#include "usuals.h"
#include "buffer.h"
#include "stringx.h"

#include <syslog.h>

/* -----------------------------------------------------------------------
 * Memory Buffer
 */

#define BUF_IS_EMPTY(b)   ((b)->_pp == (b)->_rp)
#define BUF_IN_JOIN(b)    (!BUF_IS_EMPTY(b) && *((b)->_rp - 1) != 0)
#define BUF_NEW_BLOCK(b)  ((b)->_pp = (b)->_rp)

/* TODO: Increase this size to 2048 once we're done debugging */
#define BUF_INITIAL             80
#define BUF_DELTA               16

#define INTERNAL_DATA(intl)     ((void*)(((unsigned char*)(intl)) + sizeof(*(intl))))

#define FILL_BETWEEN(b, e, x)   memset((b), x, ((char*)(e)) - ((char*)(b)));

/*
 * LEGEND:
 * _ft: first buffer block
 * _dt: current buffer block
 * _rp: read/write point
 * _pp: parse/begin point
 */

typedef struct ha_buffer_internal
{
    char* end;
    struct ha_buffer_internal* next;
}
internal_t;

void buffer_bump(ha_buffer_t* buf, int count)
{
    int allocated;
    internal_t* intl;

    ASSERT(buf && count);

    if(ha_buferr(buf))
        return;

    ASSERT(BUF_DELTA < BUF_INITIAL);

    /* Handle this common case first for efficiency */
    if(buf->_rp + (count + BUF_DELTA) < buf->_dt->end)
        return;

    /* Now when in joins we let it go closer */
    if(BUF_IN_JOIN(buf) && (buf->_rp + count < buf->_dt->end))
        return;

    /* Okay now we know we have to extend */
    allocated = buf->_dt->end - (char*)(buf->_dt);
    ASSERT(allocated > 0 && (allocated % BUF_INITIAL) == 0);

    /* Enlarge the size as much as needed */
    do
    {
        allocated *= 2;
    }
    while(allocated < count);

    ASSERT(sizeof(internal_t) < allocated);
    intl = (internal_t*)malloc(allocated);
    if(!intl)
    {
        buf->_dt = NULL;
        buf->_pp = buf->_rp = NULL;
        return;
    }
    else
    {
        void* beg = INTERNAL_DATA(intl);
        intl->end = ((char*)(intl) + allocated);
        intl->next = NULL;

#ifdef _DEBUG
        FILL_BETWEEN(beg, intl->end, 0xCD);
#endif

        if(BUF_IN_JOIN(buf))
        {
            int diff = buf->_rp - buf->_pp;

            /* Always true in a join */
            ASSERT(buf->_pp < buf->_rp);

            /* Copy the memory and blank out old */
            memcpy(beg, buf->_pp, diff);
#ifdef _DEBUG
            FILL_BETWEEN(buf->_pp, buf->_rp, 0xDD);
#endif

            buf->_pp = beg;
            buf->_rp = buf->_pp + diff;
        }
        else
        {
            buf->_rp = buf->_pp = INTERNAL_DATA(intl);
        }

        buf->_dt->next = intl;
        buf->_dt = intl;
    }
}

void ha_bufinit(ha_buffer_t* buf)
{
    ASSERT(buf);
    memset(buf, 0, sizeof(*buf));

    ASSERT(BUF_INITIAL > sizeof(internal_t));
    buf->_ft = (internal_t*)malloc(BUF_INITIAL);
    if(buf->_ft)
    {
        buf->_ft->end = ((char*)(buf->_ft) + BUF_INITIAL);
        buf->_ft->next = NULL;

#ifdef _DEBUG
        FILL_BETWEEN(INTERNAL_DATA(buf->_ft), buf->_ft->end, 0xCD);
#endif

        ha_bufreset(buf);
    }
}

void ha_bufreset(ha_buffer_t* buf)
{
#ifdef _DEBUG
    internal_t* intl;
#endif

    ASSERT(buf);
    ASSERT(buf->_ft);

#ifdef _DEBUG
    /* Go through all the buffers and set them to 0xCD */
    for(intl = buf->_ft; intl; intl = intl->next)
        FILL_BETWEEN(INTERNAL_DATA(intl), intl->end, 0xCD);
#endif

    buf->_dt = buf->_ft;
    buf->_rp = buf->_pp = (char*)INTERNAL_DATA(buf->_ft);
}

void ha_buffree(ha_buffer_t* buf)
{
    internal_t* intl;
    internal_t* next;

