diff options
| -rw-r--r-- | buf.c | 71 | ||||
| -rw-r--r-- | stdlib/doc-syms.tl | 2 | ||||
| -rw-r--r-- | txr.1 | 46 |
3 files changed, 119 insertions, 0 deletions
@@ -35,6 +35,9 @@ #include <signal.h> #include <stdio.h> #include "config.h" +#if HAVE_ZLIB +#include <zlib.h> +#endif #include "lib.h" #include "gc.h" #include "itypes.h" @@ -1223,6 +1226,69 @@ static val uint_buf(val buf) return normalize(ubn); } +#if HAVE_ZLIB + +static val buf_compress(val buf, val level_opt) +{ + val self = lit("buf-compress"); + val level = default_arg(level_opt, num_fast(6)); + int lev = c_int(level, self); + struct buf *b = buf_handle(buf, self); + ucnum size = c_unum(b->len, self); + uLong bound = compressBound(size), zsize = bound; + mem_t *zdata = chk_malloc(bound); + + if (convert(uLong, size) != size) { + free(zdata); + uw_throwf(error_s, lit("~a: array size overflow"), self, nao); + } + + if (compress2(zdata, &zsize, b->data, size, lev) != Z_OK) { + free(zdata); + uw_throwf(error_s, lit("~a: compression failed"), self, nao); + } + + zdata = chk_realloc(zdata, zsize); + return make_owned_buf(unum(zsize), zdata); +} + +static val buf_decompress(val buf) +{ + val self = lit("buf-decompress"); + struct buf *b = buf_handle(buf, self); + ucnum zsize = c_unum(b->len, self); + uLong zsz10 = 10 * zsize; + uLong size = if3(zsz10 > zsize, zsz10, convert(uLong, -1)); + mem_t *data = chk_malloc(size); + + for (;;) { + switch (uncompress(data, &size, b->data, zsize)) { + case Z_OK: + data = chk_realloc(data, size); + return make_owned_buf(unum(size), data); + case Z_BUF_ERROR: + if (size == convert(uLong, -1)) + break; + if (size * 2 > size) + size = size * 2; + else if (size == convert(uLong, -1)) + break; + else + size = convert(uLong, -1); + data = chk_realloc(data, size); + continue; + default: + break; + } + break; + } + + free(data); + uw_throwf(error_s, lit("~a: decompression failed"), self, nao); +} + +#endif + void buf_init(void) { reg_fun(intern(lit("make-buf"), user_package), func_n3o(make_buf, 1)); @@ -1311,5 +1377,10 @@ void buf_init(void) reg_fun(intern(lit("int-buf"), user_package), func_n1(int_buf)); reg_fun(intern(lit("uint-buf"), user_package), func_n1(uint_buf)); +#if HAVE_ZLIB + reg_fun(intern(lit("buf-compress"), user_package), func_n2o(buf_compress, 1)); + reg_fun(intern(lit("buf-decompress"), user_package), func_n1(buf_decompress)); +#endif + fill_stream_ops(&buf_strm_ops); } diff --git a/stdlib/doc-syms.tl b/stdlib/doc-syms.tl index ea778779..b9956422 100644 --- a/stdlib/doc-syms.tl +++ b/stdlib/doc-syms.tl @@ -175,7 +175,9 @@ ("buf" "D-005E") ("buf-alloc-size" "N-013A3727") ("buf-carray" "N-0022F54E") + ("buf-compress" "N-02DB9DFB") ("buf-d" "D-0014") + ("buf-decompress" "N-02DB9DFB") ("buf-get-char" "N-03E9074A") ("buf-get-cptr" "N-00E90766") ("buf-get-double" "N-006C6EB9") @@ -28392,6 +28392,52 @@ is of integer type and, in the case of .codn buf-uint , nonnegative. +.coNP Functions @ buf-compress and @ buf-decompress +.synb +.mets (buf-compress < buf <> [ level ]) +.mets (buf-decompress << buf ) +.syne +.desc +The +.code buf-compress +and +.code buf-decompress +functions perform compression using the Deflate algorithm, via Zlib. +These functions are only available if \*(TX is built with Zlib support. +More specifically, +.code buf-compress +uses Zlib's +.code compress2 +function; therefore it can be expected to interoperate with other software +which uses the same function. + +The +.code buf-compress +function compresses the entire contents of +.meta buf +and returns new buffer with the compressed contents. The optional +.meta level +argument specifies the compression level as an integer, which defaults to 6. +Valid values range from 0 to 9: no compression, to maximum. + +The +.code buf-decompress +function reverses the +.code buf-compress +operation: it takes a compressed +.meta buf +and returns a buffer containing the original uncompressed data. + +The +.code buf-compress +function throws an error exception if the +.meta level +value is unacceptable to Zlib. The +.code buf-decompress +function throws an error exception if +.meta buf +doesn't contain a compressed image. + .SS* Structures \*(TX supports user-defined types in the form of structures. Structures |