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Re: [Qemu-devel] [PATCH v2 08/15] Add base64 encoder/decoder
From: |
Jan Kiszka |
Subject: |
Re: [Qemu-devel] [PATCH v2 08/15] Add base64 encoder/decoder |
Date: |
Sun, 23 May 2010 09:55:25 +0200 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 |
Blue Swirl wrote:
> On Sat, May 22, 2010 at 8:18 AM, Jan Kiszka <address@hidden> wrote:
>> From: Jan Kiszka <address@hidden>
>>
>> Will be used by QBuffer.
>>
>> Signed-off-by: Jan Kiszka <address@hidden>
>> ---
>> Makefile.objs | 2 +-
>> base64.c | 202
>> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>> base64.h | 18 +++++
>> 3 files changed, 221 insertions(+), 1 deletions(-)
>> create mode 100644 base64.c
>> create mode 100644 base64.h
>>
>> diff --git a/Makefile.objs b/Makefile.objs
>> index acbaf22..2c603b2 100644
>> --- a/Makefile.objs
>> +++ b/Makefile.objs
>> @@ -2,7 +2,7 @@
>> # QObject
>> qobject-obj-y = qint.o qstring.o qdict.o qlist.o qfloat.o qbool.o
>> qobject-obj-y += qjson.o json-lexer.o json-streamer.o json-parser.o
>> -qobject-obj-y += qerror.o
>> +qobject-obj-y += qerror.o base64.o
>>
>> #######################################################################
>> # block-obj-y is code used by both qemu system emulation and qemu-img
>> diff --git a/base64.c b/base64.c
>> new file mode 100644
>> index 0000000..543e8c6
>> --- /dev/null
>> +++ b/base64.c
>> @@ -0,0 +1,202 @@
>> +/*
>> + * Base64 encoder/decoder conforming to RFC 4648
>> + * (based on Mozilla's nsprpub/lib/libc/src/base64.c)
>> + *
>> + * Copyright (C) 2010 Siemens AG
>> + *
>> + * Authors:
>> + * Jan Kiszka <address@hidden>
>> + *
>> + * This work is licensed under the terms of the GNU LGPL, version 2.1 or
>> later.
>> + * See the COPYING.LIB file in the top-level directory.
>> + *
>> + */
>> +
>> +#include "inttypes.h"
>
> Why not <inttypes.h>?
Oops, no intention.
>
>> +#include "base64.h"
>> +
>> +static const char base[] =
>> + "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
>> +
>> +static void encode3to4(const char *src, char *dest)
>> +{
>> + uint32_t b32 = 0;
>> + int i, j = 18;
>> +
>> + for (i = 0; i < 3; i++) {
>> + b32 <<= 8;
>> + b32 |= src[i];
>> + }
>> + for (i = 0; i < 4; i++) {
>> + dest[i] = base[(b32 >> j) & 0x3F];
>> + j -= 6;
>> + }
>> +}
>> +
>> +static void encode2to4(const char *src, char *dest)
>> +{
>> + dest[0] = base[(src[0] >> 2) & 0x3F];
>> + dest[1] = base[((src[0] & 0x03) << 4) | ((src[1] >> 4) & 0x0F)];
>> + dest[2] = base[(src[1] & 0x0F) << 2];
>> + dest[3] = '=';
>> +}
>> +
>> +static void encode1to4(const char *src, char *dest)
>> +{
>> + dest[0] = base[(src[0] >> 2) & 0x3F];
>> + dest[1] = base[(src[0] & 0x03) << 4];
>> + dest[2] = '=';
>> + dest[3] = '=';
>> +}
>> +
>> +/*
>> + * Encode data in 'src' of length 'srclen' to a base64 string, saving the
>> + * null-terminated result in 'dest'. The size of the destition buffer must
>> be
>> + * at least ((srclen + 2) / 3) * 4 + 1.