    ASSERT(buf);

    /* Go through free all the buffers and set them to 0xDD */
    for(intl = buf->_ft; intl; intl = next)
    {
        next = intl->next;
        FILL_BETWEEN(INTERNAL_DATA(intl), intl->end, 0xDD);
        free(intl);
    }

    buf->_ft = buf->_dt = NULL;
    buf->_rp = buf->_pp = NULL;
}


int ha_bufreadline(int fd, ha_buffer_t* buf)
{
    int l;

    ASSERT(buf);
    ASSERT(fd != -1);

    if(ha_buferr(buf))
        return 0;

    for(;;)
    {
        buffer_bump(buf, 1);
        l = read(fd, (void*)buf->_rp, sizeof(char));

        /* We got a character */
        if(l == 1)
        {
            /* Skip junky CRLFs */
            if(*(buf->_rp) == '\r')
            {
                *(buf->_rp) = ' ';
                continue;
            }

            /* End of line */
            else if(*(buf->_rp) == '\n')
            {
                buf->_rp++;
                break;
            }

            /* All other characters */
            else
            {
                buf->_rp++;
            }
        }

        /* If it's the end of file then return that */
        else if(l == 0)
            return 0;

        /* Transient errors */
        else if(l == -1 && errno == EAGAIN)
            continue;

        /* Fatal errors */
        else if(l == -1)
        {
            if(errno == EINTR)
                return 0;

            return -1;
        }
    }

    return 1;
}

char* ha_bufparseword(ha_buffer_t* buf, const char* delims)
{
    char* word = NULL;

    ASSERT(buf && delims);

    if(ha_buferr(buf))
        return NULL;

    /* Knock out any previous delims */
    while(buf->_pp < buf->_rp && strchr(delims, *(buf->_pp)))
        buf->_pp++;

    /* If at end of buffer or end of line return null */
    if(buf->_pp == buf->_rp || *(buf->_pp) == '\n')
        return NULL;

    /* We do this before we stash away a pointer */
    buffer_bump(buf, 1);

    word = buf->_pp;

    while(!strchr(delims, *(buf->_pp)))
    {
        buf->_pp++;

        /* At the end of the buffer */
        if(buf->_pp == buf->_rp)
        {
            *(buf->_rp) = 0;
            buf->_rp++;
            break;
        }

        /* At the end of a line */
        else if(*(buf->_pp) == '\n')
            break;
    }

    /* Now null terminate what we found */
    *(buf->_pp) = 0;
    buf->_pp++;

    /* We don't return empty strings */
    if(word[0] == 0)
        return NULL;

    return word;
}

char* ha_bufparseline(ha_buffer_t* buf, int trim)
{
    char* t;
    char* line = NULL;

    ASSERT(buf);

    if(ha_buferr(buf))
        return NULL;

    if(trim)
    {
        /* Knock out any previous whitespace */
        while(buf->_pp < buf->_rp && isblank(*(buf->_pp)))
            buf->_pp++;
    }

    if(buf->_pp == buf->_rp)
        return NULL;

    /* We do this before we stash away a pointer */
    buffer_bump(buf, 1);

    line = buf->_pp;

    t = (char*)memchr(buf->_pp, '\n', ha_buflen(buf));
    if(t == NULL)
    {
        t = (buf->_rp);
        buf->_rp++;
    }

    *t = 0;
    buf->_pp = t + 1;

    if(trim)
        line = trim_space(line);

    /* We don't return empty strings */
    if(line[0] == 0)
        return NULL;

    return line;
}

char* ha_bufmcat(ha_buffer_t* buf, ...)
{
    const char* str;
    va_list ap;

    ASSERT(buf);

    va_start(ap, buf);

    if(ha_buferr(buf))
        return NULL;

    if(!BUF_IN_JOIN(buf))
        BUF_NEW_BLOCK(buf);

    while((str = va_arg(ap, char*)) != NULL)
    {
        int len = strlen(str);

        /* Always add one for the terminating char */
        buffer_bump(buf, len + 1);

        if(ha_buferr(buf))
            return NULL;

