From e61fd4ac7414a52714c3288889cc754d2e11c4a8 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Mon, 10 Aug 2009 18:29:27 +0000
Subject: [PATCH] Support EEEE (scientific notation) in to_char().
Pavel Stehule, Brendan Jurd
---
doc/src/sgml/func.sgml | 17 ++-
src/backend/utils/adt/formatting.c | 188 ++++++++++++++++++++++++--
src/backend/utils/adt/numeric.c | 133 +++++++++++++++++-
src/include/utils/numeric.h | 7 +-
src/test/regress/expected/numeric.out | 15 ++
src/test/regress/sql/numeric.sql | 1 +
6 files changed, 347 insertions(+), 14 deletions(-)
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 4a890cb8b89..545ab495058 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.485 2009/08/10 16:10:19 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.486 2009/08/10 18:29:26 tgl Exp $ -->
<chapter id="functions">
<title>Functions and Operators</title>
@@ -5345,7 +5345,7 @@ SELECT SUBSTRING('XY1234Z', 'Y*?([0-9]{1,3})');
</row>
<row>
<entry><literal>EEEE</literal></entry>
- <entry>scientific notation (not implemented)</entry>
+ <entry>exponent for scientific notation</entry>
</row>
</tbody>
</tgroup>
@@ -5404,6 +5404,15 @@ SELECT SUBSTRING('XY1234Z', 'Y*?([0-9]{1,3})');
(e.g., <literal>99.9V99</literal> is not allowed).
</para>
</listitem>
+
+ <listitem>
+ <para>
+ <literal>EEEE</literal> (scientific notation) cannot be used in
+ combination with any of the other special formatting patterns or
+ modifiers, and must be at the end of the format string
+ (e.g., <literal>9.99EEEE</literal> is a valid pattern).
+ </para>
+ </listitem>
</itemizedlist>
</para>
@@ -5605,6 +5614,10 @@ SELECT SUBSTRING('XY1234Z', 'Y*?([0-9]{1,3})');
<entry><literal>to_char(12.45, '99V9')</literal></entry>
<entry><literal>' 125'</literal></entry>
</row>
+ <row>
+ <entry><literal>to_char(0.0004859, '9.99EEEE')</literal></entry>
+ <entry><literal>' 4.86e-04'</literal></entry>
+ </row>
</tbody>
</tgroup>
</table>
diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index 7dd1c1d1168..6c1b35fbe1e 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -1,7 +1,7 @@
/* -----------------------------------------------------------------------
* formatting.c
*
- * $PostgreSQL: pgsql/src/backend/utils/adt/formatting.c,v 1.159 2009/07/06 19:11:39 heikki Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/formatting.c,v 1.160 2009/08/10 18:29:26 tgl Exp $
*
*
* Portions Copyright (c) 1999-2009, PostgreSQL Global Development Group
@@ -335,6 +335,7 @@ typedef struct
#define NUM_F_MULTI (1 << 11)
#define NUM_F_PLUS_POST (1 << 12)
#define NUM_F_MINUS_POST (1 << 13)
+#define NUM_F_EEEE (1 << 14)
#define NUM_LSIGN_PRE (-1)
#define NUM_LSIGN_POST 1
@@ -355,6 +356,7 @@ typedef struct
#define IS_PLUS(_f) ((_f)->flag & NUM_F_PLUS)
#define IS_ROMAN(_f) ((_f)->flag & NUM_F_ROMAN)
#define IS_MULTI(_f) ((_f)->flag & NUM_F_MULTI)
+#define IS_EEEE(_f) ((_f)->flag & NUM_F_EEEE)
/* ----------
* Format picture cache
@@ -821,7 +823,7 @@ static const KeyWord NUM_keywords[] = {
{"B", 1, NUM_B}, /* B */
{"C", 1, NUM_C}, /* C */
{"D", 1, NUM_D}, /* D */
- {"E", 1, NUM_E}, /* E */
+ {"EEEE", 4, NUM_E}, /* E */
{"FM", 2, NUM_FM}, /* F */
{"G", 1, NUM_G}, /* G */
{"L", 1, NUM_L}, /* L */
@@ -837,7 +839,7 @@ static const KeyWord NUM_keywords[] = {
{"b", 1, NUM_B}, /* b */
{"c", 1, NUM_C}, /* c */
{"d", 1, NUM_D}, /* d */
- {"e", 1, NUM_E}, /* e */
+ {"eeee", 4, NUM_E}, /* e */
{"fm", 2, NUM_FM}, /* f */
