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Diffstat (limited to 'src/backend/utils/adt/lztext.c')
| -rw-r--r-- | src/backend/utils/adt/lztext.c | 266 |
1 files changed, 266 insertions, 0 deletions
diff --git a/src/backend/utils/adt/lztext.c b/src/backend/utils/adt/lztext.c new file mode 100644 index 00000000000..49c37def91d --- /dev/null +++ b/src/backend/utils/adt/lztext.c @@ -0,0 +1,266 @@ +/* ---------- + * lztext.c - + * + * $Header: /cvsroot/pgsql/src/backend/utils/adt/Attic/lztext.c,v 1.1 1999/11/17 21:21:50 wieck Exp $ + * + * Text type with internal LZ compressed representation. Uses the + * standard PostgreSQL compression method. + * ---------- + */ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <math.h> +#include <errno.h> + +#include "postgres.h" +#include "utils/builtins.h" +#include "utils/palloc.h" +#include "utils/pg_lzcompress.h" + + +/* ---------- + * lztextin - + * + * Input function for datatype lztext + * ---------- + */ +lztext * +lztextin(char *str) +{ + lztext *result; + int32 rawsize; + lztext *tmp; + int tmp_size; + + /* ---------- + * Handle NULL + * ---------- + */ + if (str == NULL) + return NULL; + + /* ---------- + * Determine input size and eventually tuple size + * ---------- + */ + rawsize = strlen(str); + tmp_size = PGLZ_MAX_OUTPUT(rawsize); + + /* ---------- + * Allocate a temporary result and compress into it + * ---------- + */ + tmp = (lztext *) palloc(tmp_size); + pglz_compress(str, rawsize, tmp, NULL); + + /* ---------- + * If we miss less than x% bytes at the end of the temp value, + * so be it. Therefore we save a memcpy(). + * ---------- + */ + if (tmp_size - tmp->varsize < 256 || + tmp_size - tmp->varsize < tmp_size / 4) + { + result = tmp; + } else { + result = (lztext *) palloc(tmp->varsize); + memcpy(result, tmp, tmp->varsize); + pfree(tmp); + } + + return result; +} + + +/* ---------- + * lztextout - + * + * Output function for data type lztext + * ---------- + */ +char * +lztextout(lztext *lz) +{ + char *result; + + /* ---------- + * Handle NULL + * ---------- + */ + if (lz == NULL) + { + result = (char *) palloc(2); + result[0] = '-'; + result[1] = '\0'; + return result; + } + + /* ---------- + * Allocate the result string - the required size is remembered + * in the lztext header so we don't need a temporary buffer or + * have to diddle with realloc's. + * ---------- + */ + result = (char *) palloc(PGLZ_RAW_SIZE(lz) + 1); + + /* ---------- + * Decompress and add terminating ZERO + * ---------- + */ + pglz_decompress(lz, result); + result[lz->rawsize] = '\0'; + + /* ---------- + * Return the result + * ---------- + */ + return result; +} + + +/* ---------- + * lztextlen - + * + * Logical length of lztext field (it's the uncompressed size + * of the original data). + * ---------- + */ +int32 +lztextlen(lztext *lz) +{ + /* ---------- + * Handle NULL + * ---------- + */ + if (lz == NULL) + return 0; + + /* ---------- + * without multibyte support, it's the remembered rawsize + * ---------- + */ + return lz->rawsize; +} + + +/* ---------- + * lztextoctetlen - + * + * Physical length of lztext field (it's the compressed size + * plus the rawsize field). + * ---------- + */ +int32 +lztextoctetlen(lztext *lz) +{ + /* ---------- + * Handle NULL + * ---------- + */ + if (lz == NULL) + return 0; + + /* ---------- + * Return the varsize minus the VARSIZE field itself. + * ---------- + */ + return lz->varsize - sizeof(int32); +} + + +/* ---------- + * text_lztext - + * + * Convert text to lztext + * ---------- + */ +lztext * +text_lztext(text *txt) +{ + lztext *result; + int32 rawsize; + lztext *tmp; + int tmp_size; + char *str; + + /* ---------- + * Handle NULL + * ---------- + */ + if (txt == NULL) + return NULL; + + /* ---------- + * Determine input size and eventually tuple size + * ---------- + */ + rawsize = VARSIZE(txt) - VARHDRSZ; + str = VARDATA(txt); + tmp_size = PGLZ_MAX_OUTPUT(rawsize); + + /* ---------- + * Allocate a temporary result and compress into it + * ---------- + */ + tmp = (lztext *) palloc(tmp_size); + pglz_compress(str, rawsize, tmp, NULL); + + /* ---------- + * If we miss less than x% bytes at the end of the temp value, + * so be it. Therefore we save a memcpy(). + * ---------- + */ + if (tmp_size - tmp->varsize < 256 || + tmp_size - tmp->varsize < tmp_size / 4) + { + result = tmp; + } else { + result = (lztext *) palloc(tmp->varsize); + memcpy(result, tmp, tmp->varsize); + pfree(tmp); + } + + return result; + + +} + + +/* ---------- + * lztext_text - + * + * Convert lztext to text + * ---------- + */ +text * +lztext_text(lztext *lz) +{ + text *result; + + /* ---------- + * Handle NULL + * ---------- + */ + if (lz == NULL) + return NULL; + + /* ---------- + * Allocate and initialize the text result + * ---------- + */ + result = (text *) palloc(lz->rawsize + VARHDRSZ + 1); + VARSIZE(result) = lz->rawsize + VARHDRSZ; + + /* ---------- + * Decompress directly into the text data area. + * ---------- + */ + pglz_decompress(lz, VARDATA(result)); + VARDATA(result)[lz->rawsize] = 0; + + return result; +} + + |