        /* _rp always points to the next write point */
        strcpy(buf->_rp, str);
        buf->_rp += len;
    }

    buf->_rp++;
    return buf->_pp;
}

char* ha_bufcpy(ha_buffer_t* buf, const char* src)
{
    size_t len;

    ASSERT(buf && src);

    len = strlen(src);
    return ha_bufncpy(buf, src, len);
}

char* ha_bufncpy(ha_buffer_t* buf, const char* src, size_t len)
{
    ASSERT(buf && src);

    if(ha_buferr(buf))
        return NULL;

    /* Always add one for the terminating char */
    buffer_bump(buf, len + 1);

    if(ha_buferr(buf))
        return NULL;

    if(!BUF_IN_JOIN(buf))
        BUF_NEW_BLOCK(buf);

    memcpy(buf->_rp, src, len * sizeof(char));
    buf->_rp += (len + 1);
    *(buf->_rp - 1) = 0;
    return buf->_pp;
}

void* ha_bufmalloc(ha_buffer_t* buf, size_t sz)
{
    void* ret;

    ASSERT(buf && sz);

    if(ha_buferr(buf))
        return NULL;

    /* TODO: Align memory on an appropriate boundary here */
    buffer_bump(buf, sz);

    if(ha_buferr(buf))
        return NULL;

    BUF_NEW_BLOCK(buf);
    ret = (void*)buf->_pp;
    buf->_rp += sz;
    buf->_pp = buf->_rp;
    return ret;
}

void* ha_bufmemdup(ha_buffer_t* buf, const void* src, size_t bytes)
{
    void* mem;

    ASSERT(buf && src && bytes);

    if((mem = ha_bufmalloc(buf, bytes)) != NULL)
        memcpy(mem, src, bytes);

    return mem;
}

/*
 * Portions Copyright (c) 1995 by International Business Machines, Inc.
 *
 * International Business Machines, Inc. (hereinafter called IBM) grants
 * permission under its copyrights to use, copy, modify, and distribute this
 * Software with or without fee, provided that the above copyright notice and
 * all paragraphs of this notice appear in all copies, and that the name of IBM
 * not be used in connection with the marketing of any product incorporating
 * the Software or modifications thereof, without specific, written prior
 * permission.
 *
 * To the extent it has a right to do so, IBM grants an immunity from suit
 * under its patents, if any, for the use, sale or manufacture of products to
 * the extent that such products are used for performing Domain Name System
 * dynamic updates in TCP/IP networks by means of the Software.  No immunity is
 * granted for any product per se or for any other function of any product.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", AND IBM DISCLAIMS ALL WARRANTIES,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 * PARTICULAR PURPOSE.  IN NO EVENT SHALL IBM BE LIABLE FOR ANY SPECIAL,
 * DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE, EVEN
 * IF IBM IS APPRISED OF THE POSSIBILITY OF SUCH DAMAGES.
 */

static const char BASE64C[] =
        "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
static const char PAD64C = '=';

char* ha_bufenc64(ha_buffer_t* buf, const void* source, size_t len)
{
    unsigned char input[3];
    unsigned char output[4];
    unsigned char* src = (unsigned char*)source;
    size_t i;

    ASSERT(buf && source && len);

    if(ha_buferr(buf))
        return NULL;

    if(!BUF_IN_JOIN(buf))
        BUF_NEW_BLOCK(buf);

    while(2 < len)
    {
        input[0] = *src++;
        input[1] = *src++;
        input[2] = *src++;
        len -= 3;

        output[0] = input[0] >> 2;
        output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
        output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
        output[3] = input[2] & 0x3f;

        /* This also accounts for the null terminator */
        buffer_bump(buf, 5);

        if(ha_buferr(buf))
            return NULL;

        *(buf->_rp++) = BASE64C[output[0]];
        *(buf->_rp++) = BASE64C[output[1]];
        *(buf->_rp++) = BASE64C[output[2]];
        *(buf->_rp++) = BASE64C[output[3]];
    }

    /* Now we worry about padding. */
    if(0 != len)
    {
        /* Get what's left. */
        input[0] = input[1] = input[2] = '\0';
        for(i = 0; i < len; i++)
            input[i] = *src++;

        output[0] = input[0] >> 2;
        output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
        output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);

        /* This also accounts for the null terminator */
        buffer_bump(buf, 5);

        if(ha_buferr(buf))
            return NULL;

