;;;; ripemd160-api.scm  -*- Scheme -*-
;;;; Kon Lovett, Sep '21

;; Issues

#>
typedef void (*initializef)( uint32_t * );
typedef void (*compressf)( uint32_t *, uint32_t * );
typedef void (*finishf)( uint32_t *, uint8_t *, uint32_t, uint32_t );

typedef struct {
  uint8_t rembuf[16 * sizeof(uint32_t)];
  uint32_t length[2];
  uint32_t MDbuf[0];
} ripemdctx;

static void
ripemdX_init( initializef init, ripemdctx *ctx )
{
  memset( ctx->rembuf, 0, sizeof(ctx->rembuf) );
  ctx->length[0] = ctx->length[1] = 0;
  (*init)( ctx->MDbuf );
}

static void
ripemdX_update( compressf compress, ripemdctx *ctx, uint8_t *data, size_t nbytes )
{
# define BYTES_TO_DWORD( strptr ) \
    (((uint32_t) *((strptr)+3) << 24) | \
     ((uint32_t) *((strptr)+2) << 16) | \
     ((uint32_t) *((strptr)+1) <<  8) | \
     ((uint32_t) *(strptr)))

  uint32_t X[16];
  unsigned int i, j;

  /* process all complete 16-uint32_t blocks */
  for( i = nbytes; i > 63; i -= 64 ) {
     for( j = 0; j < 16; j++ ) {
        X[j] = BYTES_TO_DWORD( data );
        data += sizeof(uint32_t);
      }
     (*compress)( ctx->MDbuf, X );
  }

  /* update length[] */
  if( ctx->length[0] + nbytes < ctx->length[0] )
     ctx->length[1]++;      /* overflow to msb of length */
  ctx->length[0] += nbytes;

  /* remaining bytes? */
  /* MUST only occur on the last call to update */
  if( i ) {
    memcpy( ctx->rembuf, data, i );
  }

# undef BYTES_TO_DWORD
}

static
void ripemdX_final( finishf finish, uint8_t *str, ripemdctx *ctx, size_t mdlen )
{
  int i;

  (*finish)( ctx->MDbuf, ctx->rembuf, ctx->length[0], ctx->length[1] );

  for( i = 0; i < mdlen; i += sizeof(uint32_t) ) {
    str[i]   =  ctx->MDbuf[i>>2];
    str[i+1] = (ctx->MDbuf[i>>2] >>  8);
    str[i+2] = (ctx->MDbuf[i>>2] >> 16);
    str[i+3] = (ctx->MDbuf[i>>2] >> 24);
  }
}

#define C_VISIBILITY static

#define dword uint32_t
#define byte uint8_t

#include "rmd160.c"
#define RMD160blksiz 64
#define RMD160hshsiz (160/8)
#define RMD160ctxsiz (sizeof(ripemdctx) + sizeof(uint32_t)*(160/32))
#undef BYTES_TO_DWORD
#undef ROL
#undef F
#undef G
#undef H
#undef I
#undef J
#undef FF
#undef GG
#undef HH
#undef II
#undef JJ
#undef FFF
#undef GGG
#undef HHH
#undef III
#undef JJJ

#undef dword
#undef byte

#undef C_VISIBILITY
<#

(module ripemd160-api

(;export
  name version
  context-size digest-length block-length
  init update final raw-update)

(import scheme
  (chicken base)
  (chicken foreign)
  (chicken type))

;;

(define name 'ripemd160)
(define version "1.0.0")

;;

(define-foreign-variable DIGEST_LENGTH size_t "RMD160hshsiz")
(define-foreign-variable BLOCK_LENGTH size_t "RMD160blksiz")
(define-foreign-variable CONTEXT_SIZE size_t "RMD160ctxsiz")

(define context-size CONTEXT_SIZE)
(define digest-length DIGEST_LENGTH)
(define block-length BLOCK_LENGTH)

(define init
  (foreign-lambda* void ((nonnull-c-pointer ctx))
    "ripemdX_init( &MDinit160, ctx );"))

(define update
  (foreign-lambda* void ((nonnull-c-pointer ctx) (nonnull-scheme-pointer obj) (size_t len))
    "ripemdX_update( &compress160, ctx, obj, len );"))

(define final
  (foreign-lambda* void ((nonnull-c-pointer ctx) (nonnull-scheme-pointer result))
    "ripemdX_final( &MDfinish160, result, ctx, RMD160hshsiz );"))

(define raw-update
  (foreign-lambda* void ((nonnull-c-pointer ctx) (nonnull-c-pointer obj) (size_t len))
    "ripemdX_update( &compress160, ctx, obj, len );"))

) ;module ripemd160-api