{"g", 1, NUM_G}, /* g */
{"l", 1, NUM_L}, /* l */
@@ -1044,6 +1046,14 @@ NUMDesc_prepare(NUMDesc *num, FormatNode *n)
if (n->type != NODE_TYPE_ACTION)
return;
+ if (IS_EEEE(num) && n->key->id != NUM_E)
+ {
+ NUM_cache_remove(last_NUMCacheEntry);
+ ereport(ERROR,
+ (errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("\"EEEE\" must be the last pattern used")));
+ }
+
switch (n->key->id)
{
case NUM_9:
@@ -1217,10 +1227,25 @@ NUMDesc_prepare(NUMDesc *num, FormatNode *n)
break;
case NUM_E:
- NUM_cache_remove(last_NUMCacheEntry);
- ereport(ERROR,
- (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
- errmsg("\"E\" is not supported")));
+ if (IS_EEEE(num))
+ {
+ NUM_cache_remove(last_NUMCacheEntry);
+ ereport(ERROR,
+ (errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("cannot use \"EEEE\" twice")));
+ }
+ if (IS_BLANK(num) || IS_FILLMODE(num) || IS_LSIGN(num) ||
+ IS_BRACKET(num) || IS_MINUS(num) || IS_PLUS(num) ||
+ IS_ROMAN(num) || IS_MULTI(num))
+ {
+ NUM_cache_remove(last_NUMCacheEntry);
+ ereport(ERROR,
+ (errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("\"EEEE\" is incompatible with other formats"),
+ errdetail("\"EEEE\" may only be used together with digit and decimal point patterns.")));
+ }
+ num->flag |= NUM_F_EEEE;
+ break;
}
return;
@@ -4145,6 +4170,15 @@ NUM_processor(FormatNode *node, NUMDesc *Num, char *inout, char *number,
if (Np->Num->zero_start)
--Np->Num->zero_start;
+ if (IS_EEEE(Np->Num))
+ {
+ if (!Np->is_to_char)
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("\"EEEE\" not supported for input")));
+ return strcpy(inout, number);
+ }
+
/*
* Roman correction
*/
@@ -4153,7 +4187,7 @@ NUM_processor(FormatNode *node, NUMDesc *Num, char *inout, char *number,
if (!Np->is_to_char)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
- errmsg("\"RN\" not supported")));
+ errmsg("\"RN\" not supported for input")));
Np->Num->lsign = Np->Num->pre_lsign_num = Np->Num->post =
Np->Num->pre = Np->num_pre = Np->sign = 0;
@@ -4240,7 +4274,7 @@ NUM_processor(FormatNode *node, NUMDesc *Num, char *inout, char *number,
#ifdef DEBUG_TO_FROM_CHAR
elog(DEBUG_elog_output,
- "\n\tSIGN: '%c'\n\tNUM: '%s'\n\tPRE: %d\n\tPOST: %d\n\tNUM_COUNT: %d\n\tNUM_PRE: %d\n\tSIGN_WROTE: %s\n\tZERO: %s\n\tZERO_START: %d\n\tZERO_END: %d\n\tLAST_RELEVANT: %s\n\tBRACKET: %s\n\tPLUS: %s\n\tMINUS: %s\n\tFILLMODE: %s\n\tROMAN: %s",
+ "\n\tSIGN: '%c'\n\tNUM: '%s'\n\tPRE: %d\n\tPOST: %d\n\tNUM_COUNT: %d\n\tNUM_PRE: %d\n\tSIGN_WROTE: %s\n\tZERO: %s\n\tZERO_START: %d\n\tZERO_END: %d\n\tLAST_RELEVANT: %s\n\tBRACKET: %s\n\tPLUS: %s\n\tMINUS: %s\n\tFILLMODE: %s\n\tROMAN: %s\n\tEEEE: %s",
Np->sign,
Np->number,
Np->Num->pre,
@@ -4256,7 +4290,8 @@ NUM_processor(FormatNode *node, NUMDesc *Num, char *inout, char *number,
IS_PLUS(Np->Num) ? "Yes" : "No",
IS_MINUS(Np->Num) ? "Yes" : "No",
IS_FILLMODE(Np->Num) ? "Yes" : "No",
- IS_ROMAN(Np->Num) ? "Yes" : "No"
+ IS_ROMAN(Np->Num) ? "Yes" : "No",
+ IS_EEEE(Np->Num) ? "Yes" : "No"
);
#endif
@@ -4626,6 +4661,39 @@ numeric_to_char(PG_FUNCTION_ARGS)
int_to_roman(DatumGetInt32(DirectFunctionCall1(numeric_int4,
NumericGetDatum(x))));
}
+ else if (IS_EEEE(&Num))
+ {
+ orgnum = numeric_out_sci(value, Num.post);
+
+ /*
+ * numeric_out_sci() does not emit a sign for positive numbers. We
+ * need to add a space in this case so that positive and negative
+ * numbers are aligned. We also have to do the right thing for NaN.
