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split: refactor suffix auto-widening and auto-width

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zhitkoff 2023-10-23 17:44:47 -04:00 committed by Sylvestre Ledru
parent 98ad01b1cc
commit 733359d48b
1 changed files with 75 additions and 56 deletions
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131
src/uu/split/src/split.rs
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@ -668,17 +668,38 @@ impl Strategy {
}
}
/// Parse the suffix type, start and length from the command-line arguments.
/// Determine if the output file names suffix is allowed to auto-widen,
/// i.e. go beyond suffix_length, when more output files need to be written into.
/// Suffix auto-widening rules are:
/// - OFF when suffix length N is specified
/// `-a N` or `--suffix-length=N`
/// - OFF when suffix start number N is specified using long option with value
/// Parse the suffix type, start and length from the command-line arguments
/// as well suffix length auto-widening and auto-width scenarios
///
/// Suffix auto-widening: Determine if the output file names suffix is allowed to dynamically auto-widen,
/// i.e. change (increase) suffix length dynamically as more files need to be written into.
/// Suffix length auto-widening rules are (in the order they are applied):
/// - ON by default
/// - OFF when suffix start N is specified via long option with a value
/// `--numeric-suffixes=N` or `--hex-suffixes=N`
/// - Exception to the above: ON with `-n`/`--number` option (N, K/N, l/N, l/K/N, r/N, r/K/N)
/// - OFF when suffix length N is specified, except for N=0 (see edge cases below)
/// `-a N` or `--suffix-length=N`
/// - OFF if suffix length is auto pre-calculated (auto-width)
///
/// Suffix auto-width: Determine if the the output file names suffix length should be automatically pre-calculated
/// based on number of files that need to written into, having number of files known upfront
/// Suffix length auto pre-calculation rules:
/// - Pre-calculate new suffix length when `-n`/`--number` option (N, K/N, l/N, l/K/N, r/N, r/K/N)
/// is used, where N is number of chunks = number of files to write into
/// and suffix start < N number of files
/// - ON when suffix start number is NOT specified
/// as in `split --numeric-suffixes=1 --number=r/100 file`
/// - Do NOT pre-calculate new suffix length otherwise, i.e. when
/// suffix start >= N number of files
/// as in `split --numeric-suffixes=100 --number=r/100 file`
/// OR when suffix length N is specified, except for N=0 (see edge cases below)
/// `-a N` or `--suffix-length=N`
///
/// Edge case:
/// - If suffix length is specified as 0 AND `-n`/`--number` option used specifying number of files:
/// set auto widening OFF AND auto pre-calculate required suffix length based on number of files needed
/// - If suffix length is specified as 0 in any other situation
/// keep auto widening ON and suffix length to default value
///
fn suffix_from(
matches: &ArgMatches,
strategy: &Strategy,
@ -701,18 +722,22 @@ fn suffix_from(
) {
(true, _, _, _) => {
suffix_type = SuffixType::Decimal;
let suffix_opt = matches.get_one::<String>(OPT_NUMERIC_SUFFIXES); // if option was specified, but without value - this will return None as there is no default value
if suffix_opt.is_some() {
(suffix_start, suffix_auto_widening) =
handle_long_suffix_opt(suffix_opt.unwrap(), strategy, false)?;
let opt = matches.get_one::<String>(OPT_NUMERIC_SUFFIXES); // if option was specified, but without value - this will return None as there is no default value
if opt.is_some() {
suffix_start = opt
.unwrap()
.parse::<usize>()
.map_err(|_| SettingsError::SuffixNotParsable(opt.unwrap().to_string()))?;
suffix_auto_widening = false;
}
}
(_, true, _, _) => {
suffix_type = SuffixType::Hexadecimal;
let suffix_opt = matches.get_one::<String>(OPT_HEX_SUFFIXES); // if option was specified, but without value - this will return None as there is no default value
