Postgres95 1.01 Distribution - Virgin SourcesPG95-1_01

1 files changed, 270 insertions, 0 deletions

diff --git a/src/backend/nodes/read.c b/src/backend/nodes/read.c
new file mode 100644
index 00000000000..dbcc59a6f93
--- /dev/null
+++ b/src/backend/nodes/read.c
@@ -0,0 +1,270 @@
+/*-------------------------------------------------------------------------
+ *
+ * read.c--
+ *    routines to convert a string (legal ascii representation of node) back
+ *    to nodes
+ *
+ * Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ *    $Header: /cvsroot/pgsql/src/backend/nodes/read.c,v 1.1.1.1 1996/07/09 06:21:33 scrappy Exp $
+ *
+ * HISTORY
+ *    AUTHOR		DATE		MAJOR EVENT
+ *    Andrew Yu		Nov 2, 1994	file creation
+ *
+ *-------------------------------------------------------------------------
+ */
+#include <stdio.h>
+#include <string.h>
+#include <ctype.h>
+#include "postgres.h"
+#include "nodes/pg_list.h"
+#include "nodes/readfuncs.h"
+#include "utils/elog.h"
+
+/*
+ * stringToNode -
+ *    returns a Node with a given legal ascii representation
+ */
+void *
+stringToNode(char *str)
+{
+    void *retval;
+
+    (void) lsptok(str, NULL);	/* set the string used in lsptok */
+    retval = nodeRead(true);	/* start reading */
+
+    return retval;
+}
+
+/*****************************************************************************
+ *
+ * the lisp token parser
+ *
+ *****************************************************************************/
+
+#define RIGHT_PAREN (1000000 + 1)
+#define LEFT_PAREN  (1000000 + 2)
+#define PLAN_SYM    (1000000 + 3)
+#define AT_SYMBOL   (1000000 + 4)
+#define ATOM_TOKEN  (1000000 + 5)
+
+/*
+ * nodeTokenType -
+ *    returns the type of the node token contained in token.
+ *    It returns one of the following valid NodeTags:
+ *	T_Integer, T_Float, T_String
+ *    and some of its own:
+ * 	RIGHT_PAREN, LEFT_PAREN, PLAN_SYM, AT_SYMBOL, ATOM_TOKEN
+ *
+ *    Assumption: the ascii representation is legal
+ */
+static NodeTag
+nodeTokenType(char *token, int length)
+{
+    NodeTag retval;
+    
+    /*
+     * Check if the token is a number (decimal or integer,
+     * positive or negative
+     */
+    if (isdigit(*token) ||
+	(length>=2 && *token=='-' && isdigit(*(token+1)) ))
+	{
+	    /*
+	     * skip the optional '-' (i.e. negative number)
+	     */
+	    if (*token == '-') {
+		token++;
+	    }
+	    
+	    /*
+	     * See if there is a decimal point
+	     */
+	    
+	    for (; length && *token != '.'; token++, length--);
+	    
+	    /*
+	     * if there isn't, token's an int, otherwise it's a float.
+	     */
+	    
+	    retval = (*token != '.') ? T_Integer : T_Float;
+	}
+    else if (isalpha(*token))
+	retval = ATOM_TOKEN;
+    else if (*token == '(')
+	retval = LEFT_PAREN;
+    else if (*token == ')')
+	retval = RIGHT_PAREN;
+    else if (*token == '@')
+	retval = AT_SYMBOL;
+    else if (*token == '\"')
+	retval = T_String;
+    else if (*token == '{')
+	retval = PLAN_SYM;
+    return(retval);
+}
+
+/*
+ * Works kinda like strtok, except it doesn't put nulls into string.
+ * 
+ * Returns the length in length instead.  The string can be set without
+ * returning a token by calling lsptok with length == NULL.
+ *
+ */
+char *
+lsptok(char *string, int *length)
+{
+    static char *local_str;
+    char *ret_string;
+    
+    if (string != NULL) {
+	local_str = string;
+	if (length == NULL) {
+	    return(NULL);
+	}
+    }
+    
+    for (; *local_str == ' '
+	 || *local_str == '\n'
+	 || *local_str == '\t'; local_str++);
+    
+    /*
+     * Now pointing at next token.