        *(buf->_rp++) = BASE64C[output[0]];
        *(buf->_rp++) = BASE64C[output[1]];
        if(len == 1)
            *(buf->_rp++) = PAD64C;
        else
            *(buf->_rp++) = BASE64C[output[2]];
        *(buf->_rp++) = PAD64C;
    }

    *(buf->_rp++) = '\0';
    return buf->_pp;
}

void* ha_bufdec64(ha_buffer_t* buf, const char* src, size_t* bytes)
{
    int state = 0;
    int ch;
    char* pos;
    void* ret;
    size_t todo = 0;
    size_t done = 0;

    ASSERT(buf && src);

    if(ha_buferr(buf))
        return NULL;

    BUF_NEW_BLOCK(buf);

    if(!bytes || *bytes == 0)
        todo = ~0;
    else
        todo = *bytes;

    while((ch = *src++) != '\0' && done < todo)
    {
        if(isspace(ch))        /* Skip whitespace anywhere. */
            continue;

        if(ch == PAD64C)
            break;

        pos = strchr(BASE64C, ch);
        if(pos == 0)           /* A non-base64 character. */
            break;

        buffer_bump(buf, 4);

        if(ha_buferr(buf))
            return NULL;

        switch(state)
        {
        case 0:
            *(buf->_rp) = (pos - BASE64C) << 2;
            state = 1;
            break;

        case 1:
            *(buf->_rp++) |= (pos - BASE64C) >> 4;
            done++;
            *(buf->_rp) = ((pos - BASE64C) & 0x0f) << 4;
            state = 2;
            break;

        case 2:
            *(buf->_rp++) |= (pos - BASE64C) >> 2;
            done++;
            *(buf->_rp) = ((pos - BASE64C) & 0x03) << 6;
            state = 3;
            break;

        case 3:
            *(buf->_rp++) |= (pos - BASE64C);
            done++;
            state = 0;
            break;
        };
    }

    if(state != 0)
        buf->_rp++;

    /* TODO: Validate ending and return error if invalid somehow */

    /* We always null terminate anyway */
    *(buf->_rp++) = 0;

    if(bytes)
        *bytes = done;

    ret = (void*)buf->_pp;
    buf->_pp = buf->_rp;
    return ret;
}

static const char HEXC[] = "0123456789abcdef";

char* ha_bufenchex(ha_buffer_t* buf, const void* source, size_t len)
{
    unsigned char* src = (unsigned char*)source;
    unsigned char j;

    ASSERT(buf && source && len);

    buffer_bump(buf, (len * 2) + 1);

    if(ha_buferr(buf))
        return NULL;

    if(!BUF_IN_JOIN(buf))
        BUF_NEW_BLOCK(buf);

    while(len > 0)
    {
        j = *(src) >> 4 & 0xf;
        *(buf->_rp++) = HEXC[j];

        j = *(src++) & 0xf;
        *(buf->_rp++) = HEXC[j];

        len--;
    }

    *(buf->_rp++) = 0;
    return buf->_pp;
}

void* ha_bufdechex(ha_buffer_t* buf, const char* src, size_t* bytes)
{
    unsigned short j;
    int state = 0;
    char* pos;
    void* ret;
    size_t done = 0;
    size_t todo = 0;

    ASSERT(buf && src);

    if(bytes && *bytes != 0)
    {
        buffer_bump(buf, *bytes + 1);
        todo = *bytes;
    }
    else
    {
        todo = ~0;
        buffer_bump(buf, (strlen(src) / 2) + 1);
    }

    if(ha_buferr(buf))
        return NULL;

    BUF_NEW_BLOCK(buf);

    while(src[0] && done < todo)
    {
        /* Find the position */
        pos = strchr(HEXC, tolower(src[0]));
        if(pos == 0)
        break;

        j = pos - HEXC;

        if(!state)
        {
            *(buf->_rp) = (j & 0xf) << 4;
            state = 1;
        }
        else
        {
            *(buf->_rp++) |= (j & 0xf);
            done++;
            state = 0;
        }

        src++;
    }

    /* We always null terminate anyway */
    *(buf->_rp++) = 0;

    /* All bytes have to come in pairs */
    if(state != 0)
        return NULL;

    if(bytes)
        *bytes = done;

    ret = (void*)buf->_pp;
    buf->_pp = buf->_rp;
    return ret;
}