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nixpkgs/lib/path/tests/generate.awk
2023-01-03 13:21:06 +01:00

65 lines
1.8 KiB
Awk

# Generate random path-like strings, separated by null characters.
#
# Invocation:
#
# awk -f ./generate.awk -v <variable>=<value> | tr '\0' '\n'
#
# Customizable variables (all default to 0):
# - seed: Deterministic random seed to use for generation
# - count: Number of paths to generate
# - extradotweight: Give extra weight to dots being generated
# - extraslashweight: Give extra weight to slashes being generated
# - extranullweight: Give extra weight to null being generated, making paths shorter
BEGIN {
# Random seed, passed explicitly for reproducibility
srand(seed)
# Don't include special characters below 32
minascii = 32
# Don't include DEL at 128
maxascii = 127
upperascii = maxascii - minascii
# add extra weight for ., in addition to the one weight from the ascii range
upperdot = upperascii + extradotweight
# add extra weight for /, in addition to the one weight from the ascii range
upperslash = upperdot + extraslashweight
# add extra weight for null, indicating the end of the string
# Must be at least 1 to have strings end at all
total = upperslash + 1 + extranullweight
# new=1 indicates that it's a new string
new=1
while (count > 0) {
# Random integer between [0, total)
value = int(rand() * total)
if (value < upperascii) {
# Ascii range
printf("%c", value + minascii)
new=0
} else if (value < upperdot) {
# Dot range
printf "."
new=0
} else if (value < upperslash) {
# If it's the start of a new path, only generate a / in 10% of cases
# This is always an invalid subpath, which is not a very interesting case
if (new && rand() > 0.1) continue
printf "/"
} else {
# Do not generate empty strings
if (new) continue
printf "\x00"
count--
new=1
}
}
}