+ */
+ if (strcmp(orgnum, "NaN") == 0)
+ {
+ /*
+ * Allow 6 characters for the leading sign, the decimal point, "e",
+ * the exponent's sign and two exponent digits.
+ */
+ numstr = (char *) palloc(Num.pre + Num.post + 7);
+ fill_str(numstr, '#', Num.pre + Num.post + 6);
+ *numstr = ' ';
+ *(numstr + Num.pre + 1) = '.';
+ }
+ else if (*orgnum != '-')
+ {
+ numstr = (char *) palloc(strlen(orgnum) + 2);
+ *numstr = ' ';
+ strcpy(numstr + 1, orgnum);
+ len = strlen(numstr);
+ }
+ else
+ {
+ numstr = orgnum;
+ len = strlen(orgnum);
+ }
+ }
else
{
Numeric val = value;
@@ -4707,6 +4775,23 @@ int4_to_char(PG_FUNCTION_ARGS)
*/
if (IS_ROMAN(&Num))
numstr = orgnum = int_to_roman(value);
+ else if (IS_EEEE(&Num))
+ {
+ /* we can do it easily because float8 won't lose any precision */
+ float8 val = (float8) value;
+
+ orgnum = (char *) palloc(MAXDOUBLEWIDTH + 1);
+ snprintf(orgnum, MAXDOUBLEWIDTH + 1, "%+.*e", Num.post, val);
+
+ /*
+ * Swap a leading positive sign for a space.
+ */
+ if (*orgnum == '+')
+ *orgnum = ' ';
+
+ len = strlen(orgnum);
+ numstr = orgnum;
+ }
else
{
if (IS_MULTI(&Num))
@@ -4785,6 +4870,33 @@ int8_to_char(PG_FUNCTION_ARGS)
numstr = orgnum = int_to_roman(DatumGetInt32(
DirectFunctionCall1(int84, Int64GetDatum(value))));
}
+ else if (IS_EEEE(&Num))
+ {
+ /* to avoid loss of precision, must go via numeric not float8 */
+ Numeric val;
+
+ val = DatumGetNumeric(DirectFunctionCall1(int8_numeric,
+ Int64GetDatum(value)));
+ orgnum = numeric_out_sci(val, Num.post);
+
+ /*
+ * numeric_out_sci() does not emit a sign for positive numbers. We
+ * need to add a space in this case so that positive and negative
+ * numbers are aligned. We don't have to worry about NaN here.
+ */
+ if (*orgnum != '-')
+ {
+ numstr = (char *) palloc(strlen(orgnum) + 2);
+ *numstr = ' ';
+ strcpy(numstr + 1, orgnum);
+ len = strlen(numstr);
+ }
+ else
+ {
+ numstr = orgnum;
+ len = strlen(orgnum);
+ }
+ }
else
{
if (IS_MULTI(&Num))
@@ -4859,6 +4971,34 @@ float4_to_char(PG_FUNCTION_ARGS)
if (IS_ROMAN(&Num))
numstr = orgnum = int_to_roman((int) rint(value));
+ else if (IS_EEEE(&Num))
+ {
+ numstr = orgnum = (char *) palloc(MAXDOUBLEWIDTH + 1);
+ if (isnan(value) || is_infinite(value))
+ {
+ /*
+ * Allow 6 characters for the leading sign, the decimal point, "e",
+ * the exponent's sign and two exponent digits.
+ */
+ numstr = (char *) palloc(Num.pre + Num.post + 7);
+ fill_str(numstr, '#', Num.pre + Num.post + 6);
+ *numstr = ' ';
+ *(numstr + Num.pre + 1) = '.';
+ }
+ else
+ {
+ snprintf(orgnum, MAXDOUBLEWIDTH + 1, "%+.*e", Num.post, value);
+
+ /*
+ * Swap a leading positive sign for a space.
