[PATCH] kernel: add helpers for ascii character conversion

From: Harvey Harrison
Date: Thu May 01 2008 - 15:22:51 EST

Add helpers for getting an ascii hex char for the high and low
nibble of a byte. Also add a small helper to get an integer
value from a given hex char.

Included here are a few of the current places that roll their
own versions being moved to the common helper.

Signed-off-by: Harvey Harrison <harvey.harrison@xxxxxxxxx>
---
Maybe I should call this RFC, but people have rolled their own all
over the place in tree, so this should go in somewhere.

arch/cris/arch-v10/kernel/kgdb.c | 94 +++++++++++---------------------------
arch/cris/arch-v32/kernel/kgdb.c | 84 +++++++++-------------------------
drivers/pnp/support.c | 8 ++--
include/linux/kernel.h | 15 ++++++
lib/hexdump.c | 4 +-
5 files changed, 70 insertions(+), 135 deletions(-)

diff --git a/arch/cris/arch-v10/kernel/kgdb.c b/arch/cris/arch-v10/kernel/kgdb.c
index a3ca551..149bd03 100644
--- a/arch/cris/arch-v10/kernel/kgdb.c
+++ b/arch/cris/arch-v10/kernel/kgdb.c
@@ -278,17 +278,6 @@ void putDebugChar (int val);

void enableDebugIRQ (void);

-/* Returns the character equivalent of a nibble, bit 7, 6, 5, and 4 of a byte,
- represented by int x. */
-static char highhex (int x);
-
-/* Returns the character equivalent of a nibble, bit 3, 2, 1, and 0 of a byte,
- represented by int x. */
-static char lowhex (int x);
-
-/* Returns the integer equivalent of a hexadecimal character. */
-static int hex (char ch);
-
/* Convert the memory, pointed to by mem into hexadecimal representation.
Put the result in buf, and return a pointer to the last character
in buf (null). */
@@ -670,35 +659,6 @@ read_register (char regno, unsigned int *valptr)
}

/********************************** Packet I/O ******************************/
-/* Returns the character equivalent of a nibble, bit 7, 6, 5, and 4 of a byte,
- represented by int x. */
-static inline char
-highhex(int x)
-{
- return hexchars[(x >> 4) & 0xf];
-}
-
-/* Returns the character equivalent of a nibble, bit 3, 2, 1, and 0 of a byte,
- represented by int x. */
-static inline char
-lowhex(int x)
-{
- return hexchars[x & 0xf];
-}
-
-/* Returns the integer equivalent of a hexadecimal character. */
-static int
-hex (char ch)
-{
- if ((ch >= 'a') && (ch <= 'f'))
- return (ch - 'a' + 10);
- if ((ch >= '0') && (ch <= '9'))
- return (ch - '0');
- if ((ch >= 'A') && (ch <= 'F'))
- return (ch - 'A' + 10);
- return (-1);
-}
-
/* Convert the memory, pointed to by mem into hexadecimal representation.
Put the result in buf, and return a pointer to the last character
in buf (null). */
@@ -721,8 +681,8 @@ mem2hex(char *buf, unsigned char *mem, int count)
/* Valid mem address. */
for (i = 0; i < count; i++) {
ch = *mem++;
- *buf++ = highhex (ch);
- *buf++ = lowhex (ch);
+ *buf++ = asc_hex_hi(ch);
+ *buf++ = asc_hex_lo(ch);
}
}

@@ -740,8 +700,8 @@ hex2mem (unsigned char *mem, char *buf, int count)
int i;
unsigned char ch;
for (i = 0; i < count; i++) {
- ch = hex (*buf++) << 4;
- ch = ch + hex (*buf++);
+ ch = hex_to_int(*buf++) << 4;
+ ch = ch + hex_to_int(*buf++);
*mem++ = ch;
}
return (mem);
@@ -800,8 +760,8 @@ getpacket (char *buffer)
buffer[count] = '\0';

if (ch == '#') {
- xmitcsum = hex (getDebugChar ()) << 4;
- xmitcsum += hex (getDebugChar ());
+ xmitcsum = hex_to_int(getDebugChar ()) << 4;
+ xmitcsum += hex_to_int(getDebugChar ());
if (checksum != xmitcsum) {
/* Wrong checksum */
putDebugChar ('-');
@@ -858,8 +818,8 @@ putpacket(char *buffer)
}
}
putDebugChar ('#');
- putDebugChar (highhex (checksum));
- putDebugChar (lowhex (checksum));
+ putDebugChar(asc_hex_hi(checksum));
+ putDebugChar(asc_hex_lo(checksum));
} while(kgdb_started && (getDebugChar() != '+'));
}

