From: Emden Gansner <erg@research.att.com>
Date: Fri, 25 Nov 2011 19:19:02 +0000 (-0500)
Subject: Add utility function agmemread (as in libgraph) to cgraph
X-Git-Tag: LAST_LIBGRAPH~32^2~585^2~4
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=90810c195ca816bfa9d7172214aa4e8a5205b9cc;p=graphviz

Add utility function agmemread (as in libgraph) to cgraph
---

diff --git a/lib/cgraph/cgraph.h b/lib/cgraph/cgraph.h
index f1672ab08..a815e8494 100644
--- a/lib/cgraph/cgraph.h
+++ b/lib/cgraph/cgraph.h
@@ -265,6 +265,7 @@ extern int agcallbacks(Agraph_t * g, int flag);	/* return prev value */
 extern Agraph_t *agopen(char *name, Agdesc_t desc, Agdisc_t * disc);
 extern int agclose(Agraph_t * g);
 extern Agraph_t *agread(void *chan, Agdisc_t * disc);
+extern Agraph_t *agmemread(const char *cp);
 extern void agreadline(int);
 extern void agsetfile(char *);
 extern Agraph_t *agconcat(Agraph_t * g, void *chan, Agdisc_t * disc);
diff --git a/lib/cgraph/grammar.y b/lib/cgraph/grammar.y
index e2128b817..3c01ae49b 100644
--- a/lib/cgraph/grammar.y
+++ b/lib/cgraph/grammar.y
@@ -540,3 +540,51 @@ Agraph_t *agconcat(Agraph_t *g, void *chan, Agdisc_t *disc)
 }
 
 Agraph_t *agread(void *fp, Agdisc_t *disc) {return agconcat(NILgraph,fp,disc); }
+
+typedef struct {
+    const char *data;
+    int len;
+    int cur;
+} rdr_t;
+
+static int
+iofread(void *chan, char *buf, int bufsize)
+{
+    const char *ptr;
+    char *optr;
+    char c;
+    int l;
+    rdr_t *s;
+
+    if (bufsize == 0) return 0;
+    s = (rdr_t *) chan;
+    if (s->cur >= s->len)
+        return 0;
+    l = 0;
+    ptr = s->data + s->cur;
+    optr = buf;
+    do {
+        *optr++ = c = *ptr++;
+        l++;
+    } while (c && (c != '\n') && (l < bufsize));
+    s->cur += l;
+    return l;
+}
+
+static Agiodisc_t memIoDisc = { iofread, AgIoDisc.putstr, AgIoDisc.flush };
+
+Agraph_t *agmemread(const char *cp)
+{
+    Agraph_t* g;
+    rdr_t rdr;
+
+    rdr.data = cp;
+    rdr.len = strlen(cp);
+    rdr.cur = 0;
+    disc.mem = &AgMemDisc;
+    disc.id = &AgIdDisc;
+    disc.io = &memIoDisc;
+    g = agread (&rdr, &disc);
+    return g;
+}
+