+ */
+ if (*orgnum == '+')
+ *orgnum = ' ';
+
+ len = strlen(orgnum);
+ numstr = orgnum;
+ }
+ }
else
{
float4 val = value;
@@ -4935,6 +5075,34 @@ float8_to_char(PG_FUNCTION_ARGS)
if (IS_ROMAN(&Num))
numstr = orgnum = int_to_roman((int) rint(value));
+ else if (IS_EEEE(&Num))
+ {
+ numstr = orgnum = (char *) palloc(MAXDOUBLEWIDTH + 1);
+ if (isnan(value) || is_infinite(value))
+ {
+ /*
+ * Allow 6 characters for the leading sign, the decimal point, "e",
+ * the exponent's sign and two exponent digits.
+ */
+ numstr = (char *) palloc(Num.pre + Num.post + 7);
+ fill_str(numstr, '#', Num.pre + Num.post + 6);
+ *numstr = ' ';
+ *(numstr + Num.pre + 1) = '.';
+ }
+ else
+ {
+ snprintf(orgnum, MAXDOUBLEWIDTH + 1, "%+.*e", Num.post, value);
+
+ /*
+ * Swap a leading positive sign for a space.
+ */
+ if (*orgnum == '+')
+ *orgnum = ' ';
+
+ len = strlen(orgnum);
+ numstr = orgnum;
+ }
+ }
else
{
float8 val = value;
diff --git a/src/backend/utils/adt/numeric.c b/src/backend/utils/adt/numeric.c
index ba3721b12b3..29b00e08e00 100644
--- a/src/backend/utils/adt/numeric.c
+++ b/src/backend/utils/adt/numeric.c
@@ -14,7 +14,7 @@
* Copyright (c) 1998-2009, PostgreSQL Global Development Group
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/utils/adt/numeric.c,v 1.118 2009/06/11 14:49:03 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/numeric.c,v 1.119 2009/08/10 18:29:27 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -247,6 +247,7 @@ static const char *set_var_from_str(const char *str, const char *cp,
static void set_var_from_num(Numeric value, NumericVar *dest);
static void set_var_from_var(NumericVar *value, NumericVar *dest);
static char *get_str_from_var(NumericVar *var, int dscale);
+static char *get_str_from_var_sci(NumericVar *var, int rscale);
static Numeric make_result(NumericVar *var);
@@ -426,6 +427,32 @@ numeric_out(PG_FUNCTION_ARGS)
PG_RETURN_CSTRING(str);
}
+/*
+ * numeric_out_sci() -
+ *
+ * Output function for numeric data type in scientific notation.
+ */
+char *
+numeric_out_sci(Numeric num, int scale)
+{
+ NumericVar x;
+ char *str;
+
+ /*
+ * Handle NaN
+ */
+ if (NUMERIC_IS_NAN(num))
+ return pstrdup("NaN");
+
+ init_var(&x);
+ set_var_from_num(num, &x);
+
+ str = get_str_from_var_sci(&x, scale);
+
+ free_var(&x);
+ return str;
+}
+
/*
* numeric_recv - converts external binary format to numeric
*
@@ -3364,6 +3391,110 @@ get_str_from_var(NumericVar *var, int dscale)
return str;
}
+/*
+ * get_str_from_var_sci() -
+ *
+ * Convert a var to a normalised scientific notation text representation.
+ * This function does the heavy lifting for numeric_out_sci().
+ *
+ * This notation has the general form a * 10^b, where a is known as the
+ * "significand" and b is known as the "exponent".
+ *
+ * Because we can't do superscript in ASCII (and because we want to copy
+ * printf's behaviour) we display the exponent using E notation, with a
+ * minimum of two exponent digits.
+ *
+ * For example, the value 1234 could be output as 1.2e+03.
+ *
+ * We assume that the exponent can fit into an int32.
+ *
+ * rscale is the number of decimal digits desired after the decimal point in
+ * the output, negative values will be treated as meaning zero.
+ *
+ * CAUTION: var's contents may be modified by rounding!
+ *
+ * Returns a palloc'd string.
+ */
+static char *
+get_str_from_var_sci(NumericVar *var, int rscale)
+{
+ int32 exponent;
+ NumericVar denominator;
+ NumericVar significand;
+ int denom_scale;
+ size_t len;
+ char *str;
+ char *sig_out;
+
+ if (rscale < 0)
+ rscale = 0;
+
+ /*
+ * Determine the exponent of this number in normalised form.
+ *
+ * This is the exponent required to represent the number with only one
+ * significant digit before the decimal place.
+ */
+ if (var->ndigits > 0)
+ {
+ exponent = (var->weight + 1) * DEC_DIGITS;
+
+ /*
+ * Compensate for leading decimal zeroes in the first numeric digit by
+ * decrementing the exponent.
