diff options
| -rw-r--r-- | NEWS | 47 |
1 files changed, 42 insertions, 5 deletions
@@ -10,17 +10,36 @@ Changes in 2.2.5 (since 2.2.4): [XXX TODO: Add more details to selected items below] -* Notable changes +* Notable improvements ** Greatly improved performance of bidirectional pipes. The performance of bidirectional pipes, as created using 'open-pipe' or -'open-pipe*' with OPEN_BOTH mode, has been improved by roughly 3 orders -of magnitude. +'open-pipe*' in OPEN_BOTH mode, has been greatly improved. When reading +large blocks of binary data from a bidirectional pipe, the maximum +bandwidth has been increased by a factor of ~10^3 in some cases. ** New 'get-bytevector-some!' I/O primitive. -** get-bytevector-{some,some!,n!} support suspendable I/O. +This new I/O primitive is similar to 'get-bytevector-some' from the +R6RS, except that it writes its data to a user-specified range of +indices in an existing bytevector. As a corollary, it is also now +possible to specify a maximum number of bytes to read. Note that +'get-bytevector-some', and now 'get-bytevector-some!', are unique among +Guile's I/O primitives in their support of efficient binary reads of +potentially large blocks while also allowing for short reads, to avoid +undesired blocking. Now these operations can be performed while also +avoiding heap-allocation. + +'get-bytevector-some!' is needed to efficiently implement the new +bidirectional pipes, which are built upon R6RS custom binary +input/output ports. + +** get-bytevector-{n!,some,some!} now support suspendable I/O. + +Scheme implementations of 'get-bytevector-n!', 'get-bytevector-some', +and 'get-bytevector-some!' have been added to (ice-9 suspendable-ports). +As a result, these I/O operations now support suspendable I/O. * Compiler improvements @@ -35,8 +54,26 @@ eval.go and psyntax-pp.go are now built before the rest of the .go files so that they are processed by a fast macro expander. This saves time when using parallel builds. -** put-u8: Always write a single byte, regardless of the port encoding. +** put-u8 now always writes a single byte, regardless of the port encoding. + +Previously, (put-u8 PORT OCTET) worked as expected only when writing to +binary ports, i.e. those with port encoding "ISO-8851-1". Strictly +speaking, this meets the requirements of the R6RS 'put-u8', which need +only support binary ports. However, Guile in fact allows binary I/O to +be performed on any port, and yet 'put-u8' behaved in a surprising way +with other port encodings: it would perform a _textual_ I/O operation, +writing the character with Unicode scalar value OCTET. Now, 'put-u8' +always writes a single byte with value OCTET, regardless of the port +encoding. + ** Optimize fixnum exact integer square roots. + +'exact-integer-sqrt' now avoids heap allocation when applied to a +fixnum. 'sqrt' also avoids heap allocation when applied to a fixnum +that's a perfect square. Fewer heap allocations are now required when +applying 'sqrt' to squares of exact rationals whose numerator or +denominator are fixnums. + ** scm_mkstrport: Optimize the POS -> BYTE_POS conversion. ** stexi->shtml: Add support for @i, @math, @tie and @dots. ** SRFI-19: Support ~N in string->date. |