[PATCH 2/2] regedit: Overhaul multibyte line processing

[Hugh McMaster]

Signed-off-by: Hugh McMaster <hugh.mcmaster at outlook.com>
---
 programs/regedit/regproc.c | 160 +++++++++++++++------------------------------
 1 file changed, 51 insertions(+), 109 deletions(-)

diff --git a/programs/regedit/regproc.c b/programs/regedit/regproc.c
index a690a10..938881e 100644
--- a/programs/regedit/regproc.c
+++ b/programs/regedit/regproc.c
@@ -607,127 +607,69 @@ static void processRegEntry(WCHAR* stdInput, BOOL isUnicode)
         return; /* skip comment lines */
 }
 
-/******************************************************************************
- * Processes a registry file.
- * Correctly processes comments (in # and ; form), line continuation.
- *
- * Parameters:
- *   in - input stream to read from
- *   first_chars - beginning of stream, read due to Unicode check
- */
-static void processRegLinesA(FILE *in, char* first_chars)
+static char *get_lineA(FILE *fp, char *first_chars)
 {
-    char *buf = NULL;  /* the line read from the input stream */
-    unsigned long line_size = REG_VAL_BUF_SIZE;
-    size_t chars_in_buf = -1;
-    char *s; /* A pointer to buf for fread */
-    char *line; /* The start of the current line */
-    WCHAR *lineW;
-
-    buf = HeapAlloc(GetProcessHeap(), 0, line_size);
-    CHECK_ENOUGH_MEMORY(buf);
-    s = buf;
-    line = buf;
-
-    memcpy(line, first_chars, 2);
+    static size_t size, count, size_remaining, offset = 0;
+    static char *buf, *s, *line, *p, *next;
 
-    if (first_chars)
+    if (!size)
+    {
+        size = REG_VAL_BUF_SIZE;
+        s = buf = HeapAlloc(GetProcessHeap(), 0, size);
+        CHECK_ENOUGH_MEMORY(buf);
+        memcpy(s, first_chars, 2);
         s += 2;
-
-    while (!feof(in)) {
-        size_t size_remaining;
-        int size_to_get;
-        char *s_eol = NULL; /* various local uses */
-
-        /* Do we need to expand the buffer? */
-        assert(s >= buf && s <= buf + line_size);
-        size_remaining = line_size - (s - buf);
-        if (size_remaining < 3) /* we need at least 3 bytes of room for \r\n\0 */
+    }
+    while (1)
+    {
+        size_remaining = size - (s - buf);
+        if (size_remaining < 3)
         {
-            char *new_buffer;
-            size_t new_size = line_size + REG_VAL_BUF_SIZE;
-            if (new_size > line_size) /* no arithmetic overflow */
-                new_buffer = HeapReAlloc(GetProcessHeap(), 0, buf, new_size);
-            else
-                new_buffer = NULL;
-            CHECK_ENOUGH_MEMORY(new_buffer);
-            buf = new_buffer;
-            line = buf;
-            s = buf + line_size - size_remaining;
-            line_size = new_size;
-            size_remaining = line_size - (s - buf);
+            char *new_buf = HeapReAlloc(GetProcessHeap(), 0, buf, size * 2);
+            CHECK_ENOUGH_MEMORY(new_buf);
+            buf = new_buf;
+            s = buf + size - size_remaining;
+            size *= 2;
+            size_remaining = size - (s - buf);
         }
+        line = s - offset;
+        count = fread(s, 1, size_remaining - 1, fp);
+        s[count] = 0;
+        s += count;
 
-        /* Get as much as possible into the buffer, terminating on EOF,
-         * error or once we have read the maximum amount. Abort on error.
-         */
-        size_to_get = (size_remaining > INT_MAX ? INT_MAX : size_remaining);
-
-        chars_in_buf = fread(s, 1, size_to_get - 1, in);
-        s[chars_in_buf] = 0;
-
-        if (chars_in_buf == 0) {
-            if (ferror(in)) {
-                perror("While reading input");
-                exit(IO_ERROR);
-            } else {
-                assert(feof(in));
-                *s = '\0';
-            }
+        p = strpbrk(line, "\r\n");
+        if (!p)
+        {
+            HeapFree(GetProcessHeap(), 0, buf);
+            return NULL;
         }
-
-        /* If we didn't read the end-of-line sequence or EOF, go around again */
-        while (1)
+        next = p + 1;
+        if (*p == '\r' && *(p + 1) == '\n') next++;
+        *p = 0;
+        if (*(p - 1) == '\\')
         {
-            s_eol = strpbrk(line, "\r\n");
-            if (!s_eol) {
-                /* Move the stub of the line to the start of the buffer so
-                 * we get the maximum space to read into, and so we don't
-                 * have to recalculate 'line' if the buffer expands */
-                MoveMemory(buf, line, strlen(line) + 1);
-                line = buf;
-                s = strchr(line, '\0');
-                break;
-            }
-
-            /* If we find a comment line, discard it and go around again */
-            if (line [0] == '#' || line [0] == ';') {
-                if (*s_eol == '\r' && *(s_eol + 1) == '\n')
-                    line = s_eol + 2;
-                else
-                    line = s_eol + 1;
-                continue;
-            }
-
-            /* If there is a concatenating '\\', go around again */
-            if (*(s_eol - 1) == '\\') {
-                char *next_line = s_eol + 1;
-
-                if (*s_eol == '\r' && *(s_eol + 1) == '\n')
-                    next_line++;
-
-                while (*(next_line + 1) == ' ' || *(next_line + 1) == '\t')
-                    next_line++;
-
-                MoveMemory(s_eol - 1, next_line, chars_in_buf - (next_line - s) + 1);
-                chars_in_buf -= next_line - s_eol + 1;
-                continue;
-            }
+            *(--p) = 0;
+            while (*next && isspace(*next)) next++;
+            MoveMemory(p, next, strlen(next) + 1);
+            continue;
+        }
+        offset = s - next;
+        return line;
+    }
+}
 
-            /* Remove any line feed. Leave s_eol on the last \0 */
-            if (*s_eol == '\r' && *(s_eol + 1) == '\n')
-                *s_eol++ = '\0';
-            *s_eol = '\0';
+static void processRegLinesA(FILE *fp, char *first_chars)
+{
+    char *line;
+    WCHAR *lineW;
 
-            lineW = GetWideString(line);
-            processRegEntry(lineW, FALSE);
-            HeapFree(GetProcessHeap(), 0, lineW);
-            line = s_eol + 1;
-        }
+    while ((line = get_lineA(fp, first_chars)))
+    {
+        lineW = GetWideString(line);
+        processRegEntry(lineW, FALSE);
+        HeapFree(GetProcessHeap(), 0, lineW);
     }
     closeKey();
-
-    HeapFree(GetProcessHeap(), 0, buf);
 }
 
 static WCHAR *get_lineW(FILE *fp)
-- 
2.7.4