@@ -896,8 +856,8 @@ stub_is_stopped(int sigval)
/* Send trap type (converted to signal) */

*ptr++ = 'T';
- *ptr++ = highhex (sigval);
- *ptr++ = lowhex (sigval);
+ *ptr++ = asc_hex_hi(sigval);
+ *ptr++ = asc_hex_lo(sigval);

/* Send register contents. We probably only need to send the
* PC, frame pointer and stack pointer here. Other registers will be
@@ -911,8 +871,8 @@ stub_is_stopped(int sigval)

if (status == SUCCESS) {

- *ptr++ = highhex (regno);
- *ptr++ = lowhex (regno);
+ *ptr++ = asc_hex_hi(regno);
+ *ptr++ = asc_hex_lo(regno);
*ptr++ = ':';

ptr = mem2hex(ptr, (unsigned char *)&reg_cont,
@@ -937,8 +897,8 @@ stub_is_stopped(int sigval)
/* Store thread:r...; with the executing task TID. */
gdb_cris_strcpy (&remcomOutBuffer[pos], "thread:");
pos += gdb_cris_strlen ("thread:");
- remcomOutBuffer[pos++] = highhex (executing_task);
- remcomOutBuffer[pos++] = lowhex (executing_task);
+ remcomOutBuffer[pos++] = asc_hex_hi(executing_task);
+ remcomOutBuffer[pos++] = asc_hex_lo(executing_task);
gdb_cris_strcpy (&remcomOutBuffer[pos], ";");
#endif

@@ -1126,8 +1086,8 @@ handle_exception (int sigval)
Success: SAA, where AA is the signal number.
Failure: void. */
remcomOutBuffer[0] = 'S';
- remcomOutBuffer[1] = highhex (sigval);
- remcomOutBuffer[2] = lowhex (sigval);
+ remcomOutBuffer[1] = asc_hex_hi(sigval);
+ remcomOutBuffer[2] = asc_hex_lo(sigval);
remcomOutBuffer[3] = 0;
break;

@@ -1224,23 +1184,23 @@ handle_exception (int sigval)
case 'C':
/* Identify the remote current thread. */
gdb_cris_strcpy (&remcomOutBuffer[0], "QC");
- remcomOutBuffer[2] = highhex (current_thread_c);
- remcomOutBuffer[3] = lowhex (current_thread_c);
+ remcomOutBuffer[2] = asc_hex_hi(current_thread_c);
+ remcomOutBuffer[3] = asc_hex_lo(current_thread_c);
remcomOutBuffer[4] = '\0';
break;
case 'L':
gdb_cris_strcpy (&remcomOutBuffer[0], "QM");
/* Reply with number of threads. */
if (os_is_started()) {
- remcomOutBuffer[2] = highhex (number_of_tasks);
- remcomOutBuffer[3] = lowhex (number_of_tasks);
+ remcomOutBuffer[2] = asc_hex_hi(number_of_tasks);
+ remcomOutBuffer[3] = asc_hex_lo(number_of_tasks);
}
else {
- remcomOutBuffer[2] = highhex (0);
- remcomOutBuffer[3] = lowhex (1);
+ remcomOutBuffer[2] = asc_hex_hi(0);
+ remcomOutBuffer[3] = asc_hex_lo(1);
}
/* Done with the reply. */
- remcomOutBuffer[4] = lowhex (1);
+ remcomOutBuffer[4] = asc_hex_lo(1);
pos = 5;
/* Expects the argument thread id. */
for (; pos < (5 + HEXCHARS_IN_THREAD_ID); pos++)
@@ -1251,16 +1211,16 @@ handle_exception (int sigval)
for (thread_id = 0; thread_id < number_of_tasks; thread_id++) {
nextpos = pos + HEXCHARS_IN_THREAD_ID - 1;
for (; pos < nextpos; pos ++)
- remcomOutBuffer[pos] = lowhex (0);
- remcomOutBuffer[pos++] = lowhex (thread_id);
+ remcomOutBuffer[pos] = asc_hex_lo(0);
+ remcomOutBuffer[pos++] = asc_hex_lo(thread_id);
}
}
else {
/* Store the thread identifier of the boot task. */
nextpos = pos + HEXCHARS_IN_THREAD_ID - 1;
for (; pos < nextpos; pos ++)
- remcomOutBuffer[pos] = lowhex (0);
- remcomOutBuffer[pos++] = lowhex (current_thread_c);
+ remcomOutBuffer[pos] = asc_hex_lo(0);
+ remcomOutBuffer[pos++] = asc_hex_lo(current_thread_c);
}
remcomOutBuffer[pos] = '\0';
break;
diff --git a/arch/cris/arch-v32/kernel/kgdb.c b/arch/cris/arch-v32/kernel/kgdb.c
index 4e2e2e2..6831c7f 100644
--- a/arch/cris/arch-v32/kernel/kgdb.c
+++ b/arch/cris/arch-v32/kernel/kgdb.c
@@ -398,17 +398,6 @@ void putDebugChar(int val)
}
#endif