>> + */
>> +void base64_encode(const void *src, size_t srclen, char *dest)
>> +{
>> + while (srclen >= 3) {
>> + encode3to4(src, dest);
>> + src += 3;
>> + dest += 4;
>> + srclen -= 3;
>> + }
>> + switch (srclen) {
>> + case 2:
>> + encode2to4(src, dest);
>> + dest += 4;
>> + break;
>> + case 1:
>> + encode1to4(src, dest);
>> + dest += 4;
>> + break;
>> + case 0:
>> + break;
>> + }
>> + dest[0] = 0;
>> +}
>> +
>> +static int32_t codetovalue(char c)
>> +{
>> + if (c >= 'A' && c <= 'Z') {
>> + return c - 'A';
>> + } else if (c >= 'a' && c <= 'z') {
>> + return c - 'a' + 26;
>> + } else if (c >= '0' && c <= '9') {
>> + return c - '0' + 52;
>> + } else if (c == '+') {
>> + return 62;
>> + } else if ( c == '/') {
>> + return 63;
>> + } else {
>> + return -1;
>> + }
>> +}
>> +
>> +static int decode4to3 (const char *src, char *dest)
>> +{
>> + uint32_t b32 = 0;
>> + int32_t bits;
>> + int i;
>> +
>> + for (i = 0; i < 4; i++) {
>> + bits = codetovalue(src[i]);
>> + if (bits < 0) {
>> + return bits;
>> + }
>> + b32 <<= 6;
>> + b32 |= bits;
>> + }
>> + dest[0] = (b32 >> 16) & 0xFF;
>> + dest[1] = (b32 >> 8) & 0xFF;
>> + dest[2] = b32 & 0xFF;
>> +
>> + return 0;
>> +}
>> +
>> +static int decode3to2(const char *src, char *dest)
>> +{
>> + uint32_t b32 = 0;
>> + int32_t bits;
>> +
>> + bits = codetovalue(src[0]);
>> + if (bits < 0) {
>> + return bits;
>> + }
>> + b32 = (uint32_t)bits;
>> + b32 <<= 6;
>> +
>> + bits = codetovalue(src[1]);
>> + if (bits < 0) {
>> + return bits;
>> + }
>> + b32 |= (uint32_t)bits;
>> + b32 <<= 4;
>> +
>> + bits = codetovalue(src[2]);
>> + if (bits < 0) {
>> + return bits;
>> + }
>> + b32 |= ((uint32_t)bits) >> 2;
>> +
>> + dest[0] = (b32 >> 8) & 0xFF;
>> + dest[1] = b32 & 0xFF;
>> +
>> + return 0;
>> +}
>> +
>> +static int decode2to1(const char *src, char *dest)
>> +{
>> + uint32_t b32;
>> + int32_t bits;
>> +
>> + bits = codetovalue(src[0]);
>> + if (bits < 0) {
>> + return bits;
>> + }
>> + b32 = (uint32_t)bits << 2;
>> +
>> + bits = codetovalue(src[1]);
>> + if (bits < 0) {
>> + return bits;
>> + }
>> + b32 |= ((uint32_t)bits) >> 4;
>> +
>> + dest[0] = b32;
>> +
>> + return 0;
>> +}
>> +
>> +/*
>> + * Convert string 'src' of length 'srclen' from base64 to binary form,
>> + * saving the result in 'dest'. The size of the destination buffer must be
>> at
>> + * least srclen * 3 / 4.
>> + *
>> + * Returns 0 on success, -1 on conversion error.
>> + */
>> +int base64_decode(const char *src, size_t srclen, void *dest)
>
> I think dest should be char *, like all the functions where dest is passed to.
The output may but need not be a string, it's binary data. And to avoid
needless warnings about signedness mismatches if unsigned char or
uint8_t buffers are passed, I chose void *.
>
>> +{
>> + int ret;
>> +
>> + while (srclen >= 4) {
>> + ret = decode4to3(src, dest);
>> + if (ret < 0) {
>> + return ret;
>> + }
>> + src += 4;
>> + dest += 3;
>> + srclen -= 4;
>> + }
>> +
>> + switch (srclen) {
>> + case 3:
>> + return decode3to2(src, dest);
>> + case 2:
>> + return decode2to1(src, dest);
>> + case 1:
>> + return -1;
>> + default: /* 0 */
>> + return 0;
>> + }
>> +}
>> diff --git a/base64.h b/base64.h
>> new file mode 100644
>> index 0000000..9a0e03a
>> --- /dev/null
>> +++ b/base64.h
>> @@ -0,0 +1,18 @@
>> +/*
>> + * Base64 encoder/decoder conforming to RFC 4648
>> + * (based on Mozilla's nsprpub/lib/libc/src/base64.c)
>> + *
>> + * Copyright (C) 2010 Siemens AG
>> + *
>> + * Authors:
>> + * Jan Kiszka <address@hidden>
>> + *
>> + * This work is licensed under the terms of the GNU LGPL, version 2.1 or
>> later.
>> + * See the COPYING.LIB file in the top-level directory.
>> + *
>> + */
>> +
>> +#include <unistd.h>
>
> Maybe <stddef.h> instead, it's only for size_t?
Makes sense.
>
>> +
>> +void base64_encode(const void *src, size_t srclen, char *dest);
>> +int base64_decode(const char *src, size_t srclen, void *dest);
>> --
>> 1.6.0.2
>>
>>
>>
Thanks,
Jan
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[Qemu-devel] [PATCH v2 04/15] qdev: Convert device and bus lists to QTAILQ, Jan Kiszka, 2010/05/22
[Qemu-devel] [PATCH v2 05/15] qdev: Allow device specification by qtree path for device_del, Jan Kiszka, 2010/05/22
[Qemu-devel] [PATCH v2 07/15] monitor: Add completion for qdev paths, Jan Kiszka, 2010/05/22
[Qemu-devel] [PATCH v2 11/15] monitor: return length of printed string via monitor_[v]printf, Jan Kiszka, 2010/05/22
[Qemu-devel] [PATCH v2 09/15] QMP: Reserve namespace for complex object classes, Jan Kiszka, 2010/05/22
[Qemu-devel] [PATCH v2 10/15] Add QBuffer, Jan Kiszka, 2010/05/22
[Qemu-devel] [PATCH v2 15/15] QMP: Add support for buffer class to qmp python helper, Jan Kiszka, 2010/05/22
[Qemu-devel] [PATCH v2 12/15] monitor: Add basic device state visualization, Jan Kiszka, 2010/05/22