Add bytea datatype to ECPG.

So far ECPG programs had to treat binary data for bytea column as 'char' type.
But this meant converting from/to escaped format with PQunescapeBytea/
PQescapeBytea() and therefore forcing users to add unnecessary code and cost
for the conversion in runtime. By adding a dedicated datatype for bytea most of
this special handling is no longer needed.

Author: Matsumura-san ("Matsumura, Ryo" <matsumura.ryo@jp.fujitsu.com>)

Discussion: https://postgr.es/m/flat/03040DFF97E6E54E88D3BFEE5F5480F737A141F9@G01JPEXMBYT04

1 files changed, 129 insertions, 0 deletions

diff --git a/src/interfaces/ecpg/ecpglib/data.c b/src/interfaces/ecpg/ecpglib/data.c
index 424b5ae5d5..81f94cc12b 100644
--- a/src/interfaces/ecpg/ecpglib/data.c
+++ b/src/interfaces/ecpg/ecpglib/data.c
@@ -122,6 +122,86 @@ check_special_value(char *ptr, double *retval, char **endptr)
 	return false;
 }
 
+/* imported from src/backend/utils/adt/encode.c */
+
+unsigned
+ecpg_hex_enc_len(unsigned srclen)
+{
+	return srclen << 1;
+}
+
+unsigned
+ecpg_hex_dec_len(unsigned srclen)
+{
+	return srclen >> 1;
+}
+
+static inline char
+get_hex(char c)
+{
+	static const int8 hexlookup[128] = {
+		-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+		-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+		-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+		0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1,
+		-1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+		-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+		-1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+		-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	};
+	int			res = -1;
+
+	if (c > 0 && c < 127)
+		res = hexlookup[(unsigned char) c];
+
+	return (char) res;
+}
+
+static unsigned
+hex_decode(const char *src, unsigned len, char *dst)
+{
+	const char *s,
+			   *srcend;
+	char		v1,
+				v2,
+			   *p;
+
+	srcend = src + len;
+	s = src;
+	p = dst;
+	while (s < srcend)
+	{
+		if (*s == ' ' || *s == '\n' || *s == '\t' || *s == '\r')
+		{
+			s++;
+			continue;
+		}
+		v1 = get_hex(*s++) << 4;
+		if (s >= srcend)
+			return -1;
+
+		v2 = get_hex(*s++);
+		*p++ = v1 | v2;
+	}
+
+	return p - dst;
+}
+
+unsigned
+ecpg_hex_encode(const char *src, unsigned len, char *dst)
+{
+	static const char hextbl[] = "0123456789abcdef";
+	const char *end = src + len;
+
+	while (src < end)
+	{
+		*dst++ = hextbl[(*src >> 4) & 0xF];
+		*dst++ = hextbl[*src & 0xF];
+		src++;
+	}
+	return len * 2;
+}
+
 bool
 ecpg_get_data(const PGresult *results, int act_tuple, int act_field, int lineno,
 			  enum ECPGttype type, enum ECPGttype ind_type,
@@ -447,6 +527,55 @@ ecpg_get_data(const PGresult *results, int act_tuple, int act_field, int lineno,
 					return false;
 					break;
 
+				case ECPGt_bytea:
+					{
+						struct ECPGgeneric_varchar *variable =
+						(struct ECPGgeneric_varchar *) (var + offset * act_tuple);
+						long		dst_size,
+									src_size,
+									dec_size;
+
+						dst_size = ecpg_hex_enc_len(varcharsize);
+						src_size = size - 2;	/* exclude backslash + 'x' */
+						dec_size = src_size < dst_size ? src_size : dst_size;
+						variable->len = hex_decode(pval + 2, dec_size, variable->arr);
+
+						if (dst_size < src_size)
+						{
+							long		rcv_size = ecpg_hex_dec_len(size - 2);
+
+							/* truncation */
+							switch (ind_type)
+							{
+								case ECPGt_short:
+								case ECPGt_unsigned_short:
+									*((short *) (ind + ind_offset * act_tuple)) = rcv_size;
+									break;
+								case ECPGt_int:
+								case ECPGt_unsigned_int:
+									*((int *) (ind + ind_offset * act_tuple)) = rcv_size;
+									break;
+								case ECPGt_long:
+								case ECPGt_unsigned_long:
+									*((long *) (ind + ind_offset * act_tuple)) = rcv_size;
+									break;
+#ifdef HAVE_LONG_LONG_INT
+								case ECPGt_long_long:
+								case ECPGt_unsigned_long_long:
+									*((long long int *) (ind + ind_offset * act_tuple)) = rcv_size;
+									break;
+#endif							/* HAVE_LONG_LONG_INT */
+								default:
+									break;
+							}
+							sqlca->sqlwarn[0] = sqlca->sqlwarn[1] = 'W';
+						}
+
+						pval += size;
+
+					}
+					break;
+
 				case ECPGt_char:
 				case ECPGt_unsigned_char:
 				case ECPGt_string: