+
+ if inrate <= 0 or outrate <= 0:
+ raise error("sampling rate not > 0")
+
+ d = gcd(inrate, outrate)
+ inrate /= d
+ outrate /= d
+
+ prev_i = [0] * nchannels
+ cur_i = [0] * nchannels
+
+ if state is None:
+ d = -outrate
+ else:
+ d, samps = state
+
+ if len(samps) != nchannels:
+ raise error("illegal state argument")
+
+ prev_i, cur_i = zip(*samps)
+ prev_i, cur_i = list(prev_i), list(cur_i)
+
+ q = frame_count / inrate
+ ceiling = (q + 1) * outrate
+ nbytes = ceiling * bytes_per_frame
+
+ result = create_string_buffer(nbytes)
+
+ samples = _get_samples(cp, size)
+ out_i = 0
+ while True:
+ while d < 0:
+ if frame_count == 0:
+ samps = zip(prev_i, cur_i)
+ retval = result.raw
+
+ # slice off extra bytes
+ trim_index = (out_i * bytes_per_frame) - len(retval)
+ retval = buffer(retval)[:trim_index]
+
+ return (retval, (d, tuple(samps)))
+
+ for chan in range(nchannels):
+ prev_i[chan] = cur_i[chan]
+ cur_i[chan] = samples.next()
+
+ cur_i[chan] = (
+ (weightA * cur_i[chan] + weightB * prev_i[chan])
+ / (weightA + weightB)
+ )
+
+ frame_count -= 1
+ d += outrate
+
+ while d >= 0:
+ for chan in range(nchannels):
+ cur_o = (
+ (prev_i[chan] * d + cur_i[chan] * (outrate - d))
+ / outrate
+ )
+ _put_sample(result, size, out_i, _overflow(cur_o, size))
+ out_i += 1
+ d -= inrate
+
+
+def lin2ulaw(cp, size):
+ raise NotImplementedError()
+
+
+def ulaw2lin(cp, size):
+ raise NotImplementedError()
+
+
+def lin2alaw(cp, size):
+ raise NotImplementedError()
+
+
+def alaw2lin(cp, size):
+ raise NotImplementedError()
+
+
+def lin2adpcm(cp, size, state):
+ raise NotImplementedError()
+
+
+def adpcm2lin(cp, size, state):
+ raise NotImplementedError()
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