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Added StringExtractor::DecodeHexU8 && GetHexBytesAvail

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DecodeHexU8 returns a decoded hex character pair, returns -1 if a
valid hex pair is not available.

GetHexBytesAvail decodes all available hex pairs.

llvm-svn: 223081
This commit is contained in:
Vince Harron
2014-12-01 22:19:33 +00:00
parent e5a9eaaaed
commit 6eddf8df2a
3 changed files with 222 additions and 69 deletions
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105
lldb/source/Utility/StringExtractor.cpp
View File

@@ -16,43 +16,6 @@
// Other libraries and framework includes
// Project includes
static const uint8_t
g_hex_ascii_to_hex_integer[256] = {
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7,
0x8, 0x9, 255, 255, 255, 255, 255, 255,
255, 0xa, 0xb, 0xc, 0xd, 0xe, 0xf, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 0xa, 0xb, 0xc, 0xd, 0xe, 0xf, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
};
static inline int
xdigit_to_sint (char ch)
{
@@ -60,7 +23,9 @@ xdigit_to_sint (char ch)
return 10 + ch - 'a';
if (ch >= 'A' && ch <= 'F')
return 10 + ch - 'A';
return ch - '0';
if (ch >= '0' && ch <= '9')
return ch - '0';
return -1;
}
//----------------------------------------------------------------------
@@ -128,6 +93,31 @@ StringExtractor::GetChar (char fail_value)
return fail_value;
}
//----------------------------------------------------------------------
// If a pair of valid hex digits exist at the head of the
// StringExtractor they are decoded into an unsigned byte and returned
// by this function
//
// If there is not a pair of valid hex digits at the head of the
// StringExtractor, it is left unchanged and -1 is returned
//----------------------------------------------------------------------
int
StringExtractor::DecodeHexU8()
{
if (GetBytesLeft() < 2)
{
return -1;
}
const int hi_nibble = xdigit_to_sint(m_packet[m_index]);
const int lo_nibble = xdigit_to_sint(m_packet[m_index+1]);
if (hi_nibble == -1 || lo_nibble == -1)
{
return -1;
}
m_index += 2;
return (uint8_t)((hi_nibble << 4) + lo_nibble);
}
//----------------------------------------------------------------------
// Extract an unsigned character from two hex ASCII chars in the packet
// string
@@ -135,19 +125,14 @@ StringExtractor::GetChar (char fail_value)
uint8_t
StringExtractor::GetHexU8 (uint8_t fail_value, bool set_eof_on_fail)
{
if (GetBytesLeft() >= 2)
int byte = DecodeHexU8();
if (byte == -1)
{
const uint8_t hi_nibble = g_hex_ascii_to_hex_integer[static_cast<uint8_t>(m_packet[m_index])];
const uint8_t lo_nibble = g_hex_ascii_to_hex_integer[static_cast<uint8_t>(m_packet[m_index+1])];
if (hi_nibble < 16 && lo_nibble < 16)
{
m_index += 2;
return (hi_nibble << 4) + lo_nibble;
}
if (set_eof_on_fail || m_index >= m_packet.size())
m_index = UINT64_MAX;
return fail_value;
}
if (set_eof_on_fail || m_index >= m_packet.size())
m_index = UINT64_MAX;
return fail_value;
return (uint8_t)byte;
}
uint32_t
@@ -372,6 +357,28 @@ StringExtractor::GetHexBytes (void *dst_void, size_t dst_len, uint8_t fail_fill_
return bytes_extracted;
}
//----------------------------------------------------------------------
// Decodes all valid hex encoded bytes at the head of the
// StringExtractor, limited by dst_len.
//
// Returns the number of bytes successfully decoded
//----------------------------------------------------------------------
size_t
StringExtractor::GetHexBytesAvail (void *dst_void, size_t dst_len)
{
uint8_t *dst = (uint8_t*)dst_void;
size_t bytes_extracted = 0;
while (bytes_extracted < dst_len)
{
int decode = DecodeHexU8();
if (decode == -1)
{
break;
}
dst[bytes_extracted++] = (uint8_t)decode;
}
return bytes_extracted;
}
// Consume ASCII hex nibble character pairs until we have decoded byte_size
// bytes of data.