Function long_double_representation

numpy/core/setup_common.py:336–392

Given a binary dump as given by GNU od -b, look for long double representation.

(lines)

                     ['000'] * 8)

def long_double_representation(lines):
    """Given a binary dump as given by GNU od -b, look for long double
    representation."""

    # Read contains a list of 32 items, each item is a byte (in octal
    # representation, as a string). We 'slide' over the output until read is of
    # the form before_seq + content + after_sequence, where content is the long double
    # representation:
    #  - content is 12 bytes: 80 bits Intel representation
    #  - content is 16 bytes: 80 bits Intel representation (64 bits) or quad precision
    #  - content is 8 bytes: same as double (not implemented yet)
    read = [''] * 32
    saw = None
    for line in lines:
        # we skip the first word, as od -b output an index at the beginning of
        # each line
        for w in line.split()[1:]:
            read.pop(0)
            read.append(w)

            # If the end of read is equal to the after_sequence, read contains
            # the long double
            if read[-8:] == _AFTER_SEQ:
                saw = copy.copy(read)
                # if the content was 12 bytes, we only have 32 - 8 - 12 = 12
                # "before" bytes. In other words the first 4 "before" bytes went
                # past the sliding window.
                if read[:12] == _BEFORE_SEQ[4:]:
                    if read[12:-8] == _INTEL_EXTENDED_12B:
                        return 'INTEL_EXTENDED_12_BYTES_LE'
                    if read[12:-8] == _MOTOROLA_EXTENDED_12B:
                        return 'MOTOROLA_EXTENDED_12_BYTES_BE'
                # if the content was 16 bytes, we are left with 32-8-16 = 16
                # "before" bytes, so 8 went past the sliding window.
                elif read[:8] == _BEFORE_SEQ[8:]:
                    if read[8:-8] == _INTEL_EXTENDED_16B:
                        return 'INTEL_EXTENDED_16_BYTES_LE'
                    elif read[8:-8] == _IEEE_QUAD_PREC_BE:
                        return 'IEEE_QUAD_BE'
                    elif read[8:-8] == _IEEE_QUAD_PREC_LE:
                        return 'IEEE_QUAD_LE'
                    elif read[8:-8] == _IBM_DOUBLE_DOUBLE_LE:
                        return 'IBM_DOUBLE_DOUBLE_LE'
                    elif read[8:-8] == _IBM_DOUBLE_DOUBLE_BE:
                        return 'IBM_DOUBLE_DOUBLE_BE'
                # if the content was 8 bytes, left with 32-8-8 = 16 bytes
                elif read[:16] == _BEFORE_SEQ:
                    if read[16:-8] == _IEEE_DOUBLE_LE:
                        return 'IEEE_DOUBLE_LE'
                    elif read[16:-8] == _IEEE_DOUBLE_BE:
                        return 'IEEE_DOUBLE_BE'

    if saw is not None:
        raise ValueError("Unrecognized format (%s)" % saw)
    else:
        # We never detected the after_sequence
        raise ValueError("Could not lock sequences (%s)" % saw)