ref: a9feb43f707673f7139317fac35e843d3bab7983
parent: b798de6161b15e503d838d1794eab1d8bc5d1760
author: Sigrid Solveig Haflínudóttir <sigrid@ftrv.se>
date: Fri Aug 11 15:02:01 EDT 2023
implement ASCIIHexDecode filter
--- a/README.md
+++ b/README.md
@@ -13,7 +13,6 @@
## TODO
-* ASCIIHexDecode filter
* CryptDecode filter
* does DCTDecode filter need to deal with ColorTransform?
* do we need predictor 5 ("optimum")?--- a/f_asciihex.c
+++ b/f_asciihex.c
@@ -4,6 +4,53 @@
/* 7.4.2 ASCIIHexDecode filter */
+static int
+hexc(int c)
+{+ if(c >= 'A' && c <= 'F')
+ return c - 'A' + 10;
+ if(c >= '0' && c <= '9')
+ return c - '0';
+ if(c >= 'a' && c <= 'f')
+ return c - 'a' + 10;
+ return -1;
+}
+
+static int
+flreadall(void *aux, Buffer *bi, Buffer *bo)
+{+ int i, insz, c, c2;
+ uchar *in, b;
+
+ USED(aux);
+
+ in = bufdata(bi, &insz);
+ for(i = 0; i < insz;){+ if((c = hexc(in[i++])) < 0){+ if(isws(in[i-1]))
+ continue;
+ if(in[i-1] == '>')
+ break;
+badchar:
+ werrstr("invalid char %02x", in[i-1]);+ return -1;
+ }
+ c2 = 0;
+ if(i < insz && (c2 = hexc(in[i++])) < 0){+ if(in[i-1] != '>')
+ c2 = 0;
+ else
+ goto badchar;
+ }
+ b = c<<4 | c2;
+ bufput(bo, &b, 1);
+ }
+ bi->off = bi->sz;
+
+ return 0;
+}
+
Filter filterASCIIHex = {.name = "ASCIIHexDecode",
+ .readall = flreadall,
};