introduce hex2chr() for converting two hexadecimal digits to a character

Add and use a helper function that decodes the char value of two
hexadecimal digits.  It returns a negative number on error, avoids
running over the end of the given string and doesn't shift negative
values.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/cache.h b/cache.h
index c141b3c..81af2c2 100644 (file)
--- a/cache.h
+++ b/cache.h
@@ -1133,6 +1133,16 @@ static inline unsigned int hexval(unsigned char c)
        return hexval_table[c];
 }
 
+/*
+ * Convert two consecutive hexadecimal digits into a char.  Return a
+ * negative value on error.  Don't run over the end of short strings.
+ */
+static inline int hex2chr(const char *s)
+{
+       int val = hexval(s[0]);
+       return (val < 0) ? val : (val << 4) | hexval(s[1]);
+}
+
 /* Convert to/from hex/sha1 representation */
 #define MINIMUM_ABBREV minimum_abbrev
 #define DEFAULT_ABBREV default_abbrev

diff --git a/hex.c b/hex.c
index 0519f85..60541c9 100644 (file)
--- a/hex.c
+++ b/hex.c
@@ -39,16 +39,8 @@ int get_sha1_hex(const char *hex, unsigned char *sha1)
 {
        int i;
        for (i = 0; i < GIT_SHA1_RAWSZ; i++) {
-               unsigned int val;
-               /*
-                * hex[1]=='\0' is caught when val is checked below,
-                * but if hex[0] is NUL we have to avoid reading
-                * past the end of the string:
-                */
-               if (!hex[0])
-                       return -1;
-               val = (hexval(hex[0]) << 4) | hexval(hex[1]);
-               if (val & ~0xff)
+               int val = hex2chr(hex);
+               if (val < 0)
                        return -1;
                *sha1++ = val;
                hex += 2;

diff --git a/pkt-line.c b/pkt-line.c
index 62fdb37..30489c6 100644 (file)
--- a/pkt-line.c
+++ b/pkt-line.c
@@ -172,27 +172,8 @@ static int get_packet_data(int fd, char **src_buf, size_t *src_size,
 
 static int packet_length(const char *linelen)
 {
-       int n;
-       int len = 0;
-
-       for (n = 0; n < 4; n++) {
-               unsigned char c = linelen[n];
-               len <<= 4;
-               if (c >= '0' && c <= '9') {
-                       len += c - '0';
-                       continue;
-               }
-               if (c >= 'a' && c <= 'f') {
-                       len += c - 'a' + 10;
-                       continue;
-               }
-               if (c >= 'A' && c <= 'F') {
-                       len += c - 'A' + 10;
-                       continue;
-               }
-               return -1;
-       }
-       return len;
+       int val = hex2chr(linelen);
+       return (val < 0) ? val : (val << 8) | hex2chr(linelen + 2);
 }
 
 int packet_read(int fd, char **src_buf, size_t *src_len,

diff --git a/pretty.c b/pretty.c
index b271656..37e74cb 100644 (file)
--- a/pretty.c
+++ b/pretty.c
@@ -1063,7 +1063,7 @@ static size_t format_commit_one(struct strbuf *sb, /* in UTF-8 */
        const struct commit *commit = c->commit;
        const char *msg = c->message;
        struct commit_list *p;
-       int h1, h2;
+       int ch;
 
        /* these are independent of the commit */
        switch (placeholder[0]) {
@@ -1087,14 +1087,11 @@ static size_t format_commit_one(struct strbuf *sb, /* in UTF-8 */
                return 1;
        case 'x':
                /* %x00 == NUL, %x0a == LF, etc. */
-               if (0 <= (h1 = hexval_table[0xff & placeholder[1]]) &&
-                   h1 <= 16 &&
-                   0 <= (h2 = hexval_table[0xff & placeholder[2]]) &&
-                   h2 <= 16) {
-                       strbuf_addch(sb, (h1<<4)|h2);
-                       return 3;
-               } else
+               ch = hex2chr(placeholder + 1);
+               if (ch < 0)
                        return 0;
+               strbuf_addch(sb, ch);
+               return 3;
        case 'w':
                if (placeholder[1] == '(') {
                        unsigned long width = 0, indent1 = 0, indent2 = 0;

diff --git a/ref-filter.c b/ref-filter.c
index bc551a7..9adbb8a 100644 (file)
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -1576,24 +1576,6 @@ void ref_array_sort(struct ref_sorting *sorting, struct ref_array *array)
        qsort(array->items, array->nr, sizeof(struct ref_array_item *), compare_refs);
 }
 
-static int hex1(char ch)
-{
-       if ('0' <= ch && ch <= '9')
-               return ch - '0';
-       else if ('a' <= ch && ch <= 'f')
-               return ch - 'a' + 10;
-       else if ('A' <= ch && ch <= 'F')
-               return ch - 'A' + 10;
-       return -1;
-}
-static int hex2(const char *cp)
-{
-       if (cp[0] && cp[1])
-               return (hex1(cp[0]) << 4) | hex1(cp[1]);
-       else
-               return -1;
-}
-
 static void append_literal(const char *cp, const char *ep, struct ref_formatting_state *state)
 {
        struct strbuf *s = &state->stack->output;
@@ -1603,7 +1585,7 @@ static void append_literal(const char *cp, const char *ep, struct ref_formatting
                        if (cp[1] == '%')
                                cp++;
                        else {
-                               int ch = hex2(cp + 1);
+                               int ch = hex2chr(cp + 1);
                                if (0 <= ch) {
                                        strbuf_addch(s, ch);
                                        cp += 3;

diff --git a/url.c b/url.c
index 2d89ad1..eaf4f07 100644 (file)
--- a/url.c
+++ b/url.c
@@ -29,25 +29,6 @@ int is_url(const char *url)
        return (url[0] == ':' && url[1] == '/' && url[2] == '/');
 }
 
-static int url_decode_char(const char *q)
-{
-       int i;
-       unsigned char val = 0;
-       for (i = 0; i < 2; i++) {
-               unsigned char c = *q++;
-               val <<= 4;
-               if (c >= '0' && c <= '9')
-                       val += c - '0';
-               else if (c >= 'a' && c <= 'f')
-                       val += c - 'a' + 10;
-               else if (c >= 'A' && c <= 'F')
-                       val += c - 'A' + 10;
-               else
-                       return -1;
-       }
-       return val;
-}
-
 static char *url_decode_internal(const char **query, int len,
                                 const char *stop_at, struct strbuf *out,
                                 int decode_plus)
@@ -66,7 +47,7 @@ static char *url_decode_internal(const char **query, int len,
                }
 
                if (c == '%') {
-                       int val = url_decode_char(q + 1);
+                       int val = hex2chr(q + 1);
                        if (0 <= val) {
                                strbuf_addch(out, val);
                                q += 3;