flac.exe : 32bit overflow when using "--skip" on large raw input files > 4 GiB, garbage audio returned

[SanLorenzo59]

I got garbage when encoding from a large raw audio file (> 7 GiB, 2 ch, 16 bit) and I tracked down this issue as a 32bit overflow.

See the output of a test case below:
--skip=1845437663 returns the same audio as
--skip=0771695839 .

1845437663-0771695839 is 2**30 which is equivalent to 4 GiB of raw audio data when using 32 bit per sample.

A self-made "FileCutter" written in C++ using long long 64bit aware counters gets what I want from the same large raw audio file.

I have seen this bug in flac-1.3.2-win and flac-1.4.3-win .

If this bug cannot be easily fixed then error action should be taken when --skip=<value> is above the limit.

G:\Music\Audacity\Joni Mitchell - Travelogue>regina
numeric digits 13; a=1845437663-0771695839 ; b=2**30 ; say a b a-b
^Z
1073741824 1073741824 0

G:\Music\Audacity\Joni Mitchell - Travelogue>

G:\Music\Audacity\Joni Mitchell - Travelogue>C:\tools\FLAC\flac-1.3.2-win\win64\flac.exe -f -o ".\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713a.BAD.flac"  --best --force-raw-format --endian=little --channels=2 --bps=16 --sample-rate=44100 --sign=signed  --skip=1845437663  --until=+21017806  ".\Joni Mitchell - Travelogue (5).raw"

G:\Music\Audacity\Joni Mitchell - Travelogue>C:\tools\FLAC\flac-1.3.2-win\win64\flac.exe -f -o ".\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713b.BAD.flac"  --best --force-raw-format --endian=little --channels=2 --bps=16 --sample-rate=44100 --sign=signed  --skip=0771695839  --until=+21017806  ".\Joni Mitchell - Travelogue (5).raw"

G:\Music\Audacity\Joni Mitchell - Travelogue>C:\tools\FLAC\flac-1.3.2-win\win64\flac.exe -d -f -o ".\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713a.BAD.raw" --force-raw-format --endian=little  --sign=signed   ".\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713a.BAD.flac"

G:\Music\Audacity\Joni Mitchell - Travelogue>C:\tools\FLAC\flac-1.3.2-win\win64\flac.exe -d -f -o ".\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713b.BAD.raw" --force-raw-format --endian=little  --sign=signed   ".\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713b.BAD.flac"

G:\Music\Audacity\Joni Mitchell - Travelogue>G:\Downloads\flac-1.4.3-win\flac-1.4.3-win\Win64\flac.exe -f -o ".\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713c.BAD.flac"  --best --force-raw-format --endian=little --channels=2 --bps=16 --sample-rate=44100 --sign=signed  --skip=1845437663  --until=+21017806  ".\Joni Mitchell - Travelogue (5).raw"

G:\Music\Audacity\Joni Mitchell - Travelogue>G:\Downloads\flac-1.4.3-win\flac-1.4.3-win\Win64\flac.exe -f -o ".\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713d.BAD.flac"  --best --force-raw-format --endian=little --channels=2 --bps=16 --sample-rate=44100 --sign=signed  --skip=0771695839  --until=+21017806  ".\Joni Mitchell - Travelogue (5).raw"

G:\Music\Audacity\Joni Mitchell - Travelogue>G:\Downloads\flac-1.4.3-win\flac-1.4.3-win\Win64\flac.exe -d -f -o ".\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713c.BAD.raw" --force-raw-format --endian=little  --sign=signed   ".\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713c.BAD.flac"

G:\Music\Audacity\Joni Mitchell - Travelogue>G:\Downloads\flac-1.4.3-win\flac-1.4.3-win\Win64\flac.exe -d -f -o ".\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713d.BAD.raw" --force-raw-format --endian=little  --sign=signed   ".\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713d.BAD.flac"

G:\Music\Audacity\Joni Mitchell - Travelogue>fc /b ".\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713a.BAD.flac" ".\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713b.BAD.flac"   | more
Comparing files .\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713a.BAD.flac and .\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713B.BAD.FLAC
FC: no differences encountered

G:\Music\Audacity\Joni Mitchell - Travelogue>fc /b ".\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713a.BAD.raw"  ".\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713b.BAD.raw"    | more
Comparing files .\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713a.BAD.raw and .\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713B.BAD.RAW
FC: no differences encountered

G:\Music\Audacity\Joni Mitchell - Travelogue>fc /b ".\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713c.BAD.flac" ".\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713d.BAD.flac"   | more
Comparing files .\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713c.BAD.flac and .\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713D.BAD.FLAC
FC: no differences encountered

G:\Music\Audacity\Joni Mitchell - Travelogue>fc /b ".\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713c.BAD.raw"  ".\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713d.BAD.raw"    | more
Comparing files .\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713c.BAD.raw and .\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713D.BAD.RAW
FC: no differences encountered

G:\Music\Audacity\Joni Mitchell - Travelogue>"C:\Program Files\Git\usr\bin\sha256sum.exe" ".\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713a.BAD.flac" ".\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713b.BAD.flac" ".\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713c.BAD.flac" ".\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713d.BAD.flac" ".\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713a.BAD.raw" ".\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713b.BAD.raw" ".\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713c.BAD.raw" ".\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713d.BAD.raw"
\80186417600636d67ca3d3979dcbccd8d6504d5df393f27ba85a8949a0efb47c *.\\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713a.BAD.flac
\80186417600636d67ca3d3979dcbccd8d6504d5df393f27ba85a8949a0efb47c *.\\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713b.BAD.flac
\cf75f3fde3cd60306d9f5ca8b7e362875ac4e475b3ddda7468f326b6110ba7c3 *.\\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713c.BAD.flac
\cf75f3fde3cd60306d9f5ca8b7e362875ac4e475b3ddda7468f326b6110ba7c3 *.\\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713d.BAD.flac
\5ae99ecfb2ee988bda4e183c49e6a06078af04a45262d759e0e127047182f4ba *.\\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713a.BAD.raw
\5ae99ecfb2ee988bda4e183c49e6a06078af04a45262d759e0e127047182f4ba *.\\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713b.BAD.raw
\5ae99ecfb2ee988bda4e183c49e6a06078af04a45262d759e0e127047182f4ba *.\\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713c.BAD.raw
\5ae99ecfb2ee988bda4e183c49e6a06078af04a45262d759e0e127047182f4ba *.\\__7-56-26206_0020961784_3E2A3C48_0015_0001845459713d.BAD.raw