+ */
+ exponent -= DEC_DIGITS - (int) log10(var->digits[0]);
+ }
+ else
+ {
+ /*
+ * If var has no digits, then it must be zero.
+ *
+ * Zero doesn't technically have a meaningful exponent in normalised
+ * notation, but we just display the exponent as zero for consistency
+ * of output.
+ */
+ exponent = 0;
+ }
+
+ /*
+ * The denominator is set to 10 raised to the power of the exponent.
+ *
+ * We then divide var by the denominator to get the significand, rounding
+ * to rscale decimal digits in the process.
+ */
+ if (exponent < 0)
+ denom_scale = -exponent;
+ else
+ denom_scale = 0;
+
+ init_var(&denominator);
+ init_var(&significand);
+
+ int8_to_numericvar((int64) 10, &denominator);
+ power_var_int(&denominator, exponent, &denominator, denom_scale);
+ div_var(var, &denominator, &significand, rscale, true);
+ sig_out = get_str_from_var(&significand, rscale);
+
+ free_var(&denominator);
+ free_var(&significand);
+
+ /*
+ * Allocate space for the result.
+ *
+ * In addition to the significand, we need room for the exponent decoration
+ * ("e"), the sign of the exponent, up to 10 digits for the exponent
+ * itself, and of course the null terminator.
+ */
+ len = strlen(sig_out) + 13;
+ str = palloc(len);
+ snprintf(str, len, "%se%+03d", sig_out, exponent);
+
+ pfree(sig_out);
+
+ return str;
+}
+
/*
* make_result() -
diff --git a/src/include/utils/numeric.h b/src/include/utils/numeric.h
index 19452b54fa3..b1aa27d88dd 100644
--- a/src/include/utils/numeric.h
+++ b/src/include/utils/numeric.h
@@ -7,7 +7,7 @@
*
* Copyright (c) 1998-2009, PostgreSQL Global Development Group
*
- * $PostgreSQL: pgsql/src/include/utils/numeric.h,v 1.27 2009/01/01 17:24:02 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/utils/numeric.h,v 1.28 2009/08/10 18:29:27 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -84,4 +84,9 @@ typedef NumericData *Numeric;
#define PG_GETARG_NUMERIC_COPY(n) DatumGetNumericCopy(PG_GETARG_DATUM(n))
#define PG_RETURN_NUMERIC(x) return NumericGetDatum(x)
+/*
+ * Utility functions in numeric.c
+ */
+extern char *numeric_out_sci(Numeric num, int scale);
+
#endif /* _PG_NUMERIC_H_ */
diff --git a/src/test/regress/expected/numeric.out b/src/test/regress/expected/numeric.out
index a3b631aabe0..857e1d83198 100644
--- a/src/test/regress/expected/numeric.out
+++ b/src/test/regress/expected/numeric.out
@@ -1139,6 +1139,21 @@ SELECT '' AS to_char_22, to_char(val, 'FM9999999999999999.999999999999999') FROM
| -24926804.04504742
(10 rows)
+SELECT '' AS to_char_23, to_char(val, '9.999EEEE') FROM num_data;
+ to_char_23 | to_char
+------------+------------
+ | 0.000e+00
+ | 0.000e+00
+ | -3.434e+07
+ | 4.310e+00
+ | 7.799e+06
+ | 1.640e+04
+ | 9.390e+04
+ | -8.303e+07
+ | 7.488e+04
+ | -2.493e+07
+(10 rows)
+
-- TO_NUMBER()
--
SELECT '' AS to_number_1, to_number('-34,338,492', '99G999G999');
diff --git a/src/test/regress/sql/numeric.sql b/src/test/regress/sql/numeric.sql
index 9fd6bba31ee..8814bba486b 100644
--- a/src/test/regress/sql/numeric.sql
+++ b/src/test/regress/sql/numeric.sql
@@ -762,6 +762,7 @@ SELECT '' AS to_char_19, to_char(val, 'FMS 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 . 9 9
SELECT '' AS to_char_20, to_char(val, E'99999 "text" 9999 "9999" 999 "\\"text between quote marks\\"" 9999') FROM num_data;
SELECT '' AS to_char_21, to_char(val, '999999SG9999999999') FROM num_data;
SELECT '' AS to_char_22, to_char(val, 'FM9999999999999999.999999999999999') FROM num_data;
+SELECT '' AS to_char_23, to_char(val, '9.999EEEE') FROM num_data;
-- TO_NUMBER()
--
--
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