-/* Returns the character equivalent of a nibble, bit 7, 6, 5, and 4 of a byte,
- represented by int x. */
-static char highhex(int x);
-
-/* Returns the character equivalent of a nibble, bit 3, 2, 1, and 0 of a byte,
- represented by int x. */
-static char lowhex(int x);
-
-/* Returns the integer equivalent of a hexadecimal character. */
-static int hex(char ch);
-
/* Convert the memory, pointed to by mem into hexadecimal representation.
Put the result in buf, and return a pointer to the last character
in buf (null). */
@@ -655,35 +644,6 @@ read_register(char regno, unsigned int *valptr)
}

/********************************** Packet I/O ******************************/
-/* Returns the character equivalent of a nibble, bit 7, 6, 5, and 4 of a byte,
- represented by int x. */
-static inline char
-highhex(int x)
-{
- return hexchars[(x >> 4) & 0xf];
-}
-
-/* Returns the character equivalent of a nibble, bit 3, 2, 1, and 0 of a byte,
- represented by int x. */
-static inline char
-lowhex(int x)
-{
- return hexchars[x & 0xf];
-}
-
-/* Returns the integer equivalent of a hexadecimal character. */
-static int
-hex(char ch)
-{
- if ((ch >= 'a') && (ch <= 'f'))
- return (ch - 'a' + 10);
- if ((ch >= '0') && (ch <= '9'))
- return (ch - '0');
- if ((ch >= 'A') && (ch <= 'F'))
- return (ch - 'A' + 10);
- return -1;
-}
-
/* Convert the memory, pointed to by mem into hexadecimal representation.
Put the result in buf, and return a pointer to the last character
in buf (null). */
@@ -704,8 +664,8 @@ mem2hex(char *buf, unsigned char *mem, int count)
/* Valid mem address. */
for (i = 0; i < count; i++) {
ch = *mem++;
- *buf++ = highhex (ch);
- *buf++ = lowhex (ch);
+ *buf++ = hex_asc_hi(ch);
+ *buf++ = hex_asc_lo(ch);
}
}
/* Terminate properly. */
@@ -723,8 +683,8 @@ mem2hex_nbo(char *buf, unsigned char *mem, int count)
mem += count - 1;
for (i = 0; i < count; i++) {
ch = *mem--;
- *buf++ = highhex (ch);
- *buf++ = lowhex (ch);
+ *buf++ = hex_asc_hi(ch);
+ *buf++ = hex_asc_lo(ch);
}

/* Terminate properly. */
@@ -741,8 +701,8 @@ hex2mem(unsigned char *mem, char *buf, int count)
int i;
unsigned char ch;
for (i = 0; i < count; i++) {
- ch = hex (*buf++) << 4;
- ch = ch + hex (*buf++);
+ ch = hex_to_int(*buf++) << 4;
+ ch = ch + hex_to_int(*buf++);
*mem++ = ch;
}
return mem;
@@ -806,8 +766,8 @@ getpacket(char *buffer)
buffer[count] = 0;

if (ch == '#') {
- xmitcsum = hex(getDebugChar()) << 4;
- xmitcsum += hex(getDebugChar());
+ xmitcsum = hex_to_int(getDebugChar()) << 4;
+ xmitcsum += hex_to_int(getDebugChar());
if (checksum != xmitcsum) {
/* Wrong checksum */
putDebugChar('-');
@@ -862,8 +822,8 @@ putpacket(char *buffer)
}
}
putDebugChar('#');
- putDebugChar(highhex (checksum));
- putDebugChar(lowhex (checksum));
+ putDebugChar(hex_asc_hi(checksum));
+ putDebugChar(hex_asc_lo(checksum));
} while(kgdb_started && (getDebugChar() != '+'));
}

@@ -909,8 +869,8 @@ stub_is_stopped(int sigval)
/* Send trap type (converted to signal) */

