postgresql/contrib/seg/segscan.l

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%{
/*
** A scanner for EMP-style numeric ranges
*/
#include "postgres.h"
/* No reason to constrain amount of data slurped */
#define YY_READ_BUF_SIZE 16777216
/* Avoid exit() on fatal scanner errors (a bit ugly -- see yy_fatal_error) */
#define fprintf(file, fmt, msg) ereport(ERROR, (errmsg_internal("%s", msg)))
/* Handles to the buffer that the lexer uses internally */
static YY_BUFFER_STATE scanbufhandle;
static char *scanbuf;
static int scanbuflen;
/* flex 2.5.4 doesn't bother with a decl for this */
int seg_yylex(void);
void seg_scanner_init(const char *str);
void seg_scanner_finish(void);
%}
%option 8bit
%option never-interactive
%option nodefault
%option nounput
%option noyywrap
%option prefix="seg_yy"
range (\.\.)(\.)?
plumin (\'\+\-\')|(\(\+\-)\)
integer [+-]?[0-9]+
real [+-]?[0-9]+\.[0-9]+
float ({integer}|{real})([eE]{integer})?
%%
{range} yylval.text = yytext; return RANGE;
{plumin} yylval.text = yytext; return PLUMIN;
{float} yylval.text = yytext; return SEGFLOAT;
\< yylval.text = "<"; return EXTENSION;
\> yylval.text = ">"; return EXTENSION;
\~ yylval.text = "~"; return EXTENSION;
[ \t\n\r\f]+ /* discard spaces */
. return yytext[0]; /* alert parser of the garbage */
%%
void
yyerror(const char *message)
{
if (*yytext == YY_END_OF_BUFFER_CHAR)
{
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("bad seg representation"),
/* translator: %s is typically "syntax error" */
errdetail("%s at end of input", message)));
}
else
{
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("bad seg representation"),
/* translator: first %s is typically "syntax error" */
errdetail("%s at or near \"%s\"", message, yytext)));
}
}
/*
* Called before any actual parsing is done
*/
void
seg_scanner_init(const char *str)
{
Size slen = strlen(str);
/*
* Might be left over after ereport()
*/
if (YY_CURRENT_BUFFER)
yy_delete_buffer(YY_CURRENT_BUFFER);
/*
* Make a scan buffer with special termination needed by flex.
*/
scanbuflen = slen;
scanbuf = palloc(slen + 2);
memcpy(scanbuf, str, slen);
scanbuf[slen] = scanbuf[slen + 1] = YY_END_OF_BUFFER_CHAR;
scanbufhandle = yy_scan_buffer(scanbuf, slen + 2);
BEGIN(INITIAL);
}
/*
* Called after parsing is done to clean up after seg_scanner_init()
*/
void
seg_scanner_finish(void)
{
yy_delete_buffer(scanbufhandle);
pfree(scanbuf);
}