[rfc patch 4/6] lib/index: separate state table definition from scanner.

[David Bremner]

We want to reuse the scanner definition with a different table
---
 lib/index.cc | 81 +++++++++++++++++++++++++++++++++++-------------------------
 1 file changed, 47 insertions(+), 34 deletions(-)

diff --git a/lib/index.cc b/lib/index.cc
index 74a750b9..02b35b81 100644
--- a/lib/index.cc
+++ b/lib/index.cc
@@ -31,6 +31,15 @@ typedef struct _NotmuchFilterDiscardUuencodeClass NotmuchFilterDiscardUuencodeCl
 
 typedef void (*filter_fun) (GMimeFilter *filter, char *in, size_t len, size_t prespace,
 			    char **out, size_t *outlen, size_t *outprespace);
+
+typedef struct {
+    int state;
+    int a;
+    int b;
+    int next_if_match;
+    int next_if_not_match;
+} scanner_state_t;
+
 /**
  * NotmuchFilterDiscardUuencode:
  *
@@ -119,46 +128,18 @@ filter_filter (GMimeFilter *gmime_filter, char *inbuf, size_t inlen, size_t pres
 }
 
 static void
-filter_filter_uuencode (GMimeFilter *gmime_filter, char *inbuf, size_t inlen, size_t prespace,
-			char **outbuf, size_t *outlen, size_t *outprespace)
+do_filter (const scanner_state_t states[],
+	   int first_skipping_state,
+	   GMimeFilter *gmime_filter, char *inbuf, size_t inlen, size_t prespace,
+	   char **outbuf, size_t *outlen, size_t *outprespace)
 {
     NotmuchFilterDiscardUuencode *filter = (NotmuchFilterDiscardUuencode *) gmime_filter;
     register const char *inptr = inbuf;
     const char *inend = inbuf + inlen;
     char *outptr;
-
+    int next;
     (void) prespace;
 
-    /* Simple, linear state-transition diagram for our filter.
-     *
-     * If the character being processed is within the range of [a, b]
-     * for the current state then we transition next_if_match
-     * state. If not, we transition to the next_if_not_match state.
-     *
-     * The final two states are special in that they are the states in
-     * which we discard data. */
-    static const struct {
-	int state;
-	int a;
-	int b;
-	int next_if_match;
-	int next_if_not_match;
-    } states[] = {
-	{0,  'b',  'b',  1,  0},
-	{1,  'e',  'e',  2,  0},
-	{2,  'g',  'g',  3,  0},
-	{3,  'i',  'i',  4,  0},
-	{4,  'n',  'n',  5,  0},
-	{5,  ' ',  ' ',  6,  0},
-	{6,  '0',  '7',  7,  0},
-	{7,  '0',  '7',  8,  0},
-	{8,  '0',  '7',  9,  0},
-	{9,  ' ',  ' ',  10, 0},
-	{10, '\n', '\n', 11, 10},
-	{11, 'M',  'M',  12, 0},
-	{12, ' ',  '`',  12, 11}
-    };
-    int next;
 
     g_mime_filter_set_size (gmime_filter, inlen, FALSE);
     outptr = gmime_filter->outbuf;
@@ -174,7 +155,7 @@ filter_filter_uuencode (GMimeFilter *gmime_filter, char *inbuf, size_t inlen, si
 	    next = states[filter->state].next_if_not_match;
 	}
 
-	if (filter->state < 11)
+	if (filter->state < first_skipping_state)
 	    *outptr++ = *inptr;
 
 	filter->state = next;
@@ -187,6 +168,38 @@ filter_filter_uuencode (GMimeFilter *gmime_filter, char *inbuf, size_t inlen, si
 }
 
 static void
+filter_filter_uuencode (GMimeFilter *gmime_filter, char *inbuf, size_t inlen, size_t prespace,
+			char **outbuf, size_t *outlen, size_t *outprespace)
+{
+    /* Simple, linear state-transition diagram for our filter.
+     *
+     * If the character being processed is within the range of [a, b]
+     * for the current state then we transition next_if_match
+     * state. If not, we transition to the next_if_not_match state.
+     *
+     * The final two states are special in that they are the states in
+     * which we discard data. */
+    static const scanner_state_t states[] = {
+	{0,  'b',  'b',  1,  0},
+	{1,  'e',  'e',  2,  0},
+	{2,  'g',  'g',  3,  0},
+	{3,  'i',  'i',  4,  0},
+	{4,  'n',  'n',  5,  0},
+	{5,  ' ',  ' ',  6,  0},
+	{6,  '0',  '7',  7,  0},
+	{7,  '0',  '7',  8,  0},
+	{8,  '0',  '7',  9,  0},
+	{9,  ' ',  ' ',  10, 0},
+	{10, '\n', '\n', 11, 10},
+	{11, 'M',  'M',  12, 0},
+	{12, ' ',  '`',  12, 11}
+    };
+
+    do_filter(states, 11,
+	      gmime_filter, inbuf, inlen, prespace, outbuf, outlen, outprespace);
+}
+
+static void
 filter_complete (GMimeFilter *filter, char *inbuf, size_t inlen, size_t prespace,
 		 char **outbuf, size_t *outlen, size_t *outprespace)
 {
-- 
2.11.0