10. Apparatus for searching a text that comprises a sequence of symbols for occurrences of a pattern of the symbols, using a sequence of evaluations at respective positions in the text, the apparatus comprising: a memory, which is configured to store the text; and a processor, which is configured to: hold the pattern to be found in the text, perform a first evaluation of whether the pattern occurs in a current position in the text by positioning the pattern so as to end at the current position in the text and comparing the symbols of the pattern to the corresponding symbols of the text while progressing from an end to a beginning of the pattern, and, upon finding a mismatch between the pattern and the text, to calculate the jump to the subsequent position depending at least on the mismatch, calculate, if the pattern does not occur in the current position, a size of a jump to a subsequent position in the text based on results of the first evaluation, and perform a second evaluation of whether the pattern occurs in the subsequent position in the text.
10. Apparatus for searching a text that comprises a sequence of symbols for occurrences of a pattern of the symbols, using a sequence of evaluations at respective positions in the text, the apparatus comprising: a memory, which is configured to store the text; and a processor, which is configured to: hold the pattern to be found in the text, perform a first evaluation of whether the pattern occurs in a current position in the text by positioning the pattern so as to end at the current position in the text and comparing the symbols of the pattern to the corresponding symbols of the text while progressing from an end to a beginning of the pattern, and, upon finding a mismatch between the pattern and the text, to calculate the jump to the subsequent position depending at least on the mismatch, calculate, if the pattern does not occur in the current position, a size of a jump to a subsequent position in the text based on results of the first evaluation, and perform a second evaluation of whether the pattern occurs in the subsequent position in the text. 11. The apparatus according to claim 10 , wherein the processor is configured to calculate the size of the jump based on the results of the first evaluation and of one or more previous evaluations that precede the first evaluation.