*ptr++ = 'T';
- *ptr++ = highhex(sigval);
- *ptr++ = lowhex(sigval);
+ *ptr++ = hex_asc_hi(sigval);
+ *ptr++ = hex_asc_lo(sigval);

if (((reg.exs & 0xff00) >> 8) == 0xc) {

@@ -1018,30 +978,30 @@ stub_is_stopped(int sigval)
}
/* Only send PC, frame and stack pointer. */
read_register(PC, &reg_cont);
- *ptr++ = highhex(PC);
- *ptr++ = lowhex(PC);
+ *ptr++ = hex_asc_hi(PC);
+ *ptr++ = hex_asc_lo(PC);
*ptr++ = ':';
ptr = mem2hex(ptr, (unsigned char *)&reg_cont, register_size[PC]);
*ptr++ = ';';

read_register(R8, &reg_cont);
- *ptr++ = highhex(R8);
- *ptr++ = lowhex(R8);
+ *ptr++ = hex_asc_hi(R8);
+ *ptr++ = hex_asc_lo(R8);
*ptr++ = ':';
ptr = mem2hex(ptr, (unsigned char *)&reg_cont, register_size[R8]);
*ptr++ = ';';

read_register(SP, &reg_cont);
- *ptr++ = highhex(SP);
- *ptr++ = lowhex(SP);
+ *ptr++ = hex_asc_hi(SP);
+ *ptr++ = hex_asc_lo(SP);
*ptr++ = ':';
ptr = mem2hex(ptr, (unsigned char *)&reg_cont, register_size[SP]);
*ptr++ = ';';

/* Send ERP as well; this will save us an entire register fetch in some cases. */
read_register(ERP, &reg_cont);
- *ptr++ = highhex(ERP);
- *ptr++ = lowhex(ERP);
+ *ptr++ = hex_asc_hi(ERP);
+ *ptr++ = hex_asc_lo(ERP);
*ptr++ = ':';
ptr = mem2hex(ptr, (unsigned char *)&reg_cont, register_size[ERP]);
*ptr++ = ';';
@@ -1533,8 +1493,8 @@ handle_exception(int sigval)
Success: SAA, where AA is the signal number.
Failure: void. */
output_buffer[0] = 'S';
- output_buffer[1] = highhex(sigval);
- output_buffer[2] = lowhex(sigval);
+ output_buffer[1] = hex_asc_hi(sigval);
+ output_buffer[2] = hex_asc_lo(sigval);
output_buffer[3] = 0;
break;

diff --git a/drivers/pnp/support.c b/drivers/pnp/support.c
index 3eba85e..95b076c 100644
--- a/drivers/pnp/support.c
+++ b/drivers/pnp/support.c
@@ -45,10 +45,10 @@ void pnp_eisa_id_to_string(u32 id, char *str)
str[0] = 'A' + ((id >> 26) & 0x3f) - 1;
str[1] = 'A' + ((id >> 21) & 0x1f) - 1;
str[2] = 'A' + ((id >> 16) & 0x1f) - 1;
- str[3] = hex_asc((id >> 12) & 0xf);
- str[4] = hex_asc((id >> 8) & 0xf);
- str[5] = hex_asc((id >> 4) & 0xf);
- str[6] = hex_asc((id >> 0) & 0xf);
+ str[3] = hex_asc_hi(id >> 8);
+ str[4] = hex_asc_lo(id >> 8);
+ str[5] = hex_asc_hi(id);
+ str[6] = hex_asc_lo(id);
str[7] = '\0';
}

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 4d46e29..63aefcf 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -277,6 +277,21 @@ extern void print_hex_dump(const char *level, const char *prefix_str,
extern void print_hex_dump_bytes(const char *prefix_str, int prefix_type,
const void *buf, size_t len);
#define hex_asc(x) "0123456789abcdef"[x]
+#define hex_asc_lo(x) hex_asc(((x) & 0x0f))
+#define hex_asc_hi(x) hex_asc(((x) & 0xf0) >> 4)
+
+static inline u8 hex_to_int(char ch)
+{
+ /*
+ * Make ch lower-case, works only for digits and letters
+ */
+ ch |= 0x20;
+ if ((ch >= 'a') && (ch <= 'f'))
+ return (ch - 'a' + 10);
+ if ((ch >= '0') && (ch <= '9'))
+ return (ch - '0');
+ return (-1);
+}

#define pr_emerg(fmt, arg...) \
printk(KERN_EMERG fmt, ##arg)
diff --git a/lib/hexdump.c b/lib/hexdump.c
index 3435465..32b0bd7 100644
--- a/lib/hexdump.c
+++ b/lib/hexdump.c
@@ -93,8 +93,8 @@ void hex_dump_to_buffer(const void *buf, size_t len, int rowsize,
for (j = 0; (j < rowsize) && (j < len) && (lx + 4) < linebuflen;
j++) {
ch = ptr[j];
- linebuf[lx++] = hex_asc(ch >> 4);
- linebuf[lx++] = hex_asc(ch & 0x0f);
+ linebuf[lx++] = hex_asc_hi(ch);
+ linebuf[lx++] = hex_asc_lo(ch);
linebuf[lx++] = ' ';
}
ascii_column = 3 * rowsize + 2;
--
1.5.5.1.305.g7c84



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