135 lines
3.6 KiB
Python
135 lines
3.6 KiB
Python
import math
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FILE_READ_CHUNK = 512 * 1024
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def chunk_sequence(sequence, chunk_length, allow_incomplete=True):
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'''
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Given a sequence, divide it into sequences of length `chunk_length`.
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allow_incomplete:
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If True, allow the final chunk to be shorter if the
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given sequence is not an exact multiple of `chunk_length`.
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If False, the incomplete chunk will be discarded.
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'''
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(complete, leftover) = divmod(len(sequence), chunk_length)
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if not allow_incomplete:
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leftover = 0
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chunk_count = complete + min(leftover, 1)
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chunks = []
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for x in range(chunk_count):
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left = chunk_length * x
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right = left + chunk_length
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chunks.append(sequence[left:right])
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return chunks
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def comma_split(s):
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'''
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Split the string apart by commas, discarding all extra whitespace and
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blank phrases.
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'''
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if s is None:
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return s
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s = s.replace(' ', ',')
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s = [x.strip() for x in s.split(',')]
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s = [x for x in s if x]
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return s
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def edit_params(original, modifications):
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'''
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Given a dictionary representing URL parameters,
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apply the modifications and return a URL parameter string.
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{'a':1, 'b':2}, {'b':3} => ?a=1&b=3
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'''
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new_params = original.copy()
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new_params.update(modifications)
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if not new_params:
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return ''
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new_params = ['%s=%s' % (k, v) for (k, v) in new_params.items() if v]
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new_params = '&'.join(new_params)
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if new_params:
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new_params = '?' + new_params
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return new_params
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def fit_into_bounds(image_width, image_height, frame_width, frame_height):
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'''
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Given the w+h of the image and the w+h of the frame,
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return new w+h that fits the image into the frame
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while maintaining the aspect ratio.
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'''
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ratio = min(frame_width/image_width, frame_height/image_height)
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new_width = int(image_width * ratio)
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new_height = int(image_height * ratio)
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return (new_width, new_height)
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def hms_to_seconds(hms):
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'''
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Convert hh:mm:ss string to an integer seconds.
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'''
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hms = hms.split(':')
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seconds = 0
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if len(hms) == 3:
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seconds += int(hms[0])*3600
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hms.pop(0)
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if len(hms) == 2:
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seconds += int(hms[0])*60
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hms.pop(0)
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if len(hms) == 1:
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seconds += int(hms[0])
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return seconds
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def is_xor(*args):
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'''
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Return True if and only if one arg is truthy.
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'''
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return [bool(a) for a in args].count(True) == 1
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def read_filebytes(filepath, range_min, range_max):
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'''
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Yield chunks of bytes from the file between the endpoints.
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'''
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range_span = range_max - range_min
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#print('read span', range_min, range_max, range_span)
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f = open(filepath, 'rb')
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f.seek(range_min)
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sent_amount = 0
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with f:
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while sent_amount < range_span:
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#print(sent_amount)
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chunk = f.read(FILE_READ_CHUNK)
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if len(chunk) == 0:
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break
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yield chunk
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sent_amount += len(chunk)
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def seconds_to_hms(seconds):
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'''
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Convert integer number of seconds to an hh:mm:ss string.
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Only the necessary fields are used.
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'''
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seconds = math.ceil(seconds)
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(minutes, seconds) = divmod(seconds, 60)
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(hours, minutes) = divmod(minutes, 60)
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parts = []
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if hours: parts.append(hours)
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if minutes: parts.append(minutes)
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parts.append(seconds)
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hms = ':'.join('%02d' % part for part in parts)
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return hms
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def truthystring(s):
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if isinstance(s, (bool, int)) or s is None:
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return s
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s = s.lower()
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if s in {'1', 'true', 't', 'yes', 'y', 'on'}:
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return True
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if s in {'null', 'none'}:
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return None
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return False
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