+     */
+    ret_string = local_str;
+    if (*local_str == '\0') return(NULL);
+    *length = 1;
+    
+    if (*local_str == '\"') {
+	for (local_str++; *local_str != '\"'; (*length)++, local_str++);
+	(*length)++; local_str++;
+    }else if (*local_str == ')' || *local_str == '(' ||
+	      *local_str == '}' || *local_str == '{') {
+	local_str++;
+    }else {
+	for (; *local_str != ' '
+	     && *local_str != '\n'
+	     && *local_str != '\t'
+	     && *local_str != '{'
+	     && *local_str != '}'
+	     && *local_str != '('
+	     && *local_str != ')'; local_str++, (*length)++);
+	(*length)--;
+    }
+    return(ret_string);
+}
+
+/*
+ * This guy does all the reading.
+ *
+ * Secrets:  He assumes that lsptok already has the string (see below).
+ * Any callers should set read_car_only to true.
+ */
+void *
+nodeRead(bool read_car_only)
+{
+    char *token;
+    NodeTag type;
+    Node *this_value, *return_value;
+    int tok_len;
+    char tmp;
+    bool make_dotted_pair_cell = false;
+    
+    token = lsptok(NULL, &tok_len);
+    
+    if (token == NULL) return(NULL);
+    
+    type = nodeTokenType(token, tok_len);
+    
+    switch(type) {
+    case PLAN_SYM:
+	this_value = parsePlanString();
+	token = lsptok(NULL, &tok_len);
+	if (token[0] != '}') return(NULL);
+
+	if (!read_car_only)
+	    make_dotted_pair_cell = true;
+	else
+	    make_dotted_pair_cell = false;
+	break;
+    case LEFT_PAREN:
+	if (!read_car_only) {
+	    List *l = makeNode(List);
+
+	    lfirst(l) = nodeRead(false);
+	    lnext(l) = nodeRead(false);
+	    this_value = (Node*)l;
+	}else {
+	    this_value = nodeRead(false);
+	}
+	break;
+    case RIGHT_PAREN:
+	this_value = NULL;
+	break;
+    case AT_SYMBOL:
+	break;
+    case ATOM_TOKEN:
+	if (!strncmp(token, "nil", 3)) {
+	    this_value = NULL;
+	    /*
+	     * It might be "nil" but it is an atom!
+	     */
+	    if (read_car_only) {
+		make_dotted_pair_cell = false;
+	    } else {
+		make_dotted_pair_cell = true;
+	    }
+	}else {
+	    tmp = token[tok_len];
+	    token[tok_len] = '\0';
+	    this_value = (Node*)pstrdup(token);	/* !attention! not a Node.
+						   use with caution */
+	    token[tok_len] = tmp;
+	    make_dotted_pair_cell = true;
+	}
+	break;
+    case T_Float:
+	tmp = token[tok_len];
+	token[tok_len] = '\0';
+	this_value = (Node*)makeFloat(atof(token));
+	token[tok_len] = tmp;
+	make_dotted_pair_cell = true;
+	break;
+    case T_Integer:
+	tmp = token[tok_len];
+	token[tok_len] = '\0';
+	this_value = (Node*)makeInteger(atoi(token));
+	token[tok_len] = tmp;
+	make_dotted_pair_cell = true;
+	break;
+    case T_String:
+	tmp = token[tok_len - 1];
+	token[tok_len - 1] = '\0';
+	token++;
+	this_value = (Node*)makeString(token);		/* !! not strdup'd */
+	token[tok_len - 2] = tmp;
+	make_dotted_pair_cell = true;
+	break;
+    default:
+	elog(WARN, "nodeRead: Bad type %d", type);
+	break;
+    }
+    if (make_dotted_pair_cell) {
+	List *l = makeNode(List);
+
+	lfirst(l) = this_value;
+	if (!read_car_only) {
+	    lnext(l) = nodeRead(false);
+	}else {
+	    lnext(l) = NULL;
+	}
+	return_value = (Node*)l;
+    }else {
+	return_value = this_value;
+    }
+    return(return_value);
+}
+