From 6bb38f6a01dbf4bbd584e038ceace0a00faa27bb Mon Sep 17 00:00:00 2001
From: Byron Rakitzis <byron@archone.tamu.edu>
Date: Wed, 27 May 1992 00:00:01 +0100
Subject: release: rc-1.4

---
 heredoc.c | 156 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 156 insertions(+)
 create mode 100644 heredoc.c

(limited to 'heredoc.c')

diff --git a/heredoc.c b/heredoc.c
new file mode 100644
index 0000000..3930d9e
--- /dev/null
+++ b/heredoc.c
@@ -0,0 +1,156 @@
+/* heredoc.c: heredoc slurping is done here */
+
+#include "rc.h"
+
+struct Hq {
+	Node *doc;
+	char *name;
+	Hq *n;
+	bool quoted;
+} *hq;
+
+static bool dead = FALSE;
+
+/*
+ * read in a heredocument. A clever trick: skip over any partially matched end-of-file
+ * marker storing only the number of characters matched. If the whole marker is matched,
+ * return from readheredoc(). If only part of the marker is matched, copy that part into
+ * the heredocument.
+ *
+ * BUG: if the eof string contains a newline, the state can get confused, and the
+ * heredoc may continue past where it should.  on the other hand, /bin/sh seems to
+ * never get out of its readheredoc() when the heredoc string contains a newline
+ */
+
+static char *readheredoc(char *eof) {
+	int c;
+	char *t, *buf, *bufend;
+	unsigned char *s;
+	SIZE_T bufsize;
+	t = buf = nalloc(bufsize = 512);
+	bufend = &buf[bufsize];
+	dead = FALSE;
+#define	RESIZE(extra) { \
+		char *nbuf; \
+		bufsize = bufsize * 2 + extra; \
+		nbuf = nalloc(bufsize); \
+		memcpy(nbuf, buf, (SIZE_T) (t - buf)); \
+		t = nbuf + (t - buf); \
+		buf = nbuf; \
+		bufend = &buf[bufsize]; \
+	}
+	for (;;) {
+		print_prompt2();
+		for (s = (unsigned char *) eof; (c = gchar()) == *s; s++)
+			;
+		if (*s == '\0' && (c == '\n' || c == EOF)) {
+			*t++ = '\0';
+			return buf;
+		}
+		if (s != (unsigned char *) eof) {
+			SIZE_T len = s - (unsigned char *) eof;
+			if (t + len >= bufend)
+				RESIZE(len);
+			memcpy(t, eof, len);
+			t += len;
+		}
+		for (;; c = gchar()) {
+			if (c == EOF) {
+				yyerror("heredoc incomplete");
+				dead = TRUE;
+				return NULL;
+			}
+			if (t + 1 >= bufend)
+				RESIZE(0);
+			*t++ = c;
+			if (c == '\n')
+				break;
+		}
+	}
+}
+
+/* parseheredoc -- turn a heredoc with variable references into a node chain */
+
+static Node *parseheredoc(char *s) {
+	int c = *s;
+	Node *result = NULL;
+	while (TRUE) {
+		Node *node;
+		switch (c) {
+		default: {
+			char *begin = s;
+			while ((c = *s++) != '\0' && c != '$')
+				;
+			*--s = '\0';
+			node = mk(nQword, begin, NULL);
+			break;
+		}
+		case '$': {
+			char *begin = ++s, *var;
+			c = *s++;
+			if (c == '$') {
+				node = mk(nQword, "$", NULL);
+				c = *s;
+			} else {
+				SIZE_T len = 0;
+				do
+					len++;
+				while (!dnw[c = *(unsigned char *) s++]);
+				if (c == '^')
+					c = *s;
+				else
+					s--;
+				var = nalloc(len + 1);
+				var[len] = '\0';
+				memcpy(var, begin, len);
+				node = mk(nFlat, mk(nWord, var, NULL));
+			}
+			break;
+		}
+		case '\0':
+			return result;
+		}
+		result = (result == NULL) ? node : mk(nConcat, result, node);
+	}
+}
+
+/* read in heredocs when yyparse hits a newline. called from yyparse */
+
+extern int heredoc(int end) {
+	Hq *here;
+	if ((here = hq) != NULL) {
+		hq = NULL;
+		if (end) {
+			yyerror("heredoc incomplete");
+			return FALSE;
+		}
+		do {
+			Node *n = here->doc;
+			char *s = readheredoc(here->name);
+			if (dead)
+				return FALSE;
+			n->u[2].p = here->quoted ? mk(nQword, s, NULL) : parseheredoc(s);
+			n->u[0].i = rHerestring;
+		} while ((here = here->n) != NULL);
+	}
+	return TRUE;
+}
+
+/* queue pending heredocs into a queue. called from yyparse */
+
+extern int qdoc(Node *name, Node *n) {
+	Hq *new, **prev;
+	if (name->type != nWord && name->type != nQword) {
+		yyerror("eof-marker not a single literal word");
+		flushu();
+		return FALSE;
+	}
+	for (prev = &hq; (new = *prev) != NULL; prev = &new->n)
+		;
+	*prev = new = nnew(Hq);
+	new->name = name->u[0].s;
+	new->quoted = (name->type == nQword);
+	new->doc = n;
+	new->n = NULL;
+	return TRUE;
+}
-- 
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