if suffix_opt.is_some() {
(suffix_start, suffix_auto_widening) =
handle_long_suffix_opt(suffix_opt.unwrap(), strategy, true)?;
let opt = matches.get_one::<String>(OPT_HEX_SUFFIXES); // if option was specified, but without value - this will return None as there is no default value
if opt.is_some() {
suffix_start = usize::from_str_radix(opt.unwrap(), 16)
.map_err(|_| SettingsError::SuffixNotParsable(opt.unwrap().to_string()))?;
suffix_auto_widening = false;
}
}
(_, _, true, _) => suffix_type = SuffixType::Decimal, // short numeric suffix '-d'
@ -720,17 +745,46 @@ fn suffix_from(
_ => suffix_type = SuffixType::Alphabetic, // no numeric/hex suffix, using default alphabetic
}
// Get suffix length (could be coming from command line of default value)
let suffix_length_str = matches.get_one::<String>(OPT_SUFFIX_LENGTH).unwrap(); // safe to unwrap here as there is default value for this option
let suffix_length: usize = suffix_length_str
let mut suffix_length: usize = suffix_length_str
.parse()
.map_err(|_| SettingsError::SuffixNotParsable(suffix_length_str.to_string()))?;
// Override suffix_auto_widening if suffix length value came from command line
// and not from default value
if matches.value_source(OPT_SUFFIX_LENGTH) == Some(ValueSource::CommandLine) {
// Disable dynamic auto-widening if suffix length was specified in command line with value > 0
if matches.value_source(OPT_SUFFIX_LENGTH) == Some(ValueSource::CommandLine)
&& suffix_length > 0
{
suffix_auto_widening = false;
}
// Auto pre-calculate new suffix length (auto-width) if necessary
if let Strategy::Number(ref number_type) = strategy {
let chunks = number_type.num_chunks();
let required_suffix_length = ((suffix_start as u64 + chunks) as f64)
.log(suffix_type.radix() as f64)
.ceil() as usize;
if (suffix_start as u64) < chunks
&& !(matches.value_source(OPT_SUFFIX_LENGTH) == Some(ValueSource::CommandLine)
&& suffix_length > 0)
{
suffix_auto_widening = false;
suffix_length = required_suffix_length;
}
if suffix_length < required_suffix_length {
return Err(SettingsError::SuffixTooSmall(required_suffix_length));
}
}
// Check suffix length == 0 edge case
// If it is still 0 at this point, then auto-width pre-calculation did not apply
// So, set it to default value and keep auto-widening ON
if suffix_length == 0 {
suffix_length = OPT_DEFAULT_SUFFIX_LENGTH.parse().unwrap();
}
Ok((
suffix_type,
suffix_start,
@ -739,30 +793,6 @@ fn suffix_from(
))
}
/// Helper function to [`suffix_from`] function
fn handle_long_suffix_opt(
suffix_opt: &String,
strategy: &Strategy,
is_hex: bool,
) -> Result<(usize, bool), SettingsError> {
let suffix_start = if is_hex {
usize::from_str_radix(suffix_opt, 16)
.map_err(|_| SettingsError::SuffixNotParsable(suffix_opt.to_string()))?
} else {
suffix_opt
.parse::<usize>()
.map_err(|_| SettingsError::SuffixNotParsable(suffix_opt.to_string()))?
};
let suffix_auto_widening = if let Strategy::Number(ref number_type) = strategy {
let chunks = number_type.num_chunks();
(suffix_start as u64) < chunks
} else {
false
};
Ok((suffix_start, suffix_auto_widening))
}
/// Parameters that control how a file gets split.
///
/// You can convert an [`ArgMatches`] instance into a [`Settings`]
@ -877,17 +907,6 @@ impl Settings {
let (suffix_type, suffix_start, suffix_auto_widening, suffix_length) =
suffix_from(matches, &strategy)?;
if let Strategy::Number(ref number_type) = strategy {
let chunks = number_type.num_chunks();
if !suffix_auto_widening {
let required_suffix_length =
(chunks as f64).log(suffix_type.radix() as f64).ceil() as usize;
if suffix_length < required_suffix_length {
return Err(SettingsError::SuffixTooSmall(required_suffix_length));
}
}
}
// Make sure that separator is only one UTF8 character (if specified)
// defaults to '\n' - newline character
// If the same separator (the same value) was used multiple times - `split` should NOT fail